" Uneven readings are not uncommon on worn engines, and as long as the difference between the highest and lowest readings are no more than 21 PSI and the lowest reading is 100 PSI or better, then the engine is acceptable."( http://www.gregsengine.com/cylinder-...n-testing.html)

Now this is for a worn engine whose rings are already seated properly. On a new engine the break in process is for the ring to seat and adequately match the piston cylinders. If that seating process isn't finished then some of the compression leaks past the rings effectively lowering it further. But if they're seated an you continue to have problems with a wide variance in readings then you would need to figure out wut about that cylinder isn't sealing properly. And as for the high compression I would be careful make sure your engine is built to handle the extra pressure and the higher temperatures associated with that higher compression.

 

And yes timing being off would also affect compression readings because your valves are somewhere in the process of opening or closing so they wouldn't seal fully allowing pressure to leak out.

 

I will keep you posted when I get my car back. As for the high compression I will keep my boost low and have the tuner tune it. my biggest issue will be octane

 

the reason i brought it up is that i think the owners manual calls for 15psi maximum in the 4G63.of course i do realize we are talking about a broken in engine but with 1500 miles it should be.


i read earlier that you are at 10:1 and if that is the case you should still be around 160-170.200psi is way too high.you might hit that on a motor with 13:1-14:1 SCR.

 

yes exactly the owners manual which is written for a stock engine. Once you add aftermarket parts such as high compression pistions you have essentially created a new engine so you mind as well throw that book out the window for anything but as a general reference for the systems that are still stock. For example when I had my balance shafts deleted in my engine build the oil pressure shot up from the 65 psi at cruising speed that is recommended by the owners manual, and even the service manual for a stock engine to ~90psi. Now this is a good bit higher than the oem spec but it is 100% acceptable and is caused by deleting the balance shafts. So long as the engine isn't missfiring or knocking when you get it back you will be fine, but I expect that after the timing is corrected the reading will level themselves out.

 

I will keep you posted as soon as I figure it out when I get my car back. It will come back towed since the mechanic is saying it needs to be reflashed and he can not do that. He is not professional mechanic just a random mechanic of CL

 

The Specs on the box of Pistons said 10:1, but I didn't factor in the block being resurfaced and the head being resurfaced and the thickness of the head gasket

 

Update on my statis. Got my car back and fixed the timing. The exhaust cam was off by a tooth. Did compression test- 1st piston was 145-147psi, 2nd piston was 175, 3rd piston was 175 & 4th piston was 175. Cam Timing really has affect on compression. The concern I have is the almost 30 psi variance from the #1 piston against the rest of the pistons. Just pulled my head off today to see whats going on. Sure enough, I had a gut feeling the mechanic or I should say want-a-be mechanic did not know how to do a timing belt, because there is a little ding on the piston. Everyone on here knows where this is going. I think I have a bent valve not 100% sure about 99% until I send it to machine shop to have them double check. God made things happen for a reason, because if I did not pull the head off I would not have discover my mistake. My mistake was I put the cam sensor gear that attaches to the cam 180 degree off. I think that is the reason why I have no spark or fuel. Correct me if I am wrong anybody

 

Just heard back from shop and Valve is bent...I hope my experience helps someone out there with the no ignition or fuel probablem...Mine turn out to be cam sensor off 180 degree