pr1689

I will be installing a ZZ4 cam into an 87 roller block which currently has a flat tappet cam in it. My question is should I use a cam retainer or a button or both? If I use a retainer to keep the cam from walking, what keeps the cam from rubbing on the retainer and producing little metal particles and floating them around the engine?

Will I need a different timing cover? I have a full roller timing set already. I will be starting the engine assembly next week as soon as I get the block back from the machine shop. I just want to get everything together beforehand so the build will go smoothly.

Any other things I should be aware of? I know about replacing the distributor gear with a melonized one, and I bought the hydraulic roller lifter kit from GM. I will be using the aluminum ZZ4 heads (ported) and the comp cams pro magnum 1.5 roller rockers, flat top hypereutectic pistons.

Thanks for all and any advice and suggestions.

Thanks,

Pat

Dialed_In

iTrader: (3)

Why is there a flat tappet cam in a roller block? If it's a true roller block use the retaining plate. If it's not a roller block use the button. You can use a stock timing cover, just manipulate it so that there is a bit of clearance between the face of the cam and the timing cover. I use a hammer and dolly to get the proper clearance.

sofakingdom

iTrader: (1)

I would recommend using the retainer.

AFAIK there is no cam button made that will work; the cam bolts are SO CLOSE together in the factory roller design, that there's no space in between them for a button. It might be possible to cut one of the nylon ones down but it would be MIGHTY THIN by the time it was small enough to fit; and pointless if you can just go ahead and use the retainer plate.

Nothing keeps the cam from rubbing on the retainer. That's the retainer's job, to get rubbed on. In general though, the force of the oil pump is continuously pulling the cam into the block, so the back of the gear rubs on the front of the retainer plate. Just like in a flat-tappet setup, the back of the gear rubs directly on the block; and nothing at all holds it from coming out of the block frontwards, because there's nothing tending to make it do that, but there's a powerful force (oil pump drag) holding it in.

pr1689

Thanks guys for the replies. We had bought the camaro from a friend in Houston and the car originally had a 305 and he had a 350 put in. The block is from an 87 which is a roller block, but it had a flat tappet cam installed when he had the engine built. I am changing that and going full roller and wanted to use the best method of holding the cam in place. When I removed the timing set, there wasn't a retainer or a cam button. So I wanted to make sure of the best way.

So the cam retainer that bolts to the front of the block behind the cam gear of the timing set is the best way to go then?


Thanks again,

Pat

sofakingdom

iTrader: (1)

Yup; especially since the cam you want to use is equipped that way.

pr1689

Great, thanks for all the great info. I guess I'll also need to get a dowel pin for the cam too. I guess GM is the best place to get that.

Thanks so much.

Pat

sofakingdom

iTrader: (1)

Should already be there?

Unless you got the cam used, and whoever you got it from, ganked it and used it in some other cam; in which case, you could do the same to yet another cam.

pr1689

It was a pullout from a ZZ4 Engine that I bought. The dowel pin wasn't there, so I guess I could use my existing one.

The cam was never used, just pulled from a new ZZ4 Crate engine.

Thanks again,

Pat