Justin Gibbons

I have a forged ls 383, built last year, custom cam(230/236, .595/.612, lsa 113), PP ls6 2.5 heads, BBK intake, 80MM TB(I know is prob holding me back) with a compression ratio around 11.3.

..trouble is the first tuner had put the car so rich, that it actually glazed the cylinder walls, so I guess the rings havent seated properly and now I have blow-by..car eats about 1 litre oil every 100k if I drive it hard. The car has since been retuned, as best it can be considering.

couple questions..

bought the car to the track anyway, best run was a 12.4@116mph ...not what I wanted, besides the burning oil, is it possible the car is losing compression?..resulting in lower times(less power). The feels strong all the same.

This is a street car, that will maybe see the track 3 to 4 times a year, and when I re-ring the car in a few months, should I lower the compression?

I cant remember the actual rings used in the car other than they weisco (weisco forged pistions)...is it possible to use a softer ring?, if that makes sense...In the beginning I was planning on using a 150 to max 200 shot someday, but just want to get the engine running correct now before thnking about power adders.

Sales4@Texas-Speed

iTrader: (4)

If the rings were washed out by fuel then they are more then likely not sealing correctly robbing you of compression. Unless the compression ratio is too high for pump gas I would not want to lower the compression. Compression in these motors is worth a lot, especially if you are using a larger cam. Wiseco rings are some of the best as far as oil consumption goes. I would not want to move away from those either, they have a napier 2nd ring which really helps keep oil from getting pushed past the rings.

Justin Gibbons

Does the trap speed seem low?? I know that if I am losing compression it wouldn't be 100% bang on, but still fiqured I would trap 2 to 3 mph faster. With a the engine being 100% I was expecting to trap low 120's.

I could way off, maybe wishful thinking.

Sales4@Texas-Speed

iTrader: (4)

With the rings possibly being washed out its pretty hard to know what to expect from the motor. I would expect a 383 to be able to trap 120's in good running order, but the rings not sealing brings in quite a variable thats impossible to make predictions with.