PCM 351W Engine - Reverse Rotation Question

There is no gear setup that will spin that cam correctly.   There are also no roller cams for reverse rotation 351s. So minimum to make it make noises in the right direction is a new reverse rotation flat tappet cam with lifters and likely new pushrods.

Then you need to worry about the rear main seal being the wrong direction and pumping oil out of the motor into the bilge.   There are a bunch of other differences to the motors but with a used motor I say swap the cam and rear main and give it a shot--- might get you skiing a good long time.    But I would be easy on her for a while after you start runnin her backards to see how she takes it .

Wouldn't it be easier to keep the engine LH?

New cam gear
New starter
New prop
Swap trans pump
Turn RWP upside down

Hollywood wrote: Wouldn't it be easier to keep the engine LH?

That's what I was thinking,   LOL.

dubseven wrote: I think you mean new distributor gear? Will that mess with the mechanical advance? What does Swap trans pump and Turn RWP upside down mean? Thanks!

If you swap the dist. gear to the truck/car gear then you can use your existing dist.
RawWaterPump, turn it over so it will pump the correct direction.
Transmission pump cover has CW/CCW direction arrows for whichever direction you need.

dubseven wrote: What does Swap trans pump and Turn RWP upside down mean? Thanks!

Andrew,
The hydraulic pump in the front of the trans can be indexed to the rotation of the engine. It basically reverses the pressure and suction ports of the fluid..

The RWP (raw water pump) is also revisable for the rotation. Turning it upside down places the cam that compresses the rubber impeller on the opposite side so the in and out ports are reversed.

If it was me, I'd rebuild for a RR. You got all winter to do it. Then you have a zero time engine.

I am being told by swapping the input rotation on the trans, and then rotating the plate, the output will stay the same, and I do not need a new prop?

dubseven wrote: I am being told by swapping the input rotation on the trans, and then rotating the plate, the output will stay the same, and I do not need a new prop?

The output of the trans matches the input rotation of the engine. Indexing the trans pump does NOT reverse the output of the trans. IE, if you index the pump for a LH engine, you are simply indexing pressure and suction ports of the pump so you would need a LH prop.

I'm with Tim - Build a RH engine!!

Just one more option to throw out there at you. In your first post you said the boat came with a completely seized up engine. Depending on the extent of the damage, you could rebuild that engine to whatever spec you want, have exactly the engine and drivetrain you need, use all the current accessories with no modification needed. You could keep or sell the roller truck motor. Just a thought.

If you want some maybe interesting, maybe confusing reading read this old thread on rotation

It'll probably have your head rotating in both directions at the same time

63 Skier wrote: Just one more option to throw out there at you. In your first post you said the boat came with a completely seized up engine. Depending on the extent of the damage, you could rebuild that engine to whatever spec you want, have exactly the engine and drivetrain you need, use all the current accessories with no modification needed. You could keep or sell the roller truck motor. Just a thought.

63 Skier suggestion makes the most sense. Some of the other suggestions are do able, questionable, and the results may work, OR NOT. At this point you have time (which = money) and money invested and possibly a season wasted.

Between the two motors you may have enough good hard parts to complete a build. If lucky, you may have a complete rotating assembly that is un-damaged with the block that it was married to. This would eliminate a lot of expensive machining if you choose to build on a budget. This is not the preferred method but it is done frequently with good results.

If you choose to splurge and add power, at your elevation you should be able to bump compression up to 9.7 :1 to 10:1 and still run 87 octane fuel. My Century Resorter runs
9.7: 1 CR on a stroker motor at 4500 ft. elevation on 87 octane without problems.

At least with 63 Skier's method you know what you have and will be up and running in spring, instead of beginning to sort out issues and possibly end up needing a new short block any way. At worst purchase a short block and install a reverse rotation cam and then bolt all of the stock hardware back on. Short blocks are not that expensive if you do not purchase all the hi end stuff.

What year was your Bronco engine?

If someone is parting out a Nautique with the 1.23 tranny and prop you could swap trannys and run a Std rotation engine while keeping the reverse rotation prop drive.
You would need the tranny and prop which would be very expensive new but maybe available in a boat parting out.

The piston issue on Piston Pin offset.   Ford did use a .060 Piston Pin offset in the 351W.
This was done for years to help the pistons take a set rather than rock in the cylinder.
This is thought to make the pistons run quieter, less piston slap and better ring seal.
Most Forged pistons ran zero offset as the goal was less friction and higher RPM ability.

If you run your std rotation engine in reverse with the right parts the piston offset will not cause any issues at all.   Many rebuilt Marine Reverse rotation engines are running with the piston offset reversed and no one knows because it causes no issues.

I knew Professional NHRA racers that ran the pistons intentionally reversed, offset on wrong side because they wanted less drag internally. RPM was the goal.
Any loss in Ring Seal was so minimal it was not a concern. The class rules mandated they run the factory type piston so they did but reversed them hoping for a gain.

Some pistons will have valve clearance issues if you choose to put the piston in reversed.
The engine spins reverse rotation but the heads are the same on both std and rev rotation engines. Intake valves are larger than exhaust valves and reversing can cause Valves to hit the piston if the valve relief is not cut the same for intake and exhaust valves.   

Look at the eyebrow cuts or valve reliefs in your pistons. If they have 4 reliefs per piston you are good to install, if they have 2 per piston you probably can't reverse them.

The 463P has a large dish and 2 valve reliefs but they are on opposite sides of the connecting rod and opposing.   You might call Sealed Power Tech Line for help they are really good. 800-325-8886.   They have access to the piston blue print and can tell you the depth and size of each eyebrow.
This piston is .060 offset.
On that piston I would set your top ring gap at .016, second ring gap at .023. This has proven to offer the best ring seal in these engines. The second ring will run fine as tight as .008 but opening it to .023 helps the top ring seat better under power.. You can do some reading on this but Sealed Power proved this in the 90's and is standard procedure in engine building today.