Still with the rough idle
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Freshman User
Joined: Sep 2003
Posts: 36
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From: Vancouver,USA
Still with the rough idle
After carefully following the advice of the experts here,I think I have only one more thing to fix to get rid of the rough idle on my 70 302. I finally got around to checking the damper and see if it had slipped. The timing mark sits at zero and the #1 piston is at the top...so,OK??
Now,someone mentioned to me that slop in the timing chain will cause a rough idle also,and the timing mark will jump around. Well,I can move the timing mark about an inch and a half without affecting the movement of the rotor. Enough slop for ya?? The rotor was replaced last year as it was sloppy in it's own right.
Time for a new chain and gears???
Now,someone mentioned to me that slop in the timing chain will cause a rough idle also,and the timing mark will jump around. Well,I can move the timing mark about an inch and a half without affecting the movement of the rotor. Enough slop for ya?? The rotor was replaced last year as it was sloppy in it's own right.
Time for a new chain and gears???
Hotshot
Joined: May 2004
Posts: 12,170
Likes: 5
From: The hills of No. Calif.
Sounds like it could be.
Did you check the distributor at all? Do you still have the original points distributor?
I've seen them get so sloppy theat you can move the breaker plate up and down by hand, which means that the points are jumping all over the place. Don't know if you've been there or not, just thought I'd mention it.
Did you check the distributor at all? Do you still have the original points distributor?
I've seen them get so sloppy theat you can move the breaker plate up and down by hand, which means that the points are jumping all over the place. Don't know if you've been there or not, just thought I'd mention it.
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Freshman User
Joined: Sep 2003
Posts: 36
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From: Vancouver,USA
Replaced that last year..as you say,just moving the cap would make the engine stall. NO I don't wanna do it,but at least it's not a particularly time consuming chore,especiallly if I get my Dad and brother in there.
Hotshot
Joined: May 2004
Posts: 12,170
Likes: 5
From: The hills of No. Calif.
Try putting a timing light on it, disconnect the vacuum advance and rev the engine while watching the mark. Hold it at about 2500 or so for a few seconds so that it stabilizes, then let it go back down a bit. You'll want to see how much movement there is whille keeping above the speed where the centrifugal advance kicks in, so you don't get any readings from that. Take the RPMs up and down a bit and see if that mark jumps around as you get on the throttle and then back off. If it does, then you've got some slop in there.
See if the advance
See if the advance
Thread Starter
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Freshman User
Joined: Sep 2003
Posts: 36
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From: Vancouver,USA
Thank you sir,I also did that when I did the new dis and tuning. It definitely jumped around. I suppose I'll get around to it eventually,(it hasn't slipped yet)but I do remember as a kid my 66 fairlane had the same problem and eventually gave up the ghost.
Hotshot
Joined: May 2004
Posts: 12,170
Likes: 5
From: The hills of No. Calif.
Well then, best to just do it. If it just gets sloppy enough to jump a tooth, that's not such a major deal but what usually happens is that nylon cam gear can go, and then you can have little piston-to-valve interference...which definitely is a major deal!
