Flywheel Question - 5.7L

[Quarterwave]

Hi everyone,

I'm converting a 5.7L SBC truck engine into a marine engine for my bowrider (the previous 5.0L Mercruiser was rusty).

The 5.7L has a flywheel on it at the moment, that looks like attachment #1.

By comparison, the 5.0 seems to have a more-heavy-duty flywheel - please see attachment #2.

My question is do I need to use the flywheel from the 5.0 and put it on the 5.7? Or is the existing 5.7 flywheel sufficient?

I have an Alpha stern drive which I believe can take up to 300 hp.

 

[Bt Doctur]

the first pic is of a "flex-plate" and is not used in the marine world. The second is of a "flywheel" that is needed to accept the coupler

 

[Scott Danforth]

marine flywheels are nothing more than truck manual transmission flywheels..... and not flex plates like Bt Doctur stated.

if both motors are post '88 vintage, bead blast the 5.0 flywheel and use it. buy new flywheel bolts

 

[Bondo]

Ayuh,..... As Noted above, the 1st picture is a Flex-plate, only used with automatic transmissions,....

The 2nd picture is a Flywheel,....

 

[Quarterwave]

Ok, got it, thanks! I have the triangle-shaped connector along with the 3 rubber stoppers and the 3 trapezium pieces already off the old engine. After I took them off I hit them with a wire wheel on a drill, some kill rust and then some engine spray enamel. I also have new flywheel bolts on hand.

Question - three of the bolts on the old flywheel are threaded. Any suggestions on how to get them out?

 

[Scott Danforth]

the triangle shaped thing is the coupling

all bolts are threaded - what are you talking about?

 

[Quarterwave]

The actual bolts that are bolting the flywheel to the crank. The heads of 3 of those bolts are almost round. I tried hammering on a metric socket to get some grip, but to no avail.

 

[Bondo]

Ayuh,.... Weld a nut to the bolt head, quench it while it's good, 'n hot, with cold water, then turn 'em out with a wrench that fits the nuts ya welded on,...

Heat, 'n quench, Usually breaks the rust free,....

 

[Quarterwave]

Thanks Bondo. Unfortunately, I do not know how to weld and I do not have a welder. Do you have any other options? Do you think an easy-out tool would maybe work?

 

[Bt Doctur]

it`s doubtful, why not grind the heads off

 

[Scott Danforth]

that is my suggestion, fire up the 4-1/2" grinder and remove the bolt heads

or simply spend $70 on a new flywheel

 

[Bt Doctur]

Now if you were close to central NJ...............................

 

[Quarterwave]

Hi everyone, I was able to get these bolts out after spraying with some Kroil and then hammering on a short, metric socket (for the 2nd time) combined with an 18" breaker bar and moving very slowly. After that and some banging on the flywheel with a brass hammer, and we were all set.

I appreciate all the responses and now have an interest in learning to weld....