Pismo10

Yes, unfortunately in the velvet drives that is all you can do.

Pismo10

What are the dimensions on the Hurth? Same as the VelvetDrive? What model?

Thanks

doggiedave

Just for info, does anyone know what the torque production figure at what rpm for the 454/340 I cannot find any figures anywhere on the net?

mcollinstn

Or a V-Drive (which could reverse in the V Drive and not in the motor itself.

I still haven't seen the model of boat mentioned, which would eliminate a bunch of head scratching. Is it a Sundancer, an Express, a Bridge boat, a Center console, an Aft Cabin ?? Knowing this would help.

And some reverse rotation motors use a STANDARD rotation cam and a gear drive instead of a cam chain. This lets you use a standard distributor and standard oil pump. If you reverse your own motor, make sure the pistons are swapped to accomodate the backwards thrust angle, water pump is different. Alternator fan is different, starter is different (unless you use a reverse mount bellhousing). Raw pump is plumbed differently.

MC

ezstriper

the V drives used in these boats are NOT reversable...been down that road...V drives have nothing to do with prop direction...simple gear to gear...yes early reverse rotation engines used the gear drive set up, but after genVI engines they no longer do that...

Mbam

Let me summarize

Inline Velvet drives (the 71 & 72 series – output is in line with input) will not change output rotation however they can be used on both standard and opposite rotation engines by changing pump mounting. Same thing for the old style Velvet V drives. However the V drives come in chain and gear versions, so it is possible to use a chain on one side and a gear on the other to reverse output. And there are a couple of the inline ratios where the output is opposite the input.

New Velvet 5000 Liberty series, Hurth & ZF all allow the reversal of the output rotation but can only be used on standard rotation engines. They are available in both down-angle (the output is offset and at an angle) and v drive.

f_inscreenname

The cam spins the normal way but the lobes on the cam are lined up different and unless you are going to use a roller there is only 1 cam available in RR in flat tappet and no others are being made.

There is no difference in pistons but if you are going to swap a motor over you do need to resurface the crank along with change the rear and front cover seals. If not oil will be pumped out of the motor.

No difference in the water pump. The veins on the wheel are straight and it don't matter what way it spins and the ALT fan also makes no difference what way it spins.

True and the raw water pump is as simple as putting the input hose on the out put side and vice versa.

I spent a year researching a RR motors and what could be done with them. My advice, run away as fast as you can.

doggiedave

It is an Express cruiser with straight velvet drives

ezstriper

more than likely have 72c trans...just work on the reverse engine, If I had it to do over I would but the high torque 502 truck engines strait from chevy have Bob match up a reverse roller cam, you will have to use the special reverse built GM EST dist from crusader with that...but should work very well in that boat...

f_inscreenname

Cam should spin the same way as normal. It's the crank that spins backward. That's why there is only 2 gears and not 2 gears and a chain timing set. The dist turns the same way you just put the plugs wires on it backward. If you spin the cam backward not only would you need a custom dist but you would also need a custom oil pump and unless someone builds it for you, you are not going to find them.