Fox Harmonic balancer questions

JMGlasgow

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Installing it won't be a problem. I was an auto mechanic for a good portion of my working life (mostly GMC light duty trucks and Ford E series vans) but I moved on to repairing equipment at a Kubota dealership. I have a harmonic balancer installation kit from Cornwell Tools.

If you heat up the balancer to 290°, how do you seal the key way? The LMR video instructs you to use silicon there to seal it off from leaking. Or do you just put sealer on the bolt head and washer?
 
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revhead347

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Interesting. I’ve never used sealer on a crank keyway and I’ve never had a leak there.
No idea what he is talking about. The key way is sealed by the washed on the bolt. I have absolutely never heard of a balancer leaking through the key way.

Some knowledge does not transfer. I have no experience with Kubota engines. Perhaps the keyway on those engines extend past the washer radius of the top bolt. In 25 years of putting SBFs together, I have never seen oil leak past the washer from the keyway. I would skip the silicone.

Kurt
 
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JMGlasgow

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I just looked through my Ford Mustang service manual (actual Ford manual) and it says to apply silicone sealant to the keyway as well.

20190910_195206.jpg
 

revhead347

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Never done it, never had one leak. Sounds like a mess to clean up the next time it's off. It certainly won't hurt anything if you do put silicone on it.

Kurt
 

HotFox

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The reason for the silicone is some manufactures cut the keyway deeper which is subject to a leak as the oil bleeds off the front main bearing. Remember it only takes a few thousands and oil will seep.
 

revhead347

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I'd use black. Much easier to see when you have to clean it out later. I'd also use only a dab. Otherwise it will all get pressed so far back it'll be stuck up in the timing gear.

I understand oil can seep past the keyway, but then it is sealed by that big washer tightened to 3 ugga duggas. I've never had oil get past that washer.

Kurt
 

revhead347

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and you can spend thousands and it still leaks.
Money doesn't solve problems sometimes. The reason I had mine back apart this week is that the Felpro Timing Cover Set came with a Chinese front main seal. I didn't even look at the stamp on it, and put it in. Sure enough, it leaked. Swapped it out for a National seal made in Mexico, and no problems.

Kurt
 
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General karthief

wonder how much it would cost to ship you a pair
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And sometimes intelligence plays a part. Does not matter what brand seal you buy if you install it backwards it will leak!
Yep, that's right! Swapped out three rear hub seals in the dump truck and they all started leaking within a month.
I did the first one (I still think that one was defective :hide: ) another mechanic at the shop did the next one, and then 'the boss' did the third one, when that one started leaking we discovered one side of the seal had a stamp 'bearing side'! :doh:
 
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revhead347

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That's one of the upsides to the SN. On the fox engine, the seal goes in from the back side of the cover, on the SN, the seal goes in the front side, so you don't have to remove the cover to change that seal.

Kurt
 
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JMGlasgow

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I just got done replacing the balancer. It went pretty smooth, no issues to speak of. The old balancer looked to be in good shape, no cracks in the rubber, no bulges either but it did wobble. I compared it to the new balancer and it looks like the counterweight spun on the rubber about 10°.

The vibration is now gone, and it runs smoother than it has since I bought the car.

I know an SFI balancer isn't necessary but I do think it's a better part than a stock replacement.
 

JMGlasgow

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I did, it isn't cracked like that, and I can still read the numbers in the rubber. The bulging isn't as bad either but it is there.
 

Blown88GT

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The front looked perfect. Couldn't see the back until it was removed. I think it slipped about 5 deg. They only dampen vibrations at the resonant frequency, about 1500 rpm for the 5.0 (302).
 

JMGlasgow

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I have the installer so I used it. I saw videos of people using a 2x4 and a hammer to install them and i cringed.