Harmonic balancer bolt

[Caminuvik]

Truck is becoming a pain in the A. Broken valve spring ( switched tanks, sputtered, back fired, ran like (censored) lucky to get home. Found one dead cylinder, removed valve cover found broken valve spring, bought an overhead valve spring compressor, leaked down compressor tester, and replaced compressor tester that died between cylinder tests on snowmobile rebuild (thought $1,000.00 down the tubes when "0" compression on the oversized rebuilt cylinder/piston that leaned out after check out run.)
Well on to the latest issuse, went to turn motor over by ratcheting on damper bolt, bolt turned with next to no torque on rachet, and that was all that turned!
Guess bolt is stripped? What to do? Find another 350? Can this be repaired? Or just push it over the bank and look for a different plow truck? Trying to finish building a house, so not a lot of time or space to play mechanic. Any suggestions would be appreciated. I have not had any luck with anything lately, and it's taking a toll. Thanks Cam

[mongocanfly]

With all that it sounds like you'd be better off finding another engine...or move futher south to a place you don't need a plow truck..hehe

[Caminuvik]

Originally Posted by mongocanfly

With all that it sounds like you'd be better off finding another engine...or move futher south to a place you don't need a plow truck..hehe

Moving is starting to sound like the smarter move. Someone interested 20 acres on small lake, backed onto crown land, drive in basement with 10,000 lb Ben Pac hoist, 35 min to ski hill, house ready for drywall tomorrow. Oh, that would be me. Finding 350 motors up here is like looking for hen teeth.

[Dead Parrot]

Try backing the bolt out. If it is stripped and you can get it to back out, you will get a whole bolt. If it broke off, you will get a short broken bolt.

If you get a whole bolt with bad threads, you can try installing a new one with a heavy dose of loctite, but give up the idea of using it to turn over the motor.
If you get a whole bolt with good threads, the crank threads are likely bad. As a interim but hard to recover from fix, you could squirt a bunch of JBWeld into the hole and install the bolt. But it would likely mean you could never remove the damper. Again, no turning the motor with the bolt.

If the bolt is broken, sell truck on CL since getting the bolt remains out likely involve removing enough stuff to allow a drill and bolt remover to be used. Plus there is no guarantee that your repairs to the valve went well.

[mongocanfly]

Sounds like ya got a nice location..just the reverse here on engjnes..seems like everyone around here has a smallblock out in the shed and they can't get rid of em..everbody going LS now..a guy I work with had a complete engine in his shop on a motor stand that he tried to sell on craigslist for $150..stayed on there a month and not one call

[Caminuvik]

Guess I need to look for a motor, this is right back to the beginning, I bought this truck as a an improvement (great looking truck) on the 83 (rough but never let me down) that the motor was seized by a trespasser (the RCMP would not deal with this.) Thought I would have a keeper that I could use and work on. Could not find a motor for the first, so bought a whole truck. 3 Square Bodies and none running. LOL
Think you are right Dead Parrot, too big a risk with unknown valve/cylinder issue.
Any idea what could cause this to be stripped/broken? Large large impact to install?

[El Dorado Jim]

take the bolt out, get a 7/16 NF tap and run the tap in,the hole is deeper than the bolt,use some cutting oil and tap the threads deeper...go slow and keep backing the tap oiut a little then run it in again, should be able to tap 1/4 inch deeper...get a longer grade 8 bolt at the hardware store and you should be good to go...

[tucsonjwt]

If you can get the bolt out, I have seen a tap with a lot of cutting fluid pretty much restore a bad thread hole. Add the proper loctite for that application(has to do with the type of materials being sealed, e.g. stainless to carbon steel, brass to steel, etc.) which the Loctite website will state.

I had a bad harmonic balancer tear up two crank pulleys until I figured out the true culprit.

[Caminuvik]

Not sure how to best try to get the bolt out. Can't drill it, it will spin. Not out at all, so can't get a puller on it. I also thought that it would be difficult (hard metal) to tap?

[Dead Parrot]

My response to your original post was based in part on your expressed need to avoid long delays in finishing your house. Broken bolts are part of the old vehicle experience. Some are easy to fix, others not so much. Depending on room available between your motor and radiator and your flexibility, getting that bolt out and fixed might require removing the radiator and other things on the front of the truck, which could take a lot of time away from the house. And once the bolt was fixed, no guarantee that your motor woes are over. Could easily turn into a week or more project and if your vehicle repair luck holds, could be longer.

Things you might try on this bolt if you decide to attempt a fix.
Strong magnet might pull the remains out if it is broken.
Could attempt to weld something on the head to pull it out. But if it won't pull out, you now have something else in the way.
Crows foot wrench would hold the bolt head in place while you drilled a hole for an extractor.

If you get all of the remains out, as others have suggested, you can retap the hole. The threads were tapped when the crank was made, they can be retapped.

As for what caused it, while lots of folks, myself included, use that bolt as a handy way to turn a motor over, don't think that is a factory recommended use. It is really there to make sure the damper stays in place. Also possible a previous owner installed a standard grade bolt.

[Peter S]

Chevy small blocks from the 50's & 60's did not even have a bolt to hold the balancer to the crank, it was a press fit only. So if your balancer hasn't come off by now, I wouldn't worry about it.

[cadillac_al]

I went through this once. I bought a new crank kit, put it in the engine and when I put the balancer on I found out the threads were stripped. Learned that lesson; check balancer threads before installing crank. I sure didn't want to take that crank out again. I managed to buy a bolt about 1/2" longer and it found some good threads to screw into. It outlasted the truck.

[Caminuvik]

Thanks Dead Parrot, the magnetic is a great idea, and though I had considered welding something on the bolt, had not considered if it did not come I would have another bump in the road. Finishing poly on interior today and will need basement shop area for drywall, fortunately I have a great neighbour who came with a back hoe and plowed so drywall can be delivered. I will attempt with magnet, check my dexterity (these fingers don't work as well as they did a few years ago) on the other suggestions before I push it out.
Thanks really appreciate the advice and support!

[nonstop]

As said earlier, these were run for years with a pressed on balancer. While it might be a little unnerving, I wouldn't see it as a deal breaker. I would run it and just watch it. If it really bothers you, then fix it once the house is done. As for the cause, my guess would be that the balancer was installed using the bolt to drag the balancer in, instead of using a balancer installation tool.

[Caminuvik]

Nonstop, thanks for the new information, I had no idea that there were special tools for balancer installation. I have been guilty of installing the damper using the bolt. I didn't install this one, but makes sense of why it broke/stripped.
Got my building insulation inspection today, "good to cover", have a couple of days to clean out shop before drywall arrives. Will attempt to remove bolt, do leak down test on cylinder (regardless of bolt issue) and see where to go from there. If cylinder/valve holds pressure I will be a happy camper.
Again thanks to all for advice and support

[Shady Rascal]

Let's take a second and analyze this.

For all we know, that bolt might have been stripped out for decades. You just now discovered it though. What would have happened if you hadn't discovered it ? Nothing. Why are you jumping to action now ? Just use the flywheel to turn the engine over and leave that balancer bolt alone.

New guy Peter posted a perfect response up above but no one seemed to acknowledge it .

[Caminuvik]

Shady, you are correct, I guess the thing is if I find something broken I have this tendency to want it fixed. What happens if it did come off, catastrophic disaster, or are you just parked beside the road? Tried the magnetic, will try a larger one today. Winch broke on quad, yesterday at finish of plowing, and loh and behold it's snowing again this morning. All plowing vehicles down now, and still a week to spring. LOL
The motor has been rebuilt, supposed to have only 40,000 km. I guess I need to see what damage is to cylinder #2, if it holds compression, then worry (or not) about the damper bolt. Too many things on the plate and I don't juggle as well as I did a few years ago.
Thanks
Cam

[Shady Rascal]

Peter S is correct. The SBC didn't use a bolt for a lot of years. Even my 74 model six cylinder doesn't have a bolt from the factory. Harmonic balancers fit snugly. If you're not spinning one up to a lot of revs, it's not likely to migrate off.

Why not keep an eye on it ? Every time you fill it with gas just pop the hood and shine a flashlight down there to make sure it's not migrating outwards. My money says if you let sleeping dogs lie that it won't ever be a problem. It hasn't been so far has it ?

[tucsonjwt]

My 83 C20 454 had the bolt holes on the crank pulley shear off twice. After the second replacement I guessed that the harmonic balancer was the problem. The balancer did not shear off with the crank pulley, but it was the cause of the crank pulley working off the bolts.

I used the proper Loctite for the crank pulley and used grade 8 bolts after the new balancer was in place. So far so good.

So, in my experience, it is best not to overlook any problems you might have with the balancer.

Disclaimer: I know almost nothing about auto/truck repairs. The value of the above advice is worth approximately $.02.