Heavy flywheel

[Broncobowsher]

Ok, way back in the late 90s you could still order a new 351W from Ford Motorsports. I remember a note that it had an extra heavy truck flywheel on it.
I'm mentally building a small block for a boat, picking what collection of parts I would love to gather for it. It would be a pleasure boat, not a race boat. I'm trying to remember the specs for that heavy flywheel. I would like the inertia since I will probably be doing a bad idea and running a little too much can and want it to idle fairly decent. I can't find my old Motorsports catalogs at the moment to look it up. Does anyone else remember it? My search skills came up blank. Most everything is directing me to a lightweight flywheel, which is exactly what I am trying to avoid. The best I found was '94 and down was 30 pounds and '95 and up was 35, but I thought this was 40+?

 

[bronco italiano]

They have a 40lb for a 460

 

[toddz69]

If you think the catalogs would have the info in it, I could dig mine out and look....

Todd Z.

 

[Broncobowsher]

If you think the catalogs would have the info in it, I could dig mine out and look....

Todd Z.

Todd, If you could that would be great. I have not found my old Motorsports catalogs since I moved. In one of those boxes...

 

[JB Fab]

Way back in the 90's

 

[Apogee]

RAM offers 34 pound billet steel units with either zero or 28 oz balance, but that's the heaviest I've seen for the Windsor engines. I've got a 40 pounder on my 429, but I haven't seen anything that heavy for the 289/302/351 applications.

 

[ntsqd]

Assuming that the heavy flywheel is NLA and someone like Wilcap to make one isn't available would it be inconsiderable to have an inertia ring made that bolts on like a pressure plate? Since we're talking about a boat, I'm guessing that you won't actually need a clutch. Although depending on the coupling you may need the pressure plate bolt holes, but might it be possible to make such an inertia ring sit on top of that coupling and clamp it to the flywheel? A a round piece of 3/8" or 1/2" steel plate, neutral balanced, shouldn't be too expensive to have made.

 

[73azbronco]

if its on a boat, why do you need a heavy flywheel? It will slow accel. It will not give a smother ride. It will not smooth a rough idle, make it harder to tune for idle really, or wrong term, it will make it run richer at idle to get a smooth idle. It is not required to engage the prop in water which is by definition a torq converter.

 

[Broncobowsher]

if its on a boat, why do you need a heavy flywheel? It will slow accel. It will not give a smother ride. It will not smooth a rough idle, make it harder to tune for idle really, or wrong term, it will make it run richer at idle to get a smooth idle. It is not required to engage the prop in water which is by definition a torq converter.

It is a plan at the moment. I have a river jet, so no real neutral. But I do have to get the idle down low since there is no neutral and in order to go slow, low idle. River jet is an oddity even among jet boats. Most people think "jet boat" and have thoughts of John Candy and Dan Akroyd in The Great Outdoors in a speed boat hauling across a lake. This is more of a general purpose pleasure boat. Acceleration is irrelevent. It is NOT A DRAG BOAT! The engine comes up to speed and just sits there at a steady speed at cruise. I also have a couple of local lakes that have miles of no wake zone that take me back to some incredible locations. So I need to be able to idle for half an hour at a time, What I want to do is build a K-code clone. Always like those engines. The power curve should be a real good match for the boat/pump. But I need to keep the idle down for the no wake. A little extra inertia would be perfect.

If I could find an off the shelf part that does this, perfect. The manufactured inertia ring is a possible idea. Adds complexity. At the moment it is all just ideas.

 

[ntsqd]

How is it coupled? Like a Berkeley Jet with a short drive-shaft bolted to a drive button, or a with a splined sprung hub like some (all?) of the I/O's use?

 

[Broncobowsher]

How is it coupled? Like a Berkeley Jet with a short drive-shaft bolted to a drive button, or a with a splined sprung hub like some (all?) of the I/O's use?

Direct. There is a hub that bolts to 4 of the 6 flywheel bolts and is a U-joint. Never measured, but about 30" of shaft and another U-joint. Directly to the pump shaft. No sprung hub drive.

 

[73azbronco]

I had a river boat with jet drive but was a mercury outboard, it had neutral reverse forward, no way to do that?

 

[ntsqd]

Direct. There is a hub that bolts to 4 of the 6 flywheel bolts and is a U-joint. Never measured, but about 30" of shaft and another U-joint. Directly to the pump shaft. No sprung hub drive.

Sounds like the usual jet boat coupling. My boss at the engine shop called that hub the "drive button" fwtw. We used one on the shop's engine dyno, so a different one for every unique crank flange.

Being a direct connection the only way to get reverse would be to put a reversing transmission between the engine and the pump. There's easier ways to back the boat up than that. I have seen a Power Glide put between the engine and the drive in a drag boat, but that wasn't done for the reverse.

 

[Broncobowsher]

Reverse is a drop gate between the pump and the steering gates. If you think about that, steering is bypassed in reverse. No real neutral, just half in reverse and sort of a neutral.
It is almost like a dyno. The few I have seen there is a splined input shaft. This is just a flange with U-joint.

Right now I have a Y-block. Looking to modernize to a small block. I already have the correct vintage marine manifolds that should fit in the engine cover. Still lots of unknown. Hence the brain storming.

 

[toddz69]

Todd, If you could that would be great. I have not found my old Motorsports catalogs since I moved. In one of those boxes...

Tim - I looked through all my catalogs from 93-99 last night and didn't come up with anything that I thought matched your description. The best I could find was the following on a number of engines they offered during that time period.

On another note, it was a trip down memory lane to look through those again - oh to have all the options of brand new 5.0 engines (and 5.8s) that we had back then....

Todd Z.

 

[Broncobowsher]

Thanks for looking Todd. I'll just keep an eye out while I work on my plans and gather random parts.