Flywheel indentification

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Sep 18, 2019 | 05:12 PM

dmock

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Flywheel indentification

How do I identify a flywheel for a FE engine to tell if it is an externally or internally balanced flywheel

Sep 19, 2019 | 07:15 AM

baddad457

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From: south louisiana

External will have a counterweight on the engine side. No counterweight = neutral balance

Sep 19, 2019 | 11:19 AM

dmock

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Ok so on the engine side I have 1 flywheel with 5 balancing holes drilled in it and I have 1 flywheel with 2 drilled in it do these make a difference ?

Sep 19, 2019 | 12:42 PM

baddad457

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From: south louisiana

Quote:

Originally Posted by dmock

Ok so on the engine side I have 1 flywheel with 5 balancing holes drilled in it and I have 1 flywheel with 2 drilled in it do these make a difference ?

Could be either neutral or counterweighted by a shop that does engine balancing by drilling those holes..Most likely the latter. I would have them checked before using them.

Sep 19, 2019 | 01:44 PM

dmock

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Sounds good I know the one is stock that has the 2 holes drilled but the one with 5 is off a rebuilt engine I have taken out of my truck guy claimed it was a 428 but not identifying as one. Was knocking with little to no oil pressure at an idle so suspect it has taken out bearings due to vibration. Does not have counter weight by the front balancer and crank is 2U. Is looking like someone didn't do home work prior to building engine. Still in process of taking it apart to check all casting #'s on con rods. Will check stroke / bore as well. I have a 390 that was in front of an automatic before that is going in it and don't want to take the bottom end out if flywheel is not balanced properly. Thanks for the help.

Sep 19, 2019 | 08:07 PM

baddad457

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Originally Posted by dmock

Yea, the wrong flywheel/flexplate will do that. Amazing it ran that long. 40 years ago when working at a sawmill, we bought a junkyard 390 to replace the tired 390 in the crew truck. Got it in and fired up. Had a granny gear 4 speed. When we tried to drive it, that long shifter was murder, shakin and rotating around. Motor wasn't a 390, but a 410. (with the old 390's flywheel on it)

I'd also suspect the two hole flywheel is probably the right one, but I'd make sure first. I had a 50 oz/in 5.0 flywheel rebalanced to 28 oz/in for my 331. That was accomplished by drilling holes in the 50 oz counterweight