Audi 3.6L V8 PT Custom Build

[CaptAmerica]

I am creating this thread as a record for myself on this project that I am attempting and also to hopefully delve into the knowledge and experience available on this forum. I have been wanting to build a four wheel vehicle for awhile, the overall vehicle idea is still undecided (bouncing between some sort of 2 seat super car, or an open wheel/closed cockpit red bull X2010 single seater. I am a big formula 1 fan and wanted to use a small V8 engine and the 3.6L Audi fits right into what I wanted, has the added benefit of the 01E FWD transaxle from europe mounting right to it, and I was lucky enough to find one for sale nearby on eBay for $375. The engine arrived condition unknown covered in dirt and grease and attached to an automatic quattro transmission. I gave the A/T transmission to a local shop as I have no room to store it or reason to have it, then started to work on the engine tear down.

During the dis-assembly I made the mistake of knocking the pistons out of the bores with 3/8" extension using a rag to stop from damaging anything, instead of something wooden or plastic. Unbeknownst to me as I was knocking out the third piston the rag tore and extension became wedged between the piston and the side wall. I noticed during my inspection after removing all the pistons that there was a bunch of nicks in one of the bores and pieced together what happened. I was up in the air on deciding whether I would go for a twin turbo build and sleeve the motor or just make sure everything looked good and rebuild it stock to try and keep costs down. This mistake forced my hand so now I am headed towards making some sort of TT monster, hopefully in the 500+hp range.

I found a couple things of note during the disassemble process. First, just after the removal of the water pump and the thermostat I noticed that the coolant ports in the engine have no corrosion and looked brand new, the coolant was a darker green blue then anything I have ever used so I need to track down what that was. Second, the head had a couple of, what I now know are, oil drain ports completely clogged with spongy carbon/oil build up. There didn't seem to be any damage or overheating anywhere though so that was a positive.

Engine as it arrived:




My work shop (apartment garage)


Disassembly cylinder issues:


The heads were completely taken apart and refreshed at a local shop who took their sweet time, luckily I am not in a time crunch, but did it for a very reasonable $350. The heads were decked 0.002" according to the shop, this will cause a minimal change to compression but I think its negligible.

Engine as it sits currently (for storage everything is just hand tight):


As with all my projects I am creating a 3D CAD model of the whole thing to assist in the fabrication process. This time I felt it was important to not only have a good engine exterior model but to also have all the internal dimensions in case I want to make mods later when the engine is put together and know what I am walking into. Currently the engine is modeled as it is, no sleeves or smaller bore size. The intake and exhaust ports are not real life, they just look good and ended up being rather easy to make which I didn't expect. I have modeled all the internal oil and coolant ports so I have a really good understanding of how the systems work, which is nice because they are rather complicated.

Current 3D Models



Current Issues/Need advice from those with experience:
-Really need to sort out finding replacement crankshaft bearings, Audi OEM seems to have stopped supporting this engine as its almost as old as me. I am hesitant to move forward with the block sleeve operation without having my hands on a new set of crankshaft bearings. If anyone one here sees and knows about cross compatibility of newer 4.2 crank bearings that are still available please let me know if that is out there.
-Need to put together a flywheel for the 01E transmission, I tossed the flexplate before I realized I needed it and that flywheels weren't commonly available for this application, worst case I buy another flex plate and get the 034 flywheel add on.
-Need to sort out whether I am going to get new pistons and knock down the compression of the engine or just not go crazy with the boost pressures, the cost here is probably in the $1000 range and if I do that I am going to knock the bore from 81mm down to 80mm to allow for thicker walls/sleeves and drop the total displacement to 3.5L which sounds better to me.
-Long term I would like to know what its going to take to swap over from the distributor ignition to coil overs and which models are cross compatible.
-There is a lot more here but at the moment nothing major is coming to my head.

Cheers,

Andrew

Shameless plug of my other project that is now completed.
http://reversetrike.proboards.com/th...-trike-project

[MagnaFlow]

Now that's an ambitious project! I've had a friend dreaming up the idea to build a hillclimb car based on an old Formula Vee chassis and a built TDI engine and this is the same kind of notion. I'd love to see this beast screaming up the Tail of the Dragon or Mt. Washington when you get it to full tilt. Good luck!

[Cacti]

This is sick, keep posting updates. As far as bearing go, have you tried anyone in the UK or Germany. Alot of parts are available over there just need to be willing to take the time to find them.

[UroTuning]

Ok this is really cool. Cant wait to see whats next.

[CaptAmerica]

I realized it has been two months since I first posted, I haven't said much because I still have no source for the bearings but I am slowly tracking down different leads that I have gotten, none have been fruitful as of yet. My current focus is the second gxsr 1000 powered reverse trike I am building, one for the masses if they so choose to build it from my designs. I have also had a recent set back with the local fire marshal finding out that I was violating all sorts of building fire codes by making lots of sparks in my chassis building efforts, they found out because I was out working when they came down my road responding to a medical emergency up the street, curious firefighter eyes looked into my "shop" and then reported me I guess. Either way things are slow moving forward, once this project becomes my main effort this thread will see a lot more updates.

EDIT
During my search for new crankshaft bearings I looking into Clevite making me new ones and found that they get their bearings coated by one of two shops in the US, conveniently one of those shops H.M. Elliot Coatings, is located in driving distance from where I live. I went by and talked to the owner about my issue and after looking over the bearings he advised me that there was nothing hugely wrong with them that coating couldn't fix. So now I have my bearing situation figured out with re-coated bearings and it only cost me $35 to boot. On to buying steel sleeves for the block from LA sleeve when I have the money available.

Andrew

[CaptAmerica]

April 2016

Slowly moving forward, I had two main issues that I wanted to sort out before I started dumping any sort of real money into this engine. The first one was the main bearings which was solved with the recoating process, the second one was finding a replacement flywheel which has now been done. The motor came with an auto trans and a flex plate, which in my haste to clean up the garage and the excess crap that came with the motor, including the transmission, I tossed it. That ruled out buying the 034 motorsports bolt on flywheel for $350 and attaching to the flex plate unless I went and found a new one which seemed hard awhile back when I first started looking because the 10 bolt crank didn't seem to be common. I am also bad at searching for these sorts of things for some reason, I usually roll craiglist and ebay and if it isn't there I move on.

In February I came across TTV industrial out of the UK which happens to make new one piece flywheels for the ABZ Block/01E Trans match up for both the 8 and 10 bolt crank as well as many other flywheels. I contacted them and even though it was a bit difficult to communicate quickly with the time difference a purchase was made for ~$550 for a flywheel, shown below. Its quite nice and matched the crank perfectly, even though it should, buying from overseas from someone that you've never met and never heard of, besides some quick forum searches, is a bit stressful especially when they are saying that the usual way to pay is a bank transfer, since its cheaper then using paypal. I paid through paypal, cost me $25 extra, but I wanted to make sure I had recourse in case they made off with the money and never spoke to me again. That being said, Ben Crisp, my contact with TTV was very helpful and made sure everything went smoothly. The flywheel is all metal, weighing in at 11.5lbs, the CAD model I made matched perfectly to the CAD crank first time out, I expected the measured metric bolt pattern to be off by 0.1mm just by chance difference in measurement when modeling them completely separately, but they were dead on the first time.




Next up is the motor cylinder sleeves from LA sleeve 3/32 wall ductile iron (non-flanged) $100/ea times 8. Block machining, sleeve placement, and decking at $800 (quoted). The new low compression pistons are an unknown at the moment but I am hoping to get them for about $100 a piece, possibly my own design. All said and done I expect sleeving with new pistons to cost ~$2400. Most of my money is going into my other vehicle projects at the moment but this is slowly moving forward as I find the pieces. Not sure if its going to be possible but I am going to try and get some milaged out indycar turbos from the indycar team that I work near, as I have contacts there, I think they will be in the ballpark flow wise (2.2L at 12k rpm vs 3.5L at 7k rpm), we shall see.

[thierryfabrice1]

subscribed!!

[forcefed7]

Definitely subscribing to this one. Very cool stuff indeed.

[CaptAmerica]

September 2016

Finally had some time and motivation to jump back on this project. Got the Main seal plate on the back of the motor modeled as well as the oil pan baffle and hopefully in the next week I will spend some time getting the oil pan done. While having a perfect engine model isn't super useful in every aspect, its cheap and it feels like I am getting something done, all about forward progress. I also threw together a header concept with a T28 turbo model I found on GrabCAD, not the highest of quality model but it would work for size and space constraints, the turbo size is also far from decided but I have a friend who does a lot of turbo work to lean on for engineering theory when that time comes. I am still undecided if I should go with smaller pistons (80mm or OEM 81mm) and thicker steel sleeves 1/16" or 3/32". I suppose I don't know enough to make the call here but I am planning on buying new pistons to go with the new sleeves of either size. At the moment I feel like i just have a pretty engine model and some dreams about what the car should look like (and even that seems to change weekly).

[CaptAmerica]

October 2016

I little bit of progress this month, the big news being that I purchased some used indycar turbos through a local distributor (SRI), shout out to Jbear who gave me a killer price on four of them. Your probably wondering why I bought four, only need 2 for the project, but as I don't know their current condition i wanted extras that I could swap in without getting stuck with the full price of a new one, plus the cost of a new Borg-Warner EFR 58mm turbo is ~1800 which is about what these all cost me. The other bit of actual work involved working with a good friend of mine who is helping me with the header design and we noticed the alternator and the starter are going to be in the way so I needed to model them and get them in there so we can make sure that the headers miss them. So I took the starter apart, been working on cars for the last decade and never really knew what the inside of the starter looks like, now I do.


A gaggle of turbos!


In their prior life.

[themadscientist]

This is an awesome project. What made you go with the 3.6 V8 instead of any of the other Audi V8s?

[CaptAmerica]

Madscientist,

I chose the 3.6L because I wanted the smallest 90 deg aluminum block v8 I could find, with a reasonable price. In this case the engine is actually pretty rare or at least seems to be, it's existence became known to me about 10 years ago when I found one in a junk yard, I didn't know what it was, went home researched it, came back two days later to get the engine and the yard had crushed the car. Another big part of the decision was the availability of the FWD E01 transmission from Europe that's is a direct bolt on. That being said finding parts is a pain since I don't actually know what differences there are to the 4.2L.

Another option was the 3.0L Ford Taurus SHO engine, steel (aluminum*) block, designed by yamaha, but I was already into this engine quite a ways but it will probably be the next engine I build if such a day ever comes.

Only downside I have found with the audi designwise is the engine is undersquare, bore over stroke, which makes it very short since the pistons are smaller but I prefer the other direction as it would rev higher and have lower torque to protect the transmission when the turbos get crazy. This Is Where The SHO wins. However the smaller pistons allow for a thicker cylinder wall which should help when max boost hits.

Also I could get the whole engine for $300. =P

[PZ.]

The 3.6L was designed/built off of the VW 1.8 16v 4cyl engine from what I remember.

[themadscientist]

Gotcha. I know a few high power builds have used the 3.6, so I was assuming there was something special that everyone knew about that I didn't. Have you seen this S1? It's twin turbo 3.6 with steel liners. http://www.epsmotorsport.com/blog/au...ild-gallary-2/

[CaptAmerica]

I have seen that forum about the S1, its one of the reasons I initially went with the engine. I have emailed, albeit briefly, with that builder and asked him for help with what he had done, he was busy and his help was limited for that reason I believe. I think his engine is bad ass, but his car is pretty ugly (personal opinion), I prescribe to the form over function philosophy. I may be wrong but I think that for the small amount of time that I will be pushing a vehicle to the edge of its limits, allowing it to be ugly is not worth the time and effort. I also truly believe there is a compromise between both of those, the correct design can also be the correct form, it can be beautiful and functional, personal favorite F1 car is the 1991 mclaren MP4/6, simple and stunning. My roommate from after college who is helping me with this on the side, prescribes to the opposing view where performance is the only thing that matters, so he helps balance me out.

Side note, it appears that the Taurus SHO engine is in fact an aluminum block engine (wikipedia says so, I remember other places disagreeing) so my initial comments from before about the engine differences may not be valid, the over square versus under square is still valid. However the audi engine makes 250hp/250ft-lb stock and the SHO makes 235/230, so its really not getting away from a balanced engine. I say balanced relative to say an F1 engine where you may have 900hp/250ft-lb torque and maybe a cummins diesel engine where you have 300hp/900ft-lbs torque. My understanding is that transaxle gearboxes dislike high levels of torque so if you want high horsepower values with reliability you would be best to still with an engine that generates less torque in doing so. The SHO engine is also a 60 degree V which makes it inherently unbalanced and requires the use of a counter rotating shaft which is not desirable.

To the other poster about the VW engine, I will look into that. My major problem is looking at parts on ebay and seeing two that look almost identical and not being able to make the call that one is correct or they are both correct. Like the alternator says its meant for a Dodge truck but also fits the 3.6L audi...that seems odd.

[Denio24]

This may, or may not help

[CaptAmerica]

Denio,

So this could be very helpful, much appreciated. I would love to know if anyone on here knows whether newer crankshaft bearings (blue/red/yellow) from newer 4.2L engines can be used on this older motor. I had HM Elliot re-coat my used bearings but I would prefer to be able to use "correct" replacement parts for this motor, especially since I am trying to double the power output from stock. I also have no replacement currently for the thrust washer pair and the ones that came out of the motor are severely worn. I was planning on just reverse engineering the ones I have and getting a new set made but I don't know what material they used originally, so that would be a guess on my part.

[Nollywood]

Nice project!

I'm also in the process of building a big-power 4.2 V8 40V BiTurbo, using the engine from a 2005 Audi A8 4.2 V8, non-FSI.

The 3.6 is what I would have used many years ago, due to the fact it will accept pistons from an Audi S2 / UrS4. Same bore size of 81,0mm. These days, I take different routes in my quest for big boosted power.

[q_dubz]

Denio,

So this could be very helpful, much appreciated. I would love to know if anyone on here knows whether newer crankshaft bearings (blue/red/yellow) from newer 4.2L engines can be used on this older motor. I had HM Elliot re-coat my used bearings but I would prefer to be able to use "correct" replacement parts for this motor, especially since I am trying to double the power output from stock. I also have no replacement currently for the thrust washer pair and the ones that came out of the motor are severely worn. I was planning on just reverse engineering the ones I have and getting a new set made but I don't know what material they used originally, so that would be a guess on my part.

Any luck with bearing compatibility?? I'm trying to see if your 3.6 rod bearings will fit in my 4.2! New 4.2 oem rod bearings for me are $960!! The 3.6 is much cheaper. Can you please measure the width of your bearings??

[q_dubz]

Also what's the rod journal diameter?

[CaptAmerica]

I will get back to you on this tonight, I haven't been on here much in quite some time as life has slowed my progress even slower then it already was. Anything else I can look at for you?

The answer here is 56.8mm for the connecting rod ID and 54mm for the crankshaft journal OD Width is ~20.1mm. Hopefully that helps you. I haven't had much time to try and look for parts and cross reference stuff on this thing.

[seekic0nic]

Any updates?

Sent from my JSN-L23 using Audizine mobile app

[CaptAmerica]

I actually thought audizine had deleted this forum page until I came across my picture on google this morning, but this project is sitting still born. I was sitting on a $3600 bill to cut and sleeve the ABH 3.6L block on top of a $4k cost for the FWD 01E transmission so I had just kinda waited to find that kinda spare money. But recently I have started look back at it, possibly changing to a ABZ audi 4.2L engine with a 01X transmission, I can find both of those for a combined 3k. This project has never left my overall goals list but life just seems to get in the way both time and money wise.

[Victorymike18]

Old thread, but I like to revisit sometimes as the photos and design direction are nice to look over.

So this is just my two-cents: Building a vehicle with a scratch-built chassis is an enormous undertaking by itself, there's a TON of custom things that need to be figured out just to bolt it together and function. Add to that rebuilding & twin turbocharging an engine beforehand and you're basically guaranteeing that it will be a very expensive pipe dream unless you have serious resources (time/money) to push it along... If I were in your position, I'd be looking for a known-running engine and a known-good FWD transaxle. It looks like these engines go for about $300-600 around the US. And I probably missed it, but would a FWD B5 transaxle bolt-up? Those pop up from time to time for a few hundred bucks. I'd do preventative maintenance on the engine, change the trans fluid, and then get the vehicle built around those...

Life is short. If you have the vision and capabilities for this, I think you'd have a lot more fun driving around with a potentially tired and imperfect NA V8 engine, than continuously looking at a pile of "someday" parts in your garage...

Just my thoughts.