ActiveAero

I will be rebuilding my B18C5 here in the near future. One of the main reasons is because of the excessive oil burning that is keeping me from doing any track events. Of course in the process I would like to upgrade in terms of reliability, power, and overall responsiveness hence the want for forged pistons. Is it common for a forged piston engine to burn more oil due to the looser clearances? Any piston/ring setups that are more prone to this? For a car those with forged pistons that see extended use under high load are you happy with your oil burning rate? Thanks in advance.

asubennett

everything that I have seen is that the loose tolerances only applies when the engine is cold- You will get the dreaded piston slap. But once everything heats up and expands it will seal fine. With chromoly rings or Total seal rings it is possible to have a better than OEM seal. Especially with the new honing techiniques a lot of machine shops have. You can literally have a nice hone drop in the forged pistons with nice rings and immediately drive hard with no typical smoke out the tail pipe during break in.

1 2 NV

i wish i had an answer for u brock but i dont. i will reply to the last post though.

i get no piston slap in my block with my forged pistons. its 2 yrs old and sees nothing below 8K except when goin to and from the line. it pulls good compression #s still and is also runnin strong ETs. it spent 1 yr of daily driving and weekend track abuse, now its just a trailer *****.

asubennett

i guarantee when your motor is cold you are getting more noise (i.e. piston slap than you did with your cast oem pisons. It is just the nature of the beast. Once they warm up they are fine and you are right zero pisotn slap but a cold forged piston is goign to a be a little loose in it's bore and there is no getting around it really.

1 2 NV

well lets just put it this way, its not audible. my other friend had the same compression pistons in his car but his were very audible at cold startup. just my experience though.

CHEETAH

iTrader: (2)

the piston's silicone content is whats gives it its expansion rate, typically Arias pistons would have a lil piston slap until warm-up, for instance. The problem you're looking at is a lose gap on your oil ring or over wear on your cylinder wall therefore rings are not sealing as good.

No matter which piston you use for rebuild, each manufacture will give you the bore clearance for the pistons and ring gaps to use as well.

Greg

ActiveAero

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CHEETAH &raquo;</TD></TR><TR><TD CLASS="quote">the piston's silicone content is whats gives it its expansion rate, typically Arias pistons would have a lil piston slap until warm-up, for instance. The problem you're looking at is a lose gap on your oil ring or over wear on your cylinder wall therefore rings are not sealing as good.

No matter which piston you use for rebuild, each manufacture will give you the bore clearance for the pistons and ring gaps to use as well.

Greg</TD></TR></TABLE>

So I'm guessing the quality of the ring package and obtaining proper clearances is far more important than the piston content (no silicon vs low silicon forged pistons) correct?

If not is there a setup/piston content that is preferred for a car that will see extended use under load, such as a lapping event, in terms of oil ring seal? In drag racing I doubt oil burning is really a huge issue since you are only running a 1/4mi at a time, but if my car is going to be on track for 30min or more I would like a setup that will burn as little oil as possible.

WAFFLES

Hey Brock, why not just get some jdm ITR pistons if you are so worried about it. There are plenty of OEM pistons that will work for what you are wanting to do, so that you can pretty much have any compression ratio that you would like.

Suprdave

I would rebuild with OEM Pistons, if using a stock bore.

Suprdave