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Discussion Starter #1
so what would cause 3 teeth to break off the distributor gear on an msd dist? took the car out last weekend, smoked the rev limiter once pretty good, then a mile or two down the road car died...no spark. pulled dist out which was tough...it was stuck...and found 3 teeth broken. no wear on the rest of the gear at all. strange.....so i guess i have to drop the pan...which really sucks.any way, any thoughts?
 

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did you put some breakin lube or assembly lube on the gear. sounds like it may have jumped a tooth when you over reved it sorry to hear of your bad luck.
 

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Something sucked into the oil pump and jamming it will do it. Predominant thing I have seen jam an oil pump is the circular clip from top of a hydraulic lifter. They sneak through the mesh. With solids?

See if you can tell the wear pattern on the distributor gear. Centered, high or low.


Does the distributor turn freely? I had one seize in the upper bearing. Is there a thrust washer between the distributor gear and the bottom of the distributor? Keeps it moving easily and prevents chewing up the bottom of the distributor.

Check the recess for the oil pump rod. Make sure it isn't torn up.
 

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Discussion Starter #8 (Edited)
well, i brought my bore scope home and checked out the cam gear...its toasted too. i checked the oil pump and it spins freely so it obviously is not the culprit. any other ideas? im going to tear into the engine later this week. so im in the market for a good camshaft..any suggestions?

385 ci sbc
5.7 rod
10.4:1 comp
patriot performance 190 cc heads

comp xe 274 solid flat tappet cam
Specifications Intake Exhaust
RPM-Range: 2000-6400 Valve Lash: .016
Valve Timing:0.015 Duration:274/280
Lobe-Center Angle:110 Duration @ .050" Lift: 236/242
Intake Centerline:106 Valve Lift:.501/.510
Lobe Lift: 0.335/0.341

performer rpm intake
demon 750 carb
max 125 shot of nitrous
95% street car
th350 with 3500 stall converter
3.73 geared 10 bolt
275/60 r15 tires for the street
26X10 slicks for the track
3400 lbs w/driver

best performance at the track to date is

60' 1.582
330' 4.662
1/8 7.289
mph 93.27
1000 9.573
1/4 11.509
mph 116.26

this is running 75 hp nitrous and on a very humid night last fall. i have not been to the track since, but am sure it would have gone a little faster with better air.

thanks for any input. rob.
 

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odds are.... a piece of casting slag? something got in between the teeth....that caused the failure...

either way.. its rebuild time..

Sorry man.. that hast to suck horrendously:(
 

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When the pan comes off, be sure and check the oil pump out carefully!! Take the bottom cover off and inspect the case and gears to see if there's any "Witness" marks.

You may have had a bum cam. Maybe the cam or distributor was dropped at one time.:rolleyes:

Make sure the distributor is setting down and meshing with the cam gear correctly. If it's setting a little too deep there will be a pretty good bind on the gears.

Sorry to hear about the carnage!!:(

I noticed you've got some Patriot heads.:rolleyes: Look carefully at your valve stem seals. If they have the wire spring on top (on the valve portion), I've seen them break and end up in the pump gears as well.:yes:


Seals like these it's not so common with:
 

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I had this happen to me 2 years ago. I made a solid roller cam for my 331 that had the pressed on cast iron gear option (Crane made the billet). After 30 passes I swapped the air gap intake for a super victor and when I pulled out the distributor I saw the gear wear. Odd that it was only worn on one side. Luckily for me the camshaft gear was fine. I went to a bronze gear and the wear went away. If you search on the MSD support forum you will find a few
threads on this subject, http://www.msdignition.com/forum/
If the distributor isn't too old, I would call MSD and ask for a new gear.

I have a 282 degree lobe, 244 @ .050" with .346" lobe lift (.519" with 1.5's) that we could put on a 110 lobe separation angle. Should work nice and give you a little more top end vs. the current cam.
 
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