I purchased and installed a remanufactured 7.4L (Gen V) to replace my 1996 Mercuiser 7.4L. I want to replace the harmonic balancer, but am confused. My previous balancer was 8" diameter, but I don't know if I need a balancer for an internally or externally balanced engine. I believe the 7.4L enigne is balanced via weights on the flywheel itself (factory Mercruiser). Therefor I think I can use a balancer for an "Internally Balanced" engine, as I would not need the weights provided by balancers for "Externally Balanced" engines.

Can anyone help here?

I think both ends have to match and be for external bal.

AnNy other input? FLuidampr perhaps?

A flywheel with visible weights is for an externally balanced engine. The dampener must also be compatible with external balance. Most "stock" motors are set up this way. Unless otherwise stated, I suspect your re-manned motor is externally balanced. Fliudampr and ATI balancers are better than stock, but the best result is obtained when the machine shop computer balances the rotating assembly (crank, rods, pistons, flywheel, and balancer/dampener) together as a complete unit.

An internal balance engine is balanced "internally" within the crank and rods only and therefore has "zero balance" flywheel and dampener. This is seen in higher-end custom built engines. An internally balance engine will have a flywheel without weights and the dampener is specifically set up for internal balance.

I think I still have a Fluidampr for an externally balanced Mark IV engine in my storage area. I don't know if it is compatible with a Gen V, but I will check around and make you a good deal on it if you can use it.

Chris
419-882-1680

Mr Ross
Pick up a copy of Dennis Moore's Book On Big Block Chevy Performance, published by HP BOOKS, it explains the differences regarding internal balancing, and shows photographs of both types of harmonic balancers. A picture is worth a thousand words.
Barnes and Noble or Borders Books will have the book.
Good Luck
Brian

there are also diff amounts of bal between ext bal. big blocks depending on year. My gen 6(truck mtr) uses a diff bal and flywheel than my gen 4 mag.

I sure could use it if he doesnt. And I can pick it up too. Ill give you a call.

Tom

Yes one piece rear main seal engines even though external balance are balanced differently than two piece rear main external balance engines.

If the flywheel has weights then the balancer must have also.

Tom,

I'll check in my storage area today when I get up (night shift ). It only has two hours on it, so is literally like new. Need any other Mark IV parts?

Chris

Great, whens a good time to call?, flywheel too, and oil pan. Building a spare engine. need a set of trw 2399 forged pistons too.

Tom