TheSamba.com :: View topic - Audi AAN 5-cyl Conversion ??

Thu Mar 18, 2010 10:14 am

The audi aan engine has been brought up a couple times in past conversion threads, but has anyone completed one. I've seen a couple engines floating around, bar carriers and the bell housing are also available. I'm intrigued by this conversion, and it could be Ca legal. Its a tight fit for the engine lid but so is the 1.8t. Is there some super obvious reason, this engine isn't used ?

Thu Mar 18, 2010 11:51 am

Hmmm lets see. The AAN was only in the s4 and similar S6 (though a different engine code I think)
Even a engine with 200k miles still sells for almost 2k, then it would need to be rebuilt.
So most of the engines out there have a lot of miles on them already, and still cost a lot. Then there is the cost of the parts, like the bellhousing and support bars. The last bellhousing I saw for sale was $600.

I figure $4000 investment and you'd still have to rebuild the engine, re-gear the trans, etc.

Probably one of those $8000 conversions in total, and that's doing it all yourself.

The reason you don't see more, is there isn't 49 different aftermarket places peddling the conversions like the subaru conversions. Less support in general.

but if you'd ask me, I'd much rather have the AAN over any Subie lump.

Thu Mar 18, 2010 12:41 pm

I have run across two 5 cyl. conversions that were completed.
It is a smoother running engine with a lower end closer to the
wbx. One had a carb and the other fuel injected. Both had
raised engine lids and were passenger vans.They were both
home brewed jobs.
The raised engine deck was a turn off for me.

I had a Tiico in my 87 syncro and put 50k miles on it before I
sold it. It was great for reliability and great highway cruizing,
but I was very disapointed with the low end power.

Thu Mar 18, 2010 1:09 pm

I saw one in the for sale in the Samba classifieds recently. Runs and drives. I too was interested at one point but then decided when the time comes to most likely go Subie. Right now I am too poor and am running my personal built 2.2 WBX.

Thu Mar 18, 2010 1:23 pm

There's a guy on the board here with a 3b powered syncro, I think he made a custom adaptor plate though.

A 3b is like a AAN but has a distributor for ignition, and is not COP/crank fire ignition.

search for posts from mcsyncro

Thu Mar 18, 2010 2:49 pm

skyboy wrote: The audi aan engine has been brought up a couple times in past conversion threads, but has anyone completed one. I've seen a couple engines floating around, bar carriers and the bell housing are also available. I'm intrigued by this conversion, and it could be Ca legal. Its a tight fit for the engine lid but so is the 1.8t. Is there some super obvious reason, this engine isn't used ?

The AAN and 3B are great engines, but they are just too rare, high mileage, and expensive to ever become a common conversion. With Subaru WRX (227hp) and STI (300hp) engines that are plentiful and fit the engine bay well, it becomes hard to justify doing an Audi turbo conversion. Still, I'm pretty much an Audi purist aside from Vanagons, and I'd gladly do an AAN conversion if all the right parts opportunities arose.

Definitely, check out MC Syncro's build thread on here. He did an amazing job on he 3B conversion. He even managed to make it clear the lid.

David

Thu Mar 18, 2010 3:40 pm

Its was mcsyncro's original thread that got me thinking about an aan conversion. The svx engines are cheaper, but the engine carriers and bell housings cost about the same as the 5cyl conversion; hence it got me thinking. I'm curious about how to plumb the turbo and if any cutting is needed inside the engine bay. Carb legal exhaust may also be a problem in California, but I keep thinking if a svx can pass smog, an aan should pass. Thank you all for the info.

Thu Mar 18, 2010 4:18 pm

I've done and still drive my syncro with a 7A N/A in it. It fits under the deck lid and goes pretty good. Used all the part from SA. I do have to make note I have a special affinity for the 5 cyl motor. maybe not the best choice for everyone, but for me it's bliss.

It is definitly a "passion over convention." Without a turbo the 5 cyl has a tendancy to drone a little on the freeway and has a heavy growl under throttle. It is not my primary van driver, but for a good time and a unique van driver it's a hoot. My wife would like me to sell it, however I just turned 40 and my midlife crisis car/vanagon is already done and I don't have to go shopping.

happy to answer any q you might have via PM.
MC

Thu Mar 18, 2010 6:15 pm

I have an Audi S4 with the AAN engine and also a 1986 Syncro westy and also an SVX attached to my engine stand. I was in fact searching for a while for an AAN but couldn't find one close to me nor find the adaptor/bellhousing and I was (then at least) in a hurry to convert.

Having the AAN in my Audi is what made me want to use it for conversion. The pluses:

1. It's only 2.2 litres and at low throttle, gets great mileage;

2. It's absolutley bulletproof when stock and very sturdy when boosted and refueled up to 400 HP. Not that anyone with a Syncro trans would be so stupid to use such power! It's jsut a measure of the reliability.

3. These engines are extremely long-lived and are seriously overbuilt. I did a compression check on mine in 2008 and my compression tester accidentally dumped a tiny ball bearing (from the check valve) in number three cylinder, which caused piston-to-head contact on start up. So I had to remove the head to deal with it. The cylinders still had the cross-hatching and cylinder wear was virtually not measurable. So I put in new exhaust valves, had the old intakes and the exhausts ground and the seats ground, decked the head 0.010", and buttoned it back together with ARP studs. There was no valve guide wear - - the old silicon-bronze guides were re-used. This was all at 220,000 km (which equals about 140,000 miles). Theses engines use the "cup" style lifters used in all Audi engines which limit valve stem and valve guide wear.

4. The power is phenomenal. Audi developed a boost-control map that gives almost no turbo lag and flat torque from 1,800 rpm to 6,000 rpm. It feels like a naturally aspirated engine until you floor it. At 3/4 or more throttle, the boost map adds in "overboost" for 18 seconds - - not something you can use on long mountain passes, but good for passing. Then boost goes from 11 or 12 PSI to, IIRC, 18 PSI.

5. The bellhousing is not that hard to find anymore. There's a vendor on the Samba and EuroPrice also sells them.

http://www.thesamba.com/vw/classifieds/detail.php?id=721148

6. The plumbing would not be that bad, I think. The stock airfilter box could fit on the driver's side in the engine bay and supply the turbo. the Turbo compressor outlet can be clocked, but points straight down in stock form.

7. The stock intercooler could fit diagonally installed in the passenger side area where the stock syncro air filter resides.

8. The oil cooler is air-to-oil and thermostatic (best approach, in my opinion) and the lines are long enough to locate it in the driver's side air stream.

9. The AAN has no distributor, so it would be shorter in height than the 7A or 3B engines and have less interference with the firewall.

10. So far as I can tell, the wiring harness is easier to unravel and transplant than my SVX harness (thanks Tom Shiels for my SVX harness).

11. The geeks like me who own these Audi URS4's and URS6's are fanatical about maintenance and all tend to run synthetic oil and keep scrupulous records.

12. Many, many owners upgraded their turbos to larger ones. Many stock, perfectly good stock K-24 turbos are available for very low prices.

13. Although they are not conversion groups, there are a number of excellent S-car groups that share useful info on these engines and there are lots of parts on Audifans.com See

http://www.audifans.com/marketplace/browse.php

14. A good part of the stock exhaust system caould be used, esp. the downpipe, which is designed to clear the drive Audi drive shaft located in the same spot as the Vanagon drive shaft (with a muffler-forward configuration).

15. My main reason: I want to see someone do what I was dreaming of doing.

Thu Mar 18, 2010 6:33 pm

Howesight wrote: 15. My main reason: I want to see someone do what I was dreaming of doing.

Wow, this is what I love about TheSamba. I have five of these 5-cyl engines (4 in Evs, and one AEL 5-cyl TDI that I plan to put in my syncro some day, and I have the SA bellhousing), and I think they are great, but I don't know the AAN so I have nothing to say about that. But then, out of the blue, here is a post that gives 15 good reasons why one should consider it. I just love these posts that have so much information (unlike this one of course).

RonC

Thu Mar 18, 2010 6:39 pm

if i could afford the fuel i put in my wbx syncro i'd go with a AAN, but i can't so I'm going TDI. I LOVE LOVE LOVE the Audi 5 cylinder (Car wise the 4kq)

Thu Mar 18, 2010 6:48 pm

Sell me your SA bellhousing______________Please. [-o<

Thu Mar 18, 2010 7:28 pm

there is one on ebay

Fri Mar 19, 2010 6:06 am

onwardtothestars wrote: there is one on ebay

Yup -- those would be surplus from the Parts Place -- that is where I got mine. Those are genuine VW South Africa OEM parts. Says he has 10, and that Buy It Now price is a fair one.

The picture doesn't show the clutch side, but mine included the cross-shaft and throwout bearing.

RonC

Fri Mar 19, 2010 9:04 am

What flywheel do/did you use with that 5cyl Bellhousing?

and their earlier photos showed w/o a cross shaft, and they wouldn't answer my inquires about that.. as I didn't want to have a 3/4 usable part on that much $$ investment.

and yes the 5cyl Bellhousing is the TIP of the CONVERSION ICEBURG, you have to be a DIY kinda install/fabricator for these.
we have ~5k miles on my brother's 5cyl Turbo running on Megasquirt engine management mated to an automatic with a custom machinist adapter plate.

snowsyncro wrote: onwardtothestars wrote: there is one on ebay

Yup -- those would be surplus from the Parts Place -- that is where I got mine. Those are genuine VW South Africa OEM parts. Says he has 10, and that Buy It Now price is a fair one.

The picture doesn't show the clutch side, but mine included the cross-shaft and throwout bearing.

RonC

Fri Mar 19, 2010 9:22 am

danfromsyr wrote: What flywheel do/did you use with that 5cyl Bellhousing?

I guess a flywheel meant to be used with a 016/013 equipped audi (pre 88)

Fri Mar 19, 2010 9:24 am

skyboy wrote: The audi aan engine has been brought up a couple times in past conversion threads, but has anyone completed one. I've seen a couple engines floating around, bar carriers and the bell housing are also available. I'm intrigued by this conversion, and it could be Ca legal. Its a tight fit for the engine lid but so is the 1.8t. Is there some super obvious reason, this engine isn't used ?
I considered this swap as well. However considering i got a great deal on a 1.8t i went that route. Believe me raiseing the deck lid aprox 1.5 inches is no big deal.

Sat Mar 20, 2010 8:20 am

danfromsyr wrote: What flywheel do/did you use with that 5cyl Bellhousing?

and their earlier photos showed w/o a cross shaft, and they wouldn't answer my inquires about that.. as I didn't want to have a 3/4 usable part on that much $$ investment.

and yes the 5cyl Bellhousing is the TIP of the CONVERSION ICEBURG, you have to be a DIY kinda install/fabricator for these.
we have ~5k miles on my brother's 5cyl Turbo running on Megasquirt engine management mated to an automatic with a custom machinist adapter plate.

snowsyncro wrote: onwardtothestars wrote: there is one on ebay

Yup -- those would be surplus from the Parts Place -- that is where I got mine. Those are genuine VW South Africa OEM parts. Says he has 10, and that Buy It Now price is a fair one.

The picture doesn't show the clutch side, but mine included the cross-shaft and throwout bearing.

RonC

OK, sorry if the cross-shaft comment has created some confusion. Mine came from the Parts Place and has the additional parts. I maybe incorrectly assumed they would all be the same.

About the flywheel, I haven't done the conversion yet. The 5-cyl TDI engines that came from the Parts Place came with the Audi dual-mass flywheel. I think most of the conversions done with those engines have used this flywheel, but I do recall a thread about using a conventional Audi gasser flywheel. That might have been Mike Ghia's conversion in the UK. The use of dual-mass flywheel is controversial. To me, from an engineering perspective it makes sense, but I think the problem might be early failures of the dual-mass mechanics. Or maybe it is resonance outside the tuned rpm range? I really don't know.

The 5-cyl TDI (AEL) can be a transmission killer -- this still makes me nervous. I don't know if I have the patience of someone like Alaric H.

RonC

Sat Mar 20, 2010 3:51 pm

Use the duel mass much kinder to the trans. T he tdi fits under the deck with out mods. I have had my trans out and apart 4 times and it check out great every time with 30K on it the G&R slider seems to be fine now I am driving to AZ from VA so I will find out.

Sun Mar 21, 2010 8:34 am

Wow, 3 days later and only one left. I thought I'd have a little more time to think about the conversion, but I bought one yesterday just incase. I guess its time to start collecting the rest of the parts. Either next year I'll have a nice conversion or I'll be selling parts on the samba for someone else to complete the dream.

snowsyncro wrote: onwardtothestars wrote: there is one on ebay

Yup -- those would be surplus from the Parts Place -- that is where I got mine. Those are genuine VW South Africa OEM parts. Says he has 10, and that Buy It Now price is a fair one.
.......
RonC