# Cutting pistons instead of head spacer



## rjones1214 (Apr 24, 2009)

Well I am going to re-ring my pistons, install newer rifle drilled rods and replace bearings and seals while I have the bottom end apart before I install my turbo kit. I recently lost timing and had to replace the head and now the pistons are dented. 
Since I'm boosting the car I need to lower my compression so I can run more than 10psi safely. 

My main question is: Can I have the tops of my pistons cut down to lower my compression?
this will also remove the valve marks in my piston tops
I want to lower my compression from the stock 10:1 to 8.5:1. I know the 9:1 spacer is only a couple mm thick so I'm assuming there is room to cut the pistons enough for this. 

This is for an AEG 2.0l 8v engine

If anybody knows of any shops in the Saginaw area please lmk as well. I will probably end up going to a local Carquest with a machine stop.


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## ALLGORIMSHOW (Jul 1, 2002)

Milling the pistons= large holes do to pressure and heat. Use a spacer or lower comp pistons.


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## rjones1214 (Apr 24, 2009)

alright thanks for the opinion, I have heard of people having their pistons skimmed to remove valve marks and I wasn't sure if this could be done to lower compression.

Anybody else have a little more info on this?
Anybody actually do this?

I would rather spend the money to have them cut then spend $100+ on a spacer


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## ALLGORIMSHOW (Jul 1, 2002)

rjones1214 said:


> alright thanks for the opinion, I have heard of people having their pistons skimmed to remove valve marks and I wasn't sure if this could be done to lower compression.
> 
> Anybody else have a little more info on this?
> Anybody actually do this?
> ...


Well you could stack two head gaskets if you want to cheap out at after forking out cash for a rebuild and a turbo kit... makes sense.


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## rjones1214 (Apr 24, 2009)

well most people prefer to have low cr pistons instead of a head spacer so I was going to see if this was possible before doing or buying anything.


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## rjones1214 (Apr 24, 2009)

anybody else?

*opcorn:*


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## boosted b5 (Nov 1, 2004)

if you cant afford to do it right, you definently cant afford to do it twice.

save your money buy pistons you can find great deals on some 9:1 or 8.5:1 JE's

you never want to mess with the compression by shaving away at the piston. youll throw off the balance of it, and the structural integrity of the piston will be lost.


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## rjones1214 (Apr 24, 2009)

I won't be spending the money on JE or any other forged pistons. I just don't need to have $600+ pistons in my 200k+ mileage jetta. This was just an idea and thought I would see what people think. I don't see how 2 or 3mms would mess up the structural integrity of the piston.


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## rhussjr (Aug 7, 2000)

The pistons are already thin as it is and taking off 2-3 mm is an easy way to weaken and melt a piston once you get the car under boost. Expecting a thinner anything to hold double the load of something is like trusting an ultra-thin rubber to save you from getting an STD. Use a spacer.


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## GinsterMan98 (May 19, 2008)

Stacking gaskets isn't a bad idea, 16V guys do it all the time. Even 400+ guys stack gaskets, the hard part is to know the final CR with two gaskets. It works, but is not the most effective and reliable way to lower your CR.


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## Corradokcid (Nov 6, 2006)

i think the guy was just asking a question:screwy:.....have any of you that say dont do it actually milled a piston??? or in that case does anybody even know somebody with milled pistons in there VR??? I think its possible... probably not worth it but its def. possible

i've seen V8 guys mill pistons down....i've also seen guys weld material onto a piston to bump up the compression...... so simply saying " stack gaskets" doesnt really answer this guys question. The question was can it be done.....

it can be done.....how much you'll be able to safely mill is up in the air because from what i know and what it seems in this post no ones done it on a VR.... i know a guy who works for manley that mills pistons on a daily basis 

is it cost effective?? maybe?

is it reliable? maybe?

i hate forged pistons personally...anything i've built ive used cast pistons just because there cheaper and easier.....and to be honest how many guys are making so much power there blowing the crowns off there pistons???The team GTR guys where making 400hp plus on there stock blocks and beating the crap out of those motors run after run after run..if the motor let go they just bought another one for 500bucks and call it a day......thats pretty good HP per dollar...not to mention trashing a built motors hurts the wallet alot more then a stock block

Thats not saying there isnt a place for forged pistons.....there strong and if your looking to make gobs of power forged is the way to go... but its kinda over kill for anything lower then 450whp.....its just like back in the EIP days people saying you needed to have the cranked balanced and knife edged but yet crank failure in these motors in almost non existant....

i mean you can buy forged anything but is it worth it for you overal power goal?? spending money on pistons to say " i have pistons" is kinda lame..because its not like your pistons make power..... they allow you to make power....so unless your making so much power you actually worried about cracking a piston whats the point??? its like being the tallest midget in the circusopcorn:


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## rjones1214 (Apr 24, 2009)

thanks guys, I will consider both options. my current head gasket barely has a couple thousand miles on it and another new gasket is $40 which is a lot cheaper than $150 spacer. 

does anybody know what cr 2 stock head gaskets gives you?
in a mk4 jetta AEG engine

edit: Corradokcid: thanks for the input, I do feel that it could be done since it doesn't take much to low the compression 1 or 1.5 points. Maybe i'll just call a machine shop and see what they have to say. This is not on a VR though, it's a AEG 2.0l 8v


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## rjones1214 (Apr 24, 2009)

*research*

Here are a few links I've found about this subject

In this thread a machinist said it wouldn't be a problem at all

This thread says as long as the dome is .25" thick it would be fine

Looks like I would want to have the dome of my pistons milled down/out to lower my compression.
Any chance someone has a stock piston they can measure??? :what:


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## GinsterMan98 (May 19, 2008)

Well, before you fly off the handle, I was just informing the other poster who said stacking gaskets was a bad idea that it is a proven method. Secondly, on the topic, VW deisel guys mill pistons that are not forged all the time. The CR in a deisel engine is much higher than our VR's, not to mention the cyclinder pressures. Those engines also have much more material on them than a gasoline engine piston for cooling purposes and have oil jets to cool the bottom of the pistons, while the VR6 does not. Point being what was posted about milling pistons is valid. You are taking a big risk of burning a hole in the top from removing material ment to cool the piston if a lean condition occurs. On a VR6, the headspacer is the cheapest, most reliable and proven method to lower the final CR with minmal side effects, while still retaining the oem build quality and piston longevity of using cast pistons. Dozens if not hundreds of people have made 400+ with OEM bottom ends with some milage on them. OP, I understand you were just asking a question. That being said, the people on here are trying to tell you the best way to do things. Go with whats proven and you will have a heathly Oem quality build that will make good power for a long time. I say go with the head spacer, you can get them for like 150 in the FI classifieds all day long.


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## GinsterMan98 (May 19, 2008)

You don't want to cut the dome off your piston. This will change the "squish" area and will affect how the cylinder fires. It can also cause hot spots on the piston surface which will most likey lead to bad things. The VR6 engine has a flat head, so it gets its cumbustion chamber shape from its piston shape. You want to keep that shape for it to make power. A headspacer does not change this shape, only lengthens it.

*EDIT*
Well I am a dumbarse, you are talking about a AEG egine. All still applies accept for the flat head part.


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## rjones1214 (Apr 24, 2009)

THIS IS NOT A VR ENGINE!! PLEASE READ IT'S A 2.0l AEG 8v

edit: Thanks for your thoughts, stacking gaskets is probably my best bet since it will cost me less money than a spacer.


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## GinsterMan98 (May 19, 2008)

No offense bro but I quessed VR due to the cr values you were talking about. You didn't tell us the engine until two posts ago. G/L with you build. Also, you don't have to *YELL*, I was still typing my post when you posted so I did not see your post until after mine was complete. One way to avoid this to put what your working on in the first post, just my .02 cents


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## rjones1214 (Apr 24, 2009)

I just realized it wasn't in the first post, sorry guys. I'll change that.


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## GinsterMan98 (May 19, 2008)

I am sorry for just asuming, lets sing Kum ba ya. The info still applys for the squish area though.


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## EL DRIFTO (Jul 11, 2004)

i know an engineer that cut the center combustion section out of his 1.8 16v pistons to lower the comp. & not kill the squish (~200whp)
the squish area is the edge of the chamber,


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## rjones1214 (Apr 24, 2009)

that's what I've read, the squish is on the outer edge and that's why you would mill down the dish area. 

I don't mind just putting 2 head gaskets on the car but researching my options before doing anything.


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## EL DRIFTO (Jul 11, 2004)

i've never heard of the timing or hot spot changes from spacers, so the squish topic is probably irrelevant


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## rjones1214 (Apr 24, 2009)

i meant the squish relative to cutting the pistons, but a lot of people run stacked gaskets or a spacer without any problems. 

i'm not sure what route I will go


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## elRey (May 15, 2001)

GinsterMan98 said:


> This will change the "squish" area and will affect how the cylinder fires.....A headspacer does not change this shape, only lengthens it.


Wrong. increasing thickness of the gasket DOES affect quinch. Quinch is not only determined by area, but also by height (how close the quinch area comes to the head).

Second to strength, retaining quinch is the main reason ppl prefer lower CR pistons over headspacers.


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## rjones1214 (Apr 24, 2009)

so both will effect it. it seems that since, from what i've read, that the squish area is on the outer edge of the piston then a head spacer would effect it and milling the dish of the piston would not, or at least less.

check this stuff out I'm working on calculating how much I would have to remove off my pistons.


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## cedricattorny (Jul 26, 2010)

*nuff said*

I wouldn't cut the piston due to the fact that it will weaken them. I am using a built short block with EIP spacer.


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## GinsterMan98 (May 19, 2008)

You are correct, I didn't think about that. Thank you for correcting my post. I would rather use a head spacer over decking the oem pistons agreed? Ideally custom pistons would be the "right" thing to do then correct? My point was that headspacers work and are safe to use vs decking the stock cast pistons. rjones1214 and all other, I am sorry for the incorrect info I put in this thread. I was confused on the squish area and how it is affected by spacers and or milling the dish. The point I was trying to make is that head spacers and stacked gaskets are viable solutions for lower CR. Again I am sorry for the bad info, guess I should do my homework next time.


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## GinsterMan98 (May 19, 2008)

Over the past couple of days I have read up on quench areas and how they affect the fuel air burn and the side effects of removing it. Spacers will have a negitive effect on combustion as stated before, more so than I thought before. It can create hot spots as adding a spacer will reduce the quench area as stated before. After doing more reading you do want to retain the origonal hight of the flat spot level with the block at all costs due to it actually reducing cylinder temps. Some people even refer to this area of the piston as free mechanical octane for this cooling effect. It also is important in the fuel air mixing prior to ignition. How much material would you have to remove from the pistons to acheive your desired cr? I know alot of people stray away from forged pistons because of cost and longevity, so it would be intresting to know if people have had sucess with milling the dish of a piston to lower cr for FI. I finally found what the vr6 oil squirters look like, I was unaware they had them. Also, do you think that coating the pistons will compensate enough for removing material to maintain proper piston cooling? Not trying to thread jack, but I feel these questions will help this thread as I have not seen one on this subject.


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## rjones1214 (Apr 24, 2009)

I don't know exactly how much material would have to be removed to drop the compression ratio. 

I did know that the spacer does have some bad effects but the drop in CR seems to outweigh the hot spots when running a low boost application.


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## danz44 (May 14, 2010)

why lower CR? just run higher octane fuel, reduce your ignition timing, or just run less boost...

id never run a spacer, and id never thin out an already thin piston crown. :banghead:

a high CR turbo build will make more power per PSI every time, as long as the fuel allows you to find MBT.


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## GinsterMan98 (May 19, 2008)

OBD2 VR6 here, can't control timing on MK3 ecu's on a chip tune or I would. I am still 10:5:1 on 12 psi with no problems, but I know honda guys like yourself have made 600+ on cast Vitara's so I was asking to see if others have had sucess with what was mentioned before. Makes me wonder if their is an OEM piston out their that would fit a VR.


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## rjones1214 (Apr 24, 2009)

I will be running the AEG tune C2 use to carry, it was written by Jeff and he is still selling the tune through his new company. With the stage 2 software it is written for lower CR and it's recommended to run an inline fuel pump and lower CR for anything over 10psi. I don't mind keeping the stock CR since my car is decently fun to drive already but I want to be able to run 15psi on a daily basis without having to worry. I'm not sure if I would be better off getting a stage 1 tune made for stock CR. 
I don't know how much timing control I will really have. I plan on using Vag-Com and Unisettings to log and tweak anything needed.


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## EL DRIFTO (Jul 11, 2004)

perhaps the pro Jeff could respond as to the actual differences he has seen in lowering the compression via HG vs "proper"

& he could report the differences of actual timing changes on knock log VS correctly anticipated changes from "proper" lowering ??


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## rjones1214 (Apr 24, 2009)

He could but I'm not sure how much time he spends on here. I may PM him and ask him as I have already been talking to him about getting my software.


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## TIGninja (Mar 21, 2010)

I personally wouldnt bother running a head spacer.I think the unwanted changes to the quench area and cam timing negate any benefits of the lower compression. I see this as a bandaid for a bad tune. Before I did anything I would look at the knock logs or bring it to a good dyno and confirm that there is a knock problem to begin with.

As far as the VW pistons go it seems the weak link is in the ring lands and under the wrist pin.I would not have a problem at all with adding some extra dish in these pistons.If anyone wants to try this I have a set of ABA pistons here we can try this on.

Yea after a quick look at these things I would do that in a second. There is atleast 1/2" material in the bottom of the shallowest part of the dish.I have a lathe here as well. Who wants to try some?


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## rjones1214 (Apr 24, 2009)

What bore are the pistons? 
I'm keeping my stock 82.5mm bore so if you want to dish them out 2-3mms (usually size of a head spacer) I would be willing to run them when I swap everything. 

If there is 1/2" and from what I read 1/4" is perfectly safe so that's 1/4" to work with for the dish. I'm just not sure exactly how much to remove.


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## TIGninja (Mar 21, 2010)

They are 82.5mm. I would have to do the calculation and see how much we would need to take out of the dish part of the piston.


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## rjones1214 (Apr 24, 2009)

Well sounds like something we can work on. I would be up to putting them in my engine. From what I've read you just weight the piston when removing metal until the proper weight is removed.


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## TIGninja (Mar 21, 2010)

I think the best way to do this is going to be to measure the cc of the dish in the stock pistons. Then machine in the amount for the desired compression into the dish part.

I think the AEG has different compression height then the ABA so my old pistons wont work. If you would like to send me the pistons though I could machine yours.


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## GinsterMan98 (May 19, 2008)

EL DRIFTO 
perhaps the pro Jeff could respond as to the actual differences he has seen in lowering the compression via HG vs "proper"

& he could report the differences of actual timing changes on knock log VS correctly anticipated changes from "proper" lowering ?? 


I would like to see that.


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## TIGninja (Mar 21, 2010)

Im kinda wondering why everyone is so stuck on this method. The whole reluctance to do something else is just odd. Every time someone asks a question the collective starts chanting "head spacer and a chip"--"head spacer and a chip". Sure it works. So did the horse and buggy. There are better ways to do things.


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## rjones1214 (Apr 24, 2009)

Yeah it looks like the ABA pistons are slightly taller. 
I want to drop my compression to 8.5:1 as suggested by Jeff as the proper compression for his stage 2 tune. I'm glad some people are looking into this and seeing that there are other options. I just had the idea to do this and was hoping someone had tried it. 
I am running a 'chip' tune because it's affordable and easier than wiring and tuning a stand alone plus the $1k+ price tag. 

How long would it take to measure and cut my pistons? 
My main problem is having my car down for too long.


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## TIGninja (Mar 21, 2010)

Its going to be $100 for shop time and I can get them done and sent back the same day.


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## rjones1214 (Apr 24, 2009)

Alright, I'm not sure if I want to be the first to do this and the cost also deters me. Shipping both ways plus $100 is more than a head spacer and stacking head gaskets would only cost me $40.


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## GinsterMan98 (May 19, 2008)

TIGninja ,
The way I see this situation is their are risks and benifits to every variable you change. I know the risks, downsides and pros of head spacers and gasket stacking, ability to increase boost. I also now know the downside of changing the quench area of the combustion chamber, thanks to everyone who pointed me in the right direction. I do not however know the possible side effects of milling piston dishes. No one here is chanting "head spacer and chip", only providing a known solution to the given problem and asking questions. Since you appear to know more about milling piston dishes than others or myself, maybe you could fill us in on the pro and cons of this process and the possible risks associated with it. No BS, I am just asking, not being a douche.:thumbup: I may have a diffrent engine, but I am at the same crossroads with what approach to take next.


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## antichristonwheels (Jun 14, 2001)

Techtonics machined my 9A pistons down to about 9:1. there is about a 10mm squish band with about a 2mm dish inside it. This is for a Kinetic 16V turbo setup.

Many years back, before a 2 liter existed, a popular trick was to take an 83mm aircooled piston, shave 2mm or .080" off the top and stick it in a 1.6 Rabbit motor. You could also do it in a 1.7, but the stroke pushed the static ratio up to over 12:1. I still have a set of these pistons new and a trio of 1.6 qnd 1.7s laying around. I'll do it again.

Don't be afraid to at least look into cutting a piston to suit.


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## rjones1214 (Apr 24, 2009)

Sounds promising. Glad to hear a respectable company actually did this, it seems like now everybody thinks it's either a head spacer or forged/custom pistons. 
I would like to get this done but it depends on the time it would take, cost and if the person doing it knows what they are doing. At this point in life my turbo build is on a tight budget and my cheapest option will probably be what I choose right now. I will have to see how this pans out once I'm closer to tearing into my engine.


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## vr-vagman (May 15, 2010)

Hi,
think Wiseco is doing exactly the same with piston's dome to obtain lower CR. It looks like the piston is just the same (different alloy though) and dome is mashined wide. These are VR pistons.


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## TIGninja (Mar 21, 2010)

All wiseco is doing if taking blank forgings and machining them to the aplication. Thats what all aftermarket piston companies do.


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## rjones1214 (Apr 24, 2009)

That makes a lot of sense and would also make doing this safer. Widening the dish area instead of making the piston thinner would give the piston more strength. 
Any chance we could get a pic of the pistons from techtonics?


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## Salsa GTI (Aug 29, 2000)

rjones1214 said:


> Well I am going to re-ring my pistons, install newer rifle drilled rods and replace bearings and seals while I have the bottom end apart before I install my turbo kit. I recently lost timing and had to replace the head and now the pistons are dented.
> Since I'm boosting the car I need to lower my compression so I can run more than 10psi safely.
> 
> My main question is: Can I have the tops of my pistons cut down to lower my compression?
> ...


all this tech talk is all well and good.....but
What are your power goals for this build?
What is its intended usage?
Everything can be done...but sometimes the answer is why....
Dont install late modle rods in there period they are crap like the 1.8t rods.....rods are 400.00 bucks buy them and be done.....and if your in there go forged pistons.....they only make std bore pistons for stock comp but they will custom machine them to whatever you want.....
another reason to switch to forged pistons and better rods is the ability to spin the engine past 7500 without venting the block....
If you want to be cheep stack head gasgets and install head studs and call it a day..
if you want tunibility instead of a chip tune...swap in a 1.8t wiring harness and go eurodyne for tunibility above and beyond any chip tune...or go full on standalone if emission inspection is out of the question.....


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## rjones1214 (Apr 24, 2009)

Salsa GTI said:


> all this tech talk is all well and good.....but
> What are your power goals for this build?
> What is its intended usage?
> Everything can be done...but sometimes the answer is why....
> ...


^^This is the kind of post that I did not want, none of this thread has been talking about any of this and I stated "this is what I'm doing" not "what is the best option?" 
I have no reason to install forged pistons/rods or do a 1.8 harness swap and buy $900 software. You're suggesting I spend $400 on rods, another $4-500 on pistons plus cost of a harness and the fact that my 2.0 doesn't have all the right sensors a 1.8 harness needs then add $900 for eurodyne = $2000 just for tuning and internals. The rods I have I picked up for $33 shipped, it cost an extra $100 to have rods rifle drilled. 
People need to open their eyes and realize that you don't need to build an engine that can handle 400+hp and 8k rpms unless that is what I'm asking for.

Edit: The rods are from a 9A engine so they are actually older, not new. Also from everything I've read stock rods, even in my 2.0 can handle up to 300+hp and stock 1.8 rods w/ APR hardware can handle 500hp. This is just from what I have read and found on this site but it also shows that you don't need $400 rods when I'm doing a $1500 build including my engine and turbo kit.


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## GinsterMan98 (May 19, 2008)

Well put sir, your question has actually made me wonder and start doing some math. I think I might try this on some stock pistons and see what happens. I trust my setup enough to start playing around with it.


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## rjones1214 (Apr 24, 2009)

I don't mean to be rude but I want this to stay on the topic at hand. I know there is better ways but I would also end up with a better engine than I truly want or need. Since I'm going to be running a 42# tune I will be limited to a max of around 300hp with the injectors maxed out which is around 18-21psi (straight from Jeff himself). 
I would like to have this done but I need to find out how much to actually remove and also find someone or a shop willing to do this. As long as this is done on a lathe the pistons should retain their stock balance so there shouldn't be any problems there. 

If anybody knows how to calculate or has calculated the amounts, sharing would be appreciated. Also if anybody actually does this please fill us in :thumbup:


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## rjones1214 (Apr 24, 2009)

I believe my stock piston look like this:


Does anybody have a set of AEG pistons out of an engine? Some measurements would be great.

From what I remember when having the head off of my car, there is not as big of a lip area as those stock VR pistons so I'm not sure if it would be a good idea to widen that, maybe only slightly. But depth shouldn't be a problem and the larger area dish would mean less depth needed :screwy:


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## EL DRIFTO (Jul 11, 2004)

in my recent search travels, i've seen others doing this with vw engines
i'm surprised you haven't tried the maths you self
PIE * (R^2) is the surface area of a circle
if the total stroke is 90mm, then 9mm would be 1/10 or the imaginary combustion chamber height, so .9mm would take it up a ~ point

so basically if 3.14 * (42^2) = 5538 mm^2
lets say the portion you mill will only be the flat surface of the piston, and that's only 80% of the overall diameter of the piston so:

3.14 * ((42 x .80) ^2) = 3544 mm^2
5538 / 3544 = 1.56
if the portion you are milling is exactly 80% the diameter of the overall piston, you'd just mill of 1.56 times more than calculated, hope that helps


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## TIGninja (Mar 21, 2010)

EL DRIFTO said:


> in my recent search travels, i've seen others doing this with vw engines
> i'm surprised you haven't tried the maths you self
> PIE * (R^2) is the surface area of a circle
> if the total stroke is 90mm, then 9mm would be 1/10 or the imaginary combustion chamber height, so .9mm would take it up a ~ point
> ...


How many CCs do I need to add to the dish? I just measured 15cc on a stock ABA piston.


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## Jeebus (Jul 8, 2001)

Dishing pistons has been done plenty of times on these motors. They both work... pick one and do it.. if you're wining about $100 to have them dished... then just run stacked gaskets as it's proven itself. For your power goals... there's no question I'd just be stacking gaskets and forgetting this thread even existed.


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## rjones1214 (Apr 24, 2009)

Thanks for the numbers, I will take some time and figure out what I'm working with. I just don't know the numbers for a point regarding compression ratio. 
I also found this pic, it's a 8.5:1 JE piston 

It looks like JE widened the outer ring. 
Does anybody know if it would be better to cut into the dish or widen the squish area ridge?

I don't have a problem paying to have this done by someone who knows what they are doing. With more and more positive things coming out I'm leaning towards this so that I don't have to worry about stacked gaskets or my head studs messing up.


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## danz44 (May 14, 2010)

you are still going on about this?

just save up a few bucks and get a set of low comp pistons if you really believe you need to lower your CR


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## rjones1214 (Apr 24, 2009)

danielzeilstra said:


> you are still going on about this?
> 
> just save up a few bucks and get a set of low comp pistons if you really believe you need to lower your CR


^^Once again I don't want to hear this! :banghead: I don't care if you think that spending hundreds of dollars on lower compression pistons is the best way, I didn't ask that. Unless you are adding to the conversation stay out.
And for a lot of people, saving up a few bucks isn't $4-500 just for pistons FYI


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## Jeebus (Jul 8, 2001)

You need to buy head studs anyways. If you're thinking about just running dished pistons and stock head studs then you need to re-evaluate your plan of attack. Just stack the gaskets and when you want more power you can save up and buy new pistons. 

stacked gaskets/ARP head studs > dished pistons and stock headstuds

Again at this point for your power goals you're wasting your time and money dishing pistons for a job that's easily done with head gaskets. 

Are you asking peoples advice, or asking them to back up what you've already made up in your mind? If your asking for advice... take it from the folks that have built these motors. If 300whp is your goal.. stack head gaskets and ARP headstuds is your answer. 

If you plan on running ARP studs no matter which way you go, then either way is completely fine. The dished pistons will just cost you more.


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## rjones1214 (Apr 24, 2009)

I am asking if it was possible to have my pistons cut, now that I know it is possible it's just a matter of either:
1) finding someone to do the work for an affordable price
2) knowing it will work but not going this route for some reason 

Why would I need APR headstuds either way?
Has anybody had problems with stock head bolts and boost? 
Stacking gaskets would leave less threads on the head bolts.

Money wise it looks like this:
APR head studs = $150 
machine work for pistons = $100 
extra head gasket = $40 

so studs and stacked gaskets would be almost $200, pistons would cost $100 plus shipping so $150 max.

edit: also 300hp is not my goal, just the max my setup would be capable of. I plan on running 10psi, eventually 15psi max which should be around 220-240hp


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## Jeebus (Jul 8, 2001)

rjones1214 said:


> 1. Why would I need APR headstuds either way?
> 2. Has anybody had problems with stock head bolts and boost?
> 3. Stacking gaskets would leave less threads on the head bolts.





1. The reason they're made for.... to prevent from lifting the head.
2. As boost increases, lifting the head becomes more of an issue on stock head bolts.
3. Haha.. that's not the issue. The issue with stock bolts comes down to the clamping force, which helps prevent lifting the head with positive pressure.


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## rjones1214 (Apr 24, 2009)

I understand why to use head studs, but I would like to know at what point do you need head studs?

Will stock head bolts fail at 10psi? 15psi? 

Please post up your experience or real world examples, not "you should because it's the right way"


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## TIGninja (Mar 21, 2010)

In my experience with the aba you can go about 250whp on stock head studs (no way with stacked gaskets though). Anything over 300whp and your on borrowed time as far as the pistons go. Eventually your going to rip the wrist pin out of the piston.


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## rjones1214 (Apr 24, 2009)

Thanks for the input :thumbup: 
I would want to get head studs eventually but I can't afford everything all at the same time.


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## groundupjetta (Feb 1, 2010)

I also have an aeg and I'm going boost and I've been going thru the same bs. 
Many people here are brainwashed with the idea of chip tuning and forged pistons. I have had the same idea of removing some material from my pistons before or mix and match piston/rods/cranks to lower compression but have had few replys. 

THERE IS always another way :thumbup: 

Btw I'm 99% sure that a stock head bolt from a 1.8T will fit just fine on our engine, l measured one and compared to my stock AEGs and they're the same size 10mm x 1.5 x 115mm . 

I'm not sure if they can hold more pressure, but since they are manufactured for a boosted engine I suspect they can handle more pressure then stock aeg bolts. AND they are cheaper then stock AEGs


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## rjones1214 (Apr 24, 2009)

Thanks for the heads up. It seems like a lot of people fun 15+psi on a stock 1.8t so the stock head bolts must hold up. I'll look into those more and see what I can find. 

edit: one difference I did notice was that the AEG head bolts use a washer and the 1.8s do not. Also the 1.8 bolts have a threaded section towards the top that the AEGs do not. I could also reuse the washer I have on 1.8 bolts. Anybody else know more about this?


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## EL DRIFTO (Jul 11, 2004)

i always reuse stock head bolts & they've never leaked, hysterized, they seem to be harder to strech :screwy: 
7 psi 10:1 vr6 & 16 psi 11.5:1 aba, riding the knock sensors 

i used a tape measure last night & came up with 3.25" bore & 3/8" squish, makes the # 1.52mm out of the center of the dish, for 1 point 

interesting to me is the cost of a new turbo & how people debate a few degrees of timing, a point of compression, tubular vs log & nevar mention the eff of their turbo, the kingpin number in the whole package 

my point is if you take a step back & consider all that's involved, you could easily use stock compression, with a safe chip tune & an ice cold turbo, a compressor map should tell you when you're


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## rjones1214 (Apr 24, 2009)

Thanks for the response. I plan on using stock head bolts for now. 
1.53mm sounds like a very reasonable about to remove without causing any problems. 
My turbo is a TB0356 which is a very small turbo so I won't be flowing a ton of air, boosting early and I won't be running my engine far out in the rpm range. 

I don't mind keeping my compression ratio stock as long as I can safely run 10 & 15psi. I need to do some research on the tune and talk to Jeff and see if there will be problems with the software.


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## NumberOne 2nd2none (Jan 30, 2010)

TIGninja said:


> I personally wouldnt bother running a head spacer.I think the unwanted changes to the quench area and cam timing negate any benefits of the lower compression. I see this as a bandaid for a bad tune. Before I did anything I would look at the knock logs or bring it to a good dyno and confirm that there is a knock problem to begin with.


 EXACTLY! Very well said... Also pistons usually have a certain top coating to withstand combustion temps, milling that off is not a good idea at all. Low compression pistons are the way to go. 
You using a 2.0L, People have successfully used t3/t4 with stock internals running less than 10psi. DONT KILL YOU PISTONS :thumbup:


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## Salsa GTI (Aug 29, 2000)

EL DRIFTO said:


> i always reuse stock head bolts & they've never leaked, hysterized, they seem to be harder to strech :screwy:
> 7 psi 10:1 vr6 & 16 psi 11.5:1 aba, riding the knock sensors
> 
> i used a tape measure last night & came up with 3.25" bore & 3/8" squish, makes the # 1.52mm out of the center of the dish, for 1 point
> ...


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## rjones1214 (Apr 24, 2009)

I looked around a little bit and I found this thread, he was running 11psi on a turbo about the same size as mine on stock compression with no problems. 

I feel that my best option is to leave my compression stock. I will be tearing into my engine to replace my rods/rod bearings and doing a slight rehone just because of the mileage on the block. I am also going to put new rings on my stock pistons. 

I'm glad people got interested in this topic and it's good information to know and have out there.


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## J.Owen (May 31, 2001)

I have been running 11 psi on my stock block AEG for a while now. I am running a turbonetics t3 Super60 with a .48 hotside.


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## rjones1214 (Apr 24, 2009)

Thanks for the input man :thumbup: Good to know stock compression runs fine. 
I think I am going to go with ARP head studs and stacked gaskets for now, maybe just head studs. 
My main reason for this is that I can reuse the head studs every time I remove my head, which saves me $40 every time I swap any parts so want to do any upgrades to the head.


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## TIGninja (Mar 21, 2010)

And just for the record we were running 15lbs on pump on my stock compression 2l. We were in the 250whp neighborhood. I know its not what you guys want to hear but I would spend the money on a standalone first.


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## rjones1214 (Apr 24, 2009)

Thanks for the info! 

I'm undecided still on what to do. I could do any of the options, all have their benefits but with my initial build and current budget the cheapest way to go is going to be best for me. I need to keep this in mind. 
The decision I want to stand by is stock CR with fresh head bolts, if that fails at any point I will have a reason to upgrade. 
My main reason for this is so that I can have more money available for a new clutch.


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## NumberOne 2nd2none (Jan 30, 2010)

TIGninja said:


> And just for the record we were running 15lbs on pump on my stock compression 2l. We were in the 250whp neighborhood. I know its not what you guys want to hear but I would spend the money on a standalone first.


 Money on a standalone first??? Sounds like someone finally did osmething right :thumbup: :thumbup: :thumbup:


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## TIGninja (Mar 21, 2010)

rjones1214 said:


> Thanks for the info!
> 
> I'm undecided still on what to do. I could do any of the options, all have their benefits but with my initial build and current budget the cheapest way to go is going to be best for me. I need to keep this in mind.
> The decision I want to stand by is stock CR with fresh head bolts, if that fails at any point I will have a reason to upgrade.
> My main reason for this is so that I can have more money available for a new clutch.


 Trust me by the time you get your "chip,MAF,and head gasket" you will have already spent the same amount of money as a good standalone will cost you. I would look into lugtronic for PNP or the new haltech sprint 500. These usually run about $800(if you cant find one for that LMK we have them).


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## rjones1214 (Apr 24, 2009)

I really wish I had the money for standalone but even at max I won't be hitting the $800 mark plus the time to tune a stand alone. If I go with stock CR I won't be getting a head spacer since I would have a stage 1 tune. 

If I could go standalone for around $500-600 I would probably go that route, I use a macbook so I can't use my laptop for tuning. 
I did see a Megasquirt for $300, would that work?


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## EL DRIFTO (Jul 11, 2004)

i dont want to say standalone sux, but considering the motronic's ignition control, i wouldn't get rid of that imo 

if i were you, i'd keep everything stock except bigger injectors, rising rate fuel pres regulator & a little e85 

everybody's got their methods, but you shouldn't need to pull timing or lower compression < 1 bar, esp with motronic & 30% e85


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## rjones1214 (Apr 24, 2009)

I'm going to run stock compression, 42# injectors and tune. If I really start to push my setup I will put in a water/meth kit to run more boost.


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## NumberOne 2nd2none (Jan 30, 2010)

rjones1214 said:


> I'm going to run stock compression, 42# injectors and tune. If I really start to push my setup I will put in a water/meth kit to run more boost.


 Sounds like a plan, man! :beer:


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## TIGninja (Mar 21, 2010)

EL DRIFTO said:


> i dont want to say standalone sux, but considering the motronic's ignition control, i wouldn't get rid of that imo
> 
> if i were you, i'd keep everything stock except bigger injectors, rising rate fuel pres regulator & a little e85
> 
> everybody's got their methods, but you shouldn't need to pull timing or lower compression < 1 bar, esp with motronic & 30% e85


 Are you serious? Thats the dumbest thing I have ever heard.


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## rjones1214 (Apr 24, 2009)

I won't even consider E85, sounds like a terrible idea plus the fact that it would destroy my fuel system.


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## TIGninja (Mar 21, 2010)

rjones1214 said:


> I won't even consider E85, sounds like a terrible idea plus the fact that it would destroy my fuel system.


 False. It will not destroy your fuel system.


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## rjones1214 (Apr 24, 2009)

I thought alcohol can degrade rubber fuel hoses? Either way I don't want to mess with switching fuels


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## rjones1214 (Apr 24, 2009)

Anybody know about E85 on a aftermarket tune? 
I found this link and sounds promising since stock 1.8 injectors are smaller than 42# 

Would Uni-settings, bigger injectors and E85 work better in preventing knock?


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## TIGninja (Mar 21, 2010)

rjones1214 said:


> I thought alcohol can degrade rubber fuel hoses? Either way I don't want to mess with switching fuels


 Everything in MK2 and MK3 runs plastic hoses and special hoses for fuel that already contains alcohol.


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## rjones1214 (Apr 24, 2009)

I have a MK4, thanks for the info that's good to know.


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## TIGninja (Mar 21, 2010)

rjones1214 said:


> I have a MK4, thanks for the info that's good to know.


 MK4 isthe same.


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## rjones1214 (Apr 24, 2009)

sounds good, I might look into E85 more since I will be putting an inline pump anyways.


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## Salsa GTI (Aug 29, 2000)

TIGninja said:


> Trust me by the time you get your "chip,MAF,and head gasket" you will have already spent the same amount of money as a good standalone will cost you. I would look into lugtronic for PNP or the new haltech sprint 500. These usually run about $800(if you cant find one for that LMK we have them).


 Correct If you want max power and the verry best drivability...forget a tune in a box..... 
with a half ass tune you will be 60whp plus with stand alone.....trust me..been there done that 
if you just want to say you have a turbo on your car and run "X" ammount of boost get a tune in a box.....just dont expect to set the world on fire....or learn anything about tuning your car.... 
Lugtronic will hook you up with what you need....and Knows how to get power from a VW engine...well any engine for that matter


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## rjones1214 (Apr 24, 2009)

I know there are benefits for going standalone but since this is my first turbo build, a weak engine to start with and my only car I don't want to go standalone. If I had a project car with a built engine I would put in a standalone.


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