Let me "pick your brain"

[Kalums]

Ok ladies and gentleman, here is a head scratcher from me. 1971 GMC K2500, with an 90s "target master" 350. When I first got the truck back in July it made a horrid grinding noise when ever you engaged the starter, found the starter bendix was eaten (not toothless just very worn) and the Flex plate had a few teeth with the tips missing(one spot of about 5 teeth) I've replaced the flex plate and starter both new AcDelco. The starter was already "upgraded" to the 90s style with 2 wires, but I have an older style that fits but I would need a new solinoid. I digress, it has since then starting fine, no grinding or whiring. Well I redid the distributor after I caught it on fire( ended up being a crack in the distrubutor caught the carb cleaner on fire) and fried some wires. Rebuilt it with All AcDelco/GM parts (didn't replace the coil). I tried cranking it when I had the dash out and it cranked fine, but I got no spark (obviously) finished putting the dash back in went to crank and got the same grinding, clunking, whiring.... Any ideas? To sum up started fine before distributor rebuild (with spark) and after without spark... Now with spark it makes horrendous noise... Thank you in advance.

**SOLVED** Apparently something shifted or wasn't tightened correctly in the first place and I needed shims for the starter, Everything is copacetic again.

[dmjlambert]

Since your engine has a history of starter gone wrong, I suggest re-check the torque on the starter bolts after 100 miles or so to see if they are loosening, and listen for changes. You may have a problem with crack in the block where the bolt goes in. I understand it happens sometimes on engines with a full size starter and no starter brace and extra advance or vacuum can with limited advance on the distributor (hot-rodding the distributor), some of which could be in your engine's past. I'm not sure if you are aware, but the starter bolts are special and have a knurled area about the point where the threads go into the block when fully seated. If you have regular bolts there you could have problems with shifting around of the starter. Interesting news about a distributor crack causing a fire, I didn't know that sort of thing could happen.

[Kalums]

Originally Posted by dmjlambert

Since your engine has a history of starter gone wrong, I suggest re-check the torque on the starter bolts after 100 miles or so to see if they are loosening, and listen for changes. You may have a problem with crack in the block where the bolt goes in. I understand it happens sometimes on engines with a full size starter and no starter brace and extra advance or vacuum can with limited advance on the distributor (hot-rodding the distributor), some of which could be in your engine's past. I'm not sure if you are aware, but the starter bolts are special and have a knurled area about the point where the threads go into the block when fully seated. If you have regular bolts there you could have problems with shifting around of the starter. Interesting news about a distributor crack causing a fire, I didn't know that sort of thing could happen.

It actually didn't have the brace on the starter when I got it, but from viewing another thread on here I bought one when I replaced the old starter. That thing is "solid as a rock" (pun intended) I did not however know about the "special bolts". I did look as well as I could at the mounting holes and surrounding area and didn't see any cracks or scratches that may be cracks anywhere. ( I thought of that too) I did throw some blue locktite on the bolts that are on there... I may regret that later😅 As for the engine... I'm pretty sure it isn't long before it will need a rebuild or replacement, but I'm going to tinker and band-aid til that time comes. Currently other than generally running rough which is made worse because it needs motor mounts, it seems to be leaps and bounds better than it was in July. On the plus side.. It shifts "like butta" smoother than any transmission I've ever had from that era. Thanks for all the help you guys give it has been rediculously helpful so far.

[RustyPile]

Originally Posted by Kalums

It actually didn't have the brace on the starter when I got it, but from viewing another thread on here I bought one when I replaced the old starter. That thing is "solid as a rock" (pun intended) I did not however know about the "special bolts". I did look as well as I could at the mounting holes and surrounding area and didn't see any cracks or scratches that may be cracks anywhere. ( I thought of that too) I did throw some blue locktite on the bolts that are on there... I may regret that later😅 As for the engine... I'm pretty sure it isn't long before it will need a rebuild or replacement, but I'm going to tinker and band-aid til that time comes. Currently other than generally running rough which is made worse because it needs motor mounts, it seems to be leaps and bounds better than it was in July. On the plus side.. It shifts "like butta" smoother than any transmission I've ever had from that era. Thanks for all the help you guys give it has been rediculously helpful so far.

Those special starter bolts are mandatory and readily available at any parts store.. You can change the bolts, one-at-a-time without removing the starter.. And give the boot to loctite on starter bolts, it's not needed.. Just tighten the bolts to ~ 30 - 33 ft lbs and be done with it..