[s-cars] Rods and high HP: Oil Issue??

[Trevor Frank]

I don't know from your description if anyone can say for sure what
happened but...

Several things could have caused it
I have seen this happen on a motor where the bearings don't come with
the retainer feature in them and it has to be carefully put in, this
motor didn't and they spun.

Break in period is a definite.  Especially early on you really want the
motor to temp before you give it much boost.

Tolerance's are often the issue here as well, could have been that his
crank had some bad wear, that his rod's where beat up a bit and not
true, same with the crank, if he had the crank ground or rod's ground
the dimensions could be off.  Too tight or too loose can result in
spinning a bearing.

I doubt that anyone needs to "improve" the oiling to the rods although
that isn't to say that he didn't have a lack of oil, bad oil pump, low
oil pressure, crap in the oil etc.....  I have heard the rally guy's had
some issues with this on an I5 motor, jumping isn't ideal for a wet sump
motor..



-----Original Message-----
From: Lewis, Gary M [mailto:gary.m.lewis2 at boeing.com]
Sent: Monday, March 22, 2004 1:37 PM
To: s-car-list at audifans.com
Subject: [s-cars] Rods and high HP: Oil Issue??

A fellow lister with about the identical spec that I am running had a
rod go and apparently destroyed the block.  His dyno numbers pre-head
rebuild were:
317hp, 380tq

With 15% correction factor for drive loss, At The Crank (ATC):

365hp, 435tq

Great numbers if you are driving a 3,800lb street car.

He gets his head rebuilt, and !boom!, block smash.

I'm thinking the HP numbers were spot on (the s/w targets 370hp), but
the torque seemed high.  Maybe not.  Perhaps the turbo is better than I
ever thought.  Anyway...

Question is, he stated that the rod bearings "slipped", which usually
welds the rod to the crank, the piston fires, rod puts hole in block.
If it happened like this, I was thinking it is an oil issue more than a
weak rod.  Comments?

Thanks,

Gary Lewis

1995.5 S6 Avant, Green/Ecru, RS2 MAF, RS2 Exhaust Manifold, RS2
Injectors, Custom Turbo (K26 Turbine, Factory K26 Cold side (Audi Works
'999' P/N) with 50mm intake and custom Innovative Turbo compressor
wheel), TurboXS Type 25 Bypass Valve, Bilsteins, Eibachs, Big Reds, Spec
II Clutch.

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