351m eating distributer
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New User
Joined: Oct 2000
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351m eating distributer
My 351m just started eating distributers. The small gear that meshes with the cam, The first ate the roll pin no problem, However the second ate 3 teeth from the distributer. Both happened climbing a steep grade in third gear it just backfires and the truck dies. Anybody have any answeres.
Junior User
Joined: Sep 1999
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351m eating distributer
Sounds like a general problem with the cam bearings being worn out or the cam is sliding back and forth due to improper shimming. Or if you recently replaced the cam then it sounds like the cam and the distributor are incompatible as far as the hardness of the gear. Some cams require special dist gears like, steel, bronze, hardened steel etc.
Junior User
Joined: Apr 2000
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351m eating distributer
The distributor dying causes the backfire, not the backfire killing the distributor. The bronze distributor gears are for steel cams so don't use one of them on a cast cam. Are you using a high volume or high pressure oil pump, it's recommended you use a hardened oil pump drive shaft due to the extra load put on the distributor to drive it. Just a few thoughts....
Jim
Jim
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351m eating distributer
I am still in the process of rebuilding my 351m, and the machinist told me that you have to be careful of the cam and the distributor in the 351m and the 351c because of this problem. He said that he had seen this several times before, what happens is the gear on the dist rubs against the block and causes it to bind then the next thing you know the cam will peel the gear off the dist. I wish I could tell you the clearance the dist gear and the block should have between them. We could easily tell while rebuilding mine the first one we put in as soon as you tightened down the dist the distributor would bind and you couldn't turn it no more, the machinist tried milling it down but then the gear was starting to go past a tolerable limit, and second dist we tried once bolted in, was very easy to turn. (Of course no crank or cam or anything in it so it made this process easy to tell) He said you would get about 500 or so miles and then it would eat the gear out. Hope this helps you understand where the problem is coming from.
Lead Driver
Joined: Nov 2000
Posts: 6,625
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From: Albuquerque
351m eating distributer
Hey Hey! Been there, done that! Actually you might have a different problem but- if your distributor has a few miles on it it may have worn out the bushings. This let the rotating assembly drop down untill it drags on the inside bottom of the dist. case. Shears pins,grinds up aluminum etc.
1977 Ford F-100
400m/c6
280,000 miles
Stock on the outside
modified/rebuilt everything
1977 Ford F-100
400m/c6
280,000 miles
Stock on the outside
modified/rebuilt everything
New User
Joined: Apr 2000
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351m eating distributer
I just had this happen on my 351W that I had just rebuilt. Same distributor, new Ford marine cam. Ate the gear off after about
5-6 hours operation. Called Fords Tech line to ask about cam compatibility and they said that should be no problem. Told me it was the high volume oil pump I put in it. Too tight of clearances, weakest link. Had the ARP pump drive shaft. So they say.Sent those little shards of metal through all the new bearings. Just getting it back together again. Trashed the distributor, pulled the shaft down and ground on the base. Not pretty. Anyone had that happen?
5-6 hours operation. Called Fords Tech line to ask about cam compatibility and they said that should be no problem. Told me it was the high volume oil pump I put in it. Too tight of clearances, weakest link. Had the ARP pump drive shaft. So they say.Sent those little shards of metal through all the new bearings. Just getting it back together again. Trashed the distributor, pulled the shaft down and ground on the base. Not pretty. Anyone had that happen?
