While taking my 65 out for a spin this morning, I heard what sounded like a short belt squeel followed by my tach dropping to zero. Upon further inspection when I got home, I have found that the cross gear had seized to the coupler causing the teeth on both the cross gear, and the main shaft to sheer. My question is....What would cause this. The distributor is brand new, purchased as a rebuilt unit from Zip Products in August. There was plenty of grease in the area. Is this a common problem, or is it a case of the coupler being overtightened during assembly causing too much friction, thus the seizing of the cross gear to the coupler. The distributor has under 250 miles since purchased, and I got the feeling when I called ZIP that they would not replace the unit, although I was told to call back on Monday....Any suggestions as to the cause, and repair if Zip does not allow me to return the unit?
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Re: C-2 Distributor Help Needed
Dave = the first thing I would check is to make sure the tach cable is free if you turn it where it couples to the distributor. If so, this would be your argument with ZIP that the problem is not the cable or tachometer head. Otherwise, they may claim they caused the gear to seize. Normally, even with the coupler tight in the distributor, there should be some end play in the cross gear, to prevent binding. If there is not, I would claim they improperly rebuilt the distributor. The only way to correct this situation, is to replace the cross gear and the mainshaft in the distributor. I don't know what mainshaft autocam is installed on your unit, GM had many autocams and only 1 or 2 remain, and I don't know what cam is used on the aftermarket shafts. The best way to keep an accurate advance for your car is to braze the original autocam onto a replacement shaft. In your case, this may not be an option. Good luck with ZIP, I would fight for them to cover this situation, as long as your tach head and cable rotate freely...Craig -
Re: C-2 Distributor Help Needed
Thanks Craig....The cable spins freely and the tach registers movememnt. My initial thought was that I broke the tach cable, which I wish was the problem. It is definately the coupler and cross gear setup that caused the problem....Guess I will take it up with ZipComment
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Re: C-2 Distributor Help Needed
check to see if the cross gear shaft seized in the brass housing.Comment
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Re: C-2 Distributor Help Needed
Clem,
That is exactly what happend. The cross gear is siezed in the brass coupler housing. The brass coupler, cross gear, and brass end piece are all one unit. I am really baffled as to how this happend?? Any ideas?Comment
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New one on me
I've never encountered that kind of failure. Usually the cross shaft eats into the far end of the cast iron housing causing so much end play that the gear teeth bind. I haven't seen a steel cross shaft seize in a brass coupler before. Your coupler is made of brass, isn't it?
After the iron distributor housing gets worn, you have to build up the sunken area with epoxy before installing a nylon thrust button at the end of the cross shaft. Was this done in your distributor? Actually, the plastic thrust buttons were installed by the factory in the seventies tach drive distributors. An extra thick replacement button is still sold by LICS.Comment
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Spacer washer?
Is the spacer washer still between the coupler and the cross shaft gear teeth?Comment
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Re: C-2 Distributor Help Needed
too tight a fit or no lube. i always used camshaft breakin compound(moly kote) for lube on all these parts. i heard some one makes a setup using a small needle bearing for the cross gear.Comment
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Re: New one on me
jerry i have see quite a number of seized cross gears in the brass housing,i think the grease gets hard and if the car set for a while it binds up. that is why i use moly kote.Comment
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PS
there also may not have been enought end play for the gear.Comment
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end thrust bearing
before the end thrust bearing were installed from the factory we drilled and tapped to use a "vlier" screw in the end of the housing. these are allen set screws with a small ball bearing in the bottom end that we used as the thrust bearing for the cross gear. we set the end play and then tightened the lock nut. not NCRS leagal but hey we were racing for money and not for glory.Comment
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Re: Spacer washer?
The thrust washer between the cross gear and the coupler is still there and free. It is the only part of the whole unit that still moves. The siezing was not a result of lack of use...I drive the car fairly regularly (couple time a week), and there seemed to be plenty of fresh, clean grease on the cross gear and main shaft teeth. I am assuming that there was inadequate clearance between the cross gear and the brass coupler....whatever the cause, it certainly locked up and took some teeth with it...Comment
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Re: C-2 Distributor Help Needed
Clem,
Do you know who makes the needle bearing for the cross shaft?
I'm currently rebuilding my Dist for my 427 and I am intrigued by the needle bearing idea.
I too, in the past, used cam break in lube on these parts.
ACComment
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Re: C-2 Distributor Help Needed
al i will check because i know i saw it in some magazine,i just have to remember where.Comment
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Re: C-2 Distributor Help Needed
al, i will check because i know i saw it in some magazine,i just have to remember where. i get 6/8 car magazine a month and when i am done with them i give them to the local library so i will keep my eyes open.Comment
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