Do I replace the base gasket if I pull the head?

[guscratter]

Hey kids, I don't plan on removing or moving the cylinder block, but do I need to lap in the valves, one is not so good. Just wondering if I remove the compression off of the base gasket do I need to replace it?

[cowboyup3371]

Yes on both accounts. Look on Basscliff's site as I posted up a how to on lapping valves thanks to Steve.

[tkent02]

One of the valves is burnt?

[almarconi]

I've done the job both ways and have not had leaks. The base gasket may or may not leak sort of a crap shoot. If you want to spend the time and money to replace the base gasket, you may want to consider honing the bores and replacing the rings. I would replace the valve stem seals and lap the valves.

[Larry D]

It a case of......you might as well, as long as you're in there.....If you're going to trouble of removing the engine and tearing it down, do anything and everything you can while it's apart. It would be a b!tch to get it all back together only to find out that the base gasket leaks or a valve stem seal is seaping oil.....

[tkent02]

It would also be a bitch to do all that work and find out you didn't have to, what's wrong with the one valve? It's not likely for one valve to wear out, if it is burnt lapping won't help. I just looked at your other posts, low compression #4. Have you adjusted the valve clearances correctly? You can't have good compession if the valves are not closing.

[1_v8_merc]

Do the base gasket, because if you don't, it's going to leak! That's just how your luck will turn out, lol. It's very simply and quick....and why not, you've already done 90% of the work after you got the heads off anyways.

Just make sure to get some ATV/Motorcycle piston ring compressors before you put the jug back on.(52mm-85mm ones on Ebay work great, remember to oil them before using)