14 replies to this topic

[bevyid31]

1. 155PSI
2. 135PSI
3. 135PSI
4. 155PSI

No1 being closet to radiator, done a wet test in no.2 and read 180 PSI, is this a piston ring issue?

[RooBoonix]

I'd say it's blown between 2 and 3, as they're both consistently low.

 

Do a wet test on 3 aswell, for the hell of it. But ultimately you need to have the head off and see.

[bevyid31]

Ok will do, I only recently had a fully reconditioned head fitted so is a
bit concerning, though from those readings being how they are
would you suspect the head rather than the rings

[ukcooper]

he dose not, he said you need to take the head off to inspec whats wrong, head gasket,crack in the haed or block ect

[RooBoonix]

I'm expecting the head gasket to have failed between cylinders 2 and 3, due to both readings being low and consistent with each other. The head itself is probably fine, unless it's an uneven head surface causing the issues.

 

It could be the rings, but it's unusual for 2 cylinders to fail in such a way that the compression readings are exactly the same if it was the rings failing.

Edited by RooBoonix, 07 June 2017 - 09:25 PM.

[ukcooper]

i'd say more like rings do a wet test an see the results

 

whu did you replace the head in the first place

[Dusky]

With a blown headgasket I d expect less compression tho?

[minimans]

With a blown headgasket I d expect less compression tho?

Exactly. if the gasket was "blown" you'd see a much lower figure than you have, you can do a wet test on all four (Don't overdo the oil, you only need a small amont) Does the engine have a problem? If it were mine I'd just run it and not worry if its not doing anything annoying............

[bevyid31]

I will do a wet test on all 4 tonight and post the results. I had the car mot'd a few weeks ago and passed emissions fine though it has in my opioids to much black in the exhaust, when I ran it a few weeks ago it ran fine until I got near home and it puffed some smoke out the back when changing down which I didn't like hence the compression test. Would a leak test determine gasket or rings or would I be wasting my time there

[bevyid31]

Ok redone the compression test
Dry
1. 150 PSI
2. 139 PSI
3. 134 PSI
4. 150 PSI
Wet
1. 182 PSI
2. 200 PSI
3. 180 PSI
4. 196 PSI
Any ideas? I only drive the car occasionally so is it ok to do so if it is the rings or I take it they will get gradually worse.

[imaparana]

these results would rule out the posibility that it is the head gasket, however i dont think it can definitely be put down to rings yet, try a leak down test.

[carbon]

Ok redone the compression test
Dry
1. 150 PSI
2. 139 PSI
3. 134 PSI
4. 150 PSI
Wet
1. 182 PSI
2. 200 PSI
3. 180 PSI
4. 196 PSI
Any ideas? I only drive the car occasionally so is it ok to do so if it is the rings or I take it they will get gradually worse.

How are you carrying out the test - is this on a cold engine or after taking it out for a run to get up to working temperature?

[Swift_General]

Throttle wide open?

[bevyid31]

I had the car running for about 15 minutes before doing the test and had the throttle wide open. Would a leak down test be recommended then?

[minimans]

Yes leak down test is a much better test for diagnosis than a simple compression test. whilst the cylinder is pressurized you can listen at the exhaust, intake, and oil filler, if you can hear hissing at the Ex. or In. it indicates a valve problem. Oil filler is a bit trickier and involves a bit of experience as you will always hear a bit of hiss there just depends how much!

 

PS your compression test results are all over the map! I think maybe your technique or equipment is a bit suspect. However once again If it's not causing a problem I'd be inclined to just drive it............................