Timing Changes!!

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Timing Changes!!

Post  774 Super Street on June 1st 2012, 5:02 pm

Ok here is a good one. My buddy put together a SCJ headed 473 and has it in a 1965 Mustang that weighs 2550 with him in it. He took it to the track about a month ago and the best run was a 9.57 @ 139 mph. Not bad
but should be better. The engine was dropping oil psi under braking past the finish line. He brought the car home and replaced the oil pan and pick up with a new Canton. He started the engine and ran it to temp and everything was fine. He then hooked up the trailer to load the car and the car wouldn't start. After some checking he found the timing had changed. So, he timed it again and ran it with no issues, shut it off and it would not restart due to the timing changing again. So he has now checked the damper, pulled the front cover and checked the timing chain, tested the MSD 7al 2 box, removed the distributor and looked it over and anything else you can think of. The only thing even remotely wrong was the timing advance plate was a little loose from when he originally locked the timing out of the MSD 8580 billet distributor. He has now tightened that and is going back together. Any ideas?
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Re: Timing Changes!!

Post  4thHorseman on June 1st 2012, 5:35 pm

What chain, dizzy? How much we talking here? Details please.
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Re: Timing Changes!!

Post  774 Super Street on June 1st 2012, 5:43 pm

Cloyes Quick Adjust Timing Chain. Timing changes up to 60 degrees.
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Re: Timing Changes!!

Post  Tommyj466 on June 1st 2012, 6:09 pm

Roll pin on dizzy sheared? May be enough interference fit there to hold timing adjustment for Short period of time.

TJ
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Re: Timing Changes!!

Post  maverick532 on June 1st 2012, 10:00 pm

ck stator in distributor it is supposed to be welded to shaft and should not move , had this exact same problem with msd distributor before drove me nuts .
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Re: Timing Changes!!

Post  powerstrokeace on June 1st 2012, 11:11 pm

Tommyj466 wrote:Roll pin on dizzy sheared? May be enough interference fit there to hold timing adjustment for Short period of time.

TJ

Ran in to the same problem. The roll pin shears and you really can tell till it frees up from the sheared end gripping the shaft. I did this 3 time last year and so far this year all i did was go from 20-50 to 10-30 oil to see what happens. The best idea i heard was to drill out the hole to X/XX size and then install a roll pin that size and then a roll pin inside of that one. Not sure what forum it was on but do a search under roll pins or sheared roll pins and see what comes up.

Ace
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Re: Timing Changes!!

Post  774 Super Street on June 12th 2012, 10:08 am

The issue turned out to be the reluctor for the magnetic pickup had moved in the distributor. It was then out of phase with the rotor causing the issue. That was fun!
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Re: Timing Changes!!

Post  rmcomprandy on June 12th 2012, 11:13 am

Use another KNOWN GOOD ignition box ... what you describe has happened before with a bad electrical part in the box.

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Re: Timing Changes!!

Post  774 Super Street on June 12th 2012, 11:50 am

Randy,
We installed another distributor and the issue is solved. The ignition box was next. Thanks
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