I am running a 90 integra LS 1.8 DOHC non-Vtec. I recently completed the following mods: Crower Retainers, Oversized Valves, Dual Springs, and PR3 pistons (high compression off ebay). During the installation of the pistons I noticed that the pistions tops actually go up into the head. Total expectation of a high PSI upon compression testing. But to my disbelief the engine has compresstion of 185 in every cylinder. Anyone have any ideas what is going on, I expected a compression of atleast 12:1 but I am reading stock as of right now. I used two compression gages and got the same readings. All input is appreciated.
this comp calc shows you should be at around 10.8:1 compared to 9.2:1 stock. 12:1 is was too high for only adding pr3 pistons.
http://www.c-speedracing.com/howto/compcalc/compcalc.php
When you changed these pistons, did you change the rings?
I installed new pistons and rings. The pistons were purchased off an ebay store and they were to be hight compression pr3 pistons and rings. The pistons have a wedged top and seats cut out for the vavles. The wedge of the pistons stuck out of the head approx 1/4 inch. Is there any way that my stock cam is holding back compression? Such as not letting the valves open far enough and/or long enough?
may sound stupid but i hope you had the block honed… cause if not thats more then likely where your compression leak is comeing from
are your valves adjusted correctly? and is your cam timeing correct?
I honed the block with the dingle berry type hone, using oil as lubricant. The car is timed to factory settings as of right now with the factory cams. I am looking to pick up a set of brian crower stage 2’s or crower 403’s.
The compression ratio of the engine and the readings that you get when you do a compression test are two different things.