Super weird compression test results!

[Chezedik]

Alright, here is the deal. I have been trying to get this motor started and have gotten to this point. I have spark and am almost certain I have dizzy timing right (although it wouldn't matter, read on). Fuel is running through the rail and the injectors are pulsing. With all of the cranking the oil smells like fuel, so it is probably getting that. Here is what is really disturbing, compression test results were as follows:

1 - 1512 - 1503 - 1504 - 210

These results were gotten on a cold, never ran rebuilt engine. The head was milled .009'' and the cyl walls were deglazed but not honed. These are chrome-moly rings.

The motor is a rebuild, and I know it needs a new intake cam gear, but surely that cannot explain the result for number four, can it? Anyway, it sputters a little and backfires on starting fluid. I get a little smoke in the timing cover, but that is just blowby I would assume. Any Q's just ask, please help!

[pregmantis]

whoa, thats weird. What is your comp ratio? off the top of my (small) head, the only thing I can think of to affect compression like that would be ....bent valves on 3 cyl, scorched lobes on 3 cyl, valves not seated/lapped on 3 cyl, blown gasket. I dont know but what does the manual say our comp #'s should be? btw, why wasnt the block honed? there needs to be a certain crosshatch pattern when you install new rings. hope you get it fixed.

[Chezedik]

I am sorry, it was honed, not bored. I used a deglazing stone to do it. Why do you think that it is number three is the problem. Also, this engine has never been run so it seems unlikely to have scorched valves or blown gasket. But anything is worth checking out. Again, why do you think #3?

[pregmantis]

chez, I meant 3 cylinders. the last one kinda seems high but try squirting oil into the cyldrs when doin a compresso n check and see if the 123 catch up with #4. without knowing wht the compressin #rs should be... I would think that the first 3 would be closer to normal than #4 I could only think tht severe mechanical differences would be the prob here... as in one big higher compression piston or freak cam lobes on #4 which is rediculous and not the case right? heh

[Chezedik]

No not the case. When I did the compression test before my cam gear 'mod' I had 180 on #1, is it possible that with my gear 'repair' that I have lost 30 pounds on 3 of them but gained 30 on one due to overlap probs? Would this remain static to the cyl? I put oil in the #1 and it didn't touch the result.

[InsanityInc]

No amount of camshaft fiddling will imbalance compression, and certainly not by that much.

Looks to me like your headgasket popped on cylinder 2.

[Chezedik]

Brand new head gasket, and head was recently resurfaced. Was told by a shop owner that it could do that, but then again he told me that I might just have the bottom end on the exhaust stroke instead of the power stroke when I put the cams in (idiot!).

[pregmantis]

its possible to get different readings from different overlap settings(maybe not by that much) but they should all be similar. some people actually tune their cams for the street that way, they time the cams to max cranking preassure.

[Chezedik]

But across different cyls? I just have stock compression, so it seems weird to have a much higher than stock compression pressure on #4. This seems to rule out head gasket failure I would think. Also, the readings don't change with oil, so the rings must be good enough right (or ultra-bad)?

[pregmantis]

chez, I meant different from cam setting to cam setting not cyl to cyl. I think for stock compression #4 is high but I can think of a couple of reasons for having 3 low cylndrs. however, I cant think why you would have 1 thats high without thinking illogical. know what i mean?

I guess what im trying to say is if your pistons,cams,ports..etc are the same as before I would be trying to find out why I have 3 lower compression readings as opposed to why I have 1 higher reading. thats the way I see it.

[Chezedik]

Well, I have already checked piston travel and piston height is the same among them. In any event I do need a new cam gear, and so I will reset cam timing today anyway. No offense, but I would love to tell you all that you are wrong, but I probably will not. Next step I guess will be a leak down test. I understand your point in finding the low compression issue, but the way I see it, the engine should not be able to make more than stock compression with stock parts, it's just too weird. I don't know. I have been testing and testing with this damn thing. What's one more day? I will let you know if anything changes.

BTW, will a failed ECU throw fluke codes without throwing a faulty ECU code. I was doing electrical diagnosis yesterday since I had 4 codes, and went through the whole diagnostic procedure and them got to the end and everything checked out. The ECU is not bolted down, could a bad ground cause that. I am beginning to loathe this car.

[Jiggyfry]

You said this comp. test was done on a cold engine after a rebuild. First a comp test should be done when the engine is warmed up to operating temp. and second if a cross hatch pattern was redone along with new rings it will take a certain period of time for the rings to seal to the cylinder walls. Im not sure but i believe chrome- moly rings will take longer than standard rings to seal to the cyl. walls. Still weird that one cyl. was ok and three were off. Id break in the new engine and then re-do the comp test.

[Chezedik]

I can't get it start or I would think about it. BTW 210 is way higher than stock. That is what my friends RSX Type S is making (at 11 to 1).

[pregmantis]

you have a shaved head,how high it would it raise your readings above stock(I dontknow)? you said you got 180 for #1 once so I wouldnt settle for what the book says 150 or whatevers. you have actually hit 210 on #4...I would be trying to make my last 3 cyl match what I think the motors potential is. jiggy is right, you need to start the engine to make good readings as I dont think the rings can be seated without runing the engine. let us know what codes you have,

btw, what did you mean by the no offense thing?

[InsanityInc]

Brand new head gasket, and head was recently resurfaced. Was told by a shop owner that it could do that, but then again he told me that I might just have the bottom end on the exhaust stroke instead of the power stroke when I put the cams in (idiot!).

I basically guarantee you have a blown headgasket. Your compression is higher on Cyl4 due to the shaved head. Even ~1mm of material will change your compression ratio pretty substantially. Chances are the headgasket was a lame gasket and couldn't handle the compression or it was torqued wrong.

[acrazyjohnny]

im having the same problem on my sohc but i have not done a compression test yet tommorrow i will though everything is dialed in tha cam the timing and everthing is hooked up but the ***** i need help iv been trying to get this car started for a month and a half

[Chezedik]

I mean I would love to tell you that you are wrong so that my car runs, that is it. If I cannot fix this engine, I will need to buy a replacement.

[Bigvinnie]

The head was milled .009'' and the cyl walls were deglazed but not honed. These are chrome-moly rings.

I would take your head off and try a stock one from a wrecking yard. I am under the assumption that whoever milled your head did not mill it to the correct @ .009. I've seen wack mill jobs before that can completely distort the compression from each cylinder.

[Chezedik]

Here is an update:Last night I reset the timing to stock, turns out I was a little off. I don't think I banged up any valves though since I always rolled the engine over by hand before making an attempt to start it, and no valve clearance issues. The compression test results are looking a little lower, but more consistant. The new results are:

1 - 1052 - 1353 - 1224 - 145

I know that is out of spec, but a few drops of oil gives me:

1 - 2202 - 2103 - 2104 - 225

If not for number four, it would meet spec for total deviation. Now here are the new questions:

1. Does this indicate anything to anyone? (the engine has never been ran, and the test was done cold, so I know ring clearance is obvious, but anything else?)

2. Am I putting too much stock in these numbers for an engine that has never ran, and the test done cold?

Any new input would be great, and thank you all for the help so far.

[zero_gripS13]

the fact that the engine hasnt ran means the rings have not seated yet, and the second test adding oil confirms this since the compression raised..

try toi start it and see what happends ...

[Chezedik]

That is what I am thinking, but I just hate reassembling and disassembling. That is why I ask.