Okay here's the run down of my problem, I just built this SBC 350 blower motor. Forged rotating assembly, 6-71, TCI flex plate and all the basics for a good motor. So after the install I wanted to start the motor and break everything in. I turn the key and nothing but the most horrible grinding noise ever. I've got two starters; one factory and one aftermarket high torque. I've shimmed both and they seem to have the same problem. I'm in SBC Starter hell, someone please help.
I used the thin metal shims that came with the starter, the starter will engage the flex plate but then it seems to slip off after a few rotations. Thanks for all the responses btw!
My buddy had this problem with an El Camino. He wound up fixing it by shimming only one side of the starter. Give it a shot.
try this.. put a shim under JUST the outside bolt , tighten the inside bolt first then the outside one. this will kick the starter into the flywheel and tighten up the clearance. I bet this works....also more than one shim maybe needed.
CHeck the block number and make sure the starter you ar using matches. I ran into this on my 36 sedan. When I put a new engine into it several years ago I used the new starter I had just put on the old engine. The old one was '72 ish. The new used an 89 block. Worked good for a while but would occationally grind. I chalked it up to needing shimmed but was lazy and did not get around to it. Finally left me stranded during the woodward cruise..... While replacing it I discovered that my new engine required a different starter. Looks similar but close inspection showed that the correct one has 3/8th inch longer throw on the bendix. correct starter and ingages every time and nice and quiet! I'd check the bendix throw to make sure it is correct Tim
Make sure the block where the starter mates up is free of any imperfections. I had a friend with a fresh engine and the block had a burr that kicked the starter up slightly causing this scenario. Make sure the block isn't cracked and allowing the starter to move once it gets a load.
Had big time starter problems on a 350 RV..ended up replacing both the starter & flex plate. problem solved. Think they say 1/8 of clearance,when engaged. We shimmed ONE side only. Rick 1939fiat
Still want to know this.....did you measure the clearance between the ring gear teeth and the starter shaft?
The SBC in my '36 3-window always gave me problems. Had to replace the flexplate. I switched starter noses, shims and several starters. No help. I had to REMOVE metal from the starter nose to cure the problem. The engine had a factory rebuilder tag on it. I think it had mains align bored enough to move the crank up in the block!!!
There is no model year difference in bendix engagement depth. You may have had a mis-drilled block or a flawed starter, but it had nothing to do with year to year changes
Don't want to get into a pissing contest BUT there is a definite difference in the older starter and the new. The one I replaced matched several onthe shelf and the "89" model had a deeper engagement throw on the bendix. Mounting holes match but nose castings differ. Tim
What about aftermarket stuff? He had a mini starter on it too. I had a late 1 piece rear seal block in my El Camino and used a Powermaster 9502 designed for 153 tooth flywheels. I sell performance parts for a living. Flipping through books I don't see any difference in starters other than teeth count on the flexplates.
A small item, but some motors and accompanying starters were meteric. Maybe you have a bolt problem. Are you using the factory knurled starter bolts? If it is not snug inside the bolt hole, you can get movement by deflection when torque is applied.
Also, can you spin the motor over by hand fairly easy? If not, maybe too much for a starter to overcome
I'm with R Pope...check your flexplate. I had the same problem on my sbc powered truck. It had a newly rebuilt engine and the flexplate was installed backwards. It would engage a little bit, but ended up stripping the starter gear. Once we flipped it, I haven't had a problem with it.
This may or may not have something to do with it. Have you checked to see what voltage you have going to your solenoid during cranking? We had a problem with my buddies BBC race car. He tried multiple starters over a years time, all with similar results. The starter would spin, then kick the gear in and out, then buck, sometimes breaking the nose cone (stock hi-torque starter) or bending the bolts (aftermarket mini starter). All starters were shimmed to factory specs. Turns out that there was a fluxuation in voltage while cranking the motor. We cured 75% of the problem by installing a hi amp relay on the "crank" wire to the solenoid. Running a good ground cable from the trunk mounted battery all the way to the block fixed the rest. Now he has a couple starters as spares since they werent all junk after all. Starter solenoids draw a lot of amps, could it be you are losing amperage, allowing the solenoid to relax, thus disengaging the drive gear? I have to ask, are you using factory style knurled starter bolts? Just a couple thoughts!
I was going to stop by the store and pick up some knurled starter bolts, looking at the flexplate today it looks like all this abuse from the starter has taken it's toll. I might pull the motor this weekend to double check everything. For some reason I think the flexplate might be on backwards. Does anybody have a measurement from the flexplate to the back of the block?
To educate a Ford guy (where starter mounting and problems are less common) can someone explain why the knurled bolts are so important? Is it to keep them from loosening? Isn't that what lockwashers are for?
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