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Forum nameTurbo/Nitrous Tech
Topic subjectCompression test results-- help!
Topic URLhttp://forums.2gnt.com/dcboard.php?az=show_topic&forum=8&topic_id=106711
106711, Compression test results-- help!
Posted by Mike431635, Dec-31-69 06:00 PM
Ok, so I had a compression test done before I went turbo, several months ago. Came up ~220 across the board, I believe the highest variance between cylinders was like 4psi.

Recently after going turbo I've been having CRAZY overheating problems. Doesn't get hot on the way to work in the morning, but in the afternoon or anytime its really hot outside (its FL-- it always is) it gets up to like 3/4 to 5/6 up the stock gauge and fluctuates-- goes back down randomly then increases again when I get on the throttle. And if I turn on the heater it drops way down to between 1/3 and 1/2 which is normal from when I was nonturbo. I won't go into all that in detail as I've done it in other threads. I suspected the headgasket may be gone. Btw, the car isn't smoking at all anymore.. it was blowing a bunch of smoke at WOT only the first time I did a WOT pull each day for a few days. After doing the wet compression test today, the same smoke came out, so I must have been burning some oil.

Anyhow here are my results. Both tests were done with the engine hot (operating temp, after driving for about 20 minutes.. and yes, it did start getting to about 3/4 up the gauge).

First test: 198, 182*, 190, 195
*-- on the #2 cylinder, the first crank didn't make the gauge JUMP, it took a bit longer to build the pressure unlike the other 3 cylinders

Wet test (1.5 capfuls of oil per cylinder): 265, 235, 230, 225

A couple things worry me..

1. #1 cylinder was always higher than the others, is that ok and why would that happen?

2. Like I mentioned above, the #2 cylinder built pressure more slowly, so I'm fearing the rings may be worn on that one for some reason.

3. All the compression numbers were significantly better on the wet test, which leads me to believe I may HAVE blown the HG or all the rings need to be replaced.

Help! What do you recommend, and what do you think these results mean?
106712, RE: Compression test results-- help!
Posted by CODE4, Dec-31-69 06:00 PM
Your wet test does indicate some leakage on the rings.

Is it safe to assume you turbo'ed your stock motor? If so another possibility is that you cracked a ringland. I have seen that happen on two separate stock motors with HRC kits.

Do you have any foreign fluid travel? IE oil in coolant, coolant in oil etc. That would definitely be an indication of a HG problem.

Additionally how to the spark plugs compare across the cylinders?
106713, RE: Compression test results-- help!
Posted by Slo2g, Dec-31-69 06:00 PM
Do you have a FMIC? Do you have the heat wrap that goes around the upper radiator hose with the Hahn kit? Do you have the stock radiator?
106715, RE: Compression test results-- help!
Posted by Mike431635, Dec-31-69 06:00 PM
No oil in the coolant, and I've checked the oil on the dipstick and it appears to be straight oil. I was almost at the low mark on the dipstick so I added about 3/4 quart yesterday and now I'm a bit over the full mark today-- oops! So I'm hoping that's not coolant leaking in. Guess I better do an oil change.

Spark plugs are all good between all cylinders, looking just as they should. Obvious signs of running a little rich, but that's likely because I have a massive exhaust leak at the manifold.

How to go about checking the ring lands? Will there be any sure give-away? And would this cause the overheating I'm encountering? Yes, it's a stock motor. Only seen 8psi except for the night I first got it together, the wastegate line melted and I saw a single 16psi spike. Immediately checked everything out and no signs of damage, but then again that COULD have been it..

And yes, I have an FMIC. 3" thick and completely fills the front bumper. No heat wrap on the upper radiator hose, and I'm using a stock radiator. Replaced the cap & flushed + filled the system, no difference. I have a 90 degree off the turbo which is pushing on the lower IC hose. Stock radiator, stock driver's side fan, no passenger's side fan..

I do have a Visteon aluminum radiator which is a bit thicker and some slim fans, but need to have the dp modified for clearance before I can put it on (got an appointment @ the exhaust shop next weekend). While I'm at it I'm heat wrapping the metal pipe that goes to the water pump, putting on silicon radiator hoses (OBX), and heat wrapping those too.

Really hoping I don't have to rebuild.. but, you know, my credit's already *&^@*&$%@'ed, getting married so I'm gonna get even more debt there, I'm 22 so I have plenty of time to recover, might as well not be a &*@$ pussy about it, pull out the VISA, and do what I gotta do.
106721, RE: Compression test results-- help!
Posted by turbosrule, Dec-31-69 06:00 PM
if you have no oil in your coolant or coolant in your oil your and still producing power I'd just ride in till it dies and /or rebuild at your leisure



As far as over heating a couple things you can do
replace thermostat
Flush and fill the coolant
get some REDLINE water wetter mix in with the coolant

insulate that upper radiator hose.
106728, RE: Compression test results-- help!
Posted by DarkOne, Dec-31-69 06:00 PM
Most likely you have a headgasket issue. The random overheating is the dead giveaway.
106742, RE: Compression test results-- help!
Posted by justins71, Dec-31-69 06:00 PM
I'd look more into the radiator, mine was like 1/3 blocked and only had issues when it was really warm outside and it lost efficiency. May wanna toss in a new t-stat while you're at it, just to be on the safe side - doesn't sound bad but they're cheap enough. Your numbers are still on the high side IMO - what's your setup by the way?
106745, RE: Compression test results-- help!
Posted by Mike431635, Dec-31-69 06:00 PM
Yeah, I do have an aluminum Visteon radiator to put in with slim fans. Only problem is the clearance with the downpipe (treadstone) is terrible so I can't fit the thicker rad. So tomorrow morning I have an appointment at the exhaust shop to have them modify the dp for more clearance. Then I'll get the radiator on and see how that helps. Btw, I did replace the thermostat, radiator cap, coolant (and flushed radiator). No difference.

My setup is as follows:
Star manifold
T3/T4 super 60 .63 A/R
Tial 38mm wastegate (knockoff, works great)
Treadstone 2.5" downpipe + WG dump tube (gonna dump into exhaust, right now its open)
Hallman Pro MBC
Custom intercooler piping
HKS SSQV
3" thick FMIC (CX Racing) with inlet/outlet on same side
4an oil feed line, fed from back of block
10an oil return line
12:1 FMU on stock injectors
NGK BKR7E plugs gapped to .032

I've also purchased ARP head studs & 2.7L V6 rockers/PT lifters. Looking at buying dougie2's built block, and if that falls through I'm starting to buy internals as I have a feeling I've cracked the ringlands on at least 1 piston. Then I'll be going with the 420A MSnS setup from Symtech.
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