Oil Consumption - Wiesco Pistons

[twacker]

I had this on the M3 board. Let's see if ya'll can help. Thanks.

Do the Forged Wiesco piston/rings burn more oil than the stock setup? When I run the car on the highway for 50 miles or more at a constant speed, come to a stop, and then get on it: It blows out smoke/carbon as if an old lady had been driving it. There is always an amount of carbon/oil on the rear of the car after some "sprited driving". Keep in mind I have only 3500 miles on this engine. Is this typical for a modified engine? High compression forged pistons, cams, intake, chip, injectors, etc, etc. etc.

This engine was built from the ground-up by yours truly. Not my first time to the rodeo. But this is my first time working with forged pistons. I had noticed on high performance cars at the track that seem to have the same oil/carbon sludge on the back of thier cars as well. I helped crew the #77 BMW at the 1996 24 Hr Rolex and it was covered the same way!! So, I'm just wondering if this is part of the price I'm paying for performance or if I have a cracked/unseated ring issue. I seriously doubt a leak down or pressure test will apply for this diagnosis.

[Harti]

I don't know about the pistons used, but any engine should not blow that much oil out of the car that the cars behind them get oiled.
There is seriously something wrong with your engine when you experience this kind of oil blowby.

Harti

[anthony]

of oil on my newish motor with wisecos and 0.005 of clearance.

[Austin]

The wiseco forged shouldn't contribute to the consumption like that, there's something awry, I suspect it's rings clearances or seating, hopefully seating in just 1 cylinder. Are you running the stock lining, ie Nikasil or Alusil? Were they re-coated or sleeved or something different like that at all? It really sounds like rings to me, better do some tests and or inspection.

[Rob]

I don't have a BMW but I use Wiesco forged pistons in both my drag cars (434 CI SBC). Both of these engies make around 14:1 compression. After initial running of the motors I have found some excessive crankcase pressures. Most of this is due to the low tension, 1/16 in compression rings and seating time. However, I installed electric vacuum pumps on both cars, running it into a valve cover where the PCV valve would normally be and blocked the other valve cover. This pump pulls about 8lbs of vacuum in and pulls the excess compression out of the crankcase. it fixed the problem I was having. Not sure if it is the same issue you are having but it sounds similar. After about 15 passes at the track I noticed an increase in vaccum telling me the rings were completely sealed. This also increased my ETs by eliminating any pressure in the crankcase.