Mercrusier GM 350.

[clanton]

Mercrusier GM 350.

What parts must be change to convert counter rotating engine to standard rotating, beside the cam?

 

[rodbolt]

Re: Mercrusier GM 350.

Re: Mercrusier GM 350.

hello<br /> I am currently working on a MIE 340 7.4. its cw rotation. this particular unit uses a gear driven cam and I belive the distributer drive is the same as standard on this version. the distributor rotation is the same as standard. the two gear gear drive means the cam rotates opposite the crank while a two sprocket chain set up the cam and crank rotate the same direction. which would mean both cams rotate left. why are you asking? are you going to try to convert something?<br /> good luck and keep posting

 

[clanton]

Re: Mercrusier GM 350.

Re: Mercrusier GM 350.

Yes, convert the reverse rotating engine to a standard rotating engine, I looked in a set of parts books I have, could only find standard set up. I know the cam and gear/chain would have to be changed, but what about oil pump,and dist. Will be monday before I can get the serial numbers from the engines.

 

[BRIAN03]

Re: Mercrusier GM 350.

Re: Mercrusier GM 350.

Some seals have direction. Timing chain and main. Felpro's counter rotator seals are yellow. If you put the wrong one in they will leak. Distributor is the same the gear is different. Cam and gear set to gears and chain. Starter drive too.

 

[clanton]

Re: Mercrusier GM 350.

Re: Mercrusier GM 350.

Thanks, never thought about the seals.

 

[imported_Mike_M2]

Re: Mercrusier GM 350.

Re: Mercrusier GM 350.

So, out of curiosity, does the distributor still rotate the same direction with the CR gear?

 

[rodbolt]

Re: Mercrusier GM 350.

Re: Mercrusier GM 350.

hello<br /> yep brian remembers more than I. the starters are wired differently at the brushes and field coils as well as the chamfer on the drive. the crank and timing cover seals have the little deflectors in the opposite direction. and he is right they will leak. got a reman unit 2 years ago that we installed and the rear main dripped. the dist rotation is usually the same. most small and big block crusaders and MIE that I deal will the oil pump and dist rotation stay the same.<br /> mike<br /> the cam rotational direction is the same on both engines.<br /> to convert the CW rotation back to stabdard wouls be involved. you will need to change main seals dist drive, timing gears,camshaft starter assy. and if the CW motor has much time on it it will probably wear faster as the load surfaces will be backwards and will wear again.<br /> I would look into finding another standard rotating motor.<br /> good luck and keep posting

 

[flashback]

Re: Mercrusier GM 350.

Re: Mercrusier GM 350.

could you leave the engine as is and just change the prop?

 

[clanton]

Re: Mercrusier GM 350.

Re: Mercrusier GM 350.

I found one serial number, and looked at parts express, says crank is different. Serial number B719511 for CW engine, B719398 for CCW engine. CCW engine not listed parts express.

 

[BRIAN03]

Re: Mercrusier GM 350.

Re: Mercrusier GM 350.

Old days we turned the engine different directions. Todays the engine turn the same way and we turn the trans different ways. You can't drive the trans in reverse for forward. You need to change the front pumps direction. Same thing with and outboard you cant drive the lower unit backwards it will blow up. There are counters for outboard and sterndrives. Yamaha cuts the gears backwards and still uses the front bearing and gear as foward Mercury and Mercruiser uses(back gear) reverse as forward and streathens up the bearing carrier. I like the cut gear the best and they hold up well.

 

[BRIAN03]

Re: Mercrusier GM 350.

Re: Mercrusier GM 350.

There is a nurling on the crank for the rear main seal The counter the nurling goes in the oppisite direction. There is two different cranks two piece(rear main) and the new one piece design(rear main). The one piece crank is polished where the rear main runs and the nurling is on the seal.

 

[clanton]

Re: Mercrusier GM 350.

Re: Mercrusier GM 350.

Thanks to all for the replys. The parts manual for this engine shows 2 piece seal, but we will pull flywheel for a look. If it is a 2 piece seal, will move on to something else.

 

[bomar76]

Re: Mercrusier GM 350.

Re: Mercrusier GM 350.

Aren't the pistons installed turned the other way (rotated 180 degrees) in SBC counter rotating engines?

 

[BRIAN03]

Re: Mercrusier GM 350.

Re: Mercrusier GM 350.

yes

 

[CCrew]

Re: Mercrusier GM 350.

Re: Mercrusier GM 350.

Use the motor as-is and change to a LH prop.....<br /><br />-Roger