Addition of a Harmonic Balancer Crankshaft bolt

[Mark P.]

My 1960 harmonic balancer does not have a bolt to keep the harmonic balancer in place if it should no longer be held on by the friction fit. I was told to use a speed sleeve when I installed it.

In a recent article of the Solid Axle Corvette Club's magazine, there was an article of how to install the bolt used on 62 and later Corvettes.

What would the point deduction be on this addition ?

If I plan to drive my car more than show it would it be a good idea to do this ?

[Joel T.]

Re: Addition of a Harmonic Balancer Crankshaft bolt

Mark,

I had a 1961 283/245 car a few years back which I "drove". One night my wife and I were coming home from a summer night ice cream run and the harmonic balancer basically fell off as I was driving... I had no prior warning and candidly did not suspect there was a potential problem. It made a ton of noise as it bounced along the undercarriage but did no real damage (I have heard of cases where they have broken through a fender). It was "interesting" to get home to say the least (I had nothing with me to reinstall it so I did a lot of building up speed and coasting with the motor off). I bought a replacement/refurbished unit which was also a press fit... That too started to come loose after not too many miles.

Regardless of the point deduction, I would have the crank drilled and tapped and have the bolt installed.... your basic peace on mind thing....

I suspect others will have information and opinions....

Regards,

Joel

[Mike B.]

Re: Addition of a Harmonic Balancer Crankshaft bolt

Mark,

As Joel indicated, the crankshaft snout has to be drilled and tapped and I believe to do so you have to pull the crank out of the car which is not a small job. But if you were to do that, simply remove the bolt before judging then replace it afterwards. The balancer sticks out a good ways past the snout, especially with the necessary 1/8" spacer between the balancer and crank shoulder. Thus the drilled hole could not be seen but only felt. Do the judges "look" that hard? I don't know.

But more important than bolt or no bolt is the fact that if the balancer is at all loose or goes on without much resistance, then you need to replace it. The sleeve that you were advised about goes on the outside of the balancer and it is intended to repair a groove that gets worn in the circumference from millions of revolutions against the timing cover oil seal. But to my knowlege there is no satisfactory repair for the inside of the balancer. They were designed to be an interference fit and after a few on and off iterations, the metal stretches slightly and then the balancer is good for nothing more than a paperweight. I have a few myself.

But the good news is that unless you plan on judging the car and need an original balancer, virtually every SBC Chevy balancer out there old and new (of the same diameter) will fit and line up fore and aft as did the original (for pulley alignment). They might look a lot different, and the timing mark may be off by 10 degrees, but it will work. Perhaps Joe Lucia or others can weigh in with the suggestions for best replacement balancers.

If you need an original hunt around at swap meets. They are not unique to Corvettes so you can get lucky. But to be sure you don't buy a pig in a poke, buy it with the condition that you will be back if it is sloppy (if the front has been smashed by Bubba's hammer that is not a good sign). If you come across a good looking example, then simply find someone selling an engine or crank from the period and try it on for size. By hand only you should not be able to get it on any further than the small chamfer on the edge. I did exactly that at Englishtown, NJ last year and found a gem for $15 with the three original bolts still attached!

Good luck in your quest.

Mike

[Mark P.]

Re: Addition of a Harmonic Balancer Crankshaft bolt

Thanks Joel and Mike. I bought an original balancer for my car that looks practically new. The guy I bought it from was referred to me by several NCRS members and has a reputation for refunding or replacing parts that don't work out.

I am in the process of accumulating all the parts to put together an original motor to replace the mid-80's crate 350 motor and will have the machine shop drill and tap the crank for the balancer bolt.

Here is what I have bought so far for my 245HP engine:

standard bore block with restamped pad
crank and rods
heads
intake manifold and dual quads
exhaust manifolds
distributor
timing cover
generator
top shielding over the distributor
valve covers

All have the right casting numbers and dates

Here are some questions I have:

1. Should I buy a 14" 168 tooth 30lb Hays flywheel or try to find an original ?

2. Any suggestions for the cam and pistons to use ? I want it to perform like stock.

3. are there any parts that will be really difficult to find ?

4. should I go with stainless exhaust valves ? what about stainless intake valves ?

5. what would be a good reference source to use to put this engine together correctly. My plan is to have the machine shop assemble a long block for me.

I plan to have this car judged someday but I plan to still drive it.

Thanks,

Mark

[Mike B.]

Re: Addition of a Harmonic Balancer Crankshaft bolt

Hi Mark,

I am traveling for a few days and forgot my charger so my response must be limited as my battery is crap.

But I did exactly what you are proposing - I had a short block professionally machined/assembled and built up the rest of the engine myself to stock specs using original parts. I am not the final authority, but I can point you in the right direction on most of your questions. SBC engines are a dream to work on and there were about 50 million built, so parts are plentiful!

I will reply with a detailed message Saturday or Sunday.

Best,
Mike