How can I switch from R to L rotation on a Chevy 350 V8

[rino]

I have an opportunity to buy an almost ready boat with a 260 Merc (Chevy 350 V8, corvette marine block), which is right-hand turning and needs to be left hand turning (or vice versa).<br /><br />The owner didn't know he had the wrong rotation until he tried to start it up with a left-hand turning starter and it backfired.<br /><br />The owner told me all I need to do to switch the rotation is put in a different cam, then everything would work. Is there anything else to switching rotation on these engines?<br /><br />Do the distributor, crankshaft need to be changed?<br /><br />I thought the engines rotated the same but the outdrive was counterrotating.<br /><br />The boat's a bit sketchy and has "custom engine mounts" so it might be more work than it's worth and no guarantee it'll run.<br /><br />Thanks in advance.

 

[djvan]

Re: How can I switch from R to L rotation on a Chevy 350 V8

I have no experience with this, but I would think the cam would not work spinning the other direction, also I would have concerns with the oil pump. I'm sure somebody else will chime in with experience in this matter.<br /><br />DougV>

 

[Rainmaker]

Re: How can I switch from R to L rotation on a Chevy 350 V8

Rino,<br />You may want to be careful here. Sounds like a heavily monkeyed-with vessel.<br /><br />Anyway, the main difference is the cam and the cam drive. Reverse rotation cams have a gear-to-gear drive system that allows the cam (along with the oil pump and distributor) to turn in the "normal" direction. There is no such things as reverse rotation distributors and oil pumps (for a small block Chevy).<br /><br />The cam lobes are completely different for reverse rotation, so you'll need a new cam and a normal chain drive. [Crane Cams makes a reverse rotation cam that uses a normal chain drive and rotates backwards. But the worm gear and the distributor gear are special, to drive the distributor and the oil pump in the proper direction. This is an aftermarket cam, most likely you won't have it.]<br /><br />Another difference (more difficult to correct) is the fact that the front and rear seals are different. If you reverse the rotation of the engine it will leak, guaranteed.<br /><br />Hope this helps.

 

[Bondo]

Re: How can I switch from R to L rotation on a Chevy 350 V8

Right-Handed Small Block Chevies'<br />Are Few, And Far Between........<br />

260 Merc (Chevy 350 V8, corvette marine block), <br /> The owner didn't know he had the wrong rotation until he tried to start it up with a left-hand turning starter and it backfired.<br />

A 260 Merc. will be Standard......<br />A Corvette will be Standard......<br /><br />I'd sooner Think the Owner has the Dist. In,<br />180* Off........................................

 

[hondon]

Re: How can I switch from R to L rotation on a Chevy 350 V8

Lets do it this way.If you hook this thing up to a starter button and crank it over the pulleys at front of the engine as you are looking at them will turn clockwise.Standard lefthand rotation.

 

[f_inscreenname]

Re: How can I switch from R to L rotation on a Chevy 350 V8

"I'd sooner Think the Owner has the Dist. In,<br />180* Off" <br />That is what I first thought to.

 

[TwoBallScrewBall]

Re: How can I switch from R to L rotation on a Chevy 350 V8

My first though too. I've done it, it's easy to do and will drive you nuts if you don't realize that's the problem. Try yanking the dist if you are allowed to play with the boat. Drop it back in with the rotor facing the exact opposite direction. If it starts, then quickly switch it back and tell the owner you'll take it even though it don't run!

 

[chadh]

Re: How can I switch from R to L rotation on a Chevy 350 V8

Rino, I think the connecting rods may be differnt. In a standard smallblock the rods are bent in a specif direction , for standard rotation, but I think you need to change them to spin it the other way. May want to go to a automotive machine shop in your area and ask.

 

[John Carpenter]

Re: How can I switch from R to L rotation on a Chevy 350 V8

I have a RH 305 Chevy in my Chris Craft...thought we would never get it to run when my mechanic friend swapped out the distributor for an HEI setup. As soon as we realised what we had and swapped the wires around...she started right up and has run fine since. On mine, the firing order is on a plate on the exhaust manifold...we just didn't read it!

 

[vinney]

Re: How can I switch from R to L rotation on a Chevy 350 V8

Is there a sterndrive bolted to this engine. Sterndrives use left hand/standard rotation engines. Standard and counter rotating engine the distibutor rotor turns clockwise. If you put the wrong starter in the rotor will turn counter -clockwise. Right hand engines. Piston go in different. Camshaft different, timing chain seal is different rear main is different. firing order too. Crankshaft nurling on two piece rear main seal engine. nurling goes oppisite direction. Fire order std. 18436572 counter 12756348.

 

[rino]

Re: How can I switch from R to L rotation on a Chevy 350 V8

I won't need to do this any more.<br /><br />The owner cut the engine out of the boat to give to somebody else so I just took his OMC 225 outdrive for my Reinell (on a different post) and he kept the boat and engine.

 

[Bondo]

Re: How can I switch from R to L rotation on a Chevy 350 V8

Pretty Hard to say Who Won that 1.............