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Running KB Claimer pistons .465 dome true 14-1 comprssion (alky). Engine is down on power, did compression test cold and only had 150 psi. So i warmed the engine and it dropped to 120 psi!!! Shouldnt it easily be 200-220? With these pistons/alky/bore the ring end gap factor is .03248 comp ring gap which i set at .033. Engine has 7 races on it but only 2 since it sat for 3 years. Im guessing the rings are gone? Anyone else run these pistons/have this issue? Thanks
Sounds more like a valve spring problem. A leakdown test will confirm.
Would need cam specs to guestimate.
Advertised Duration (Int/Exh): 304/312
Duration @ .050 (Int/Exh): 268/276
Gross Valve Lift (Int/Exh): .576/.586
LSA/ICL: 106/102
Could the valve lash be a tick tight?
With that big of a cam, that compression reading is about right. What size engine is this? Cam seems really big, low to mid 260's with about 4* split would really liven the thing up. Give some more details of the combo, heads, intake, CI. A better check of engine health would be to perform a leak down check.
.060 350, dart platinum 230cc, 64cc 2.08/1.6. Victor jr intake.Yes i know heads are to big but this thing was running insane and stupid fast. 7 races since freshened (cracked block)
What do u mean by mid 260's & 4* split? Duration? Lsa?
Power loss im feelin- last week in the heat was wet slick only turned 7k rpm should of been bouncing of the rev limiter set at 8k ( ive turned this motor 9400 on a 1/2 mile track with no issues) this is a big 3/8 track and im running a 6.00 gear! The main was slick up top and i only turned 7200 and car wasnt spinning tires. The engine hit 7600 in the shop but obviously no load on it! It feels like i lost 100 hp on the track.This is in a mod 4/4. Wanted to run tonight but thought about tearing it down to see if i can find anything!
KB claimer pistons over 9000???? You more than likley killed the pistons.
Dont want to argue with what i should be running. Just looking for help with current issue. That was prior to being freashened everything checked out. Have to run 8k chip now USRA rules.
Well i feel like an idiot!!! I have a double adjustable gas peddle and the arm cam lose just enough that it wasnt opening the trottle all the way!
hey at least it was an easy fix sometimes crap like that you will chase for a month