'63 Balancer -to- Crank
I picked up my my crank shaft from the machine shop and the machinist there asked me if I wanted them to tap out the crank so I could attach the balancer with a bolt instead of pressing it on. I told him 'no' and he said 'okay suit yourself'. Now, I'm kinda questioning myself. Should I have let him tap it out?
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Re: '63 Balancer -to- Crank
Joe, thanks. Another question if you know...the crankshaft pulley I have is 3765987. Would you know if that is the correct part number for the 340hp?
edit: I found it in the AIM. It's actually part number 3766987 pg.286. Aloha.Last edited by Irby G.; February 1, 2009, 11:36 PM.Comment
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Re: '63 Balancer -to- Crank
Irby;
I have a '63 and the crank should have been drilled and tapped from the factory..... As Joe said, go get it done before you do anything else... I had a 1961 with a pressed on balancer... not pretty when they let loose, and they will....
JoelComment
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Re: '63 Balancer -to- Crank
Irby, I believe the correct bolt for the high HP 63 is a grade 8 TR(6 lines) that is drilled for safety wire although no wire is used. It's 7/16 fine thread. The shank is about 2-1/4" long. Could be a tad longer. The huge flat washer is about 5/16 thick and 1/-7/8" OD. Originals had a small symbol on them.
Someone told me the lower HP engines used the same bolt but it was not drilled. But that is heresay and I don't know if its true. All the repro catalog have a bolt that will work. Mr Gasket sells them or used to sell them also. Anyone that doesn't use one of these bolts is living on the wild side as it doesn't take much for our worn harmonic balancers to come flying thru the radiator, etc.
I forget if the bolt is supposed to be blackened or zincad. I think zincad but I am not sure as in recovery from our Steelers winning the super bowl. Listen to your engine builder or you will be truely sorry. JohnComment
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Re: '63 Balancer -to- Crank
John----
250 and 300 hp engines originally used NO bolt. However, if Irby's engine is an original 340 hp, I don't understand why it was not originally drilled and tapped as others have mentioned.
The bolt was zinc plated and had a safety wire hole. It's still available from GM.In Appreciation of John HinckleyComment
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Re: '63 Balancer -to- Crank
John DeGregory quoted earlier!
"Someone told me the lower HP engines used the same bolt but it was not drilled."
John,
Please splain to me how they could use the same bolt when the crank was not drilled?????????
Did they safety wire it on or use Super Glue??????????
JRComment
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Re: '63 Balancer -to- Crank
Had '63 340 (in 1967), it was bolted-have '62 360 now ,and it's boltedComment
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Re: '63 Balancer -to- Crank
The crank in my 63 300 HP car is cast 4577 and I believe the correct crank is 2680. Can anyone tell me why the part # change and difference between these cranks?
My crank has been drilled for 1/2" fine thread bolt and I would like to return to 7/16, can this be done with heli coil??Last edited by Timothy B.; February 3, 2009, 10:33 AM.Comment
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Re: '63 Balancer -to- Crank
Joe Ray, After reading your nicely put comments I called a friend yesterday and asked him to explain in further detail where he got the non drilled TR grade 8 harmonic balancer bolts. He said he has removed a lot of them from NON Corvette engines in junk yards. He didn't know if they were truck or passenger car engines. Just that they were small block Chevy engines.
So you are right for once.
Thanx for very polite reply. JDComment
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Re: '63 Balancer -to- Crank
Tim,The crank in my 63 300 HP car is cast 4577 and I believe the correct crank is 2680. Can anyone tell me why the part # change and difference between these cranks?
My crank has been drilled for 1/2" fine thread bolt and I would like to return to 7/16, can this be done with heli coil??
To install a 7/16" heli coil you use a 29/64" drill bit.
To install a 1/2" heli coil requires a 33/64" drill bit
That's 1/16" difference between the two bits.
Now I don't know the OD of the 7/16 heli coil. You may be able to do a Rube on this project with the add of loctites. Or you could listen to the good advise of JR and use super glue.
7/16 or 1/2" doesn't really matter as a good judge will ding you anyhow. But knowing how fussy you are a nice 7/16 bolt would look right at home and would probably only get one little ding. Finding the correct 63 pulley is in itself an accomplishment. Most 63's I see have the service replacement pulley on them. JDComment
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Re: '63 Balancer -to- Crank
The "typical" drilled vs. non drilled bolt breaks down like this. Most drilled bolts were from 60 -68 and some 69's. But for the most part the non drilled bolts are 69-up (On the non drilled bolts I have seen headmarkings of TR, M, A, C and others)
Most of the original washers had an "S" stamped on them.
Now I have restored low HP cars that had drilled cranks and I have done High H/P cars (mostly L-79's not L-76, L-84 or L-T1's) that did not have a drilled crank.
RichComment
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Re: '63 Balancer -to- Crank
Rich-----
That's absolutely correct. The 62-68 327 applications with crank snout bolt used bolt GM #3815933. This is the bolt with the head drilled for a safety wire. It is trimmed hex head, zinc plated, 7/16"-20 X 2-1/4"and GM 300-M material. A common original headmark was "TR". Currently available bolts usually have an "LE" headmarking.
1969 302 and 350 cid small blocks with crank snout bolt used a different bolt. It was GM #9428643. This is the bolt NOT drilled for a safety wire. It is a trimmed hex head, phosphate-finished, 7/16-20 X 2-1/4", and GM 300-M material.In Appreciation of John HinckleyComment
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Re: '63 Balancer -to- Crank
What's the purpose of the drilled crankshaft bolt, how do you secure it with wire? The bolt must be for some other application, is this bolt also a replacement for the shock bolt?
John, I am fussy, I believe the crank in my engine has been replaced but I have the correct small balancer on the engine and would like to install the 7/16 bolt just because the hole is there. I know it was a life saver when I installed the balancer with the engine in the car as I could draw it up with the bolt.
The original small balancer is a tighter fit and the doner I used had only been off it's engine once. When I pulled it off, I thought it was not going to come for a moment then pop. I know it was tight going back on the 4577 crank in my car and I believe without the hole to draw it up working with the engine in car would have been difficult.
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Re: '63 Balancer -to- Crank
In a race application, the drilled balancer bolt would be safety-wired to a similarly-drilled pulley bolt head.
You do NOT want to use the balancer bolt to pull the balancer on - you run the risk of stripping the threads, then you're SOL. Use the installer tool, which gets full thread depth engagement in the crank before any pressure is applied.Comment
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