jdm pr3 b16, fully built head....

cyl 1 =200
cyl 2 =205
cyl 3 =155
cyl 4 =160

timing jumped 90degrees so i did a compression test to see if i have bent valves and after the wierd compression test i decided to pull the head and see after the compression test and this is what i saw. NOTE** there is NOO sign of valves contacting the pistons.


this is the two with the lower compression

 

It is hard to tell from the pics, but i would take it to a machine shop and have them pressurize the chamber to see if it is leaking. The shop i go to has a rubber pad that covers the surface of the combustion chamber with a pressure guage that hooks to an air compressor. They mostly use it to make sure the valves seal correctly after a valve job, but that simple test will also tell you see whats up with your valves, whether they are bent, etc. That will atleast give you an idea of whether its the head or the bottom end, and should'nt cost you much since you've already done the hard work. good luck

 

i never even thought of this at the time but if you squirt a little oil on the cylinder walls it helps give a better/ more accurate test, specially after you turn the motor over a couple time for the first few cylinders... crap i'm an idiot. lol

 

yeah, thats another good idea.. much easier than pulling the head and testing it separately. Although since you did that, if the bottom end is messed up, you will probably see some scoring on the cylinder walls too.

 

nope the cylinder walls look good, no scoring.

time to reassemble!

 

Squirting oil in the cylinder will help tell you if you rings are bad. If you have low compression on a cylinder and you squirt oil in (wet compression test) and it reads higher that tells you there is a poor seal between your rings and cylinder wall. If you have compressed air you could have done a leak down test before pulling the head and if there was leakage you might have been able to hear where it was leaking pass. Get that head pressure tested be for putting it back on.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by red91hatch &raquo;</TD></TR><TR><TD CLASS="quote">Squirting oil in the cylinder will help tell you if you rings are bad. If you have low compression on a cylinder and you squirt oil in (wet compression test) and it reads higher that tells you there is a poor seal between your rings and cylinder wall. </TD></TR></TABLE> YES, but also if the the motor has been turned over to many times and not started you can "wash out" your rings and squirting oil into the cylinders and turning over the motor (with NO fuel or spark) can reseat the rings. Which in my case i do believe we washed out the rings on those two cylinders because the car was not starting for alittle over two weeks and turned over i cant tell you how many times with MORE then enough fuel.

 

Very true. I have washed out cylinders before, it happens.

 

weird guys. Good info. I have been doing my compression test on my a Turbo EM1 with my fuel off, an disconected dizzy. i have gotten 180 after 5 cranks,

think i could of damaged my rings by doing that?