Hi,

I have rebuild my 3.5 v8 fitted with su carbs. the old head gasket was a comp and i replaced it with a metal one. Took it to the mot station and it failed on emissions. the garage have said its got a bit of blue smoke.

Would changing the gasket from comp to metal have change the engine timing?

Milesm said:

Hi,

I have rebuild my 3.5 v8 fitted with su carbs. the old head gasket was a comp and i replaced it with a metal one. Took it to the mot station and it failed on emissions. the garage have said its got a bit of blue smoke.

Would changing the gasket from comp to metal have change the engine timing?

Click to expand...

Shouldn't have changed the timing but if there is blue smoke, it could be burning a bit of oil in which case I would suggest you do a proper compression test (dry then wet). If compression increases on wet test then you probably need new rings, if it doesn't change much then the problem is probably valve stem seals but either way I'm afraid the heads will have to come off again.

What were the emissions results?

HTH

Blue smoke usually oil, did you replace the valve stem oil seals? they usually come with the head kit.
Changing head gasket wont effect timing, though can slightly change compression ratio if different thickness from previous one.
Could also be small oilway leak getting in somewhere if new gasket got damaged on fitting.

Hi, I did replace the valve stem seals, as for the gasket I did make sure it wasn't damaged. but I did torque the heads to factory settings using the same head bolts, might this cause the issue? The only reason I saying this cos a year ago I replace the head gasket with the comp one(water pump went on M5)! Re-seated the valves and cleaned all the crap from the top of the pistons and heads. with through mot and the guy said the emissions were just like it would be if it had just rolled out of the factory.

I'll need to find out when I get the mot failure cert back.
I just find it hard that now its just failing emissions, its killing me!:Cry:

Best to use a composite gasket on a rebuild, not the metal type. The steel gasket tends to leave eroded areas around the fire ring area where it contacts the block.

Did the valve seals fit properly? We've had more than one set of gaskets where the valve stem seals were a joke, too small to fit over the valve guides.

We have used Reinz gaskets sets since then, good quality and the valve stem seals fit perfectly, very close to new LR seals.

Peter

well, this morning the curse of the defender struck again! Whilst the defender was being sent to the mot station the bloody throttle linkage roller broke! The rest of the morning involve me with my head in my hands being unable to get a replacement.

Get this land rover Bristol wanted to charge me £28 for the linkage arm as for the roller I had to buy a ten pack a £4 each ex vat just to get 1! :crazy:

went back to the the garage where my landy was being sorted and they helped create a new roller unit, which was nice.

I asked to start the landy to check the smoke level and it ran clean!! Turns out they may have over topped the oil in the dash pots, hence the smoke.

Beast is going back to get tested.

Will find out the results on monday

Thanks for everyone advice as this is my first landy\v8 and working on a car

:5bcheers2: