Drezi

So I have this engine that is showing 75-80 psi dry and 100-125 wet across the board except for cylinder one which was 60 and 125. yikes.

#1 60 - 125 wet
#2 80 - 110 wet
#3 75 - 125 wet
#4 75 - 100 wet

The engine pulls fine, just a bit slower than a 1.8 low mileage car my buddy has. The car could even run 16's in the quarter mile.
The car is test piped, and a different catback, besides that, the drivetrain is stock.
The car shoots fire only at ~7500 rpm when shifting fast.
It is running 10w30 and it is summertime right now about 90 degrees outside when compression tested.
It does burn oil, yet I have never replaced the pcv valve, so it could be that. About a quart every 1000-2000 miles.
The engine also has a lot more top end power than bottom end, yet starts very quickly. Like the first turn of the crank.
Could valve timing be throwing the compression numbers off?

Any ideas would be helpful. How could the car still pull extremely well(probably the same as another stock 1.6) with that low of compression?
Engine history was unknown, It was apparently rebuilt 50,000 ago and the person bought it to boost it, but had his car stolen and crashed. I know this is probably bs, but maybe it explains something about it.
I have had it for 30,000 of those miles. Could I have just destroyed the rings in that amount of time? x)

BogusSVO

iTrader: (1)

a leak down test will tell you more than a compression test.

with compression numbers that low , it should take forever to start if at all

How long ago was it you ran the compression test? was the engine hot? the TB wide open? all 4 spark plugs out?

Did you confirm the gauge is accurate? also was it installed properly?

Drezi

I'll try to do a leak down test today or tomorrow.
I did the compression test today. The engine had been sitting off for maybe 30minutes before, but was up to temperature.
Not 100% about the TB. Someone else did it for me, but I am sure all 4 plugs were removed. If the TB was wide open, would it make that much of a difference and may that be the issue?
Gauge or may not be accurate. I'll try another gauge to see.

18psi

iTrader: (76)

you gotta do the test correctly, and post each and every cyl result, for this to be in any way shape or form useful

I get a handful of kids every month that come over saying "I had comp/leakdown done and they said it was good".

Ok, what's "good?"

How was the test done?

What was the numbers?

..........."I don't know, they just said it was good"

lol

Drezi

Updated the main post with the numbers. Perhaps the test wasn't done correctly. A shop did it for me. all 4 plugs were out, that much I know for sure. No idea if it was at wot.

18psi

iTrader: (76)

interesting results. seems to be a combination of tired engine (the fact that it eats oil confirms that.), low reading gauge, and they probably didn't do it with throttle at WOT.

BogusSVO

iTrader: (1)

I have no idea what your skill level is, or what is in your tool box, if you have one at all

But you may want to go buy your own compression tester and watch a vid on how its done, and come back with your findings.


18psi... or even how much oil they put in for the wet test.. 4cc or 40 cc?

Drezi

Going to do my own compression test and maybe a leakdown(I think I know someone with a gauge I can borrow) and report back.

Art

.

Drezi

Did a compression test myself. The engine sat for 1-1.5 hours prior. all plugs removed and wide open throttle when cranking. I did about 3-4 cranks. Only did a dry test and this is what I got.
The gauge was a Bosch 2827.

#1 150psi
#2 135psi
#3 150psi
#4 150psi

18psi

iTrader: (76)

doesn't look too bad. not great on #2, but not terrible either. tired but still kickin

ryansmoneypit

iTrader: (6)

I bet the PO did not rebuild the head and used shitty rings. Both make for a short life If you are shifting on the redline, it will consume oil.

z31maniac

My ratty 1.6 track rat went from burning oil, to the tune of a 1/3qt per 20 min session, to burning neglible at the end of the track weekend. And I beat that car like a red headed step mule.

Italian tuneup for the win.

pc9527

Not too bad as long as the numbers on the other 3 cylinders are even