Need a reverse rotation cam

[Panther]

Could be wrong but I thought the cam was the same as std. rotation, the difference being the gear turns it the opposite way? Cam actually turns the same direction as standard but the rotating assembly turns reverse and has a reverse starter etc.

[larry smith 34]

call me i have a pair with gears 301 529 6371

[f_inscreenname]

Originally Posted by Panther

Could be wrong but I thought the cam was the same as std. rotation, the difference being the gear turns it the opposite way? Cam actually turns the same direction as standard but the rotating assembly turns reverse and has a reverse starter etc.

It does turn the same way but the lobes on the shaft are different to accommodate for the new firing order.

Larry, I can give you a call in a couple hours when I get home from work.
What you have? any specs?

[Panther]

Originally Posted by f_inscreenname

It does turn the same way but the lobes on the shaft are different to accommodate for the new firing order.

You said you're using the gear instead of the chain so I'm pretty sure you can use a standard camshaft but would just need to change the firing order on the distributor.

Try a search on here, there have been many posts about it.
http://www.offshoreonly.com/forums/g...502-motor.html

[f_inscreenname]

Originally Posted by Panther

You said you're using the gear instead of the chain so I'm pretty sure you can use a standard camshaft but would just need to change the firing order on the distributor.

Try a search on here, there have been many posts about it.
http://www.offshoreonly.com/forums/g...502-motor.html

You see, without getting to deep in this, the cam spins the normal way. The crank is the only thing that spins in reverse. With the crank spinning backward the cam events are set up to happen in order but unless the crank journals actually mirrored a normal crank they come up in the wrong order. If I was to use a normal cam and just try to spin it backwards it would suck up exhaust and blow gas out the carb. You also have to take into account that a cam like this works off a gear and gear slips over the cam shaft and is held in place with a key. Most cams do not come with the little core extension for the gear to ride on.

[Panther]

See below;

Originally Posted by Young Performance

If it uses a gear drive, then the cam and distributor spin in the standard left hand direction. The only thing that spins backwards is the crank. You will need a timing set and a starter. The cam and distributor are the same as the left hand engine.
Eddie

[f_inscreenname]

Originally Posted by Panther

See below;

Sorry but that's not true. I have two cams sitting on a work bench now. They are nothing alike and they are both from Merc 454 motors. Just one is a right and the other is a left.
Just think of this. If you run a cam normally it is by design to open and close the intake and the exhaust valves at a certain time. Like when it opens the intake just as the piston starts it down stroke. Now if you spin the crank backwards you may get #1 to work but then the cam is designed to "set up" #8 not #2 (it's next in line on a reverse rotation motor). The lobes on the cam have to be just a little different to set up the next numbers in the firing order.

[a to z marine]

That is correct the cams are different r/h uses a gear to gear and the cam is grind is different for a reverse fire order you can not use a l/h in a r/h motor you can look part #up on www.mercruiserparts.com

[KNOT-RIGHT]

There were to ways this is accomplished.
1) Gear drive which keeps the cam rotation standard.( Crank
rotates opposite).
2)Chain drive which rotates cam aswell
as the crank opposite. The gear at the end of the cam
is machined to mate with a special distributer gear.
This in turn (no pun intended) spins the oilpump the
proper way.

LH Cam is a different grind then RH.

Hope this helps
KR

[f_inscreenname]

Bob is no help.