# AEB head question



## Krissrock (Sep 10, 2005)

Hey guys, I'm the proud owner of a used AEB head i picked up off of ebay. I've been a lot of "show" for a long time and I'm really happy to start getting into more depth of the "go" for my car. 

I got the AEB pretty cheap because there are bent valves, and apparently the timing belt went on the car. OK no prob, i would just replace them. 

Upon receiving and inspecting the head, i noticed that there is plastic cam chain. The bottom plastic rail from the tensioner (i assume) was chewed up, and if you look at the pics, the top rail you can see that the chain is wearing through the rail at an angle... 

Now, i'm not gonna pretend that I know much of anything about heads...but is could that type of damage (the plastic in the chain and the uneven wear on the guide) be caused by the timing belt breaking...or could be from some other issue? Is it even possible for these to be misaligned? 










Notice that the guide is thinner on the right side, and the plastic in the chain. 










more plastic stuck in the chain 




:thumbup:Also, I would truly appreciate any suggestion on replacement stuff. 
I was considering the strip/street cams from IE. Anyone have any experience with them? 
I'm not thinking about super high revs, 7k is good for me now, but would it behoove me to get the IE Ti valve train, or just get some new OEM parts? I don't think i want to use the parts off this head as I have no idea how well it was kept. I guess i could transfer my valvetrain...? yay nay?


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## Doooglasss (Aug 28, 2009)

You have a lot of work ahead of you and I'm sorry to say little power to gain on a stock turbo. I'd consider selling that and swapping turbo's before putting a big port head on a small turbo (small turbo as in anything smaller than a GT30).

With a head that age you're going to need to do new valve guides and have the seats cut. Commonly labor on a head rebuild is $650-700 depending on where you go and who you know, parts will be added on top of that. All seals will have to be done as well and as you're looking at now the cam chain tensioner too- You can use the Amazon chinese part for $75 to $100. I'd also do the chain which I've found cheap too.

Sorry, I'm not trying to be such a downer- just letting you know what you're in for and what type of gains you can expect. Plan on spending about a grand to rebuild that head- add what you already spent on it and if that gets you an F23- I'd go with the F23.

Don't forget to add to that cost list a big port manifold or 034 transition spacer.


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## warranty225cpe (Dec 3, 2008)

Yeah, I was about to pull the trigger on one of these too. Im going to spend my money on a JBS knockoff instead, and have it hogged out and port/gasket matched. Should be much more productive in the power dept than the AEB head swap.


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## Forty-six and 2 (Jan 21, 2007)

Also, before counting on any 20v head, pull the cams so you can check the journals. I have bought two different AEB's that were said to be perfect, even pulled from running cars, and both had major journal scoring damage... That is what stopped me from building my motor before all of the sh*t I started on the rest of the car.


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## Doooglasss (Aug 28, 2009)

Forty-six and 2 said:


> Also, before counting on any 20v head, pull the cams so you can check the journals. I have bought two different AEB's that were said to be perfect, even pulled from running cars, and both had major journal scoring damage... That is what stopped me from building my motor before all of the sh*t I started on the rest of the car.


 Yeah these things are all going on 13 to 15 years old now-- they need a major overhaul. Plus the cars they came in were some of the oil starvation / oil sludge issue longitudinal motors. I think they might be more trouble than it's worth after going through this all myself and having a head for sale that is fully finished that nobody wants to spend the money on.


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## Krissrock (Sep 10, 2005)

i knew the head rebuild would cost some money. I'm not even thinking about putting it on for a long time. but it's still nice to have. Since i'm broke, i gotta get my stuff piece by piece. I know i'll need the intake, i'm planning on cams too...it's everything else i'm unsure about whether they need to be replaced or not... and whether or not to get aftermarket or OEM? 

So, so far, i'm looking at: 

1. cam chain tensioner 
2. cam chain 
3. valve guides 
3. cams (IE, anyone have any experience with these?) 
4. valves 
5. seals, gaskets and bolts.. 

I appreciate all of your input...even if it is hitting me in the gut...this is a new territory for me so i want to learn all i can


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## Krissrock (Sep 10, 2005)

Forty-six and 2 said:


> major journal scoring damage...


 i'll see if i can get a pic of these for you... Now all of the bolts, like for the journals n stuff up there, are not reusable correct? Are these stretch bolts like the head bolts?


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## 20v master (May 7, 2009)

Krissrock said:


> i'll see if i can get a pic of these for you... Now all of the bolts, like for the journals n stuff up there, are not reusable correct? Are these stretch bolts like the head bolts?


 All bolts are stretch bolts technically, but the torque is so low on the cam cap bolts that you'll be fine reusing them.


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## Marcus_Aurelius (Mar 1, 2012)

What's the goal with the big port head though? If Aaron has similar/better results on a small port with improved transient response, I can't put my finger on what you're trying to achieve going this route.


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## Forty-six and 2 (Jan 21, 2007)

Max is correct. I have read guys with small port builds, making great power, switching over to a big port, in hopes to squeeze out a little more. Only to switch back to the small port due to drivability issues. Small ports will flow plenty. If you are going for a dyno king, big port makes a lot of sense, but probably not worth the trouble for a powerful street driving car.


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## 20v master (May 7, 2009)

Marcus_Aurelius said:


> What's the goal with the big port head though? If Aaron has similar/better results on a small port with improved transient response, I can't put my finger on what you're trying to achieve going this route.


 What were his exact results? Were there comparison dynos with no other changes? How much transient response is involved in drag racing?  While Aaron is obviously after every HP, he doesn't document things very well, and I'm not going to id=27 to try and sort through his posts. Does he still post at all? Anyways, flowbench results between small and big port heads shows a clear difference, but like said, total max flow isn't the only criteria that we use to judge if upgrades are worthwhile, but I never had any driveability issues with AEB's and I certainly would want one over a small port for anything over 400hp.


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## Krissrock (Sep 10, 2005)

from my understanding, ( i coulda swore i read on here) that even a ported small head doesn't flow as well as the AEB head because of the lack of room to port out. i don't doubt that they could be close though. 
My goal of course is a power increase for my long term/big turbo plans... 
i'm not worried about what gains i would see in my current form. 

I thought it was common knowledge that an AEB head was a good item to increase flow (with corresponding intake manifold of course)


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## 20v master (May 7, 2009)

Krissrock said:


> from my understanding, ( i coulda swore i read on here) that even a ported small head doesn't flow as well as the AEB head because of the lack of room to port out.


 No, the small port castings don't have enough material to port out to throat of the ports to AEB size. If you aren't concerned with immediate gains, and are going to install a bigger turbo in the future, then go ahead and run the AEB. You won't suffer or lose anything. To me, without quantifiable results, it's a removal of restriction from the entire intake tract, from filter to valve face. The larger ports allow more flow and less resistance. Obviously, intake charge velocity you don't want to suffer, but the AEB isn't so much bigger than small ports that that happens.


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## Marcus_Aurelius (Mar 1, 2012)

20v master said:


> What were his exact results? Were there comparison dynos with no other changes? How much transient response is involved in drag racing?  While Aaron is obviously after every HP, he doesn't document things very well, and I'm not going to id=27 to try and sort through his posts. Does he still post at all? Anyways, flowbench results between small and big port heads shows a clear difference, but like said, total max flow isn't the only criteria that we use to judge if upgrades are worthwhile, but I never had any driveability issues with AEB's and I certainly would want one over a small port for anything over 400hp.


 I quoted Aaron's numbers below (if that's even usable by us, the OP, or others with less wild setups). The transient response comment was a generalization from other swaps I've seen that left people not very satisfied with response down low after the conversion. There is also that guy that did a swap, same day, on a 3071 and gained 3 WHP with a slight lost of TQ (looked for the thread but couldn't find it). Another real example is Matt that post here sometimes, he "upgraded" to an AEB and then went back to a SP head... or Doug at FT that did not gain any measurable MAF increase or power gains from the swap. 

I'm not saying that a big port can't be optimized, and flow numbers on a bench suggest a clear improvement, but most of the straight swaps I've seen didn't provide any gains to be worth the effort. I am no expert and have not tried it personally, but my take is that although flow is improved, the velocity is also reduced when going to a big port making it a compromise that may not be worth it to a great range of setups. 




Powdered Toast Man said:


> ... always have made more power/less torque on the PORTED AWP.
> 
> 82mm bore x ported AWP x stock sized valves = 592 AWHP/434 WTQ.
> 
> ...





Powdered Toast Man said:


> for the first two motors that i ran an AEB block with.
> 
> and again, now i am 480wtq and 648 AWHP on the worked AWP head all things the same.
> 
> ...


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## 20v master (May 7, 2009)

Yeah, you can't draw many conclusions from that data. Different displacement, different sized valves and cams, ported vs non, compression ratio changes, different fuel types, all adds up too many variables to isolate conclusions. Like I said, 400 and up for me = big port if I'm dealing with a 1.8T. Obviously, others have different experiences from mine, but I never had a problem with low end response. Also obviously, throttle size, IC core and piping layout/size, intake manifold design, etc all factor in to it. Any AEB I've ran had either an 007 intake mani or the SEM unit, with 75 or 80mm throttles, and my throttle response was "woken up" a lot when I installed the head and intake mani. The mani may have been the bigger contributor, but I had no problems making good power (for the platform at the time) with relatively lower boost numbers compared to other setups, and never thought my throttle response suffered. I wouldn't say MAF numbers are going to be a clear indicator, especially if you're not really pushing the turbo. You wouldn't see much difference in the MAF on your setup with 1 psi lower boost, but the AEB may have allowed the same flow rate at 1 psi less boost compared to the small port head. Basically, bigger isn't always better, and we don't know. That said, efficiency, whether mechanical, thermal, chemical, etc, is all we are after, and a slightly (relatively) larger port size isn't a bad thing from a conceptual stance.


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## Marcus_Aurelius (Mar 1, 2012)

I agree that larger port sizes isn't a bad thing from a conceptual stance... but so is keeping velocity high, and especially on such a low lift and duration motor as the 1.8t (even upgraded, it inherently shows relatively low practical ceiling). I think it could be argued both ways as your personal comparisons had variables that must have impacted the response and possibly counteract or even mask the low end losses reported by others (you said it yourself, you had other changes such as throttle body plate increases, manifold upgrades etc. all I them things that would have substantial impact on response even if they were done to a small port head). As it sits, the few apple-to-apple comparisons (with no big variables like Aaron's tries or yours) have not been promising... and I've yet to see a true swap without a crapload of variables that shows anything to show the contrary. 

As I said, anything can be optimized, you did so with a big port, Aaron made it work to his advantage with a small port and he's way above that 400 hp threshold that vortexers like to toss around. Until there is true data that proves apple-to-apple improvements from SP to BP, people are shooting in the dark and the results should be expected to represent just that. All I know is that I won't blindly go swap a BP on my car on good faith and gamble on unproven results... but to each their own :beer:


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## Krissrock (Sep 10, 2005)

thanks for the discussion. :thumbup: 

I'll have no issue getting another dyno run once I get everything on (head, cams, mani, Throttle body)...but as you guys have said, without a big turbo, results aren't to be expected. I know that would be 4 changes, but I don't mind keeping a dyno diary for changes I've made. i'm always curious to see if anything changes. it's all a learning process 

would u two happen to have any insight on the uneven wear on the tensioner guide? do you that damage could have happened at the time of the timing belt break? 

and 

Do you have any recommendations on valvetrain or should I keep it stock since I'm not looking for super revs?


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## 20v master (May 7, 2009)

The reason there is no good comparison is because of the throttle sides also. You can't dyno a SP vs BP without changing the manifold, so do you do a baseline with OEM and SP and compare to aftermarket and BP to extract head benefits only. You have to consider the whole system, as you know by optimizing everything from filter to throttle, though I still think there are nice gains for your setup to be had with Mani and throttle upgrades. The point remains that the gains seen on a flow bench and from my comparison of the intake manifolds is that going to a large port setup can not hurt total flow. Velocity will remain high due to the small lift that you say needs the velocity. There's only so many ways to increase head flow. Bigger valves, bigger cams, or to remove other restrictions. My point of my experience was that I had no negatives associated with making the change on my GT30 and 35 setups, which was removing restrictions. I have both the SP and BP SEMs and both heads. Would that be a good comparison to draw conclusions about port size from? I have a few sets of head bolts around, maybe I need to order a head gasket.


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## Krissrock (Sep 10, 2005)

20v master said:


> The reason there is no good comparison is because of the throttle sides also. You can't dyno a SP vs BP without changing the manifold, so do you do a baseline with OEM and SP and compare to aftermarket and BP to extract head benefits only. You have to consider the whole system, as you know by optimizing everything from filter to throttle, though I still think there are nice gains for your setup to be had with Mani and throttle upgrades.


 true, i'm not really trying to see the gains of each individual part. In blocks I guess. I don't have the money or time to dyno after each thing. but i don't mind getting a dyno after I do a couple things, or a couple things that work in concert. 
Just as I did with the headers n down pipe. 
But yes, you're right, there's no way to extract the head gains alone w/o doing a back-to-back of just the head.


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## 20v master (May 7, 2009)

Krissrock said:


> would u two happen to have any insight on the uneven wear on the tensioner guide? do you that damage could have happened at the time of the timing belt break?
> 
> and
> 
> Do you have any recommendations on valvetrain or should I keep it stock since I'm not looking for super revs?


 The plastic/phenolic guides are what usually wears. With the age of these motors, I doubt it had anything to do with the timing belt breaking. Unfortunately, the guides aren't available seperately. 

If you aren't planning on doing cams/springs, at a minimum I'd do aftermarket exhaust valves if the budget allows. Dropping a valve sucks.


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## Doooglasss (Aug 28, 2009)

(without sounding too critical) I find it interesting you state to have low funds to spend but want to chase down a multi thousand dollar head project (labor, oem hardware, aftermarket cams, aftermarket valves, intake manifold, throttle body upgrade it sounds like, possibly installation labor if you're not DIY'ing). The most dollars to power upgrade ratio after software would definitely be a turbo upgrade - I still think you should go that route. Just sharing my opinion.



Krissrock said:


> Do you have any recommendations on valvetrain or should I keep it stock since I'm not looking for super revs?


 Like Adam said - aftermarket exhaust valves at a minimum.

To support Max's argument for the SP head I've met a few guys not on Vortex, one with a 2.4L custom built 1.8T w/ SP and a HUGE GT40 making serious power in an unconventional way (2.5" DP to decrease spool w/ expansion chamber & SP was kept to keep spool low). Also a S372 on a SP making big power again. Both AWD TT's.


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## 20v master (May 7, 2009)

There's been big power made on both. What is "serious power"? Just because they exist doesn't mean one is better than the other. Were they able to quantify how much spool was helped? This is sort of like the old 1.8T debates about a 3" DP/TBE causing a "loss" of low end torque. If the turbo is spooling sooner, how are you losing torque at any point in the RPM range? To me, if the port size flows more, it's a removal of a restriction. Quantifying it obviously isn't easy to do, and I suffered no loss of throttle response or increased lag from going bigger. Doug, were your built heads small or big port or both in your build over the years?


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## Krissrock (Sep 10, 2005)

DougLoBue said:


> (without sounding too critical) I find it interesting you state to have low funds to spend but want to chase down a multi thousand dollar head project (labor, oem hardware, aftermarket cams, aftermarket valves, intake manifold, throttle body upgrade it sounds like, possibly installation labor if you're not DIY'ing). The most dollars to power upgrade ratio after software would definitely be a turbo upgrade - I still think you should go that route. Just sharing my opinion.


i don't have the money to get this together right now...i can get things slowly over time, and i don't see anything wrong with that plan. are we ever "finished" modding our cars? 

going big turbo would require a lot more money. 3-4k for the turbo kit itself...+ another $800 for rods...I spent $200 on this head...i'll spend maybe another $1-2k (hopefully) in other parts before i can put his head on...
I am a DIY'er...I've done everything to my car except for my cat back exhaust. I'll do what i can, but i also know what's over my head...that's why i am here to gather information for you guys:thumbup:


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## Krissrock (Sep 10, 2005)

Forty-six and 2 said:


> Also, before counting on any 20v head, pull the cams so you can check the journals. I have bought two different AEB's that were said to be perfect, even pulled from running cars, and both had major journal scoring damage... That is what stopped me from building my motor before all of the sh*t I started on the rest of the car.


well... here you go. 
I started to break down the head. I don't know why in the world audi uses bolts with such short head. I had 3 cap bolts that refused to come out. The cam tensioner was completely destroyed. There's plastic all in the area under it. A metal part of the lower guide is bent and cracked. but that was just sitting in the head anyway... i forgot to get a pic of that. 




















out of all the caps, there were 3 that appears to be scored. Two were the caps right behind the tensioner. The cams weren't. but i'm not using them anyway. I don't recall seeing any scoring on the head itself. 



I'm assuming its not recommended to use the caps from my main engine (even if they're completely fine). So can OEM caps be purchased or is aftermarket the way to go?


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## Krissrock (Sep 10, 2005)

looking around, i see more recommendations to get used caps over new...so i guess i'll swap mine in there when it comes times...

since i only need to replace a couple caps, i guess it would be best to do the used one. 
if i were replacing all of the caps, i guess new would be better.


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## 20v master (May 7, 2009)

You can't purchase caps seperately. They're line honed with the head and as such are unique to the head. All documentation will tell you that you can't mix and match caps to a different head. However, I've done this without an issue, but that doesn't mean you wouldn't have an issue. If the caps are scored, how are the journals in the head where those caps were? They should match. You might want to consider having a machine shop look at this head before continuing.


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## Krissrock (Sep 10, 2005)

i don't recall seeing scoring on the journals. 

but i'll look when i get a chance. 

ok, so i get the line hone...i think saw a video o' that recently actually. 

i'm assuming they'd have to do some measuring of the cams and caps to see if theres enough space to hone/polish them ...?


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## Chickenman35 (Jul 28, 2006)

Krissrock said:


> i don't recall seeing scoring on the journals.
> 
> but i'll look when i get a chance.
> 
> ...


Line honing involves machining a small amount of material at the parting lines of the cam shaft caps and cam journals on the head. The result is that the hole is now slightly oval and undersized. You then assemble and torque the caps to the head and line hone the assembly. Result is that bores are now, round, in line and with new surfaces. Same procedure used for Crankshaft Main Bearing caps/block and Rod big ends.

Let a machine shop determine if caps can be line honed. They should be able to give you a yes or no almost immediately.

Edit: From the pictures I'd say it's probably no problem. You could probably even clean them up ( Polish ) with some Crocus cloth. They don't really look that bad. Camshaft journals are a rotating load only, and " relatively " insensitive to clearances ( < .002" enlargement ) and minor scratches. I've seen worse damage to cam caps repaired with polishing. It's ghetto..and not a preferred method...but it can work. 

Just be sure that you don't run too thin of an oil if you decide top polish caps. Nothing under a 5w-40. A 10w-40 would be preferred.

Edit: Mind you, polishing caps is a Finesse type of thing, not for the inexperienced and it is a Ghetto fix. *If you're going to be sinking some money into this head to make some power, do it right and have a machine shop line hone the cam bores.*


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## Krissrock (Sep 10, 2005)

thanks for the info. :thumbup: I've been learning a lot about cylinder heads, but this is something I wouldn't attempt to fix myself. 
I've already emailed my fabricator who also works for a restoration garage to see if they can look at it, or recommend another shop.


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