any one ever heard of the distributor gear breaking theeth? little story. i have owned this truck (79 4wd 150)for obout 15 years and know it very well. the problem is the gear gets ground down till the theeth are thin and break. this is 2nd time this has happened on differant motors. the newst motor is 2yrs old with about 10,000 miles. motor has been running flawless since the install. change oil way more often than needed, just dont like it when sits. the first time was about 10yrs ago with the old motor. i was young and dumb and chalked it up to my heavy right foot. but now new motor, reman dist form napa and same thing! any ideas????

 

That is an interesting situation. Try cross posting this into the engine forum, this might start an interesting conversation.

 

cant. im computer dumb and wont copy and paste

 

Highlight the text, right click, copy. Find the forum you want, click new topic, go to the text body, right click, paste, fill in topic, click post button, done.

 

dosent work, invaild thread and contact adminastrator

 

You are doing something to make it angry.

The only suggestions I can make, aside from saying I have never seen stock parts wear like that is either you need to upgrade to a better engine oil, or there is a tolerance that is waaay off. It seems unlikely that you would have the same problem on two separate motors. It could be that the drive gear was not hardened correctly?

 

I've sold 100's of dizzy gears, so what you are experiencing is nothing new.

There were three different gears offered for 1975/82 351M dizzy's, so you may be installing the wrong one.

This is the gear used 1978/79: C4TZ12390A (Motorcraft DZ365)

 

replaced the dist. with a reman from napa. when first fired got bad back fire thru the exhaust. adjusted timing to 12 degrees and and it idled great. changed the oil not knowing where the dist gear theeth,shavings or what ever might have gone. well let it run till temp came up and took it for a test ride for about 2 miles and it ran great. i was at work fixin truck and work was closing so i left it there and drove the mstang home. latter that night the wife took me to work to get the truck. truck started right up and ran great. on my may home about 10 miles i heard a ticking or taping coming from the motor but runing fine. i figured header gasket leak from the backfire before. as i kept driving the taping got worse and then it started to miss badly. runing on 7 cyls i limped it home the rest of the way. parked it and went to the bar to drown my sorrows. any way , every thing i think of would cause miss but not tap or tap but no miss. havent looked at much yet, dist is still tight, pulled number 1 plug to set top dead center when seting dist, so checked plug and still tight, didnt see any sign of exhaust leak or burnt wire. dont know oil pressure as i only have dumby light(did not come on). any ideas and, or do think the problems may be related?

 

Make sure the pickup in the bottom of the distributer looks good, is not broken, loose... Mine ran like you described in your last post and the pickup had come loose. It's a wonder it ran at all. New distributer fixed the problem.

 

It sounds like you either did not have any oil, or oil pressure. The exhaust leak is lifter noise when they do not have any oil in them. Check your oil level first. Take the distributor out, and make sure the distributor driveshaft is seated correctly. Either it will be there correctly, or in the bottom of the pan. Take a 5/16" (I think) 1/4" drive deep socket taped to a 12" extension chucked to a drill, and spin it counter clockwise. The drill will turn easy for a few seconds, then really have to work hard. If you are using a 3/8 drill, you will burn it up. If the driveshaft is gone, order a new hardened one from the parts house, insert it with a magnet (and luck), reinstall distributor, and see if you hurt your motor or not. Chances are you did not kill it, however you did not do it any favors either.

GET A REAL GAUGE ON THAT THING! 351M/400 are known for eating bearings for lunch, dinner, brunch, breakfast, supper, snack time, you name it....

 

got good compression on all cyls, all with in 135- 150. all plugs look good. took off valve covers and all rocker arms move and have oil coming out of them when cranking over. its making a taping noise from both rear cyls. i think i read valves are not adjustable? is this correct? sound just like a valve tap. when a idle taps are consistant but when reving to around 2grand taps seem to come and go. put cheap oil gauge on and pressure is great. any ideas? im lost

 

anyone? im lost

 

Exhaust leak? Could be that your valve keepers are giving up the ghost??? Keep the hood shut, only to open for checking oil and water, drive it till it blows???

How bad is it still running still? I guess I should suggest measuring the amount of lift at the vavle stem? Pull the fuel pump off, see how much play is in your timing chain. If its too worn, it might have jumped a tooth? Do a leakdown test?

 

Topic 2: Excessive Distributor Gear Wear on Ford

Excessive distributor gear wear can be a problem with Ford engines. Most of the time, the problem is a result from the use of a high volume oil pump. High volume oil pumps put a lot of stress on the distributor and cam gears. A high volume oil pump is not necessary on a street driven engine that turns no more than 7000 rpms. Only extreme racing engines require the high volume pump. Should you use this type of oil pump, the following precautions will save your distributor gear from early destruction.
(1) Drill a .030" hole in the lifter/oil galley plug behind the distributor. This will allow additional lubrication on the distributor and cam gears. This will not lower oil pressure enough to hurt the engine.
(2) Ford oil pump mounting brackets have elongated holes. Due to this, the distributor shaft and oil pump shaft should be aligned so that the distributor turns freely before tightening the mounting bracket bolts. Failure to do this will cause a binding situation, thus damaging the gear.
(3) Stock Ford hex oil pump drive shafts are know to vary in length which could cause a bottoming or binding situation.
(4) Brass distributor gears can be used to avoid damaging the cam gear. Brass gears are softer and can wear out quicker than the cast gear, but will not cause damage to the cam gear. If using a brass gear, check it occasionally for wear.

www.PerformanceDistributors.com