flywheel or flex plate?

[maddad]

It is time to balance the insides of my next small block chevy boat motor. This is a 400 that's getting 6" rods on the original crank. The motor came with a flex plate from a marine installation. I'm going to be hooking up to a volvo drive and need to know if the f.p. is OK, or do I need a flywheel. The bolt pattern is not an issue, they match. It just seems to be so umm, well, flexible. If someone would like to take this time to tell me to get rid of the chevy crank and balance it internally, I may just listen.

[BUIZILLA]

Is There A Balance Weight On The 400 Flywheel And A Casting Weight On The 400 Balancer?

[maddad]

Yes, this motor had the factory external balance on the bottom end. I'm trying to do this as cheap as possible, but will listen to reason if it makes good dollars and sense.

[vrod02]

It is time to balance the insides of my next small block chevy boat motor. This is a 400 that's getting 6" rods on the original crank. The motor came with a flex plate from a marine installation. I'm going to be hooking up to a volvo drive and need to know if the f.p. is OK, or do I need a flywheel. The bolt pattern is not an issue, they match. It just seems to be so umm, well, flexible. If someone would like to take this time to tell me to get rid of the chevy crank and balance it internally, I may just listen.
About the only thing to go wrong with a MARINE flywheel is the starter ring.I usually heat them up bang them off and flip 180 so the starters got new meat to grab. The flywheel will need to go to machine shop for proper balance. As far as your Damper plate there for maintaining the outdrive. Check the HP rating of the plate to what you think you will be getting out of the motor. I use universal plates that are good to 350Hp for about 85 bucks. Borg/Wagner sells what they call "proper" plates but there up in the 250-300 buck range.The machine shop will tell you if your crank is good.

[maddad]

The crank and flex plate/ring gear are in very good condition. I'm just wondering if the flex plate to volvo drive is OK. The new crank, internal balance part of this question is me trying to find out if it is really so much better, that I shouldn't consider not doing it.

[vrod02]

Can you see the springs or is there riveted plates covering them? Is it a triangular plate or round?

[maddad]

Vrod, my vibration damper is a volvo unit with exposed springs. I never even thought about that holding up. My question was can I use the flex plate that came on the motor(8-10 lbs. thin and flexy), or do I need to get a flywheel(25-30lbs. don't drop it on your toes) to bolt the damper on.

[maddad]

Triangular, by the way. I also had to trim it a little for the chevy flywheel dia.

[mrfixxall]

are you talking about a flex plate for a auto trans? then No you cant use a flex plate in the boat,,the flex plate is designed so that the torque converter keeps it from flexing or coming apart..

[maddad]

mrfixxall, thank you. Now I need to chase down a flywheel.

[mrfixxall]

mrfixxall, thank you. Now I need to chase down a flywheel.
You can use a 454 flywheel...their close but still need to ballance it and for the 180 bucks you may as well have everything ballanced...

good luck..

[MOP]

Mike you said you got a flex plate for a Marine install! Was it bolted to a flywheel or is it an auto trans flex plate? If it was a thin plate with springs bolted to a flywheel it probably matches the engine, if it is an auto trans flex plate that is a different story

[maddad]

Phil, the plate with springs is the same part I used on the ford motors,with a bit of trimming. On the 400, there was a auto tran type flex plate. I was wondering if I could use that on a volvo setup, by bolting the plate/spring on it, instead of a flywheel. I need to collect all these pieces because its time balance the new motor. That 400 came from Scott P., and I'm pretty sure he said it came from a boat. That means there is a setup somewhere that uses a flex plate instead of a flywheel.