Hi all, Ive got a 396 with hyd roller Comp Cams camshaft and a MSD Pro Billet distributor. Per both MSD and Comp Cams Im using the steel gear on the distributor since the cam is NOT from a billet core, I have already wore out two distributor gears. I have taken the intake off and have tried to move the cam fore/aft to check if there is any end play or what I think is the problem in my case is a lack of end play but it wont budge. I think the cam button is against my timing cover and is being pushed into the gear since the wear is on the drive side of the gear. My question to everyone is other than taking the timing cover off and using a material like clay or putty to press between the cam button and timing cover whats the best way to check this and correct this.

thanks again

You might be experiencing too deep an engagement between the gears. Have you had the heads milled, or has the intake been shaved? I would recommend that you replace the gear, and then shim your distributor so that it sits up higher and see if that corrects the problem. Also, if you don't have a magnetic drain plug-GET ONE! I would also recommend one of those magnets that wrap around your oil filter as you don't want those loose particles circulating in the engine. Change the oil!

After shimming the distributor, run the new gear for 1000 miles, and then pull it and check it every 1000 until you are certain you have eliminated the problem. If you still find that you are experiencing wear, you might try a bronze or mellonized distributor gear.

Let us know how this works out because I too have a Comp Cams hydraulic roller soon to be installed and I will be using the factory iron distributor gear with it. I have inspected my cam and can see that it has an iron (steel?) drive gear pressed onto the rear of it so it should work well with the standard distributor gear.

Best of luck with your set up.

69,
Camshaft walk has absolutely nothing to do with distributor gear wear. The main stress on the gear is from driving the oil pump. Do you have excessive oil pressure ? This could be putting a lot of drag on the gear, causing it to wear. The distributor itself contributes very little to the wear on the gear. Also, check gear engagement like go said. A simple test is to install the distributor WITHOUT the gasket under it. If it goes down far enough to touch the intake manifold, then it will be fine with the gasket.
My personal experience has been that once it kills one gear, it is done with and you will have to replace the cam and find out what the cause was to begin with.

Hi Again Guys,

For Go69:
Yes the heads and intake have been cut about .018-.020. First the heads were cut then I had a very hard time getting all the intake bolts to line up so my engine builder/machinist recommended we cut the intake. Where do I get shims from? Are these made for this or do you have to make your own?

For BillK
I racked my brains trying to think why this is happening and I remember when I had installed the timing cover it had touched the cam button before it came in contact with the face of the block and as I mentioned in my first post when I took the intake off I tried to pry the cam back and forth to see if there was any movement at all and there is no movement at all, so my question for Bill is do you really think that if the cam is being pushed back into the cam it wont cause this sort of wear? Also I do have a high volume oil pump which I thought originally may be the problem, I wont use one again. What is to much oil pressure? Im pretty sure Im between 40-60 depending on the temp and the driving condition.

So taking the timing cover of is a waste of time you think then huh? Id hate to go through all that BS and it not fix the problem so if you think its a waste of time I wont bother.

Also I had not metioned in my first post, the gears are NOT wearing out on all the teeth, it starts at one gear and slowly gets worse as it goes around the gear, a few teeth have almost no wear at all on them.

I should probably find pics I took of one of them to show you. Do you guys think that seeign the wear pattern will help you in determining whats messed up?

thanks again guys!!
Chris Galea

Since your heads have been cut, and your intake as well, I would guess that the engagement between the two gears is definitely too deep.

When I shimmed my distributor, I simply added an extra gasket or two between the intake and the distributor to put it up a little higher. I don't know if anyone makes a true shim (metal) just for that use.

I do know that there are several distributor manufacturers that sell distributors with adjustable collars. The collar (piece that your hold down presses against on one side, and the seal is on the other) slides up and down the body of the distributor to where you need it to be, then you lock it in place with a set screw/pinch bolt arrangement. This is probably the ideal way to address this problem! But if you are cheap like me, you could double, or triple the distributor gasket, or maybe find a thick metal washer to use in that area.

Your hi-volume oil pump may be a part of the problem, but my guess is that once you get the depth engagement problem fixed, you will have solved your issue.

The part about uneven wear on the gear tells me that the hole in the gear may not be concentric. However, once you resolve the depth engagement, that should not be a problem at all.

You might have one other thing to resolve. You state that your timing cover hits your cam button BEFORE the cover physically touches the block???

You are supposed to have around .005" clearance between the nose of the cam button and the timing cover. Otherwise, you will either wear a hole in the cover, or wear the nose off the button. Perhaps you got lucky and the items clearanced themselves by wearing enough material away that they are not in constant contact, but not causing catastrophic damage either. Maybe you got lucky. Maybe the button will fall apart soon and litter your engine with tiny needle bearings, or metal shavings. I would not take the chance. Remove the timing cover and inspect for damage if you really think there is not enough clearance.

Lastly, I hate to say it but I think Bill was right in his previous post. Once you have a cam that starts to eat gears, most times the only way to stop it is to replace the cam. You can try shimming the distributor and running a new gear and then checking it often for wear and maybe there won't be a problem. But if it continues to happen, it is time to buy a new cam.

If you go the new cam route, make certain you get the distributor, and cam button/spacer set up right the first time so you don't have any future issues. Good luck with your project!

CHris,
First of all, did you try the deal with installing the distributor without the gasket to see if it will go all the way down against the intake ? If it does not, it is bottoming out in the oil pump and has probably damaged it.
It is very difficult to see the wear on the camshaft gear with it in the engine. If you have worn out two gears, something is seriously wrong and needs to be fixed. I really think at this point, it might not be a bad idea to get someone a bit more knowledgable to come and take a look at it. These types of problems are very difficult to troubleshoot without having the engine to look at. See if your engine builder will come over and take a look at it for you. Pay him for his time, sometimes an experience eye can look at it and see something wrong that you will never see.