gw204

I'm in the process of installing a Cloyes double roller timing set (the original had 2 broken nylon teeth and a lot of stretch) on my son's '86 Firebird with the 305 and was hoping to get some advice on 2 things:

1. The instructions say to check for interference w/ the block before buttoning everything up. The only spot I have some concern about is between the chain/cam sprocket and center oil galley. I was able to slip a thin piece of cardboard in between the two so they aren't touching...but there is only about .030" of clearance. We rolled the engine over manually and didn't hear anything making contact. I'm thinking it'll be ok and that gap shouldn't decrease unless something else bad happens. Agree or should I pull the chain and sprocket off and grind some of that galley away?

2. None of my reference material (FSM for an '88 and a Haynes manual) mentions anything about thread locker on the cam sprocket bolts...nor was there any evidence that it was put on at the factory. When I removed the old sprocket the bolts weren't very tight, but they didn't seem like they had backed out at all. So I just cleaned the bolts off, ran them back in and torqued to 20 ft. lbs. Should I back them out, get any oil out of the threaded holes in the cam and then reinstall with blue thread locker?

Thanks.

sofakingdom

iTrader: (1)

The oil galley isn't the location of the interference top begin with. .030" clearance is fine. After all, it's in the same plane that the thrust surface of the cam sprocket is in, thus the sprocket can't get any closer to that surface anyway, because it's already up against it at the center. Where the rub might occur, is at the outer edge, where the chain comes close to some of the timing cover screw hole bosses.

I've never used thread locker on those. 20 ft-lbs is a little on the light side; they should probably go just a bit tighter, like 25 or so.

gw204

Thanks sofakingdom.

Not the best pic, but you can see I've got plenty of clearance at the timing cover bolt locations. The chain and sprockets of this set are definitely thicker than the stock setup and aren't in the same plan as the case thrust surface, so they do sit closer to the oil galley. But as you said, the sprocket can't get any closer. Just a little paranoid about the .030".

The set is a Cloyes 9-1100. Zero slack upon installation. So much better than what we took off.



I would have gone with a silent chain replacement, but since my boy and I are building this thing together I'm letting him have some input.

Thanks!

gw204

This is an example of the grinding I was wondering about...



vs.

sofakingdom

iTrader: (1)

Yeah your block doesn't have the bolt hole boss issue; but some do. Their bosses are real wide and protrude too far into the volume where the (wider) chain needs to be. Yours looks completely normal and OK.

As a potential useful FYI, I always drill the 2 plugs to the sides that terminate the lifter feed passages, with about a #70 or so drill bit; to squirt oil on the chain. (on the sprocket actually but it gets slung out to the chain)

That chain won't make any extraneous noise, fortunately. It's a decent setup.