need some engine help -Chevy

orange150

orange150

Well-Known Member
Joined
Mar 20, 2005
Location
Fairfax City, VA
a buddy of mine is building a 383 stroker. He has the bottom end together, and heads on it. he is now trying to install his cam but it keeps hitting part of the engine (not sure which part, he mumbles a lot). He has been through two cams from comp cams trying to figure it out but they all hit still. He's beginning to think the timing is off. Anyone know off hand or anyone around the wakeforest road/whitaker mill area of Raleigh mind lending a helping hand?
 
was he able to spin the motor before he put the cam in?
 
timing shouldn't matter at this point, as long as the lifters are not in it, it should slip in, if you don't line it up straight, occasionally a cam lobe will hit the block causing it to stop, but gently moving it it should find it's way through, try standing the motor vertical, so you can slowly drop the cam in.
 
One tip I use...

I screw a long (4" or so) bolt in to the cam. The added length will give you "leverage" to lift the back of the cam over the guides.

But a SBC isnt bad a 258 cam is a long hard to control beootch.

Like has been said.
Timing means nothing at this point. Just make sure #1 is at TDC for alignment purposes.
Lifters should be out and dropped in aftercam is in place.
Ditto on dizzy...depending on how far back he is "hitting" something that may be it. Thought not sure how old cam would have been pulled with dizzy in.
 
a boogered up cam bearing would/could cause that as well, not hard to mushroom one during install if you are not using the right tools.
 
ok, just got over to his house so i can better describe the problem. when he rotates his engine (it will rotate w/o the cam in it) you can hear one of the cam lobes hit what he thinks to be the connecting rod on the journal of the #5 cylinder.

the cam bearings aren't/shouldn't be "boogered up" he just got the block redone at T-Hoff (new cam bearings etc.)
 
we have also tried it at 4* retarded, 0*, and 4* advanced, same thing. the cam will spin 360 when the crank isn't in, and the crank + connecting rods will spin 360 when cam isn't in
 
And how bad does it hit? Is it a small enough interference that a little grinding would take care of it?

How big is the cam lift?
 
Ok, im not too sure if Im reading the right lift here, But:
the cam that comp cams said would work:
lobe lift .3080 intake .3200 exhaust
the cam that he ordered on his own:
lobe lift .2830 intake .2830 exhaust
 
That is not a huge cam. .32 lobe lift is .480 inch valve lift (1.5:1 rocker arms).

I have heard of this happening with really big cams, but that should not be the case here, I wouldn't think. Or do you have to run a special cam with smaller base circle in these 383 Chevys? The cam manufacturer would definitely know this, as popular as 383 small blocks have become.

How much of an interference is it? Could minor grinding on the rod cap fix it?
 
grind just enough materal off the rod cap to gain clearance.
check clearance on all cam lobes thru 360 degrees rotation.
 
just to check but, how are you aligning the cam shaft to the crank?

The timing marks need to BOTH point straight up NOT at each other.. Is it possible your cam is in wrong?
 
I'd be a little concerned with arbitrarily grinding material off the rotating assembly.. (assuming they are balanced)
 
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