So I decided to help my buddy out some with his civic. its basically all stock except cold air intake and exhaust and coil overs. its a 95 with im not sure how many miles. It has some oil leaks and is pretty dirty on the motor. The problem or at least I suspect is bad headgasket. iv fixed the coolant leak he had from a line but he still has to add coolant everyday (I suspect its burning some of it) and he says the coolant is flowing back out through the reservoir. Im pretty sure it may have gotten warm a couple times in the past. I took a comp test to the motor and these are the results:
Cylinder 1: 170
Cylinder 2: 140
Cylinder 3: 90
Cylinder 4: 150

the needle on the gauge gradually increased in compression with each stroke until it reached peak value. I also didn't have any oil to touch each cylinder with and re run the test

I suspect its the headgasket but was wandering if someone could confirm?

 

Try a new OEM radiator cap first but, most likely a blown head gasket. Can test with a block tester (free rental at autozone and Oreilly's) and purchase $10 test fluid. Do not cheap out and try a head gasket fix in a bottle..will make things worst (clog radiator, heater core) Plan on spending a total of $300 to 400 depending on cost of all gaskets needed and machine shop: resurface head, valve lapp, new valve seals insert, clean cylinder head. Good time to do a timing belt (kit) change too depending on when last one was done or service record history.

A good possibility the head hgaasket is breached between cylinder 2 & 3 or 3 & 4 and that's causing the low compression. Other possibilty is cylinder 3 compression ring is shot.

 

So Hendrix is...partially correct. Don't waste your time with a radiator cap. Yes, do a block test. If the head gasket is damaged, no, it's not damaged between cylinders, it's damaged directly on the cyl 3 water jacket. Your testing and probable solution are the same, but...accuracy is important.

 

OP: here's another good video explaining head gasket breech diagnosed through a Leakdown test.

 

I can attest to how valuable the information provided by a leak down test is. There are many great guides on youtube. Don't buy the leakdown tester from harbor freight, I had 3 and they were no good, if you choose to do it follow Jimi's advice and "rent" one. I've heard of a lot of single cam's overheating and losing head gaskets, that's likely the problem. Good luck.

 

The guy in the leakdown video has a vid on how to make a home-made leakdown tester.. very good.

 

Alright cool thanks for the information, givin the condition of the motor ill probably just do the whole top end deal (water pump, timing belt/tensioner, tdc etc) and atleast at resurface on the head. thanks again.

 

YW. Just make sure to check the block for warpage as shown in the video.
Using a razor blade to clean the top of the block can be tedious. Hopefully, others will chime in with alternative or additional methods.
Follow the Honda FSM guide to the letter. This guy has great tips that applies to any engine: