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How to convert truck 454 to reverse rotation or change pump in transmission?

J

JEPLWP

New member
81 Gibson house boat, twin Crusader 350, big block 454 inboard acked. I replaced it with 454 truck engine and installed the starter to find that it turned in reverse.
I will appreciate any suggestion.
 
Ditto on the "acked" question...

FWIW, marine engine rotation is defined by looking at the flywheel; RH is for CW rotation, LH is for CCW rotation.....most auto engines are LH'ed.

Hopefully, the engine went thru some effort to ensure compatibility with its intended use. Reversing is rotation will require a complete disassembly, a new cam and lifters, reversing the pistons on the rods, and a careful reassembly....assuming what you have is within service limits....
 
Is it the starter that tried to turn over the engine in reverse? If the starter and engine are both of the same rotation and the engine runs (does it?), some trannies can be reversed but then you may have 2 engines rotating in the same direction, which is not ideal.
 
IF the transmissions are Borg Warner's, like 72's you can just spin the pump cover on the front of the transmission, those transmissions will work for either engine rotation. It will NOT change output rotation.
You can use the truck engine just make sure it has a starter that spins the correct way, a MARINE starter,MARINE alternator and spark arrester for the carburetor.
 
fastjeff said:
The, ah, prop will also need changing if the replacement motor spins the other way.

Jeff
Click to expand...

I'm confused, if they are Borg Warner Velvet Drives, then why is the input rotation reversible by rotating the pump cover?
The out put rotation on a Velvet Drive can not be changed by turning the pump cover.

If input rotation has to match output rotation then why are the pump covers on the transmission made to rotate?
I'm looking at this wrong some how ?
 
Last edited:
CASTLE_CAPE said:
I'm confused, if they are Borg Warner Velvet Drives, then why is the input rotation reversible by rotating the pump cover?
The out put rotation on a Velvet Drive can not be changed by turning the pump cover.

If input rotation has to match output rotation then why are the pump covers on the transmission made to rotate?
I'm looking at this wrong some how ?
Click to expand...

Your looking at it wrong. The pump does not control rotation. Turning the pump cover switches the pump inlet and discharge ports allowing it to pump in the direction the motor is turning it. What goes in is what comes out as far as shaft rotation.
 
To the OP.
Do some research and find out if these transmissions are "opposite of engine rotation" capable.
If so, you will not need to build a RH reverse rotation engine.

This would not be uncommon or unheard of.



.
 
Thanks. We will pull the transmission and try this. May be able to remount starter or find reverse starter. do I have to open the transmission up to spin this cover.
Thanks again James
 
Personally, I'd suggest you figure out what you have and then what you need and then seeing what has to be changed to make it work.

The reverse rotation starter should be an off the shelf item...or you can take what you have to a quality rebuilder and they can work their magic.

The answer to your last question is No.
 
with velvet drives, they are built so that the input rotation = output rotation except for the 1.91:1 ratio which are "backwards".

It would also be good to know which direction the original engine rotated - easiest to determine by the serial number plate - it will have a RH or LH designator....also good to have would be the gear's model number ...something like 10-18-xyz to determine its characteristics....
 
FWIW, you pull the four bolts securing the pump cover and rotate the cover so the arrow on top matches the engine rotation and then reinstall the bolts.

Sometimes, you'll need a mallet to free the cover. If you rip the gasket under the cover, you'll need to replace it.
 
You never did state what direction the original engine turned and you need to find the little brass plate with the model and serial number on it.


FYI Borg Warner 71C (10-17) and 72C (10-18) made several ratios. The 1.0, 1.52, 2.0 and 2.59 could turn CCW (normal) or CW (reverse rotation) simply by changing the indexing of the pump assembly. The pump housing has two arrows cast into it and needs to be rotated so that the arrow at the top points in the same direction as the crankshaft turns.

If you have a 1.91 (10-17-05 or 10-18-05), it is NOT reversable.

If you have BW model CR-2 transmission (10-13 and 10-14), these are reversing transmissions, that is, they will change the direction of the crankshaft so that a CCW crankshaft engine can turn a CW shaft and propeller.

Older BWs also used model numbers starting with "AS" followed by a number that indicates the ratio. IIRC the 1.91 was AS-17, 10-17-05 and 10-18-05.

Gene
 
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