1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fins"?

[Jim S.]

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

You're welcome, if better pictures would help, or if you need any specific information from the sticker that doesn't show up well in the pictures, just let me know and I'll take a closer look at it for you.

.

If you don't mind , I would like one of the whole unit close up , not just the decal.

Thanks again ,

Jim

[Jim S.]

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Jim-----


I hate to disappoint but I'm afraid I don't know when the change was made. However, I have said before that I believe the use of the "finned" balancers ended, in whole or part, prior to the end of the C2 period. Just when it was. I do not know. It's very hard to pin that down because the part number never changed from 1962 right through to the present.

It may also be that both types of balancers were used for awhile----possibly the product of different manufacturers.

Joe,

You are still "The Man" ! I do admit however, to being somewhat
shocked and disillusioned.

Luckily , you have never "not known" any question I have posed ! I therefore will probably recover from my disappointment rather quickly !

Jim

[Scott S.]

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

.

If you don't mind , I would like one of the whole unit close up , not just the decal.

Thanks again ,

Jim

I took these pictures about two weeks ago. They blow up very well without blurring [1600 x 1200 resolution pictures], so if you would like to zoom in on specific parts or manipulate the contrast and sharpness for better detail, send me a PM with your email and I'll send them over to you.

If more pictures would help, or different angles, etc., just let me know.

P.S. If you see anything that looks wrong, please let me know!

[Randy R.]

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Scott,

The balancer on my L79 looks like yours. The car is a May 67 built car W/O A/C or PS. I have had the car since 68 and do not recall changing the part in question.

Randy

[Scott S.]

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

I don't know how the brown/rust grunge got under where the paint used to be, but the "stains" visible in some of my "before" pictures (on top of the orange paint) of the balancer appear to be consistent with the stains in the "after" pictures of the balancer, minus the paint (i.e., very similar shaped-stains that were visible while it was still painted orange are still there now, despite the paint having been stripped away).

This is what I mean by the "stains". In the previous pictures, where the balancer was still mounted on the engine, it was oriented straight up, by which I mean the single groove "centerline" cutting across the outer circumference (from front side to back side) was facing straight up toward the underside of the hood. In that orientation, looking at it from the front, there are 3 circular "scoops" near the outer rim at 10 o'clock, and 2 circular "scoops" at 1 o'clock. These are clearly visible when it was mounted on the engine before disassembly, and they appear in the same areas on the "cleaned" part now.

I found the first picture below that appears to show that the balancer that was on the engine before disassembly was non-finned. From this angle it appears to catch just enough of the back side of the balancer to show that there are no fins inside.

Also, this picture shows the "stains" on the outer surface (around the outer circumference) well. I just took the other two pictures below from approximately the same angle and orientation as the first picture, the "stains" may not show too well in the pictures of the "cleaned" part, but they appear consistent to the naked eye, and by all these comparisons, this does appear to be the balancer that was on the car for at least the last 20 years. Before that, I don't know.

[Joe L.]

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

This is what I mean by the "stains". In the previous pictures, where the balancer was still mounted on the engine, it was oriented straight up, by which I mean the single groove "centerline" cutting across the outer circumference (from front side to back side) was facing straight up toward the underside of the hood. In that orientation, looking at it from the front, there are 3 circular "scoops" near the outer rim at 10 o'clock, and 2 circular "scoops" at 1 o'clock. These are clearly visible when it was mounted on the engine before disassembly, and they appear in the same areas on the "cleaned" part now.

I found the first picture below that appears to show that the balancer that was on the engine before disassembly was non-finned. From this angle it appears to catch just enough of the back side of the balancer to show that there are no fins inside.

Also, this picture shows the "stains" on the outer surface (around the outer circumference) well. I just took the other two pictures below from approximately the same angle and orientation as the first picture, the "stains" may not show too well in the pictures of the "cleaned" part, but they appear consistent to the naked eye, and by all these comparisons, this does appear to be the balancer that was on the car for at least the last 20 years. Before that, I don't know.

Scott------


A lot of times, a balancer received a rather thin coat of paint when the engine was painted at Flint. I think that a combination of this and deterioration of the paint over the years is what allowed the rust to form. There may also have been some rust on the balancer BEFORE it was painted, so the rust just proceeded under the paint.

Once again, from your pictures and description of the history of the engine, I think it's very likely that this is the original balancer. It seems quite unlikely to me that a balancer was replaced during the "early days" of the car. It's not beyond the realm of possibility, but I think it's very unlikely.

As far as the markings go from a previous question of yours, I do not know what they denote. They are some sort of manufacturing codes I suspect, though. I have seen the "M-C" on other balancers and I think it's a manufacturer's ID OR an identifier for malleable cast iron. The latter is a material that some balancer rings are cast from.

[Jim S.]

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

I took these pictures about two weeks ago. They blow up very well without blurring [1600 x 1200 resolution pictures], so if you would like to zoom in on specific parts or manipulate the contrast and sharpness for better detail, send me a PM with your email and I'll send them over to you.

If more pictures would help, or different angles, etc., just let me know.

P.S. If you see anything that looks wrong, please let me know!

Scott,

Thats exactly what I needed , thanks !

The end of the Bracket holding the POA valve in the close up pictures you sent earlier was throwing me off, I could not determine where it was exactly. It turns out they (66 and 67) are different, due to the STV on 66s and the POAs on 67s . Now I can tell where the label goes exactlly and which way it faces.

The only thing I see wrong is all the clean up you have to do on yours!
After several months of effort , ,blasting , new foam inside and out ,cleaning and testing the evaporator, rebuilding the STV.....etc.etc, etc. here is what you can expect .

Ps. Don't mind the paper , it is there to prevent any dust from sticking to the black caulking ,or whatever you call it , until I put it back in !

Jim

[Jack P.]

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

My L79 327/350 Build date 4/07/66 has the 8" fined balancer. #3817173 Its is not suppose to be according to Colvin, but it came with the car from the factory. Original engine , and balancer. see photos, you can read numbers if you enlarge

Jack

[Joe L.]

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

I'm trying to identify the (probably incorrect) harmonic balancer that came off of a 1967 L79 engine, to determine whether to have it restored or to begin looking for the correct balancer.

According to the 1967 TIM & JG (Fourth Edition, p. 86):
"The L79 350 hp engines use a heavy 1 3/4 inch thick balancer with an outside diameter of 8 inches. The interior surface has twelve integrally cast fins."

Also, in at least two NCRS Forum Threads, the 1967 L79 harmonic balancer should be (or is correct as) a "finned" balancer:

1967 L79 HT Harmonic Balancer
https://www.forums.ncrs.org/showthre...ancer&uid=2389

327/350HP engine
https://www.forums.ncrs.org/showthre...ering&uid=5910


However, according to "Corvette by the Numbers" (Alan L. Colvin, p. 511-514), the "finned" balancers were only used from 1962-1965 ("third design", date coded) and the 1966-1967 L79 harmonic balancer was NOT "finned" and did NOT have a date code. The 1967 balancer in Colvin's book is close to (but not exactly like) the one I have in the pictures below that came off the '67 L79 I'm in the process of restoring. The inside view of the Fifth design in the "Corvette by the Numbers" book matches the inside view of mine, but the outside view is different in the book than the one I have.



The markings on mine (8 inch diameter) are the following:
One the outside, there is "M - C" at the top (12 o'clock), and "S - 4" at the bottom (at 6 o'clock). On the inside, on the left-hand "spoke", is cast "F 1" on one side of the hole, and "6 - 2" on the other side of the hole. On the inside top spoke (pointing toward 12 o'clock) there is a diamond cast on the right hand side of the hole, and a capital "L" cast on the left-hand side of the hole. I have no idea what these casting numbers mean, and the book does not identify them.


So after all of this, I have three questions:

1. Is it for sure that the only correct harmonic balancer for a 1967 L79 327/350hp engine is a "finned" balancer with a date code, in which case the one that I have is definitely wrong?

2. The TIM & JG appears to be in conflict with the book referenced above. Is the book "Corvette by the Numbers" incorrect when it says the 1962-1965 "third design" was the only 8" finned harmonic SB balancer in a Corvette application, or am I misunderstanding something?

3. Can anyone identify what kind of balancer I actually have, and what application it must have originally come from?


Thanks to anyone who has read this far, comments and replies very much appreciated,

Scott

Scott------


One other thing I noted in the second photo in your series. Note that the balancer has a weight (short dowel) installed in one of the circumferential holes on the hub. I believe that this type of weight is installed, as necessary, at the engine test at Flint. I don't think you would find one of these installed on a SERVICE balancer. At least, I've never seen one installed on a SERVICE balancer. Balancers are balanced at the time of manufacture by drilling the shallow, large diameter holes you see in the ring section. Any "fine tuning" for a particular engine is done on the final test stand using the weights.

[Joe L.]

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

My L79 327/350 Build date 4/07/66 has the 8" fined balancer. #3817173 Its is not suppose to be according to Colvin, but it came with the car from the factory. Original engine , and balancer. see photos, you can read numbers if you enlarge

Jack

Jack------


This balancer has been removed and re-installed at least once. Note the damage from "impactive force" applied to the center of the hub. Believe me, the factory NEVER did this.

It's especially dumb for someone to do this when installing this balancer. All engines that originally used this balancer also were equipped with a cranshaft snout bolt tapping. So, a balancer installer tool can be used to install the balancer; no "impactive force" is necessary or advisable.

[Scott S.]

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Scott,

Thats exactly what I needed , thanks !

The end of the Bracket holding the POA valve in the close up pictures you sent earlier was throwing me off, I could not determine where it was exactly. It turns out they (66 and 67) are different, due to the STV on 66s and the POAs on 67s . Now I can tell where the label goes exactlly and which way it faces.

The only thing I see wrong is all the clean up you have to do on yours!
After several months of effort , ,blasting , new foam inside and out ,cleaning and testing the evaporator, rebuilding the STV.....etc.etc, etc. here is what you can expect .

Ps. Don't mind the paper , it is there to prevent any dust from sticking to the black caulking ,or whatever you call it , until I put it back in !

Jim

yeah... I have a little cleaning to do, here and there... after a little more disassembly...

But yours gives me inspiration, that sure looks nice!

[Scott S.]

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Thanks to Chris, Ray, Randy and Jack for your replies.

[Scott S.]

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Scott------


One other thing I noted in the second photo in your series. Note that the balancer has a weight (short dowel) installed in one of the circumferential holes on the hub. I believe that this type of weight is installed, as necessary, at the engine test at Flint. I don't think you would find one of these installed on a SERVICE balancer. At least, I've never seen one installed on a SERVICE balancer. Balancers are balanced at the time of manufacture by drilling the shallow, large diameter holes you see in the ring section. Any "fine tuning" for a particular engine is done on the final test stand using the weights.

.

Thanks again for your posts Joe, from your comments and the posts of a few others with the same balancer, it sounds like I should be okay to get this one refurbished as an original part to this car.

When you mentioned the impact marks on Jack's balancer, it reminded me of something my (former) engine builder said. The end of the engine crank was slightly bent ("crank has a .004 T.I.R."). He said this could be ground "true" again, but that it's usually the result of someone improperly "hammering" the balancer onto the crank, whether hammering directly on the balancer or hammering on a wood block against the balancer.

[Jack P.]

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Jack------


This balancer has been removed and re-installed at least once. Note the damage from "impactive force" applied to the center of the hub. Believe me, the factory NEVER did this.

It's especially dumb for someone to do this when installing this balancer. All engines that originally used this balancer also were equipped with a cranshaft snout bolt tapping. So, a balancer installer tool can be used to install the balancer; no "impactive force" is necessary or advisable.

I have removed it 3 times, engine rebuilders 3 times, I was not gentle with it

Jack

[Paul D.]

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

I have a very original L-79 '67.My balancer is non finned with "1266" stamped on the back of the outer wheel.The engine build date is B-15-7.It went thru judging with no deduct.....Paul....