Socom's 69 Z/28 Refresh Thread

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  #11  
Old 04-29-2013, 12:38 AM
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Originally Posted by Camaro 69
Even still, you shouldn't be eating up a distributor gear in that short time, miles wise.
What kind of a cam did you have? Make sure you have the right type of gear (metal compound) on the distributor to go with it.
Does your distributor have too much up and down slop?
Does your distributor have an adjustable collar, or is it cast into the body like a standard dizzy? You want to make sure the dist. gear isn't too deep or too shallow into the cam gear.
I dont know what kind cam was in there, I think it was custom ground for the motor. Im thinking about buying a brass gear for the new dizzy. The dizzy had about an quarter inch of slop in it. I had an msd 8361. Ill definitely be checking all that when it goes back together.

I believe this is the cam I have thats going in, I cant remember if it was the first design or second design, but its a crane blueprint cam. Ill have to look at the cam card again.
First Design Off-Road cam, P/N 3927140
Casting #3927141
Intake 257 duration @ .050" (333 advertised)
Exh. 269 duration @ .050" (346 advertised)
Lift: .493" intake, .512" exhaust
Intake Max lift @ 108 deg. ATDC
Exhaust Max lift @ 116 deg. BTDC
 
  #12  
Old 04-29-2013, 12:51 AM
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What new distributor are you putting in. Do you want to get rid of that old MSD clunker? I have the Pro-Billet, but I think I would want to play around with vac advance to see what that does to my off idle response. Given what happened to yours, it would be a good idea to check your new gear mesh with marking paint.
 
  #13  
Old 04-29-2013, 01:20 AM
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Mine was a pro-billet too, and thats what I plan on running again since I have a 6AL box on the car too. I'll definitely be checking it though, I dont need any more broken parts :P
 
  #14  
Old 04-29-2013, 08:37 AM
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Cam end play was the most likely the issue. If the center line of the Cam gear does not "stay put" you can get funny wear. It must have been pretty bad. I have seen racing motors that ran at 9000 RPMs and ended up with too much cam end play and had less then half the wear that gear had on it. That is the worst wear I have ever seen. At least the worst wear I have seen with a cam still in one piece. When the Cams blow a part they tend to take the bottom part of the distributer with them into the clutch assembly and ruin all that. You dodge a bullit on the one. Good catch.
 
  #15  
Old 04-29-2013, 09:02 AM
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The most likely reasons for a failure like yours are: not enough oil flow to the gears, a cam/distributor gear metal incompatibility, the extra stress of a high volume oil pump, or any combination of the three. That's what you need to focus on with the new setup.
 
  #16  
Old 04-29-2013, 10:21 AM
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wow looks like the cam was not in all the way. check timing gears for any unusuall wear.
 
  #17  
Old 04-29-2013, 10:59 AM
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Could also be the distributer end play. That almost has to be a alignment issue, I have seen plenty of oil pump twist off their drive shaft and not seen anywhere near that wear. Could be a combination of Cam endplay and distributer endplay.
 

Last edited by Gorn; 04-29-2013 at 04:08 PM.
  #18  
Old 04-29-2013, 11:33 AM
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Distributor end play...I like the more technical term I used: up and down slop.
In response, he said his dizzy had about 1/4" of slop. I'd like to see that in action.
 
  #19  
Old 04-29-2013, 02:08 PM
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Would a cam button be a good investment to keep the cam from walking back and forth too much?
 
  #20  
Old 04-29-2013, 02:53 PM
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Cam thrust control wouldn't hurt as an extra safeguard, just in case that does have anything to do with it.
 


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