Balancer question, 289/351W
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Lead Driver
Joined: Dec 2002
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From: Kuna ID
Balancer question, 289/351W
I have to remove my timing cover on my 1969 351W to get a broken water pump bolt. I figured I would get a new balancer since the one thats on there came from a junkyard 16 years ago. Apparently the balancer I was using is a 3 bolt 289 balancer. I ordered a 3 bolt 351W balancer for a 1969 motor. Everything I have read tells me both of these balancers have the 28oz counter weight. The new balancer has a thicker outer ring and feels a bit heavier than the old one though. As long as the counterweight is the same I should be good to use the new balancer...right? I can order a 289 balancer if I need to, just trying to figure out if I should. I also had this motor balanced when it was rebuilt, that wouldn't have involved modifying the balancer would it? Here are some pics of the balancers, 351 on the left, 289 on the right.
Cargo Master
Joined: May 2007
Posts: 2,071
Likes: 36
From: British Columbia
Balancers
Yes both those engines should be 28 oz in unbalance. The extra ring material is to help dampen vibration from the larger rotating mass.
Is your new damper a genuine Ford unit? If so, what is the casting number?
During the engine balance, they shouldn't have altered the damper or the flywheel, but look for non-original drill holes that would indicate they did.
Is your new damper a genuine Ford unit? If so, what is the casting number?
During the engine balance, they shouldn't have altered the damper or the flywheel, but look for non-original drill holes that would indicate they did.
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Lead Driver
Joined: Dec 2002
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From: Kuna ID
The new balancer is aftermarket, so no casting number. The pictures I saw of another 289 balancer had a bunch of holes drilled in it, just in a different pattern. I figure it's just manufacturing differences.
So I should probably be better off using the correct balancer then?
So I should probably be better off using the correct balancer then?
Cargo Master
Joined: May 2007
Posts: 2,071
Likes: 36
From: British Columbia
Damper foibles
I checked the balancer on my original car 1969 351W engine, and lo and behold, it's the thinner type. A 351M damper in my parts storage is the thin type as well. So it seems the 351 engines didn't necessarily have the thick outer ring.
Possibly truck engines had the thicker ring. I believe they retained the three bolt pulley pattern for many years whereas the cars switched to four bolts in 1970.
Going back to the beginning, how do you know for sure the damper you had was from a 289? What is its casting number?
289 dampers from different years could well have different patterns of holes drilled in them. Looking back at your images though, I see there are four shallow drilled holes in the outer ring in your original damper. I wonder if they are factory or if they were drilled by the machine shop that balanced your motor. If the latter, then you should just continue to use that damper. I kind of doubt that they are factory holes, as they would seem to weaken the damper outer ring. Try contacting the machine shop if it's still around and ask them if they would have done this kind of damper rebalancing.
As for your last question, yes, you should definitely use the correct damper!
(But what is it?)
Possibly truck engines had the thicker ring. I believe they retained the three bolt pulley pattern for many years whereas the cars switched to four bolts in 1970.
Going back to the beginning, how do you know for sure the damper you had was from a 289? What is its casting number?
289 dampers from different years could well have different patterns of holes drilled in them. Looking back at your images though, I see there are four shallow drilled holes in the outer ring in your original damper. I wonder if they are factory or if they were drilled by the machine shop that balanced your motor. If the latter, then you should just continue to use that damper. I kind of doubt that they are factory holes, as they would seem to weaken the damper outer ring. Try contacting the machine shop if it's still around and ask them if they would have done this kind of damper rebalancing.
As for your last question, yes, you should definitely use the correct damper!
(But what is it?)
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Lead Driver
Joined: Dec 2002
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From: Kuna ID
The damper I have been using came from a junkyard, I found it on a shelf and it had 65 289 written on it...and still does. I guess I didn't clean that off before I painted it. I assume that meant someone pulled it from a 289. I used it because it was identical to the one I had broken when I took the motor apart.
Getting ahold of the shop could be difficult as I had it rebuilt 16 years ago and he had another shop do the balancing as it was the only equipment he didn't own.
Do you think the truck 351W balancer would be different from a mustang 351W balancer. The unit I ordered was for a 1969 mustang with a 351W. It didn't even cross my mind the motor may have come from a truck. The motor is currently in my 67 mustang, hence the reason I ordered a balancer for a mustang.
Getting ahold of the shop could be difficult as I had it rebuilt 16 years ago and he had another shop do the balancing as it was the only equipment he didn't own.
Do you think the truck 351W balancer would be different from a mustang 351W balancer. The unit I ordered was for a 1969 mustang with a 351W. It didn't even cross my mind the motor may have come from a truck. The motor is currently in my 67 mustang, hence the reason I ordered a balancer for a mustang.
Cargo Master
Joined: May 2007
Posts: 2,071
Likes: 36
From: British Columbia
Well I checked out the dampers in my parts pile, and I actually have a C9TE unit which is presumably a 1969 truck piece, originally. Unfortunately I don't know what engine it came from, but it is a small block type, has the counterweight so would seem to be either a 302 or 351 (or both).
The weird thing is that this thing has four pulley bolt holes. It also is "taller", so would project its pulley further forward. Plus it has a thicker, stepped outer ring than the 289 or car 351 type.
All three of the stock balancers in my parts collection have balancing holes drilled in their outer rings, so this must be factory balancing. The holes were all the same size though, so it's still unclear if your 289 damper, with two different size balancing holes, was rebalanced to suit your 351 engine.
Your new aftermarket damper doesn't appear to have any factory balancing drilled holes, so either the manufacturer is amazingly good at casting exactly right, or it isn't so precisely balanced as a stock part.
I would use the 289 type that you had, but first polish the seal area by spinning the damper in a lathe and applying fine emery paper to it. Also, you can push the seal on the timing cover in a little bit more or less than the old one was so that it seals other than right on the old groove.
The weird thing is that this thing has four pulley bolt holes. It also is "taller", so would project its pulley further forward. Plus it has a thicker, stepped outer ring than the 289 or car 351 type.
All three of the stock balancers in my parts collection have balancing holes drilled in their outer rings, so this must be factory balancing. The holes were all the same size though, so it's still unclear if your 289 damper, with two different size balancing holes, was rebalanced to suit your 351 engine.
Your new aftermarket damper doesn't appear to have any factory balancing drilled holes, so either the manufacturer is amazingly good at casting exactly right, or it isn't so precisely balanced as a stock part.
I would use the 289 type that you had, but first polish the seal area by spinning the damper in a lathe and applying fine emery paper to it. Also, you can push the seal on the timing cover in a little bit more or less than the old one was so that it seals other than right on the old groove.
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Lead Driver
Joined: Dec 2002
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From: Kuna ID
I guess it would be best to reuse the old one. Comparing them it doesn't appear the ring has slipped as the timing numbers are in the same place and the rubber doesn't look that bad either. That puts $60 back in my pocket. My old one has a repair sleeve on it and has only been used about 20k miles so it should be ok.
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Cargo Master
Joined: May 2007
Posts: 2,071
Likes: 36
From: British Columbia
Yes, I think reusing your old one is the best plan. By the way, I read some time ago that Ford considered balancers to be still okay even if the rubber is cracked a bit.
You have the better of the stock type. The other type has the counterweight on the outer ring, which of course will confound the balance if the ring slips.
You have the better of the stock type. The other type has the counterweight on the outer ring, which of course will confound the balance if the ring slips.
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