Rb26 low compression

[smackdownz]

Hey guys, just need some kind of guidance here, So long story short bought a 32 gtr roller. Friend of mine had a motor 26dett that had been sitting around for abit but said ran ok. Gave him a carton of beer and took the motor home and dropped it in. 

Started up great, no smoke all fine etc just made sure everything worked. Idles smooth revs up smooth gets up to temp etc etc

Turned off. Cooled down and did compression check, dry test. 150psi on clyinder 1,2 and 3 cylinder 4 145psi 

Cylinder 5 plug was abit wet and smelt of fuel was 90psi

Cylinder 6 plug was wet and smelt of fuel and was 70psi


So obviously problem at back two cylinders. Need to get a leak down test done but anyone got any ideas?? Headgasket? It really idles and drives fine loke there is no problem? 

 Cheersf

Edited July 10, 2016 by smackdownz

[KiwiRS4T]

 

Did you try dropping a little oil in the cylinders and repeating the test? If it doesn't change problem is likely in the head or gasket. Do a leakdown test  - it might pin point the problem. What do you use the car for? You could just keep driving it. Otherwise you need to pull the head off at least and check the head and valves unless testing says its the short assembly.

 

Personally I would have pulled the motor down for a look and rings and bearings at least before installing.

[smackdownz]

Yeah absolutely kicking myself i didnt go further thru it when i had it out.  Did things like timing belt etc but yeah guess ill pay now lol

Is purely a weekend car,  got a leakdown test booked in for friday so will see how that goes. 

 

Tried a cap of oil down the bad cylinders raised the reading 5psi if that. So thinking valves or headgasket and maybe not rings.  So might not be all bad just yet.  

 

Cheers

 

[Dobz]

Is the cooling system over pressurising and filling the overflow after a drive? 

[smackdownz]

Hey,  thanks for the reply and helping out,  it doesnt seem to be.  Hasnt used a drop of water from radiator or overflow if it was what would that be anyways?  Cheers

[r32-25t]

Rip it out and rebuild it

[Dobz]

The overflow bottle would be abnormally filling up if the head gasket had blown into a water jacket.

You need to just bite the bullet and pull it out for a rebuild as r32-25t said. There could potentially be other problems just around the corner eg.oil pump drive