Compression Test

[SwissR34]

Hello guys

i need help

my car r34 gtt

the headgasket on zylinder 6 is going down. I rebuild it and have checked the compression

166tkm on clock

Hot engine test dry

#1 10,6 bar

#2 10,8 bar

#3 9,8 bar

#4 10 bar

#5 10,4 bar

#6 11 bar

Wet

#1 11,4 bar

#2 11,2 bar

#3 11,2 bar

#4 10,8 bar

#5 10,8 bar

#6 11,8 bar

Is that good or need new piston rings?

Mods

Hks hi power catback apexi air intake hks bov

boost is 0.9 bar on stock gauge.

car is not mapped there a stock ecu in.

thanks for help from switzerland

[SwissR34]

The headgasket is not changed the test results are with the shi××× headgasket

[KiwiRS4T]

Those compressions do not suggest any problems with the rings. From 10.8 to 11.8 bar is a little more than ideal but nothing to panic about. What's wrong with your headgasket?

[SwissR34]

First the oil temp goes up to 110 grad

than the water temp go over the half mark.

as i start the engine after 10 minutes cold down it runs on 5 cylinders

after i pull the gas it runs normal on 6.

Pull coils and sparks out tho check compression.after the test wi give pressure on the cooling system and leave it for 20 minutes.

with an endoscope going in each cylinder to check it inside. At the 6 cylinder we are going diving.

Water floating from headgasket in the cylinder thats why the car runs after start only on 5 cylinders.

but no oil in water and no water in oil.

it doesnt smoke from exhaust.

but i have power leaks sometime when i pull hard but i think this comes from the headgasket too on pressure the gases pressing in to the water so they doesnt have a good mixture on cylinder 6. Thats why the car overheating.

sry for my bad englisch

[admS15]

Compression seems ok for age of engine. Replace the head gasket and then keep monitoring oil and water temperatures in case there is some other fault with the cooling system and that was the cause of the gasket failure. If all checks out good, enjoy driving it.

[SwissR34]

I think it comes from the headgasket.

hot exhaust gases heating the water up and the water gives it to oil.

Thanks for helping

[KiwiRS4T]

If you are taking the head off check it for straightness and maybe get it crack tested.

[SwissR34]

Yes i must do this.

So i can the shortblock let it be.

[SwissR34]

Other ideas?

Rebuild block or not?

[admS15]

I wouldn't, unless you can see something very wrong when you take the head off. These engines are very strong, even with high mileage. The compression in yours seems ok.

[SwissR34]

Ok

in a few weeks i pull of the head make some pictures from cylinderwall and pistons.