R34 Overheated And Now Wont Start

[kyle345]

So simple run down, my water pump bearing was f**ked and shaking itself to shit. Water started to pour out of the waterpump all over the belts (i heard the belts squeeling whilst driving). Then i started to feel a loss of power so i went to pull over and as i did the engine cut out. I got it towed back home, topped up radiator with water and you can see the water pissing out of the water pump like someone left the tap on.
Tried to start car, cranks but wont fire up sounds like low compression.

Just compression tested all cylinders and these are the results.

Cylinder 1: 90 psi
Cylinder 2: 30 psi
Cylinder 3: 30 psi
Cylinder 4: 30 psi
Cylinder 5: 30 psi
Cylinder 6: 90 psi

Im not sure what sort of compression these rb25's are meant to have but it seems very low.

Spark plugs when taken out were very dry, so that tells me that fuel hasnt been getting into the cylinders so not sure whats going on there.

Looked down plug holes and cannot see any holes in pistons, so im gonna try and get a tool do cylinder leak tests.


Anybody have any idea what problems there could be? Why the car is not starting is obviously due to low compression, im curious as to whether it may just be the head gasket though.

When running the car i never let the temp go over 3/4 so it never hit the red margin, so i doubt piston rings are fried.

[Ben C34]

That result is crazy low. Unlikely all cylinders died, could be cam timing related. You have a bit of work to do.

You have to realise that when there is no water in the rad the temp gauge doesn't work properly, so you could have got it really really hot.

[kyle345]

Yeah i realized that it would of been reading air temp and not water temp so could of been way hotter.
How would cam timing be related? I understand what you mean that the valves couldnt be closing soon enough, but how would overheating actually change the timing?

Usually when all cylinders are dead its just the head gasket?

[Ben C34]

It isn't directly related to the overheating the cam timing being wrong, but it could cause the low results.

a I've never seen an entire head gasket blow.

[kyle345]

Cam timing wouldnt be wrong because its always be fine, and almost impossible for the belt to slip

[blind_elk]

You have more than likely warped the head. It will require a new head - DO NOT get this one shaved flat, toss it and get a new one.

[kyle345]

Why cant you machine them?

[Ben C34]

Because when you machine them flat the cam tunnels are bent still.

[StevenCJR31]

The head cant be straightened? Surely if the cam tunnel was that far out of alignment the cam would no longer turn ?

[kyle345]

Is it worth trying to get a tool to do a compression leak test?

Or should i just start to get the head off and check straightness

[StevenCJR31]

If your compression test results( very very low) are accurate/correct then a leak down test is pointless as your engine is borked anyway

[kyle345]

Yeah but we want to know where its leaking, out of the inlet, exhaust? Could just be leaking cuz of head gasket, could be leaking through valves, could be leaking because of warped head with a leak test we would be able to see where its leaking?

[StevenCJR31]

Could be leaking from any off the places youve mentioned, cant tell where from over the Internet. . Either way im thinking you are going to be doing a partial strip down of the engine and if you are going to that much trouble then you might as well rebuild it as engines are never quite the same after they have been cooked

Edited February 11, 2014 by StevenCJR31

[89CAL]

Head off. You'll see if its gasket or warped head then.

Your not going to be able to fix it with the head on

[kyle345]

Compression leak tested the cylinders.

Piston rings are leaking and inlet valves are also leaking.

Gonna replace rings and rebuild head, lap valves.

Gonna be a hell of a fun job -.-

But atleast it will be like having a brand new motor

[Shoujiki]

Expensive repair for a naturally aspirated engine. Far cheaper to buy a 2nd hand unit and put it in yourself (could do under a grand if you look well enough).

Unless your rebuilding it for the fun/learning. Then that's a different story, and have fun!

[kyle345]

Yeah can get a motor for $600 but then again wheres the proof that say the motor has done 80,000km

Skylines are driven by grandmas either so the motor is gaurenteed to of been thrashed, better off rebuilding the motor you have and making that one good because then essentially you have a motor in your car with 0km on it

[kyle345]

Are not driven*