Harmonic Balancer applications

[Joe L.]

Re: Harmonic Balancer applications

I am a little confused as to when GM converted to the one piece oil pan gasket on SBC's. Does this engine normally use one.....or has someone engineered a one piece replacement for the normal 4-piece gasket set used on the early 283's and 327's that I haven't heard about? I'd sure like to have the details if they have!

Brad-------

No 1953-85 Corvette ever originally used a 1 piece oil pan gasket. All were originally the 4 piece style. The first Corvette small block to use the 1 piece gasket was 1986, the same year GM went to the 1 piece rear seal. So, the 1986+ gasket is not retrofitable to earlier small blocks. However, the aftermarket soon came up with similar 1 piece gaskets for pre-1986 applications, both left and right side dipstick small block applications as well as big block.

[Brad K.]

Re: Harmonic Balancer applications

Joe.....That aftermarket 1 piece gasket is what I am interested in. Do you have any particulars on it....like who makes it, etc.?

[Joe L.]

Re: Harmonic Balancer applications

Joe.....That aftermarket 1 piece gasket is what I am interested in. Do you have any particulars on it....like who makes it, etc.?

Brad-------


All of the major gasket manufacturers offer them. The Fel-Pro part number for pre-1975 small blocks with original oil pan is OS-34509T. This gasket is blue silicone material. I think that Corteco or Cometic makes one in black silicone. Victor-Reinz also makes one.

[Brad K.]

Re: Harmonic Balancer applications

Thanks a lot, Joe.....I'm off to the parts house!

[Joe L.]

Re: Harmonic Balancer applications

Thanks a lot, Joe.....I'm off to the parts house!

Brad-------

You should have no trouble finding this gasket, either Fel-Pro or otherwise. However, I want to emphasize that you must be sure that you have an original oil pan and not a 1975+ replacement oil pan. The original and 1975+ replacement are configured almost the same EXCEPT for the front oil pan gasket radius. If you use the 1955-74 1 piece gasket with the 1975+ replacement pan, you WILL have a oil leak.

You can easily check the pan. Just lay it upside down on a flat surface. Then, measure the radius of the front seal surface from the apex to the flat surface. 2-1/4"= 1955-74; 2-3/8"= 1975 replacement pan.

[Brad K.]

Re: Harmonic Balancer applications

Joe...Thanks again for the additional info....I've built a couple dozen early SBC's through the years on a small time basis for friends and neighbors (along with a few 350's with the one piece ... which were much easier). I've had a couple leaks with the 4 piece Fel Pro system which I thought were the only ones available. Now that I know otherwise....I'm looking forward to using the 1 piece on any more early SBC's that I do......Once again, thanks

[Larry S.]

Re: Harmonic Balancer applications

Joe,
New member can't find box to post new item so I am asking you. Building a 71 454 425HP motor. In the NCRS parts book I have it shows a different harmonic part # for the 365HP part# 396330 and the 425hp shows part # 3963530 What is the difference never known GM to list different part # for no reason. When you search for 8" 454 Harmonic balancer they all come up as one, i don't care if it is a Chevelle balancer but is the everyday 8" 454 balancer good for whatever horsepower and if so, why does GM list different part #'s

Thanks

Longhornlarry

[Joe L.]

Re: Harmonic Balancer applications

Joe,
New member can't find box to post new item so I am asking you. Building a 71 454 425HP motor. In the NCRS parts book I have it shows a different harmonic part # for the 365HP part# 396330 and the 425hp shows part # 3963530 What is the difference never known GM to list different part # for no reason. When you search for 8" 454 Harmonic balancer they all come up as one, i don't care if it is a Chevelle balancer but is the everyday 8" 454 balancer good for whatever horsepower and if so, why does GM list different part #'s

Thanks

Longhornlarry

Larry-------


Originally, the 1970-72 LS-5 balancer was GM #3963529. The 1971 LS-6 balancer was GM #3963530. Both were 8", counterweighted balancers and of the same thickness. As far as I know, the only difference in these balancers was a difference in "tuning" to account for the difference in crankshaft material (i.e. nodular iron versus forged steel). Just how this tuning difference was accomplished, I do not know. Configurationally, the balancers were the same. Later, GM #3963529 was replaced with GM #14097023 and GM #3963530 was replaced with GM #14097024.

The difference in the balancers got "erased" later as GM replaced ALL of the above balancers with GM #10216339 which remains available to this very day.

[Larry S.]

Re: Harmonic Balancer applications

Good Morning Joe,

Thanks for your prompt reply to my post.


Feliz Navidad

Larry W Smith