I plan to use the 77 302 that is in the Bronco. I have the flywheel off the donor 302-C4 and I see it is balanced. Do I have to also remove the harmonic balancer for the install of the C4?
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C4 install Harmonic balancer question
- Thread starter DonH
- Start date
You will receive two very different answers to your question.
This is because you did not ask a specific question, but instead asked a general question with a specific detail. So the vast majority of responses will say "no" you do not need to swap your harmonic balancer.
But your use of the term "I see it is balanced" is troublesome. I cannot see what you see. So you will have to tell me what that means.
1.) IF you see that there is a factory installed 28.2 oz steel weight welded to your flexplate, and it appears unmolested, and in good condition...then you are fine.
2.) IF you see that your C4 flex-plate looks strangely balanced with random drilled holes, and obviously added washers, welds, and weights...then the answer is still "no" for the harmonic balancer, but also "no, you can't run that flywheel." This happens when high performance race car engine builders balance the engine using the flywheel, instead of balancing the crankshaft. I have seen it countless times. If someone re-balanced your donor 302 by adding or subtracting weight to your flexplate, they effectively make the flexplate useless for any other crankshaft/reciprocating assembly. It is similar to seeing someone balance a tire by drilling holes in the rim.
If you post a pic, It will be easy enough to tell if you are case 1, or 2.
This is because you did not ask a specific question, but instead asked a general question with a specific detail. So the vast majority of responses will say "no" you do not need to swap your harmonic balancer.
But your use of the term "I see it is balanced" is troublesome. I cannot see what you see. So you will have to tell me what that means.
1.) IF you see that there is a factory installed 28.2 oz steel weight welded to your flexplate, and it appears unmolested, and in good condition...then you are fine.
2.) IF you see that your C4 flex-plate looks strangely balanced with random drilled holes, and obviously added washers, welds, and weights...then the answer is still "no" for the harmonic balancer, but also "no, you can't run that flywheel." This happens when high performance race car engine builders balance the engine using the flywheel, instead of balancing the crankshaft. I have seen it countless times. If someone re-balanced your donor 302 by adding or subtracting weight to your flexplate, they effectively make the flexplate useless for any other crankshaft/reciprocating assembly. It is similar to seeing someone balance a tire by drilling holes in the rim.
If you post a pic, It will be easy enough to tell if you are case 1, or 2.
OP
OP
Taking a picture will take awhile. There was no 28 Oz welded on the flex plate. It was maybe 3-4 oz. This was a stock flexplate. I have never taken a 77 off before and there was a strange weld connecting the plate to the ring gear. It appears to maybe lazer welded.
OK. If you can't easily take a pic...then just go to your local parts house, and look at a factory flex plate for a 77 Bronco. (or look at pics)
Check to see if the weight is "almost exactly the same" as the weight you have. If they look almost exactly the same and they are in about the same place compared to the crankshaft index hole...you'll know that your flexplate is still native 28.2 oz-in
Do NOT be confused by the size of the weight and the name of the weight. UNLIKE a 2 ounce weight on your wheels, the balance weights are specified as a mass and a distance. So a 28 oz-in weight will weigh 28 ounces if it's an inch from the crank center-line. But it will weigh 4 ounces if it is 7 inches from the crank centerline. The 28.2 ounce imbalance weight on the harmonic balancer weighs about 5 times the weight on the flywheel.
I would tell you exactly how big the weight should be if I had one. (but I don't) I usually cut them off, because I'm the guy that balances my engines internally whenever possible. But someone here will have an old factory 77 164 tooth C4 flexplate with the factory weight.
I want to say it's about 3/4 inch wide, 3/8 inch thick, and about 4 inches long. But I might be thinking of the 50 oz one. They look very similar, just one's fatter.
Taking a picture will take less time than installing the engine, running it, having it shake, removing it, changing the flexplate, re-installing the engine, running it, having it still shake, removing the balancer, swapping it, having it still shake, parking it, waiting a year, and then selling me the engine for $500. (Laugh now, but that's how I got my fully forged 347 stroker for $500.
OP
OP
Attachments
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The oil is coming from the rear intake manifold.
OP
OP
I could not find a part number. It does look to be a stock part to me. Does that mean the harmonic balancer on the manual 77 is compatible?
That looks like a factory weight in the factory location. And I can see what look like 6 factory lightening holes drilled 1/2 way thru on the opposite side of the weight. Very typical.
Yes, your factory 28.2 oz harmonic balancer should be compatible, no problem. Just take a quick look at the back of your crankshaft and make certain that it does NOT have a 1 piece rear main. As long as it has the original 1977 crankshaft, and 1977 damper, it should be fine.
Yes, your factory 28.2 oz harmonic balancer should be compatible, no problem. Just take a quick look at the back of your crankshaft and make certain that it does NOT have a 1 piece rear main. As long as it has the original 1977 crankshaft, and 1977 damper, it should be fine.
OP
OP
It does not have a one piece seal.
There is another thing, the donner 77 has a cast three grove front pulley and my 77 has a two grove stamped pulley. From what I can see the dampers look the same.
the decal on the doner valve cover says 1977 but it does look like the heads were pulled at one time. The intake manifold both front and rear were leaking.
When you do not remember for sure you have to ask questions. I have done this before and tryng not to make a mistake.
There is another thing, the donner 77 has a cast three grove front pulley and my 77 has a two grove stamped pulley. From what I can see the dampers look the same.
the decal on the doner valve cover says 1977 but it does look like the heads were pulled at one time. The intake manifold both front and rear were leaking.
When you do not remember for sure you have to ask questions. I have done this before and tryng not to make a mistake.
So you have a 1977 Bronco, and you ALSO have a 1977 Bronco doner engine?
Of do you have a 1977 Bronco, and you have a 1977 Ford Engine from something else?
Count the number of bolts attaching your cast front pulley to your damper. It will either be 3, or 4.
The 77 Bronco with power steering used a 3 bolt damper with a raised hub to pilot the stamped 2 groove pulley. If someone added Air conditioning, then a 3 groove pulley would have been added.
I'm checking out for a few hours. Gotta get back in the shop...
OP
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Both have three bolt pulleys.
I purchased a complete radiator to C4 to dana 20 and including drivelines from a donner 1977 Bronco.
I have a 1977 Bronco manual three speed project I want to install the C4 into.
As we all know to keep out Broncos running requires maintence.
I did not talk with the donner person just the shop the did a Coyote swap for them. I got the left over bones.
The C4 is connected to the Dana 20 and frame mount. easy swap Sounds simple right.
I have also to decide what engine to use. Both have around seventy thousand miles on them.
My 77 had not run for at least 15 years. I got it running it sounded great but it was smoking very bad. I shut it down before it got worm maybe it would clean up.
Was told the donner engine was a good runner but I can see it must have using oil much of it on the ground.
I am leaning a little with freshing the doner engine up.
I am going to start my 77 again to see if it will clean up. That will make the C4 sway much easier. Maybe
I have to remember this a project for me.
Don
I purchased a complete radiator to C4 to dana 20 and including drivelines from a donner 1977 Bronco.
I have a 1977 Bronco manual three speed project I want to install the C4 into.
As we all know to keep out Broncos running requires maintence.
I did not talk with the donner person just the shop the did a Coyote swap for them. I got the left over bones.
The C4 is connected to the Dana 20 and frame mount. easy swap Sounds simple right.
I have also to decide what engine to use. Both have around seventy thousand miles on them.
My 77 had not run for at least 15 years. I got it running it sounded great but it was smoking very bad. I shut it down before it got worm maybe it would clean up.
Was told the donner engine was a good runner but I can see it must have using oil much of it on the ground.
I am leaning a little with freshing the doner engine up.
I am going to start my 77 again to see if it will clean up. That will make the C4 sway much easier. Maybe
I have to remember this a project for me.
Don
Broncobowsher
Total hack
- Joined
- Jun 4, 2002
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Your core engine is interchangable. You can mix and match either crank pulley, either harmonic damper, with either engine, and the flexplate will work with either.
This is one of the rare times on a small block Ford in a Bronco where it all actually interchanges.
While we have things apart, check the convertor bolt circle diameter. It should be 11-7/16 for being a '77. That is a good thing, that is the one that they still make replacments for. If it happens to be a 10-1/2" bolt circle. There have been no service flexplates for that for decades now. You can still run it, but if you ever need a new flexplate you will need a new torque convertor to match. If you get the transmission rebuilt, and they go for a new torque convertor, be sure it is the large bolt circle and pick up a flexplate to match.
But for a '77, it should have the good stuff already.
This is one of the rare times on a small block Ford in a Bronco where it all actually interchanges.
While we have things apart, check the convertor bolt circle diameter. It should be 11-7/16 for being a '77. That is a good thing, that is the one that they still make replacments for. If it happens to be a 10-1/2" bolt circle. There have been no service flexplates for that for decades now. You can still run it, but if you ever need a new flexplate you will need a new torque convertor to match. If you get the transmission rebuilt, and they go for a new torque convertor, be sure it is the large bolt circle and pick up a flexplate to match.
But for a '77, it should have the good stuff already.
