VelvetDrive reduction vs Down Angle box ??

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VelvetDrive reduction vs Down Angle box ??

Post by kens » Mon Jul 11, 2016 8:31 pm

Hello all,
My Double Eagle has a 4cyl gasser with Velvet 71c reduction box. My DIY engine mounts have slumped here.

I got a 6 cyl inline sitting on the garage floor and it also needs engine mounts. I got a ZF 45a down angle box also
I think I should just build 1 set of engine mounts, and use the 6-cyl along with the ZF 45a box
delete the 4-cyl along with VelvetDrive.
the OAL of both is within 3/4" each other. it should be a drop in fit

Can anyone verify to me how much the FWD end of engine moves if I swap from a Velvet 71c to ZF45?
From the drawings, the bellhousing end raises up 2 1/4" with the down angle box,
but what happens to the front end?
can I duplicate my current FWD mounts with beefier material?
or, do I need to compensate for different engine height, forward?

The inline 6-cyl is 9" longer than the 4-cyl, but, the down angle box is 9" shorter than the Velvet reduction box.
that is why I say it should be a drop in fit.
what happens to the FWD engine mounts, do they move up or, down?
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

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Re: VelvetDrive reduction vs Down Angle box ??

Post by jenko » Tue Jul 12, 2016 1:59 am

depends on the angle of the trans output but having a guess the whole thing would rotate around the centre so front mounts would be down around the 2'' mark as they are not at the very front of the engine? we need more info and drawings

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Re: VelvetDrive reduction vs Down Angle box ??

Post by Roberta » Tue Jul 12, 2016 4:52 am

As you probably know, the engine angle will be 8 deg. lower making the front of the engine lower and the rear of the engine higher due to the lower prop shaft flange on the down angle ZF. There probably will be little technical info on this conversion so you may need to do some custom fitting. I would remove the prop shaft and get a piece of tubing to use as a temporary prop shaft to locate the best position of the output flange on the ZF and angle of the engine. On the Torpedo, I made 3" X 3/8" AL angle mounts that are bolted to the stringers. You could C-clamp these to the stringers and then hang the engine over them at the proper angle, fore and aft position, and height to get an idea what needs to be raised, moved, or lowered and what mods might be necessary to make on the engine mounts. I'm sure you will figure this out. It's possible Mercury might have some installation drawings with various engine and transmission configurations that could be helpful. Check their website.

Roberta :D
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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