Ford 302-internally or externally balanced?

[frclarke]

Hi Guys:
This is the ongoing restoration of Sugar Shaker, Hull #C16-577, a 69 Ski Sporter, 302 H&M with a 250 Volvo drive.

I'm working on getting the engine rebuilt - got the cam from H&M as per the boards suggestions... Anyway one rebuilder says it's externally balanced and if I I change the flywheel I'll have rebalance from the dampner to the flywheel. Another says it's internally balanced-

Whats the right answer?

On the issue of the flywheel - the original is large and very heavy. I have a newer flywheel that is about 2" smaller and offcourse much lighter. I'm thinking that a lighter flywheel will do a number of positive things:
- lighten the boat
- faster throttle response since the rotating mass is less
- provide more torque to the drive on acceleration.

What are the negatives?

Thanks
Fred

[Danny]

Hi Fred
Can't comment about the balancing.
Was in Larry's shop a couple of weeks ago and saw your boat. I think Rob did a hell of a job on it. I watched it at different stages because I wanted to see how Rob did some things. I am probably going to seperate my 16 next year, do the gas tank and have Larry spray on new gel. I'll do a lot of the prep myself and sand out the gel myself. Larry did some work on the GT last year and I was very pleased with the results.
Yours looks great, looking forwared to seeing the finished project.
Who's doing the rebuilt of your 302? Have you got Larry's friend Lee doing anything mechanical for you, I think he's pretty good.
Danny

[MOP]

Contrary to some beliefs there are atleast 3 flywheels for the small block ford, one of our mechs found this out the hard way. Replaced a flywheel instaed of re ringing it, put the engine back in the boat when he started it up it damn near shook its self out of the boat. The flywheel must match the application, if you don't believe me start it on blocks and watcht it roll across your shop!!!!

Phil

[Carl C]

Phil, you are absolutely right. There are both types. Be sure to use the correct flywheel. :redface:

[maddad]

A 302 carries almost 1/3 of it's eccentric balance weight on the balancer and flywheel. It's pretty important to use the right amount of offset weight on both parts and balance the motor with the parts you will be using.

[mphatc]

Fred,

I just went thru this whole procedure twice on my H&M 302 . .

As built by Ford in 1969 (and not altered by H&M) your engine is externally balanced. Your harmonic balancer and flywheel must match your crankshaft.

Not until I changed to the new Eagle forged steel crank could I go to an internally balanced set up. Even then I retained my stock flywheel, but only after we removed the cast in counterweight on the forward side and rebalanced the flywheel. I also needed to change my harmonic balancer.

I'd stay with the stock flywheel, it will not limit your ability to jump out of the water with a 16', and a lighter flywheel will not help you to reach a higher top speed.

Mario

[Carl C]

This is a little embarrasing to ask since I'm very familiar with the 302 motor but if the flywheel balances some model years, what balances the automatic trans engines which do not have a flywheel but use a light weight flex plate?

[mphatc]

The flex plate will have a weight welded on to it, most likely on the inside.

clutches as used on heavy flywheels are all balanced assemblies.

inspection of the stock harmonic balancer from Ford one can see an offset weight on the back side and a raised surface inside / forward side of the flywheel. On the flwheel this is what I removed to run it internally balanced
I replaced the harmonic balancer with a Ford Motorsport piece.

Mario

[Carl C]

The flex plate will have a weight welded on to it, most likely on the inside.
Yup, it sure does! I did some prowling in the garage and here is a 302 flywheel with offset weight cast in and a flexplate with a large weight welded on. They are not all like this. Be sure to match the correct parts with the crankshaft in use.

[BillG]

All 302 engines from 1968 to 1980 used 28 oz. in. external imbalance factor. All 1981 to 2001 use 50 oz. in. external imbalance factor. All 351 Windsor engines use 28 oz. in. external imbalance factor.

BillG