Harmonic Balancer Confusion

68Blue302Coupe · Oct 10, 2009

Hey All,

Having some trouble identifying the correct harmonic balancer for my engine and hoped you could help.

My current engine is a 1971 302 (D10E-6015-AA) and is installed in my '68 Mustang. The current balancer appears to have gone bad (has a slight wobble) and uses 3 bolts for the pulley.

I went to a parts store and asked for a balancer for a 1971 Ford 302 and they supplied me with a 4 bolt version that looks significantly more robust than my current balancer.

On my engine, the water pump is from a 1968 Mustang, which leads me to suspect that the balancer and pulley is also from a 1968 Mustang.

So... the big question is which balancer is correct? Do I currently have the wrong balancer installed and it should in fact use the 4 bolt model the parts store supplied? If so, what do I do about the pulley (replace, drill for 4 bolt, etc.?).

I am stumped and would appreciate any help. Thanks!

2+2GT · Oct 10, 2009

Ford totally changed the pulley system in 1970, requiring entirely different pulleys and a completely different configuration of the harmonic balancer. Buy a correct 1968 289/302 harmonic balancer and you'll be fine. It sounds like someone already did the change from 71 style to 68 style, and yours has gone bad. Harmonic balancers can be repaired, too, if the rubber has gone bad. Any number of suppliers have these dampers, I prefer Glazier Nolan.

rbohm · Oct 10, 2009

2+2GT said:
Ford totally changed the pulley system in 1970, requiring entirely different pulleys and a completely different configuration of the harmonic balancer. Buy a correct 1968 289/302 harmonic balancer and you'll be fine. It sounds like someone already did the change from 71 style to 68 style, and yours has gone bad. Harmonic balancers can be repaired, too, if the rubber has gone bad. Any number of suppliers have these dampers, I prefer Glazier Nolan.

68Blue302Coupe · Oct 10, 2009

Ah that explains it, thank you. Looks like another trip back to the parts store. At least pulling the old balancer was easy.

D.Hearne · Oct 10, 2009

68Blue302Coupe said:
My current engine is a 1971 302 (D10E-6015-AA) and is installed in my '68 Mustang.

These numbers are the engineering numbers for the block only. The actual year it was made can be determined by the date code next to these numbers. It'll be a number/letter/number(s) combo on what looks like a screwed tag cast into the block.

68Blue302Coupe · Oct 11, 2009

D.Hearne said:
These numbers are the engineering numbers for the block only.

Does this make a difference in whether or not I can use the '68 balancer?

2+2GT · Oct 11, 2009

68Blue302Coupe said:
Does this make a difference in whether or not I can use the '68 balancer?

None whatsoever. The balance is still 28 oz., so you're good to go. If your local store doesn't have it, I know one that sells them.

D.Hearne · Oct 11, 2009

68Blue302Coupe said:
Does this make a difference in whether or not I can use the '68 balancer?

If you're using the 68 accessories, timing cover and water pump, you'll need a 68 3 bolt balancer.

68Blue302Coupe · Oct 13, 2009

Argh... I am starting to get pretty frustrated now. OK, so I special ordered a harmonic balancer from Autozone, P/N DA-2008, which according to their site is for a 1968 Mustang with a 302. Looked right enough on the screen, and it is a 3-bolt.

I just picked it up and noticed right away that it is heavier than the balancer I pulled from the engine (see pic, the blue one). I actually weighed the two and the current balancer is 6 lb. 12 oz., and the replacement 9 lbs.

Both balancers are the same overall width (end to end). BUT, the replacement balancer has a small lip where the pulley attaches, and the old balancer does not. The pulley I have has a lip as well, so I can't bolt the pulley to the new balancer without removing the lip on the pulley.

Just for fun, I looked up the balancer for a 1967 Mustang with a 289 on Autozone's site, and it listed a weight of 6.15 lbs. I am wondering now if my old balancer is actually for a 289? Keep in mind this engine is not original, someone could have put the wrong one on here.

So what do I do now? Go with the new balancer and modify the pulley so it can attach? Order yet another balancer? Throw both balancers into a brick wall?

68Blue302Coupe · Oct 13, 2009

OK. I was looking through Mustangs Unlimited's online catalog and think I may know what happened. Their catalog had pictures of a '65-'68 260/289 balancer that looks exactly like the one I pulled off of my 302. They also had pictures of the one for a 302 that looked like the new one I picked up today. They also had this note:

"Early 302's had a locating ring built into the crankshaft pulley to align it with the balancer. Later years had the ring cast into the balancer. Check yours to be sure."

So it looks like--and please tell me what you think--my '71ish 302 was sporting a 289 balancer and matching pulley from (possibly) a '65-'68.

So now what should I do?

2+2GT · Oct 13, 2009

68Blue302Coupe said:
Argh... I am starting to get pretty frustrated now. OK, so I special ordered a harmonic balancer from Autozone, P/N DA-2008, which according to their site is for a 1968 Mustang with a 302. Looked right enough on the screen, and it is a 3-bolt.

I just picked it up and noticed right away that it is heavier than the balancer I pulled from the engine (see pic, the blue one). I actually weighed the two and the current balancer is 6 lb. 12 oz., and the replacement 9 lbs.

Both balancers are the same overall width (end to end). BUT, the replacement balancer has a small lip where the pulley attaches, and the old balancer does not. The pulley I have has a lip as well, so I can't bolt the pulley to the new balancer without removing the lip on the pulley.

Just for fun, I looked up the balancer for a 1967 Mustang with a 289 on Autozone's site, and it listed a weight of 6.15 lbs. I am wondering now if my old balancer is actually for a 289? Keep in mind this engine is not original, someone could have put the wrong one on here.

So what do I do now? Go with the new balancer and modify the pulley so it can attach? Order yet another balancer? Throw both balancers into a brick wall?

You are correct, your old balancer and pulley are 289. The 302 had higher overall weight, but the same 28oz. offset. If you have access to a lathe, the 302 pulley was identical to the 289 except for the lip situation. Or you could get a 289 balancer. I suspect, however, Ford had a reason for the heavier ring on the 302.

D.Hearne · Oct 13, 2009

The heavier balancer does a better job of cancelling out vibes at higher rpms. As long as the offset of the pulley mounting face is the same, just have the lip machined off the pulley.

96 DOHC Cobra · Oct 13, 2009

Find a replacement crank pulley What's the part number on youe old pulley? How many grooves? Maybe someone has or knows of the correct replacement for you.

2+2GT · Oct 13, 2009

The 68-69 302 crank pulley is findable used, but not reproduced.

D.Hearne · Oct 13, 2009

I have a spare, but it's a single groove. And the balancer & water pump pulley to match

68Blue302Coupe · Oct 13, 2009

Hey All,

The pulley is a 2-groove, although for now I have manual steering I will probably convert it to power in the future. I looked for a P/N but didn't see one on the pulley, could be burried under the paint (looks to have been repainted).

So my options are to either have the pulley machined (or trade/replace) or return the balancer and try to find one without the lip? I would like to use the 302 balancer, it looks a lot more solid than the 289 version I removed. I don't suppose I can modify the pulley on my own with a grinder, right--it needs to be exact?

2+2GT · Oct 13, 2009

68Blue302Coupe said:
Hey All,

The pulley is a 2-groove, although for now I have manual steering I will probably convert it to power in the future. I looked for a P/N but didn't see one on the pulley, could be burried under the paint (looks to have been repainted).

So my options are to either have the pulley machined (or trade/replace) or return the balancer and try to find one without the lip? I would like to use the 302 balancer, it looks a lot more solid than the 289 version I removed. I don't suppose I can modify the pulley on my own with a grinder, right--it needs to be exact?

Yeah the lip goes, but the hole gets a little bigger, too. Not a big job, any high school metal shop student could fix it in about 15 minutes.

D.Hearne · Oct 14, 2009

68Blue302Coupe said:
Hey All,

The pulley is a 2-groove, although for now I have manual steering I will probably convert it to power in the future. I looked for a P/N but didn't see one on the pulley, could be burried under the paint (looks to have been repainted).

So my options are to either have the pulley machined (or trade/replace) or return the balancer and try to find one without the lip? I would like to use the 302 balancer, it looks a lot more solid than the 289 version I removed. I don't suppose I can modify the pulley on my own with a grinder, right--it needs to be exact?

The engineering numbers are usually inside the cup of the pulley. Machining the lip off needs to be done on a lathe. A grinder will usually do a hatchet job of it. You don't want that.

68Blue302Coupe · Nov 8, 2009

Hey All,

Just getting back to the car after a few weeks away. I was able to source a correct used 2-groove pulley from a used Mustang parts shop in Maryland. Having it mailed over, should do the trick. It always seems that simple jobs on this car turn into epic repairs....

2+2GT · Nov 8, 2009

68Blue302Coupe said:
Hey All,

Just getting back to the car after a few weeks away. I was able to source a correct used 2-groove pulley from a used Mustang parts shop in Maryland. Having it mailed over, should do the trick. It always seems that simple jobs on this car turn into epic repairs....

Yeah. The repro 2-sheave crank is made wrong. They simply leave the third sheave off of a repro 3-sheave, and think they're OK. They're wrong. The 3-sheave AC pulley is considerably larger in diameter than the 2 sheave, because the 2-sheave AC water pump pulley is smaller, so it will be overdriven by the large AC crank pulley. The 2-sheave PS pulley is supposed to be smaller, to clear the single sheave standard or PS water pump pulley. They got lazy, and tried to pull a fast one, and it sucks. IIRC, the 2-sheave repro is about 5/16 larger than it should be, making it 5/32 too close to the water pump pulley, which results in about 1/8" overlap. Not gonna work.

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