1960 Crankshaft Tapped on the Outside End

[Joe M.]

I was noticing that there are 3 bolts that hold the pulley on the balancer, but there is also a grade 8 bolt in the center with a large, thick washer underneath the bolt head. I don't think this is original design, correct?

What is the purpose of drilling/tapping the end of the crankshaft? Would it help with removal and installation of the balancer?

[Richard M.]

Re: 1960 Crankshaft Tapped on the Outside End

The 283 on a '60 never had the crank tapped for the bolt. It must have been done later by a rebuilder. It's a good thing to do as you'll read later....

IIRC it started on High Performance engines on the C2 327's but I could be wrong. It helps to install it using a special tool.

My '59 283/270 never was bolted on. Until I rebuilt it and had the crank drilled & tapped for the 7/16-20 bolt.

Before that, on the highway long ago after work, I heard a big bang. I looked in my rear view mirror and saw this big round orange & black object spinning along. It passed me and ended up in the median. The balancer/pulley came off the crank, likely hit the third arm and dropped out. I was lucky I didn't run over it. It was a long Friday night waiting for the flatbed.

[Joe L.]

Re: 1960 Crankshaft Tapped on the Outside End

The 283 on a '60 never had the crank tapped for the bolt. It must have been done later by a rebuilder. It's a good thing to do as you'll read later....

IIRC it started on High Performance engines on the C2 327's but I could be wrong. It helps to install it using a special tool.

My '59 283/270 never was bolted on. Until I rebuilt it and had the crank drilled & tapped for the 7/16-20 bolt.

Before that, on the highway long ago after work, I heard a big bang. I looked in my rear view mirror and saw this big round orange & black object spinning along. It passed me and ended up in the median. The balancer/pulley came off the crank, likely hit the third arm and dropped out. I was lucky I didn't run over it. It was a long Friday night waiting for the flatbed.

Richard------


The first Chevrolet small block V-8 with a balancer retaining bolt was 1962 with 340 or 360 HP.

I HIGHLY recommend the installation of a balancer retaining bolt for any Chevrolet V-8 not originally equipped with one, especially when the engine is disassembled for overhaul. Is it NCRS-correct for such applications? No, of course it's not. Install one anyway if you plan to drive the car.

[Richard M.]

Re: 1960 Crankshaft Tapped on the Outside End

"The first Chevrolet small block V-8 with a balancer retaining bolt was 1962 with 340 or 360 HP."

Joe, Thanks for clarifying this. The 1962 340 and 360 were considered High Performance, correct?

Do you know when the balancer retainer bolt began usage on non-HP engines?

Rich

[Donald H.]

Re: 1960 Crankshaft Tapped on the Outside End

I had it done to my 1960 by the mechanist while the engine was being rebuilt. I did it because of what I had read here and elsewhere regarding the potential of loosing it at an inappropriate time and place

[Joe L.]

Re: 1960 Crankshaft Tapped on the Outside End

"The first Chevrolet small block V-8 with a balancer retaining bolt was 1962 with 340 or 360 HP."

Joe, Thanks for clarifying this. The 1962 340 and 360 were considered High Performance, correct?

Do you know when the balancer retainer bolt began usage on non-HP engines?

Rich

Rich-----

The 340 and 360 HP engines were referred to as SPECIAL HIGH PERFORMANCE for the 1962-63 model years. The 300 HP engine was just plain HIGH PERFORMANCE for 1962-65 model years.

For 1962-68 the balancer bolt was used only for special high performance small block engines (i.e. 340, 350, 360, 365, and 375 HP). The balancer retaining bolt was added to all Corvette small blocks for the 1969 model year and thereafter. I believe it was also added to most, if not all, other non Corvette small blocks effective with the 1969 model year, too.

[Joe M.]

Re: 1960 Crankshaft Tapped on the Outside End

It sounds like my engine rebuilder did a good thing without asking me about it. He also replaced the drain plugs on the sides of the block with allen head plugs and I could not get them out to drain the block, but I got over it and moved on.

[Joe L.]

Re: 1960 Crankshaft Tapped on the Outside End

It sounds like my engine rebuilder did a good thing without asking me about it. He also replaced the drain plugs on the sides of the block with allen head plugs and I could not get them out to drain the block, but I got over it and moved on.

Joe-----


Yes, the snout bolt is the way to go, original or not. Among the important benefits is that you can use a balancer installer tool to install the balancer when necessary. Otherwise, they have to be installed using impactive force (hammering). The latter has always made me cringe.