1967 Vette 350 HP Harmonic Balancer No Fins

[Paul B.]

I purchased a 1967 350hp Air Coupe that has been sitting since 1984 with 50,000 miles on it. After pulling the engine and working with a friend that has been working with classic car engines for 40 plus years we believe this engine to be the Original Engine except for the water pump. According to the NCRS Judging manual it looks like this engine was suppose to have a Finned Harmonic Balancer but this engine did not but we believe it to be the one GM put on during assembly. In referencing the Corvette By The Numbers books by Alan Colvin his research says in 1967 the Harmonic Balancer on the 350hp in 1967 would not have fins. This car would have been an early March Build.

So far all the numbers and dates including the A/C Compressor, alternator, starter, intake, etc are correct for the car. The stampings on the engine are correct and believed to be original stampings. My engine builder I would consider an more than knowledgable individual on correct stampings. The engine still has standard pistons with only .007 wear on the cylinder walls.

I'm in the Omaha area if there is someone in the C2 Judging world in the area that would want to look at the engine and Harmonic Balancer, or anything else.

Regards,
Paul H. Bohannon Jr.

[Michael H.]

Re: 1967 Vette 350 HP Harmonic Balancer No Fins

Paul you are correct and the manual is wrong it should not have fins. You'll find other threads that talk about this on the TDB. My 67 S/N 12706 L79 engine build 02/23 and assembly build March 03 does not have fins either.

Mike

[Paul B.]

Re: 1967 Vette 350 HP Harmonic Balancer No Fins

Thanks Mike,

That makes sense. My S/N is 12551 and also was Assembled on 3/3/67. This car still had the Gas Tank Sticker (Build Sheet) and it is in one piece and completely readable. Maybe my judging manual is old and NCRS has corrected their Mistake. Also Alan Colvin's book said they started with the non finned balancer in 1966 HP Corvettes also. I've seen that the Parts Catalog Companies sell a repo Finned for the 67 but they are probably going off of the NCRS Judging manual.

Regards,
Paul

[Larry M.]

Re: 1967 Vette 350 HP Harmonic Balancer No Fins

Paul:

aka POWERSHIFT from the other forum. My 1967 car is #14845 with engine and body built mid-March and car built late March due to AOS body. Engine is 327/350 HP factory air only (HT coded). Balancer is not finned. Mileage is 26,000 miles from new.

Larry

[Michael H.]

Re: 1967 Vette 350 HP Harmonic Balancer No Fins

Thanks Mike,

That makes sense. My S/N is 12551 and also was Assembled on 3/3/67. This car still had the Gas Tank Sticker (Build Sheet) and it is in one piece and completely readable. Maybe my judging manual is old and NCRS has corrected their Mistake. Also Alan Colvin's book said they started with the non finned balancer in 1966 HP Corvettes also. I've seen that the Parts Catalog Companies sell a repo Finned for the 67 but they are probably going off of the NCRS Judging manual.

Regards,
Paul

Paul the a new 67 judging just came out in Feb 2016 I'll check it tonight and see if it addresses this issue. I believe from what I've read in the past is the fin balancers went away in late 66 for L79 motors. What is your engine assembly date ? Mine was 02/23.

Paul the new judging manual still states that the L79 had fin balancers which I believe is wrong, I've seen a lot of disscussion on this subject on the TBD with other people having low mileage cars with no fin balancers. My no fin balancer is staying on my car.

Mike

[Duke W.]

Re: 1967 Vette 350 HP Harmonic Balancer No Fins

The engine still has standard pistons with only .007 wear on the cylinder walls.

Seven thou is way excessive bore wear for an engine with only 50K miles. Did you drive it enough to determine if the odometer is functional? Odometer failure was a common problem on C2s over 50K miles.

Whatever the miles a '67 L-79 with A/C is a great find.

Duke

[Joe L.]

Re: 1967 Vette 350 HP Harmonic Balancer No Fins

I purchased a 1967 350hp Air Coupe that has been sitting since 1984 with 50,000 miles on it. After pulling the engine and working with a friend that has been working with classic car engines for 40 plus years we believe this engine to be the Original Engine except for the water pump. According to the NCRS Judging manual it looks like this engine was suppose to have a Finned Harmonic Balancer but this engine did not but we believe it to be the one GM put on during assembly. In referencing the Corvette By The Numbers books by Alan Colvin his research says in 1967 the Harmonic Balancer on the 350hp in 1967 would not have fins. This car would have been an early March Build.

So far all the numbers and dates including the A/C Compressor, alternator, starter, intake, etc are correct for the car. The stampings on the engine are correct and believed to be original stampings. My engine builder I would consider an more than knowledgable individual on correct stampings. The engine still has standard pistons with only .007 wear on the cylinder walls.

I'm in the Omaha area if there is someone in the C2 Judging world in the area that would want to look at the engine and Harmonic Balancer, or anything else.

Regards,
Paul H. Bohannon Jr.

Paul-------


What you and others reporting here have found is exactly what I've been saying for a long time. The fins disappeared from the 3817173 balancer sometime in the 1966 model year, if not even earlier. Could some SHP small blocks manufactured after this time have been originally fitted with finned balancers? I suppose it's possible for several reasons but I highly doubt that it's typical. However, if such a balancer is found on a 1967-68 I believe it would need to be the version with balance weight holes around the full perimeter of the outer portion of the hub. I believe that any judging standard that claims that only a finned balancer is correct for 1967-68 is wrong. I strongly believe that during the 67-68 period, if not somewhat earlier, any finned balancer found is, AT MOST, the exception rather than the rule. Or, it's a case of someone installing a finned balancer to conform to an incorrect judging standard or belief.

[Joe R.]

Re: 1967 Vette 350 HP Harmonic Balancer No Fins

Paul the a new 67 judging just came out in Feb 2016 I'll check it tonight and see if it addresses this issue. I believe from what I've read in the past is the fin balancers went away in late 66 for L79 motors. What is your engine assembly date ? Mine was 02/23.

Paul the new judging manual still states that the L79 had fin balancers which I believe is wrong, I've seen a lot of disscussion on this subject on the TBD with other people having low mileage cars with no fin balancers. My no fin balancer is staying on my car.

Mike

Wow, this thread is interesting to me. I have a '67 L79 that was purchased from GM in 1967 as a complete engine. These engines were built on the same Flint assembly line as the engines that went into production cars. The Flint engine stamping is V0302HT (March 2). The guy who bought this engine in 1967 put it into a hod rod, drove it about 50K miles, and then sold the engine to me.

He said the engine had never been apart, and when I disassembled it, it certainly appeared that way. It had rusty, original-style steel shim head gaskets and all the intake seals looked original. However, when I pulled the damper, it had no fins. Since I thought that "all" 1967 L79 engines had finned dampers, I called the original owner to see if he remembered replacing it at some point. He said the damper that was on it is the one it came with. I can say that based on the overall degree of grime and patina, it appeared to have been on the engine since day one.

I set this damper aside, figuring it would just be one of those "unanswerable mysteries." For what it's worth, attached are three photos of the damper after I cleaned it up. Note that it appears to have a date code, but the stamping is poor. Still, I think the first two characters are B7, indicating February 1967.

Anyone else have a photo of their non-finned damper? If they were all stamped where mine was, I think that by carefully rotating the crank and looking from under the car, you could find the date code with the damper still installed on the car.

[Nick C.]

Re: 1967 Vette 350 HP Harmonic Balancer No Fins

Paul-------


What you and others reporting here have found is exactly what I've been saying for a long time. The fins disappeared from the 3817173 balancer sometime in the 1966 model year, if not even earlier. Could some SHP small blocks manufactured after this time have been originally fitted with finned balancers? I suppose it's possible for several reasons but I highly doubt that it's typical. However, if such a balancer is found on a 1967-68 I believe it would need to be the version with balance weight holes around the full perimeter of the outer ring. I believe that any judging standard that claims that only a finned balancer is correct for 1967-68 is wrong. I strongly believe that during the 67-68 period, if not somewhat earlier, any finned balancer found is, AT MOST, the exception rather than the rule. Or, it's a case of someone installing a finned balancer to conform to an incorrect judging standard or belief.

I think we can make everyone happy by simply deleting the second sentence; "The interior surface has 12 integrally cast fins." in the description of the 1967 L79-350 hp Small Block Crankshaft Balancer found on pg 146 of the 6th ed 67 TIMJG.

[Mike E.]

Re: 1967 Vette 350 HP Harmonic Balancer No Fins

Nick,
i would amend that to "may or may not have...." #8286 (an early-January car) is a 30k-mile car with a finned balancer. Both the balancer and timing chain cover are stamped with 1966 dates.

[Gene M.]

Re: 1967 Vette 350 HP Harmonic Balancer No Fins

Wow, this thread is interesting to me. I have a '67 L79 that was purchased from GM in 1967 as a complete engine. These engines were built on the same Flint assembly line as the engines that went into production cars. The Flint engine stamping is V0302HT (March 2). The guy who bought this engine in 1967 put it into a hod rod, drove it about 50K miles, and then sold the engine to me.

He said the engine had never been apart, and when I disassembled it, it certainly appeared that way. It had rusty, original-style steel shim head gaskets and all the intake seals looked original. However, when I pulled the damper, it had no fins. Since I thought that "all" 1967 L79 engines had finned dampers, I called the original owner to see if he remembered replacing it at some point. He said the damper that was on it is the one it came with. I can say that based on the overall degree of grime and patina, it appeared to have been on the engine since day one.

I set this damper aside, figuring it would just be one of those "unanswerable mysteries." For what it's worth, attached are three photos of the damper after I cleaned it up. Note that it appears to have a date code, but the stamping is poor. Still, I think the first two characters are B7, indicating February 1967.

Anyone else have a photo of their non-finned damper? If they were all stamped where mine was, I think that by carefully rotating the crank and looking from under the car, you could find the date code with the damper still installed on the car.

Hi Joe,
Is this a small journal engine? I would thing it would be since it is March build.
It looks like there are no weights in the balancer holes. Was there at any time that you know of?
thanks
Gene

[Joe R.]

Re: 1967 Vette 350 HP Harmonic Balancer No Fins

Hi Joe,
Is this a small journal engine? I would thing it would be since it is March build.
It looks like there are no weights in the balancer holes. Was there at any time that you know of?
thanks
Gene

Hi Gene:

It's a small-journal block, casting date February 21, 1967, assembly date March 2.

The damper is just the way it came off the engine, other than being bead blasted. Did GM put weights in the hub to balance these? I didn't know they did that.

You can see in the photos that this damper has two balancing holes drilled in the outer ring. That's the only sign of any balancing.

[Joe L.]

Re: 1967 Vette 350 HP Harmonic Balancer No Fins

Hi Gene:

It's a small-journal block, casting date February 21, 1967, assembly date March 2.

The damper is just the way it came off the engine, other than being bead blasted. Did GM put weights in the hub to balance these? I didn't know they did that.

You can see in the photos that this damper has two balancing holes drilled in the outer ring. That's the only sign of any balancing.

Joe-------


The balance holes drilled in the outer ring was done to neutral balance the balancer at the time the balancer was manufactured.

The circumferential holes in the balancer hub were used for final engine balance performed at the time of initial engine start-up at the engine plants. Usually, no weights were needed to bring the engine within whatever the GM spec was. However, apparently at times the engines were outside the range and a weight or weights were added by driving them into the appropriate holes.

[Joe R.]

Re: 1967 Vette 350 HP Harmonic Balancer No Fins

Joe-------


The balance holes drilled in the outer ring was done to neutral balance the balancer at the time the balancer was manufactured.

The circumferential holes in the balancer hub were used for final engine balance performed at the time of initial engine start-up at the engine plants. Usually, no weights were needed to bring the engine within whatever the GM spec was. However, apparently at times the engines were outside the range and a weight or weights were added by driving them into the appropriate holes.

Hi Joe L:

That's very interesting. I was not aware that GM tried to fine-tune the engine's balance after the engine was assembled.

BTW, does the balancer in my photos look like what you would expect for a 1967 no-fin, factory-installed balancer? Based on what I have read in this thread, I'm beginning to suspect that it may indeed be original. However, I have no idea how the general appearance of the 8" balancers evolved over the years.

[Joe L.]

Re: 1967 Vette 350 HP Harmonic Balancer No Fins

Hi Joe L:

That's very interesting. I was not aware that GM tried to fine-tune the engine's balance after the engine was assembled.

BTW, does the balancer in my photos look like what you would expect for a 1967 no-fin, factory-installed balancer? Based on what I have read in this thread, I'm beginning to suspect that it may indeed be original. However, I have no idea how the general appearance of the 8" balancers evolved over the years.

Joe------


It's exactly what I would expect and I have absolutely no doubt, whatsoever, that it's original to the engine.

I think the final balancing of the engine began around 1966. That's why the balance weight holes were added to all balancers about this time. I have seen some finned balances that have the holes, too.