Loose camshaft rivets, What's the best way to remove them? |
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Loose camshaft rivets, What's the best way to remove them? |
914Sixer |
Jan 11 2016, 09:29 PM
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#1
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914 Guru Group: Members Posts: 8,882 Joined: 17-January 05 From: San Angelo Texas Member No.: 3,457 Region Association: Southwest Region |
My camshaft rivets are loose and turn freely back and forth about 1/16-1/8 inch. (IMG:style_emoticons/default/headbang.gif) 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? (IMG:style_emoticons/default/idea.gif) Attached image(s) |
76-914 |
Jan 11 2016, 09:54 PM
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#2
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Repeat Offender & Resident Subaru Antagonist Group: Members Posts: 13,502 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California |
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? |
ThePaintedMan |
Jan 11 2016, 10:03 PM
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#3
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Advanced Member Group: Members Posts: 3,886 Joined: 6-September 11 From: St. Petersburg, FL Member No.: 13,527 Region Association: South East States |
Silly question, but could they be welded?
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r_towle |
Jan 11 2016, 10:14 PM
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#4
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Custom Member Group: Members Posts: 24,574 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
I suppose you could tighten the rivets but I would remove them as you are going to do.
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aircooledtechguy |
Jan 11 2016, 10:22 PM
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#5
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The Aircooledtech Guy Group: Members Posts: 1,966 Joined: 8-November 08 From: Anacortes, WA Member No.: 9,730 Region Association: Pacific Northwest |
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.
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914Sixer |
Jan 11 2016, 10:26 PM
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#6
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914 Guru Group: Members Posts: 8,882 Joined: 17-January 05 From: San Angelo Texas Member No.: 3,457 Region Association: Southwest Region |
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.
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r_towle |
Jan 11 2016, 11:06 PM
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#7
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Custom Member Group: Members Posts: 24,574 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
Get a price, then price out a new camshaft and gear....
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porschetub |
Jan 12 2016, 02:32 AM
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#8
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Advanced Member Group: Members Posts: 4,699 Joined: 25-July 15 From: New Zealand Member No.: 18,995 Region Association: None |
My camshaft rivets are loose and turn freely back and forth about 1/16-1/8 inch. (IMG:style_emoticons/default/headbang.gif) 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? (IMG:style_emoticons/default/idea.gif) Not a very common problem,its a form of uncontrolled variable cam timing (IMG:style_emoticons/default/lol-2.gif), 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. |
914Sixer |
Jan 12 2016, 06:32 AM
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#9
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914 Guru Group: Members Posts: 8,882 Joined: 17-January 05 From: San Angelo Texas Member No.: 3,457 Region Association: Southwest Region |
I guess I will be going with a different camshaft and gear. Going to toss this one.
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barefoot |
Jan 12 2016, 07:15 AM
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#10
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Senior Member Group: Members Posts: 1,274 Joined: 19-March 13 From: Charleston SC Member No.: 15,673 Region Association: South East States |
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. |
stugray |
Jan 12 2016, 08:10 AM
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#11
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Advanced Member Group: Members Posts: 3,824 Joined: 17-September 09 From: Longmont, CO Member No.: 10,819 Region Association: None |
For the cost of one trip to a machine shop, you can buy a bench top drill press from HD.
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aircooledtechguy |
Jan 12 2016, 08:19 AM
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#12
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The Aircooledtech Guy Group: Members Posts: 1,966 Joined: 8-November 08 From: Anacortes, WA Member No.: 9,730 Region Association: Pacific Northwest |
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. |
r_towle |
Jan 12 2016, 08:28 AM
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#13
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Custom Member Group: Members Posts: 24,574 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
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. |
Valy |
Jan 12 2016, 11:34 AM
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#14
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Senior Member Group: Members Posts: 1,675 Joined: 6-April 10 From: Sunnyvale, CA Member No.: 11,573 Region Association: Northern California |
Your camshaft lobes don't look good. I would replace that camshaft anyway.
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ClayPerrine |
Jan 12 2016, 04:55 PM
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#15
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Life's been good to me so far..... Group: Admin Posts: 15,465 Joined: 11-September 03 From: Hurst, TX. Member No.: 1,143 Region Association: NineFourteenerVille |
Not a very common problem,its a form of uncontrolled variable cam timing (IMG:style_emoticons/default/lol-2.gif), 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. 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. |
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