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Posted by: 914Sixer Jan 11 2016, 09:29 PM

My camshaft rivets are loose and turn freely back and forth about 1/16-1/8 inch. I contacted Elgin cams and they say I need to tighten up the rivets. Is that possible? Thinking of using a drill press to drill the center out and use a punch on the rest? Then go back and tap the holes for bolts.

Ideas?




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Posted by: 76-914 Jan 11 2016, 09:54 PM

Center punch each rivet then start step drilling with 1/8" on up to the depth of the head. Somewhere around 8mm the bit will be large enough to separate the head from the stem.
I don't know how the Hell you tighten a rivet and I've seen a few. Be sure that the holes in the gear aren't ovaling. Is that a word?

Posted by: ThePaintedMan Jan 11 2016, 10:03 PM

Silly question, but could they be welded?

Posted by: r_towle Jan 11 2016, 10:14 PM

I suppose you could tighten the rivets but I would remove them as you are going to do.

Posted by: aircooledtechguy Jan 11 2016, 10:22 PM

The best way I know is to replace it with a Web cam with a bolt-on gear doing away with the problem once and for all. That is exactly what riveted cams do.

Posted by: 914Sixer Jan 11 2016, 10:26 PM

I am guessing the holes are ovaled too. I will take it to a machine shop for the drilling since I do not have a drill press. I do have the tap set for the holes.

Posted by: r_towle Jan 11 2016, 11:06 PM

Get a price, then price out a new camshaft and gear....

Posted by: porschetub Jan 12 2016, 02:32 AM

Not a very common problem,its a form of uncontrolled variable cam timing ,
issue is the camgear rivet holes go really oval and there is no longer a reference to redrill and fit bolts to get the timing correct.
Replace with a good used cam or aftermarket kit.

Posted by: 914Sixer Jan 12 2016, 06:32 AM

I guess I will be going with a different camshaft and gear. Going to toss this one.

Posted by: barefoot Jan 12 2016, 07:15 AM

You should be able to re-tighten the rivets by just pounding them down. Would have to back up the backside to do a good job.
Also could drill & tap some extra holes in between rivets and add bolts.

Posted by: stugray Jan 12 2016, 08:10 AM

For the cost of one trip to a machine shop, you can buy a bench top drill press from HD.

Posted by: aircooledtechguy Jan 12 2016, 08:19 AM

As porschetub mentioned, the issue is the aluminum cam gear holes are ovaled. Re squeezing rivets will not fix that and you have no way to ensure it's in the right position anyway. This was either a stock cam (yuck) or a re-ground stock cam with a performance grind (double yuck because now you are likely through the case hardening on the cam billet) AND to top it off, it's already used. . . To pay money to "fix" that cam and re-install it is just plain foolish if you ask me.

Get a new cam in a grind that makes sense for your application with a bolt-on gear and be done with it.

Posted by: r_towle Jan 12 2016, 08:28 AM

As you shop for a camshaft, be cautious of the overall height of the top of the bolt, the head itself. If standard bolts are used they will interfere with the oil pump and make a metal mess.
I have used standard bolts when I could not find what is required and ground down the height of the head on a bench grinder in the past.

I suspect someone like Elgin Camshafts would provide the proper bolts for this application.

Posted by: Valy Jan 12 2016, 11:34 AM

Your camshaft lobes don't look good. I would replace that camshaft anyway.

Posted by: ClayPerrine Jan 12 2016, 04:55 PM

It is more of a problem than you think. I just finished up redoing the cam in the wife's 914 because of this problem.

Go buy a new cam and lifters. Cheaping out here and trying to "tighten" will just make you tear down the engine again in a few months. By replacing it, you get a new cam and some piece of mind.