Im in the planning stages of a twin engine boat build. Due to the surface drives one of the engines (BBC) rotates clockwise when looking at the bellhousing end (reverse of "normal").

Can megasquirt read the 36-1 wheel spinning this way?

I believe it can as the hall effect doesnt know which way the tooth is coming in. As long as I have the sensor/missing tooth relationship leading the opposite of "normal" and reverse firing order accounted for I think it should work. However, Im simply looking for confirmation.

Addtionally, have any GM LS engines been spun reverse of "normal"?....trigger wheel, cam and oil pump changes would be required....if I can source parts I may repower the boat with some.,

 

Yeah, no reason you cant go reverse. Just make sure the -1 tooth is 5 teeth away in the right direction.

 

Thanks for the confirmation.

Anyone else know about reversing the rotation of an LS? Custom cam would be needed for the firing order and probably have to switch to a external oil pump $$$$

How are cam blanks start out before they are ground? bunch of complete circles and the profile is ground in? Or are the lobes cast in then finished up to what every the final specs are?

If it is the former....a custom cam with the reverse firing order shouldnt be difficult....if it is the later it could pose to be a serious obstacle to overcome.

Perhaps I should post this second question in another section.

 

It depends on construction rollers are typically a billet blank anyways so your odds are better. Comp would be the obvious place to ask for something like that then work towards specialty houses like Bullet. Someone has to make marine reverse rotation LS cams at this point though I would think, they're in darn near everything else.

Besides that in terms of the EFI/ignition, could you reverse the order of the injectors and coils? I'd be curious what they do with Vortec 8100s since those are a super common marine engine and they use a very similar ignition system and pickup. Then again if you're using the 36-1 wheel you just flip it 180, reorder the coil packs etc. to the right firing order and move on.

 

Yes it would be simple repinning for the "new" firing order....and of course a RR cam

Im not aware of an 8.1 install that is reverse rotation...that doesnt mean it isnt out there. Most newer (early 90's up) set ups the prop direction is handled by the outdrive or transmission...that way a RR engine isnt needed.

Unfortunately the transmissions (72C borg warners) that are in the boat cannot take full power in reverse like many more modern marine gears.