Was the engine at operating temperature? Those numbers look fine; only 2psi difference.

Yeah I'm thinking your engine wasn't warm enough.

140000km. car felt slow so i tested it 160,170,160,170. i dont think i let it turn ove r enough on the 160 cylinders. Guess car is just slow...but at least no issues.

150 across the board! Car was tested cold and warm, and tested on another car which tested 180 in all four!

Intake Valve Cleaning?

Got any datalogs?

I run meth but probably need a valve cleaning (although before and after dynos dont really show that much of an improvement...). I ve got lots of logs and all is well in those. I went from a speed3 to a speed6 and the 6 is just heaver wwith more drivetrain loss so is slower than iam used to.

Oh, ye of little faith. Don't believe my two (2) testers within 5lbs of each other, hummmmm?
:twak:

Oh I do. But this guy has crazy high numbers, so I wanted to be blessed by his tester.

this guy also has crazy flow/power on his k04. borrow his car not the tester ;)

I make 230 PSi on 3 out of 4 cylinders. Am I cool?

You're very cool @Micha;! Any ideas what happened with the other one?

Well 75% is a passing grade in college.;)

Sent via blown passenger side speakers.

Had 15-20 minutes on the highway right before the test. ECT was normal

First compression check ever, 83.xxx miles BT 3071, 415whp 12.0 quarter mile.

165 167 165 167

The car has been running flawless until the last week when there is oil coming out of the valve cover breather. I have a little filter on it that came with my cp-e kit.

Saikou catch can hooked up the old school way with two check valves. I know a leak down test is the next step but in the mean time I am going to go over the catch can and pcv system.

Might as well start saving for a rebuild ...

Sent via blown passenger side speakers.

How many miles on BT and how much boost?

@Snyeed; was telling me altitude will mess with compression numbers. I looked it up briefly and people seemed to concur. If usual is 180, and we are at 4500ft would that be accurate for a healthy motor?

He runs 25ish, but is on 18psi for the winter months. bt has been in for 2 years?

CPolly, had to bump this since I am getting through a qt every 200 miles as well. Are you suggesting that my rings are fucked and the blowby is forcing oil through the pcv into the IM ? Did a compression test and one cylinder was 30psi below the rest. Also, all four plugs were fouled like I've never seen and they were only 30K miles old. Covered in encrusted white deposits. Doing a leakdown test this weekend.

Wouldn't that suggest a blocked PCV system forcing the pressure out through the valve cover ?
The compressions look reasonable....and more importantly, even.

What did you mean by flush chemicals ?

I had 160 PSI accross the board and I was filling my SSP Vented Catch can with 3 WOT Pulls. I had the TIP and the Mani blocked off. Your rings could be fucked or you could have multiple cracked ringlands even though you have good compression. You might as well save for a rebuild because once you have retarded amounts of blowby occurring, that is the only real fix for it.

Yeah, that's kinda where I'm headed. I'm completely stock and always used whatever oil the dealer put in it as they did all changes up to 100K. OCI's were not always good so I think I may be paying the price for it now. There's an outfit on ebay that sells refurbished motors (all kinds) for $3K plus a core deposit. I don't have time to rebuild my motor since it's my DD.
I changed the pcv and the turbo and still get through the same amount of oil so it must be rings, ringlands or valves. Low compression in cylinder 4 will be checked with leak down this weekend.

Barely over that will get you a built shortblock from @SPEEDPERF6RMANC3; just sayin'

Thanks but I'm looking to keep it stock. My DD with a 70 mile daily commute so I need it to be very reliable......not that I am saying his built blocks are no good.....just figure that staying stock is the most reliable. Besides that, I can't afford to rebuild my head etc.

Gotcha... Just putting it out there. IF your head were good you could get a block built with upgraded rods and OEM pistons; should be completely reliable and have good power potential for the future.

Of course if your head isn't good that doesn't matter.

Thanks. I'll keep it in mind. Hopefully the leak down will reveal all this weekend. A qt of oil every 200 miles is getting to be a bit much, plus I have CEL P0401 now which will fail CT emissions when the time comes. Anyway, if I have a cracked piston, ringland etc I imagine it's only a matter of time before Zoom Zoom Boom. I've already done about 20,000 miles or more with it burning oil like this, I magine the cats are toast by now.

@maisonvi;

Are you staying out of boost? I noticed that blowby is reduced if you don't punch it all of the time. Do you still have both cats installed? My motor went like that for 7,000 miles and I was still able to save my cats.

Yeah, I’m completely stock.
I boost here and there and usually when I do I get a cloud of black smoke and misfires.
I attended an install meet with the CT Nator guys a few weeks ago and we pulled the plugs, they were caked with white deposits. So, we put new plugs in and this weekend I pulled them to do compression tests and they were almost as bad again – maybe 4 thousand miles on them.

So, I’m totally stock, have a rebuilt KO4 in it as well as a new PCV valve. I burn a quart of oil every 200 miles. I did compression tests yesterday at a Nator BBQ and got the following results…..cylinder, dry test, wet test.

1 / 180 / 200
2 / 180 / 210
3 / 185 / 200
4 / 200 / 205

We tried to do leakdown tests but for some reason the tester wouldn’t work properly…..either that or it was operator fail ;-)

One thing we did notice was that the plug in cylinder 4 came out very easily…it was loose. Also, the end of the plug socket had about a 1/8” wide ring of oil on it. One of the guys also said he saw a lot of junk on top of the piston.
My guess looking at the numbers is that 4 is already seeing a lot of oil so the wet test made no difference.

One of the guys from the NY Nator who was at the BBQ suggested a catch can to see how quickly it filled up. I had another thought on this and wanted your opinion.
Rather than buying a catch can could I just disconnect the hose that connects the PCV to the IM, block the IM hole and see what pukes out of the PCV ?
With the oil consumption I’m seeing I doubt it would be long before it was obvious that I was pushing oil through the PCV (if that’s what my issue is).
If I didn’t see evidence of that then I could switch my attention to the valves.

Thoughts ?

I assume your valve cover gasket is ok.....I havent taken the valve cover off in a while but i think you have a gasket that goes around the spark plug holes in the valve cover.

New dry test yesterday on warmed up engine when replacing spark plugs.

#1 - 193
#2 - 192
#3 - 180
#4 - 195

If you look at my older post in this thread, these numbers are about 10 psi HIGHER than my last test.

In August of last year the numbers were:


#1 - 180
#2 - 180
#3 - 172
#4 - 180


No change in engine mods. Same compression gauge used. Same testing technique of testing with all four plugs removed and cranking engine until needle stopped rising, same differential on #3 cylinder.

The only explanations I can offer is that I am now running Rotella T6 5w-40 oil instead of Mobil 1 5w-30 and perhaps I had the engine warmer this time. Maybe someone else has an opinion. I know the car did not magically get better compression, ha ha.

Valve cover gasket is ok, no leaks anywhere. I drop absolutely no oil on my garage floor.

Just a guess here but maybe the T6 makes the rings seal better.

How many of you guys actually pull the fuel pump relay and wait for the car to die before checking compression?

Never did that once.

Me neither. Just push and hold the gas pedal to the floor - that disables the injectors. Apparently it's a built in system to clear flooded engines but it works for compression tests as well.

^^ Exactly.. I once did it by pulling the fuel pump relay, now I just slam the gas pedal.

ring gaps just lined up for the previous test, or were closer.

Carbon buildup = smaller combustion chamber = higher compression?

Maybe. Did not think of that and would have thought that any changes in carbon deposits in the combustion chamber or on top of the pistons would not be enough to account for that. Dunno.

I just think it may be the built in margin of error in the cheap Actron compression gauge I have. If I checked it again tomorrow, it might be somewhere between the two readings above. I guess the important thing is to compare cylinder-to-cylinder on the same day. Both sets of numbers are pretty good. I need to continue to watch cylinder #3 , which is a bit lower than the others, as so many other people are experiencing. Down maybe what 6-8% compared to the average of the others?

When Omar checked my compression right after it was built, he got around 180-190 across the board; when he referred to the manual it directed him to pull the relay, etc. When he did that he got 210 on all four.

I'd be interested in an explanation for that....

Unless ya'll cranked it longer/harder.