theedge

The pilot bearing is in the clutch end of the crank in a little "cup". If something changes (ie driveshaft is longer, or crank sticks further back, or engine sits further back, etc) then when its assembled the end of the driveshaft might push on the crank, rather than just sitting in the bearing like it should. That means its pushing forward on the crank.

DDP

Ok, but how could things change? HOw could the engine move back or the driveshaft move forward? Even if you have a lightweight FW (thinner then stock) it won't change anything because the bellhousing is what the TT Is bolted to. So the driveshaft goes in the same distance anyways.

Chris White

I believe what he is really referring to is that the drive shaft does not always (in fact rarely) slides right into the pilot bearing. Heavy handed mechanics have been known to use the torque tube mounting bolts to force the drive shaft into place. It doesn’t work, the shaft will not magically, though the use of force, get into the correct poison. It usually crushes the pilot bearings and moves the drive shaft towards the back of the car.

The thing that changes is the clutch alignment – if it is not perfectly centered then the driveshaft will not slide into the pilot bearing.

If it requires fore then you are doing it wrong. Stop and fix the problem (clutch alignment).

Chris White

tedesco

Chris got the point. Sorry for beeing not clear or precise enough. Still I see another aspect. If the axial position of the pilot bearing in refference to the engine changes than the driceshaft length would need to change accordingly otherwise (if the bearing sits further away from the engine) axial tension is transferred from the engine through the pilot bearing and the driveshaft into the gearbox. The gearbox bearings are very strong and can take the load. The pilot bearing and the thrust bearing of the crankshaft are much weaker.
The position of the pilot bearing can change due changing a flywheel, dirt/corrosion between crank and flywheel... but not due a pressureplate change. ALso engine position changes are irrelevant because the assembly of torque tube + clutch housing + engine block form a closed unit. and do not change position in refference to each other.
Hope it was more understandable this time.

Chris White

I know what you are saying – the pilot bearing is fragile – but the thrust bearing is pretty much uncompressible!

Chris

JET951

isnt it funny how nearly all the engine falures seem to be on mobil synthetics.

Chris White

It might be because that is the most common oil on modded engeins...

Markus951

Well

It looks like the rod's I bought second hand where bent before they went into the engine.. The cilinder what remained ok had the rod witch was bent less than the other. Te diffenence from wirt pin was allmost a 1mm.. damn.. Mechanic who put the engine together did not measure the rods.. And I changed them due to reason that I had cast ones in there before...so it was sort of a upgrade hahaaaa....

How the rods where bent you can see easily from ciliner wall..all of the rods where pushed backwords not let or right.. I Am doubting that they came from NA car with had enormous amount of water in the cilinder Never seen rods bent like this on the turbocar.

The reason why I went lean on the 4th (last) cilinder is due to reason that I modified the fuel rail. Fuel return to the adjustable fpr is been taken before the last injector, this is the only sensible solution for my the problem..


Anyway. I am now thinking how to go further. Most likely I will go with bigger displacement and this time there are not mutch left what you can find on stock cars..
3.0 liter
9:1 comp Ratio
3.5 downpipe with 3" catback exhaust
Darton Mid-sleeves + forged pistons + honed with torque plate
Ceramic coated stock header with modified crossover pipe..
Custom H-profile con.rods made of PO metal (prooved to be good 200hp/per rod on audi 20 valves)
Custom P.O metal flywheel with GT2 pressure plate and PO metal clutch disk with cerametallic blades.
Custom Intake maifold with dual plenum and velocity stack's (plenum size 5.5 liters with BMW throttle body (+9mm compaire to stock)
Webcam 274 grind cam (for start)
48mm intake valves + ported head I have from my last engine. I just have to modify the water channel.
New raceware head.studs.
New raceware rod bolt + nuts
Full balancing for crank rods pistons..

What I haven't really decided is the turbo.. It is obvious that GT30R will be too restrictive for 3.0 liter therefore I have thoght about 2 options,

Garrett GT35/40R with 0.82 AR


Or Innovative GT61 with ceramic ballbearings..
http://www.innovativeturbo.com/pages...asp?sku=GT61BB


Is there any users with real life experience with innovative turbos.. I've heard from differnet places that they had some bearing problems..

On my future engine I am looking more for good response and good drivability, not so much top end.. I would be glad with 550 crank hp not more but with decent broad powerband..

Are the innovative turbos up to their price or would it be reasonable for me to go with Garrett..

BR
Markus

pete95zhn

PO as Pasi Ojennus...?

For those there on the other side,local craftsman with his own products...sorry,no web pages.Racers here worship him...

How will you manage with 9.0:1 compression?

Duke

Glad you found out some details on how the last engine broke. Such a shame that the rods were bad, IMHO it would be fun with more people pushing the limits of the 2.5 8v concept.
Especially since it seems us Euro-guys are the only ones that actually do some real life performance tests instead of just posting numbers that really don't mean anything

Sorry no IRL experience with the Innovative turbos but I can vouch for the Garrett.
Your new planned engine sounds excellent, but just make sure the custom engine parts come from solid sources so you don't have another failure because of questionable workmanship.

Markus951

Pete. Yes it should be the sourse. He can custom make most of the con.rods. Price varies between 200-220EUR. So I will just send him my cast rod + stock flywheel as an example and he will fabricate a new one. Flywheel for Audi 20 valve vas 350 EUR.. I am not directly spoken with the guy but my friend good friend Jyrki Repo from Pro-Mo Racing service can help me out here..

Duke:

I found a place who is able to install steel sleeves into porsche engines. and therefore its not so big diffenence to go with 2.5 stock or 3.0 turbocharged with steel sleeves.. The mid-sleeve service here is 2 times cheaper then it is in sweden. If Id have'nt found this contact I would go with stock motor.

How is Puppans car running?

Most likely I will make custom fulelling system with 2*walbro255lbs inside of the rear passenger fender. Custom twin steelbaided hoses going from each pump to the both sides of fuel rail and from the middle of the fuel rail going back to the SX fuel pressure regulator. THis way I can assure proper equal fuelling on both sides of FR.

I think most popular ballbearing turbo among 3.0 liter 8 valves seems to be the GT3540R. At least this side of the ocean. People who are using them, feel free to use my thread for your experience, comments on this field..

I would love to have something like 550hp/700nm@crank..

pete95zhn

Markus,some PM's sent.

Olli Snellman

Markus,just sent mail to you

Markus951

Hey again guy's

Can someone make a wild quess why the rods where bent this way as they where? Just opposite how they usually bent under heavy load!

On this picture here you can see the broken rod and the rod what has been bent!
Its just htat it's not wisible because you'd need to lift up the rod and look on it from side( not from top as seen on picture)

As I bought them second hand and I do not know the history of them. Could it be that they've been taken from older NA engine (what had the rarst pistons in stock). The engine has broke the toothbelt and exhaust valves (all rods are bent tho exhaust valve side) have hit the pistons on high rev? and thats why all the rods have been bent exactly the same way, some are more some are less, but they all are bent! If its to much boost or water in the cilinder, rod usually bends like this:



Damn..

PS! I have no sign in the pistons regarding valves.. Has anyone seen rod's that condition before? My experience say's that power is what bent's things but my car was slower/less power then last year (this is what dyno also show'd us) Last year I used cast rods and they where fine with 400 hp /550nm/7200 rpm. no sign of wear what so ever. Rarst rods should be a lot stronger..

Markus951

anyone?