1964 L76 Harmonic Balancer replacement

[Geoff B.]

I have a 1964 L76 and the water pump went out. Ater removing it I decided to check the pulleys and balancer to make sure they were correct. The balancer is not the 1 3/4' original but is a 1 5/8' after market replacement w/o the reinforcing fins, so I'd like to replace it with the original type.

I have a few questions I'm hoping someone can help with.

1. the balancer installed does not appear to have any mounting bolt, so I assume I just need to remove it with a puller, is that correct?

2. At this point, I don't see any threads in the end of the crank and I believe the correct balancer uses a hex bolt to attach to the crank. Does this mean the crank has been replaced at some point and I no longer have the correct L76 crank?

3. If I no longer have the correct crank that will accept a mounting bolt for the new original style balancer, can I still install the original style balancer by just pressing it onto the crank? If so, can this be done with the engine still in the car?

[Joe L.]

Re: 1964 L76 Harmonic Balancer replacement

I have a 1964 L76 and the water pump went out. Ater removing it I decided to check the pulleys and balancer to make sure they were correct. The balancer is not the 1 3/4' original but is a 1 5/8' after market replacement w/o the reinforcing fins, so I'd like to replace it with the original type.

I have a few questions I'm hoping someone can help with.

1. the balancer installed does not appear to have any mounting bolt, so I assume I just need to remove it with a puller, is that correct?

2. At this point, I don't see any threads in the end of the crank and I believe the correct balancer uses a hex bolt to attach to the crank. Does this mean the crank has been replaced at some point and I no longer have the correct L76 crank?

3. If I no longer have the correct crank that will accept a mounting bolt for the new original style balancer, can I still install the original style balancer by just pressing it onto the crank? If so, can this be done with the engine still in the car?

Geoff------


1) Yes, you would remove this balancer with a puller just like any balancer. No balancer snout tapping is needed for a puller;

2) If the crank has no snout tapping for a balancer retaining bolt the crank has been replaced with a non-tapped type crank (or the engine is not an original L-76 to begin with and has been externally "converted" to appear like one);

3) Your engine has apparently been operating ok with an 8" 3817173 balancer and without a snout bolt. However, would I be comfortable with such an installation? Absolutely not. No 3817173 balancer was EVER originally used without a balancer retaining bolt

[Domenic T.]

Re: 1964 L76 Harmonic Balancer replacement

Tap the crank for the bolt.

DOM

[Geoff B.]

Re: 1964 L76 Harmonic Balancer replacement

Thanks Dom. Is it possible to remove the balancer, install a correct one and tap the crank for the new bolt with the engine in the car?

[Domenic T.]

Re: 1964 L76 Harmonic Balancer replacement

Geoff,
I think yes. I have done it before but not on a vette. I am sure your crank is cast iron as the steel one's were usually tapped. Cast is easy to tap.
The centering hole is already there for you and all you have to do is make sure you drill straight and DON'T break the bitt. The radiator will have to come out I'm sure but other wise it's not a big deal.
I usually make a centering jig to keep the drills and tap started straight now that I am older. I have the equipment to make the jig and it seems like a waste of time till you try to remove a broken bit or tap.
use a sharp starter drill about 1/4" before you use the correct drill for the tap and a good cutting oil.
I drill the cranks I put in engines but truthfully found very few that got away from their seat on the crank that were stock without the bolt as they are pressed or drawn on tightly. The large HP ballancers are a must. But if it was to have the bolt then put it there and be easy on the RPM's as I think your crank is cast.
It is not automatic is it?

DOM

[Joe L.]

Re: 1964 L76 Harmonic Balancer replacement

Geoff,
I think yes. I have done it before but not on a vette. I am sure your crank is cast iron as the steel one's were usually tapped. Cast is easy to tap.
The centering hole is already there for you and all you have to do is make sure you drill straight and DON'T break the bitt. The radiator will have to come out I'm sure but other wise it's not a big deal.
I usually make a centering jig to keep the drills and tap started straight now that I am older. I have the equipment to make the jig and it seems like a waste of time till you try to remove a broken bit or tap.
use a sharp starter drill about 1/4" before you use the correct drill for the tap and a good cutting oil.
I drill the cranks I put in engines but truthfully found very few that got away from their seat on the crank that were stock without the bolt as they are pressed or drawn on tightly. The large HP ballancers are a must. But if it was to have the bolt then put it there and be easy on the RPM's as I think your crank is cast.
It is not automatic is it?

DOM

DOM------


Small journal 327 cranks are almost always, if not always, forged steel whether they are equipped with a balancer bolt, or not. Some small journal 283 cranks are nodular iron, though.

[Geoff B.]

Re: 1964 L76 Harmonic Balancer replacement

Thanks for the great info. The car is a 4 speed. The engine was rebuilt by a prior owner about 7 years ago. Maybe the crank was replaced at that point. When they restored this car, they didn't worry too much about 'correctness', so I spend a lot of time stripping off after marker replacement parts and rolling it back to original form.