Worn dist. gear teeth?
Thread Starter
|
Senior User
Joined: Dec 2018
Posts: 152
Likes: 3
From: NEPA
Worn dist. gear teeth?
So my '77 351M broke down on the highway coming home from work last week and I finally got a chance to look at it today. Figured it was the timing chain/sprockets but found this. Any ideas of what would cause this before I replace the chintzy napa reman distributor with the big buck duraspark distributor I've been sitting on? Don't want to besmirch the expensive one if I can avoid it.
Thread Starter
|
Senior User
Joined: Dec 2018
Posts: 152
Likes: 3
From: NEPA
Last year I replaced the original distributor with a napa reman because the original's vacuum advance was rusted solid......but it still ran. Stabbed that napa reman and it drove almost 3 miles and the shaft broke in half. Got THIS reman and now the gear teeth are kaput about 400 miles later! What the fork!!!!
Thread Starter
|
Senior User
Joined: Dec 2018
Posts: 152
Likes: 3
From: NEPA
Was actually 11/6/2018 I got this reman distributor (just found the receipt). So in 6 months and only a couple hundred miles it's dead? I only drove it to work and back at most maybe 6 times. 35ish miles one way.
Lead Driver
Joined: Oct 2018
Posts: 7,864
Likes: 2,359
Lots of cheap Chinese gears out there these days.
if your cam is stock I'd check out the gear on it as best you can and make sure it's not toast then put an MSD gear on your distributor. if your cam is a roller you need a hardened steel or bronze gear.
Even the Chinese junk should last longer than that. hopefully a new gear will fix it but it would suggest you have other problems.
if your cam is stock I'd check out the gear on it as best you can and make sure it's not toast then put an MSD gear on your distributor. if your cam is a roller you need a hardened steel or bronze gear.
Even the Chinese junk should last longer than that. hopefully a new gear will fix it but it would suggest you have other problems.
Thread Starter
|
Senior User
Joined: Dec 2018
Posts: 152
Likes: 3
From: NEPA
Well without holding the cam in my hands to verify the lobe profiles I'm gonna assume it's stock because I don't see any lifter keepers or anything down there by the lifters. Also found that #1 intake lifter looks to be toast rocker is flopping like a mackerel. With the pressure off the pushrod, I can slip .160" worth of feeler gauges under it. Yippeee. It'll pump up tight with a drill spinning the oil pump rod but as soon as stop the drill, it goes soft again. I'm thinking the crappy oil pressure wasn't getting oil to the dizzy gear. Can I possibly drill a small hole in that oil gallery plug right above the dizzy gear to get more oil to it or would that lower my oil pressure too much?
Trending Topics
Lead Driver
Joined: Oct 2018
Posts: 7,864
Likes: 2,359
if your oil pressure is so bad you're not getting enough oil to the distributor gear you're done for anyway.
If you have any slack between the rocker and pushrod it's too much.
you have the classic example of this series of engine that made them so unpopular
If you have any slack between the rocker and pushrod it's too much.
you have the classic example of this series of engine that made them so unpopular
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 784
From: Simi Valley, CA
It was not uncommon for dizzy gears to chip, didn't matter if it was an I-4, I-6, V6 or V8. Chip happens!
Originally the roll pin to retain the gear to the shaft was split, had to be driven in. Later Ford replaced it with a pin w/a head on one end. You could install it with your fingers.
That pin worked loose causing the gear to wobble on the shaft. Didn't take too long after this occurred for the gear to chip.
And there are different gears, 1977/79 F100/350 351M/400 used this puppy: C4TZ-12390-A
But a 351M/400 dizzy bought in an auto parts store may use a different gear.
Originally the roll pin to retain the gear to the shaft was split, had to be driven in. Later Ford replaced it with a pin w/a head on one end. You could install it with your fingers.
That pin worked loose causing the gear to wobble on the shaft. Didn't take too long after this occurred for the gear to chip.
And there are different gears, 1977/79 F100/350 351M/400 used this puppy: C4TZ-12390-A
But a 351M/400 dizzy bought in an auto parts store may use a different gear.
Mountain Pass
Joined: May 2006
Posts: 217
Likes: 5
type of cam has nothing to do with distributor drive gear wear, assuming proper match of materials. the cam drives the distributor. the only load on the distributor is the bushings and of course the oil pump. pull the shaft and check the top bushing.
Mountain Pass
Joined: May 2006
Posts: 217
Likes: 5
please review and comment on the highlighted portion of my post.
to clarify, I was thinking of hi performance vs stock wearing the gear.
and post # 2.
Last edited by 78Broncoinpieces; May 14, 2019 at 09:09 AM. Reason: nothing better to do.
Lead Driver
Joined: Mar 2004
Posts: 8,922
Likes: 153
Whatever distributor you put in, you should always check the position of it's gear. Too many verables to deal with when your dealing in thousandth of a inch. Too far down on the shaft and the cam and block will end up junk. It's a very important step in changing distributors.