Running issues

[FST FOX]

Ok Wednesday night I broke the Poly gear in the dist. well when it broke te car backfired. I replaced the gear, timed it and thought I was good to go, car ran rough had all the symptoms of a blown power valve, so I replaced the power valve and still acting the same. I'm at a loose now as I am not to familiar with carbs. the set up 408 w/ a 750 quick fuel carb. Any Idea's or suggestions.

[Seagull81]

Call Keith Craft and talk it over with him. I'll bet he has some ideas.

[RICK LAKE]

FST FOX You are missing somethings in the motor. Where you able to recover the complete gear or just parts?? If you got the whole gear, was just the pin snapped off?? MSD has had problems with the roll pin, ( expansion pin for the gear) Alot of guys have gone up to the next size pin for this problem. I don't have the correct size in front of me, but can find out. That gear is stronger that steel and should last for years. I have been running 1 for 2 years, all racing. HVHP oil pump with 100 psi spring. Cold oil pressure is 135-138. I would not run this motor any more until you pull the oil pan and check for damage in the motor. Look for metal in the pan, then pull the oil pump and make sure it spins easy. While the pan is down check every lobe on the camshaft for wear or damage. This is a pain but could save you thousands if the motor is hurt and you stopped now for repair. Pictures and a little more info would help. IMO you could also do alot more damage to the motor before you find what cause this. Spinning cam bearings or main bearings is almost a sure death for this motor and you will need a whole new block plus the machine work.$$$$$ Rick L.

[FST FOX]

Originally Posted by RICK LAKE

FST FOX You are missing somethings in the motor. Where you able to recover the complete gear or just parts?? If you got the whole gear, was just the pin snapped off?? MSD has had problems with the roll pin, ( expansion pin for the gear) Alot of guys have gone up to the next size pin for this problem. I don't have the correct size in front of me, but can find out. That gear is stronger that steel and should last for years. I have been running 1 for 2 years, all racing. HVHP oil pump with 100 psi spring. Cold oil pressure is 135-138. I would not run this motor any more until you pull the oil pan and check for damage in the motor. Look for metal in the pan, then pull the oil pump and make sure it spins easy. While the pan is down check every lobe on the camshaft for wear or damage. This is a pain but could save you thousands if the motor is hurt and you stopped now for repair. Pictures and a little more info would help. IMO you could also do alot more damage to the motor before you find what cause this. Spinning cam bearings or main bearings is almost a sure death for this motor and you will need a whole new block plus the machine work.$$$$$ Rick L.

It's a poly gear which came with the motor, and basically plastic, yes it's flushed out, the problem is either the carb or atiming issue.

[RICK LAKE]

FST FOX Fox this gear is not plastic. It's a carbon poly material that is made under extreme heat and pressure. KCR would NOT put a plastic gear in one of his $15-40K motors. These gears have been tested for years to get the correct carbon mixture. Too soft they wear out the gears, too hard they snap in half. Is it possible that you could shoot a couple of pictures here to see the gear and pin? Are the teeth on the gears shaved? The poly gear is stronger that steel or bronze gears. Nascar guys use these gears to save wieght and HP in there motors. I would talk to Keith but also recheck the bottom end of the motor and pull the oil pump and check for any metal in it. Pull the bottom cover and check the gears for clearance and look for any grooves in the body of the pump or gears. You didn't say if this car gets alot of hard abuse?? If the gear broke and the motor was running or cranking, you could have bent some valves or hit pistons. You might want to do a basic couple of tests, Vacuum test looking for a steady reading at idle , if the car has a mild camshaft, and 2,000 rpms, a leak down test will tell if the valves are sealing in each cylinder and are not bent, a compression test also to check for rings and valves seating. Just a suggestion. I am guessing you rephazed the distributor on the motor after repairing the gear? Rick L.