So I recently bought a 67 f85 with full knowledge and plans to replace motor that has a tapping noise. It sounded to me like a top end issue, maybe stuck valve with floating lifter or flattened lobe on cam. So I took heads and intake off and heads appeared ok so I'm assuming cam issue. It's not a hollow knock like the sound you usually identify as coming from bottom end. Anyway, I'm not really concerned with what the issue is with the motor. My question is, should I use new head and intake gaskets to put it back together? I want to be able to drive it so I can put it on trailer and remove and maybe drive in and out of driveway so I don't have to go through all the headaches of loading and unloading manually. Thoughts?

 

I guess you could reuse the shim gaskets, the chances of a failure are great. I wouldn't be making any long trips like this though.

 

I would not reuse gaskets, worn rockers are the 1st thing I would look for with a tapping noise.

 

The old gaskets won't seal. Don't even waste your time.

 

Huh?

That sound in an Olds is VERY often a worn rocker bridge - about $8 for the set, if I recall, and no disassembly other than the valve cover.

You did take a look at the rocker bridges, right?

- Eric

 

He just wants to reassemble engine to move the car around. I'm assuming this is just temporary and for short period runs. He may get away with it for a short time if he does not pressurize the cooling system very high.

 

I got that. When the head gaskets don't seal, he'll be pressurizing the cooling system with combustion pressure. When the intake doesn't seal, the car will run like crap. The intake and head gasket sets can be had on RockAuto for about $40 for everything.

 

Thanks guys. I think I'll just get a gasket set. For 40 bucks it's a safe bet.

 

Some of the push rods feel loose. Some feel tight. I assume they should all feel snug. Or is that just dependent on cam position? I would think springs should hold push rods snug against lifters? And lifters would be in contact with cam regardless of rotation position of cam?

 

ive reused a turkey tray gasket on a 455 before. lost a lifter after first long drive, i had no ill affects. cleaned off all the old rtv and put new on. also ive always been under the impression that shim gaskets were completely reusable, to a point.

 

The position of the cam lobes has everything to do with the tension in the pushrods. When the lifters are on the base circle there is very little pressure on the pushrods and they turn easily and may even wiggle a little. If the engine has a lot of miles on it the rocker bridges may be worn which causes a bit too much clearance in the valve geometry. Installing aftermarket head gaskets adds to that. If you are going to drive the car at all, put in the new gaskets and reassemble the valve train and check the lifter pre-load. Eric has posted what it should be many times, you can probably find it with a search, that's what I do when I need info like that. Or if he is feeling generous he will post it again. The contact cup in the lifters moves freely when there is no pressure on it so you have to watch closely to see when the pushrod makes contact as you tighten the rockers down. If you don't have enough pre-load, you get ticking noises from the rockers/lifters. If the pivots are worn, it is best to replace them, they are not expensive.