SBF Distributor Gear Stripped WTF

i can tell you exactly why that happened: you were on your way to a great show and chosen to be the "sacrificial rodder" by the BILLETPROOF GODS! HUGE BUMMER DUDE!

 

Did you check camshaft end play. I have seen a motor that had the wrong camshaft retainer plate on and it had excessive end play. Knife edged the distributor gear and eventually broke the gear. Tore the motor apart for him and replaced with correct retainer plate (which brought end play into spec) and has never had another problem.

 

Hard to say from here, but your pic sure looks as though there's no roll pin installed in the gear...???

 

figures lol it was problem after problem that day. Litteraly 15 things went wrong that day!

theres no cam play

yes there was, we pulled it to take a look.

we"re betting that it was damaged before and we didnt notice it before we put it in.

a new gear is $33 and a completely new distributor is $40. so on payday im buying a new distributor

 

60, you must have end play or end float with the cam, no different than with a crankshaft. Camshaft axial play or end float is .001"-.007" for your SBF. Be sure that your cam thrust plate is correctly orientated so that the small groove on the back or inside allows oil to flow from the second groove/slot in the cam bearing to the thrust surface between the thrust plate and the camshaft. Torque these bolts to 105-155 INCH pounds with BLUE Loc-Tite. Coat the new gear GOOD with 50wt engine oil or even better engine assembly lube. Absolutely pull the oil pump and do a basic tear down and inspection. Make sure the oil pump housing is flat as well as the cover. Pack the pump with Vaseline when you are finished, never grease. Did you remember the oil pump mounting gasket? Check the fit between the pump and the drive shaft and the distributor, it should have approximately .200" of movement up and down! That is just over 3/16" of an inch OK. Also if you use the Ford Racing drive shaft, it only goes in one way. Nothing can be to chance here, all the best, TR

 

60, also for any lower end priced Internal Wet-Sump SBF builds I do, I use the Melling SELECT oil pump in STANDARD VOLUME, never the High Volume. I know you didn't use the HV and that is good. If you need a new pump go the few extra $$$ for the SELECT, and yes I still take it apart for a complete inspection regardless of who makes it. TR

 

Check the roll pin closely. One of the times mine sheared, it sheared in 3 pieces. The piece in the shaft was one piece and the two pieces in each hold of the gear were the other two. From the outside, you couldn't tell...

 

Flat Ernie... I had that one happen in a 390 FE.... At the wrongest time and place, of course.....

4TTRUK

 

Is there any chance that this motor has a Comp Cams cam in it?

 

As my 289 has one, why are you asking?

 

There was a run of Comp Cams for SBF that had an issue with the cut on the cam gear a few years back. Seems there was some dispute as to whether it was the angle the gear teeth were cut at or just a matter of them being too "Square edged" and sharp which caused them to eat dist gears. Many said that "Burnishing the gear" cured the problem, but it was fairly well known for a short period about 2 years ago or so. There could be some of those cams still in warehouse inventory.

 

Look right at the end of my arrow, I could be wrong but it appears as though the lower bushing is shot.

Worth looking into. That will knock a gear in a heart beat.

 

1) Gear MUST match the cam - material wise.
b. Gear MUST be installed to proper ht. Either read the documentation or find someone to explain it to you. CHECK it when you put it in and then in a couple of hundred miles.

That .030 squirter trick can't hurt.

 

I had the same issue with a fresh rebuild (and a Comp Cam). distributer gear wore to a knife edge in less than 50 miles.

Upon teardown I found the cam retaining bolts were loose, allowing excessive cam endplay, which in turn took out the distributer gear. I don't really see how it could have been a cam problem in my case, as the thrust loads would have to be pretty hellacious to overload and yield the thrust plate bolts, relaxing clamp load and allowing excess axial movement.

I think I just screwed up the assembly and forgot to touque the thrust plate bolts.

Your engine is going to have to be completely disassembled so the oil galleries can be cleand out. The mains and rods are also toast. Drain your oil into a clean pan and you will see a beautiful glitter in the drain oil and pan.

Good luck!

 

Thanks. Mine could be in that time frame, although I believe it is closer to 3 or 4 years ago that I installed it. The engine has only been through the break in time. I will have to check my receipts.

 

Many early Ford V8 distributors did not have a lower bushing, and by 1975 they did away with the lower one once again.

 

And that closeup of the distributor gear roll pin hole sure looks like the hole is shiny and wallowed a bit - as if the roll pin was loose or broke.

 

Yup comp 280

I'm buying a new distributor on payday

Oil came out clean. I even sprayed the inside with Carb clean to see if I could get anything still came out clean.

 

Sharp eyes. That could be it. Ill have to look at it when I go back to the shop at my buddy house. Ill get back to you on that though

 

That is actually in the collar with the roll pin or set screw.
The shaft bushing still might be worn though.

 

Well I bought a brand new distributor with a lifetime warranty and drove my Galaxie around seemed fine. So me and dynaflash_8 decided to go to the local cruise in when it decided to eat another damn distributor gear.

So I guess I'm buying a new cam

Reporting to you from the side of the road. Fml

 

Just for the record Traditions Racing was right. I was missing my thrust plate. Everything is good now

 

Missing? How did that happen?

 

hey hey, not so fast buddy. you know how they say every one has a twin? well your twin in up in detroit chewing through gears right now! I have eaten 6 gears. 4 cast, 1 bronze , and a very expensive composite gear also. unlike your self, i did have a high volume pump which has already been taken out. I know for a fact that i installed a thrust plate, but i do not remember the bearings as much. but I HAVE NO ENDPLAY. so my question to you is, did you have no end play and did you install thrust plate bearings when you re-installed, and how is that working. I was just going to do a full cam swap with the whole new shabang! any real assistance would be great! thanks guys