leaking cylinder head

[Seight-v8]

Hello all,

Does anyone know what effect a blown cylinder head would have on the running of the vems ecu.

Looks like its using coolant, nothing large, and leaking though the middle two cylinders on the rover v8.

I am guessing it might muck around with the lambda readings, and cause inefficient combustion somewhere along the line.

Any ideas welcome.

cheers

scott

[gunni]

Thats about it,

sensor readings won´t be affected other then lambda,

[Seight-v8]

thought as much, think a compression test or leak down test might be next.

plan to replace head gaskets over the winter layup....and try again with engine next year.

regards

scott

[dnb]

There is one thing I can think of.  And I hope I'm completely wrong.
It's unusual for Rover v8 head gaskets to go in the centre cylinders, so I wonder if you have a slipped or porous liner
Either way, you'll get a diagnosis when you take the heads off.

It's what got the engine on my TVR - it starts out as coolant use and ratty lambda values (but the VEMS seems to cope with these) followed by not restarting well when hot.  Email/PM me if you want to know more about what happened to my engine.

[Seight-v8]

Yes I just hope it's not a slipped liner too
as it's the same on both sides...Won't know till I take heads off....it's hard to tell if leak is coolant or oil/petrol from cylinders....it's definitely oily fluid and engine is loosing small amounts of coolant too.

Worst case is top hats or new cosworth block....both expensive...

Where did you get yours done?

Cheers scott

[dnb]

I gave the block to V8 developments because they were close to my parents.  They organised the work to be done rather than doing it themselves.  Mine was using a lot of water so hopefully yours is not the same problem.

[Seight-v8]

I'm sure my block had blue paint in the valley, which means it has the thickest wall of the v8's.
so am hoping this isn't the problem, going to do compression test first, and a block pressure test if I take the heads off, although I won't be able to do that hot.
My block has been rebored to plus 0.02ins pistons, so new block means new pistons and a re-balance, so costs keep going up..and up...

Scott

[dnb]

Mine was confirmed as one of the thinnest walled, so no real surprise on a very high mileage TVR.  I too went for the oversized pistons - there's so much more choice when you do that...   I got a bit carried away somewhere in the build so hopefully I've ended up with a nice engine.

[Seight-v8]

I am still confused as to what's going on here, I've done a compression test and got 205psi +/-5% on all cylinders......

Yet when the engines about 90+ degc, looks like fluid leaking from both lower edges of the head gasket.....yet compression is fine.

Not sure if head gasket is the problem here, but I am wondering if the coolant is passing up through the liners and out the head gasket....looks like a strip down is the only way I am going to tell, it is also loosing slight coolant, but cant think of any other reasons why this would happen.

Unless head is lifting at higher temps?....is this possible?.

cheers

scott

[gunni]

The amount of head lifting at running temp is less then minimal.

Of course it could be gasket as you do pass coolant through the gasket between head and block. might have nothing to do with your liners.