# 2.0 8V (3A) + 1.8 8V head etc?



## DtiJ (Jan 14, 2019)

*2.0 8V (3A) + 1.8 8V head compression etc (project)*

Hello,

I'm doing low budget block swap 1.8 8v to 2.0 8v [bubble block], keeping 1.8 8V head + weber carb (Audi 80 B3).



Some things occupy me;


Do I change pistons to... X?
Do I use thicker head gasket?
Do I modify combustion chamber or keep it stock (bore goes 81->82.5)?

Is there ANY way to fit mechanical fuel pump to 3A ? You can recommend electric pumps also.. Facet 60300 is what maybe good?



Mechanical things in this project are no problem for me but this things..

I'll certainly ask more later.

Am I calculating correct??


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## garryt (Dec 22, 2016)

it all bolts together just fine. make sure you use the 2.0 head gasket though. you cant use mechanical fuel pump as there is not cam lobe on the intermediate shaft to operate it. I'm doing the same build on a gti:thumbup: the 3a has slightly higher compression than the 1.8. 3a-10.5-1. 1.8-10-1. but you could adjust your ignition timing slightly if the engine knocks.


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## DtiJ (Jan 14, 2019)

garryt said:


> it all bolts together just fine. make sure you use the 2.0 head gasket though. you cant use mechanical fuel pump as there is not cam lobe on the intermediate shaft to operate it. I'm doing the same build on a gti:thumbup: the 3a has slightly higher compression than the 1.8. 3a-10.5-1. 1.8-10-1. but you could adjust your ignition timing slightly if the engine knocks.


Yes 3A with stock 3A head is 10.5:1 but with swapping head to 1.8 8V it goes to ~12. 

However with "G" cam or 3A stock cam* dynamic* compression is something like about 10,72:1 so it's pretty OK.
with 276 cam dynamic it's around 10.07:1
with very mild 1.8 8v stock cam it's around 11.84:1

I've now calculated it zillion times and pretty sure about that. I used these:

http://www.not2fast.com/vw/stuff/vw_engines.shtml
http://www.csgnetwork.com/compcalc.html
http://blackartdynamics.com/Compression/EngineCompression.php

I've found cometic makes head gaskets with very different thicknesses, but they cost €€€


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## garryt (Dec 22, 2016)

I always thought the 3a head and the 1.8 head had the same cc's. and the difference was in the piston bowls. the last 3a engine I had, had a 1.8 head that had been skimmed about 1mm. gave 215psi in a compression test.


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## DtiJ (Jan 14, 2019)

2.0 8V out of donor car


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## Butcher (Jan 31, 2001)

DtiJ said:


> Yes 3A with stock 3A head is 10.5:1 but with swapping head to 1.8 8V it goes to ~12.


I'm pretty certain you are a bit off base on this one.

I'm pretty certain the 3A head and a standard 8v head [JH] has the same 30cc combustion chamber. Keeping all things the same, how is swapping the stock head with a 30cc chamber with a JH head with a 30cc chamber going to raise your compression? 

Simple answer, it will not.


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## DtiJ (Jan 14, 2019)

Butcher said:


> I'm pretty certain you are a bit off base on this one.
> 
> I'm pretty certain the 3A head and a standard 8v head [JH] has the same 30cc combustion chamber. Keeping all things the same, how is swapping the stock head with a 30cc chamber with a JH head with a 30cc chamber going to raise your compression?
> 
> Simple answer, it will not.


Do you think piston dimensions do not affect cr ratio? I'm going to change from 1.8L to 2.0L block. If combustion chamber volume does no go up, cr ratio goes up. Well piston dish also is effecting but in principle.

BTW, i'm not using JH (stock 8.5:1) head, but 1.8 Audi PM (10:1 stock)



> Compression ratio is the ratio of the compression volume of the internal combustion engine to the sum of the stroke volume to the compression volume


edit:
1.8 8V stock piston should be this: http://www.partsdirect.nl/15908-thickbox_default/vw---vag-vw026107065n.jpg
2.0 8V stock piston should be this: http://trshop.audi.de/konakart/images/053107065f_053107065f053107065f.jpg

There must be some difference in head, i'll report when i see...


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## Butcher (Jan 31, 2001)

I think you are over thinking this way too much. Sit back, grab a beer and think about it slowly.

You want a 2.0L, great, a lot of people want to go 2.0L when they have a 1.8L. Bigger is better, right? You also want to keep it simple and install your 1.8L head on it, no problem there. Use the stock 3A headgasket and bolt it right up. Whatever the compression ratio is in the 3A, it will be the same with the 1.8L head since the combustion chamber size is the same [30cc].

This is what you need to grasp. *Both heads have 30cc dimensions* [there are tolerances and I'm not factoring this and you are not going to blueprint this too]. What makes you think the compression is going to change? Both rooms are 30cc. Grasp that fact, believe it, own it like it's yours. Once you believe that, the rest should make more sense.

Your basically done with the modification. Simple easy.

What your issues are going to be is getting the spark to work. You'll have to search about distributor adapters.

Why you want carbs is beyond me but it's your engine and you want to do it your way. Good for you. I would not go with a mechanical fuel pump. Get an electrical low pressure pump. Electrical pumps are great at pushing but do not suck well so it should be as close to the tank as possible. The feed line should original from the bottom of the fuel tank. if your tank is not that way, then you may need a transfer pump. If you have a transfer pump, you may not need an additional pump at all since you could just use that one.

I'm an auto mechanic. I own my own shop. I've worked on German cars [Mercedes/BMW] since 84, I was a top 10 Mercedes mechanic for 2 years and top 200 for over 20. I may not grasp the English language well, but I do know what I'm talking about. Put the 1.8L head on and enjoy the 10+ compression ratio. It will not change more than factory tolerances. Keep the fuel injection. It's so much better in EVERY level.


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## garryt (Dec 22, 2016)

are you sure that's a 3a motor??? the oil filter looks very vertical to me. were they not angled back towards the gearbox?


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## DtiJ (Jan 14, 2019)

garryt said:


> are you sure that's a 3a motor??? the oil filter looks very vertical to me. were they not angled back towards the gearbox?


I think it is unless someone has swapped engine in donor car :banghead:

2 litre it is and 8 valve, thats for sure 

However pistons are like this, not flat:


Always thought there is flat pistons in 3A.


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## DtiJ (Jan 14, 2019)

Butcher said:


> What your issues are going to be is getting the spark to work. You'll have to search about distributor adapters.




Whats problem with that?


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## Butcher (Jan 31, 2001)

I have never done what you did. I have a lot of experience in my field. Keep that in mind with my comments.

The 3A block has a bigger hole for the distributor. It is because the 3A distributor has a bigger gear. If you use a 3A distributor, you need to have an ignition system that will play with the distributor properly. I would imagine the 3A distributor has a hall effect sensor and the timing is all done in the ignition module. Some of the older VW engines, had all the timing done in the distributor and the ignition module just amplified the signal for the coil. 

I hope that makes sense.


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## garryt (Dec 22, 2016)

yeah them pistons look 3a. and the head gasket dowel is nearer the centre of the block ( further out on 1.8). if you are using a carb/ignition set up, you will need a mechanical advance dizzy with the 3a lower drive gear and a spacer ring:thumbup:


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## DtiJ (Jan 14, 2019)

garryt said:


> yeah them pistons look 3a. and the head gasket dowel is nearer the centre of the block ( further out on 1.8). if you are using a carb/ignition set up, you will need a mechanical advance dizzy with the 3a lower drive gear and a spacer ring:thumbup:


Do you know if I can combine distributor from 1.8 carb engine and this 3A distributor into one working unit?

Is "mechanical advance dizzy" meaning it has centrifugal advance of spark and 3A motronic distributor does not have?


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## DtiJ (Jan 14, 2019)

Butcher said:


> I have never done what you did. I have a lot of experience in my field. Keep that in mind with my comments.
> 
> The 3A block has a bigger hole for the distributor. It is because the 3A distributor has a bigger gear. If you use a 3A distributor, you need to have an ignition system that will play with the distributor properly. I would imagine the 3A distributor has a hall effect sensor and the timing is all done in the ignition module. Some of the older VW engines, had all the timing done in the distributor and the ignition module just amplified the signal for the coil.
> 
> I hope that makes sense.


Car where this package is going has distributor with hall + 7 pin ignition module + big cylinder shaped coil. Basically same stuff than 3A donor.


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## garryt (Dec 22, 2016)

yeah if you are sticking with the carb set up, you will need the matching dizzy with a spacer ring and the 3a drive gear. if you are tuning the engine at all, you might be better with an early 1.8 gti dizzy. but if it's just a block swap, your original dizzy should be ok.


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## garryt (Dec 22, 2016)

don't forget to check the intermediate shaft end bearing for wear:thumbup:


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## Butcher (Jan 31, 2001)

If you are using the 3A block, I thought you had to use a 3A gear. If you are using the older block, the stock intermediate gear must be shaved so the crank/rod won't hit it.

Remember, I have not done this, but I plan on stroking an old block this year.


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## DtiJ (Jan 14, 2019)

Inlet valves are 2mm bigger in 2.0 8v. (40mm vs 38mm in 1.8 8v)


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## garryt (Dec 22, 2016)

yeah you need the 3a drive gear, 1.8 dizzy and a spacer ring.


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## DtiJ (Jan 14, 2019)

garryt said:


> yeah you need the 3a drive gear, 1.8 dizzy and a spacer ring.


I don't understand why I need 1.8 distributor :screwy:

I've read 2.0 is "electronical" but.. 2.0 distributor looks same except without vacuum retard. Is only that a reason? 

Vacuum retarding is just for better emissions during idle on catalysator cars (which my car is not, but it still has that vacuum thing)



my 1.8 distributor is like this:


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## garryt (Dec 22, 2016)

there is a centrifugal advance mechanism inside the 1.8 dizzy. the advance in the 2.0 dizzy is controlled by the ecu. if you use the 2.0 dizzy on a carb'd engine without an ecu style management, you will have no ignition advance, and therefor, no power:thumbup:


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## garryt (Dec 22, 2016)

the vacuum advance unit gives the engine more timing during light throttle cruising (increases efficiency)


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## Butcher (Jan 31, 2001)

Butcher said:


> The 3A block has a bigger hole for the distributor. It is because the 3A distributor has a bigger gear. If you use a 3A distributor, you need to have an ignition system that will play with the distributor properly. I would imagine the 3A distributor has a hall effect sensor and the timing is all done in the ignition module. Some of the older VW engines, had all the timing done in the distributor and the ignition module just amplified the signal for the coil..


I know this may not come out right, but you really need to grasp what you are doing because if you do not, then the project ends up in a disaster.

The 2.0 and 1.8 distributors are different sizes. A 2.0 dist will not fit a 1.8 block and visa versa. I'm pretty certain the intermediate shafts are different too [since the dist gears are different]. The ignitions system are different because of the way to provide the correct ignition timing to the engine. If you use a 1.8 dist you will need a spacer ring. 

Just compare intermediate shafts and distributors. You should see the differences. Then the questions you are asking will seem elementary.

Again, I'm not trying to sound like a jerk, but I do not grasp the English language well enough to sound like I'm a prince charming.

There were different size valves on the 8V heads. They surely look to be the same size in the pictures, but a ruler certainly would do better than any picture. If I were to do that swap, I would install valves with the 7mm stem. It takes a few more parts but it should flow more air and you know what that does. Of course a good cam [not a high RPM version] and exhaust would certainly wake up that engine too.


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## DtiJ (Jan 14, 2019)

garryt said:


> there is a centrifugal advance mechanism inside the 1.8 dizzy. the advance in the 2.0 dizzy is controlled by the ecu. if you use the 2.0 dizzy on a carb'd engine without an ecu style management, you will have no ignition advance, and therefor, no power:thumbup:


Thanks, that was exhaustive answer I was looking for. I am going to adapt 1.8 distributor to 2.0 block (with spacer, gear and so on). Makes more sense than adapt 3A ignition system to 1.8 carb car.




Butcher said:


> There were different size valves on the 8V heads. They surely look to be the same size in the pictures, but a ruler certainly would do better than any picture. If I were to do that swap, I would install valves with the 7mm stem. It takes a few more parts but it should flow more air and you know what that does. Of course a good cam [not a high RPM version] and exhaust would certainly wake up that engine too.


Yes, I have 8mm valves (or actually ~7,9mm from shaft) and there is tiny bit of play between them and guides, especially #1 inlet valve. Didn't took accurate measurements, but about 0.5-1mm of movement when valve 5-10mm open. What is specs for measuring that?

So it may be time for guide job anyway. Changing valves to 7mm, I need new valves, not so sure want to do that. Is it worth it? And does 7mm guides go straight to in place of 8mm?

And for camshaft I think I'm going with 2.0 8v (3A) "G"-marked cam.


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## garryt (Dec 22, 2016)

if it's a budget build then you might want to stick with 8mm valves. unless you can get a second hand head and swap it all over. if you are having porting/valve job done, then the 40mm inlets will fit the 1.8 head and work well if done right. the 3a camshaft is an identical spec to the digifant gti engine, so you might be better with a gti dizzy. also, I wouldn't skim to much off the head as you have no knock control.


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## DtiJ (Jan 14, 2019)

garryt said:


> i40mm inlets will fit the 1.8 head and work well if done right.


What you mean "done right" ? Doesn't it need machining and putting in new valve seat etc in machining workshop...beyond what I can do myself.


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## garryt (Dec 22, 2016)

now you mention it, i'm not certain if it's the same seats for the 38 and 40mm valve. but you can make the 38mm valve flow pretty good with the right porting and valve angles. the later mk2 gti had the same power output as the earlier one, but the valves were up to 40mm. so the increase in size was obviously not night and day. I think what you need to do is decide, how much you want to spend? and how much power you're after?


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## Butcher (Jan 31, 2001)

Being old also means I'm slow. 

I forgot you are putting in the VW head. If the valves are smaller, the seats will not work. Replacing the seats are really a bad idea. I would suggest you just get a big valve head and rebuild that. 

With a bigger 2.0 engine, I believe the larger valve head is the only way to go. They made a big difference with the 1.8 engines, I can only imagine that they would be good for the 2.0 too.


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## DtiJ (Jan 14, 2019)

Butcher said:


> With a bigger 2.0 engine, I believe the larger valve head is the only way to go. They made a big difference with the 1.8 engines, I can only imagine that they would be good for the 2.0 too.


There just 1 problem:

Affordable inlet manifold for carb does not exist as 40/33 cylinder head looks like this:


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## Butcher (Jan 31, 2001)

I understand that the 3A head will not work for your project, but there are regular 8V heads that have the bigger valves. JH, 2H are just a few engines that I can say for certain that do.


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## garryt (Dec 22, 2016)

get a manifold to head adaptor plate:thumbup:


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## DtiJ (Jan 14, 2019)

little bit blow-by maybe :sly:


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## DtiJ (Jan 14, 2019)

Hello

does anyone have exact measures for distributor spacer ring ? for 3d-printing or lathe


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## Butcher (Jan 31, 2001)

I do not know the dimensions, but I know the link.

http://techtonicstuning.com/main/index.php?main_page=product_info&cPath=2_11_5_248&products_id=1370


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## DtiJ (Jan 14, 2019)

Butcher said:


> I do not know the dimensions, but I know the link.
> 
> http://techtonicstuning.com/main/index.php?main_page=product_info&cPath=2_11_5_248&products_id=1370


30 usd
+ shipping $48.41 usd
vat 16,87 eur

total 87,15 eur

:sly::banghead::screwy::what::thumbdown:

I'll combine 1.8 8v carb distributor internals to 2.0 8v dist or something like that. :sly:


Got new piston rings + main bearings + big end bearings + timing side oil seals

Someone stupid has changed main bearings wrong (other side should have oil hole and other not. They were put like random there, some blocking oil passage :banghead


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## Butcher (Jan 31, 2001)

I would invite you to my country, but they are in the process of building a wall. 

The dimensions cannot be that difficult to fine. The OD must fit inside the block, the ID must be large enough for the small distributor to fit. If you have both items, a hunk of aluminum, and a lathe, you should be fine.


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## garryt (Dec 22, 2016)

dizzy spacer ring dimensions= 51.5mm od (top) 44.5mm od (main section) height 12mm. 34.5mm id. and the top locating section is 1.5mm thick:thumbup:


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## garryt (Dec 22, 2016)

you will need the ring as you can't interchange the dizzy parts.


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## DtiJ (Jan 14, 2019)

garryt said:


> dizzy spacer ring dimensions= 51.5mm od (top) 44.5mm od (main section) height 12mm. 34.5mm id. and the top locating section is 1.5mm thick:thumbup:


Thanks a lot!

soon it's time to focus on getting the distributor fitted.

Already have put

- bottom together
- intermediate and crank seals
- breather stuff and seals
- oil cooler seals
- water pump and thermostat + cover + o-rings replaced


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## DtiJ (Jan 14, 2019)

garryt said:


> dizzy spacer ring dimensions= 51.5mm od (top) 44.5mm od (main section) height 12mm. 34.5mm id. and the top locating section is 1.5mm thick:thumbup:


Orange looking thing is gasket or vibration isolator? what material, where it goes (below or above) and what is thickness?


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## DtiJ (Jan 14, 2019)

While I'm waiting for 3d-printed nylon spacer, started doing head

Water outlet also must be solved as new inlet manifold / carb does not have water inlets, but cylinderhead has hole where comes heating for carb. I'll tap threads in it, but should I block it or put flow straight past carb....


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## Butcher (Jan 31, 2001)

Send a picture of the hole you are trying to plug/tap.


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## DtiJ (Jan 14, 2019)

Butcher said:


> Send a picture of the hole you are trying to plug/tap.


If you see picture in message above, it's in very lower right corner below thread pin.


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## Butcher (Jan 31, 2001)

That is not for coolant. I believe that is for the air for the injectors [air shroud fuel injectors]. It would be simple to check where that port goes to.


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## DtiJ (Jan 14, 2019)

Butcher said:


> That is not for coolant. I believe that is for the air for the injectors [air shroud fuel injectors]. It would be simple to check where that port goes to.


It IS for coolant. Does not show much but there's one L shaped water hose coming from original inlet manifold (goes through to manifold to that hole and o-ring in manifold seals it): 

However I didn't remember my new manifold actually has water channel (not direct fit to head though but via barb fittings), so I'm going to use it.
Did some port matching today. Exhaust has lot of material to remove.


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## Butcher (Jan 31, 2001)

The USA never got a lot of carburetors and the CIS had air shroud injectors. So on an injected head, that would be an air port. I will check my head in the shop sometime soon to make certain I do not have my head up my as*.


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## garryt (Dec 22, 2016)

there are no injector ports in that head. so its defo a water way.


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## LT1M21Stingray (Sep 14, 2006)

DtiJ said:


> And for camshaft I think I'm going with 2.0 8v (3A) "G"-marked cam.


If you install a free flow exhaust, get a bigger cam, like a 268 or 272.

Also, it would help us if we know in which country you live.


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## garryt (Dec 22, 2016)

don't want your couch. it would clash with my wallpaper


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## ToddA1 (Apr 22, 2002)

I’m a little late to the party, but I ran a 3A with a JH head. This was about 20 years ago, but I’m 99.9% sure I ran the stock 1.8 distributor, with no adapter ring. I remember it was a very tight fit, and I needed to sand the aluminum distributor, to make timing adjustments possible. 

I think that TT adapter ring is for the ABA block. I’m actually in the middle of a ABA/JH swap, and have that, along with the brother block off plate. You’ll also need to make a block off plate for the 3A, to mount the cpr. 

Like others said, measure the block hole and compare it to the distributor base. 

The bigger the cam you run, the less you’ll need to worry about the compression ratio and pinging.... run the highest octane gas or get a knock sensor ignition box. 

I’m planning on running an old Schrick 280° or TT 288°, which is a Schrick copy.... both of these are on a shelf in my shed, but I never ran the 288°. I just spoke to Collin at TT, and he said to install the 288°, “just to experience it”, lol. He said it’ll make power to 8,000 rpm. 

-Todd


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## DtiJ (Jan 14, 2019)

Little update:

I did manufacture that TT adapter ring from nylon, fits like a glove in 3A. 

Fitted breather pipes from 3A. 

Electrical fuel pump found it's place also.


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## Butcher (Jan 31, 2001)

Using nylon may sound like a good idea for you, but that is a terrible idea. I hope it works for you.


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## DtiJ (Jan 14, 2019)

Butcher said:


> Using nylon may sound like a good idea for you, but that is a terrible idea. I hope it works for you.



How so? It's oil and temperature resistant.


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## garryt (Dec 22, 2016)

you have side loads off the intermediate shaft though. the spacer I have is steel. don't think I would risk the nylon:facepalm:


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## garryt (Dec 22, 2016)

think it came from Poland or somewhere close by. £20 delivered to uk. seems pretty well made too:thumbup:


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## Butcher (Jan 31, 2001)

Just because I think PVC is a terrible idea, does not make it so. There may be other plastics that may work for that situation, but I'm not a plastic engineer.

I think it is worth posting your PVC idea on other sites and see what the response is. Who knows it may be a great idea.


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## vwpat (Oct 25, 2000)

DtiJ said:


> Yes 3A with stock 3A head is 10.5:1 but with swapping head to 1.8 8V it goes to ~12.
> 
> However with "G" cam or 3A stock cam* dynamic* compression is something like about 10,72:1 so it's pretty OK.
> with 276 cam dynamic it's around 10.07:1
> ...


Compression stays same 10.5:1 since both heads have 30 cc chambers.


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## vwpat (Oct 25, 2000)

DtiJ said:


> Inlet valves are 2mm bigger in 2.0 8v. (40mm vs 38mm in 1.8 8v)


Only Carbed heads and low compression hydraulic heads have 38 mm intakes, the rest have 40s.


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## DtiJ (Jan 14, 2019)

Where can I get distributor sprocket that works with 2.0 8v intermediate shaft? Or tell me how to remove it from 3A 2.0 8v distributor. I have heated and hammered but no luck.

1.8 8v dist has too small sprocket, it wont reach shaft when using adapter in hole.


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## Butcher (Jan 31, 2001)

I believe you need to drill the pin holding the gear on the distributor shaft and when it comes time to assembly things, you use a hardened roll pin.


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## DtiJ (Jan 14, 2019)

I got it.

Now I need sensors/switches (full throttle [F81] and closed throttle [F60]) for knock sensor control unit (811907397E). Like old K(E)-jet engines in mk2 golf or Audi 80 (NG etc) had.

I have Golf mk3 2E 2.0 8V intake manifold + throttle body. TPS sensor has only 3 pins. Is there compatible TPS which has maybe idle switch but also WOT switch? Found NISSAN Tps but its very bulky and strange connectors, and not compatible axle.

Am I correct 93-95 ABA has idle switch in TPS ?

Is ABA TPS compatible to 2E throttle body? or Can I fit whole ABA throttle body?


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## Butcher (Jan 31, 2001)

Depends on the fuel system if it has throttle switches or sensor. Usually the more modern/strict the fuel system, the more likely it has a sensor.


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## DtiJ (Jan 14, 2019)

I think im going with 078133154 from Audi A6 C4 V6. Small enough and it has potentiometer and idle switch in same device. WOT switch I'm using from Audi 90 2.3 NG and put it near to throttle cable bracket.

I need potentiometer for Ecumaster Det3+ (controller for injectors)

edit:
fits like a glove. shaft needed little extension.


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