Reverse rotation camshaft

G

Glyn Farrell

New member
Hi
To attain a reverse flow engine, if the method used is to change to a Windsor chain and gearset to run the camshaft clockwise, thus the oil pump and distributor drives must rotate clockwise instead of the usual anticlockwise.
Question: does oil pump still function properly and the distributor also??
Is there any detrimental effect on the camshaft or oil pump gears???
Does the timing gear/chain set need to be set a number of degrees advanced or retarded???
Any modifications required for the surfaces of the pistons or valves or exhaust passages like ceramic coating to diminish heat effect on the 'new' exhaust passages, valve seats etc.
Very interested in any response and any other potential glitches of the conversion.
Could Les Schubert or Wayne Atkinson comment??
Regards
Glyn F
 
If you change the direction the cam rotates you also change the direction the oil pump and dist turns

The dist could function, the rotor tip position could be off though, the oil pump will need to be different

if you want to change port flow your besty results would be a custom cam

If you look at the block construction ---there is no provisions for cooling in the block deck area between 1-2, 3-4 of the siamesed ports
 
That would allow 4 intake ports instead of two in stock setup.

Many people did this with the Flathead V-8, Model T and other engines many years ago.
 
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Better breathing ...

More air/fuel mixture into an engine makes more power.

But from what Kurt said about cooling in the port area it might take more work to have a reliable Model A engine.
 
Boats with twin in board engines often have one turn the opposite of the other for better balance. I have an older tri-hull with a single Volvo engine that turns backwards of a Volvo car engine.
 
Tom Wesenberg said:
Boats with twin in board engines often have one turn the opposite of the other for better balance. I have an older tri-hull with a single Volvo engine that turns backwards of a Volvo car engine.
Click to expand...

Yes my brother's 38 foot has twin 140 HP Volvos and they turn opposite.

I think that the P-38 twin fighter engines turned opposite also to counteract the torque. More of a problem with an airplane on take off so the plane did not pull to one side under full power.
 
Tom Wesenberg said:
Boats with twin in board engines often have one turn the opposite of the other for better balance. I have an older tri-hull with a single Volvo engine that turns backwards of a Volvo car engine.
Click to expand...
When doing my FIRST tune up on an earlier HONDA, while setting the timing & advance, WHOA! THIS THING TURNS ***-BACKWARDS:eek::eek::eek:
Bill W.
 
Glyn Farrell said:
Hi
To attain a reverse flow engine, if the method used is to change to a Windsor chain and gearset to run the camshaft clockwise, thus the oil pump and distributor drives must rotate clockwise instead of the usual anticlockwise.
Click to expand...


The easiest way to accomplish this is use a flathead V-8 oil pump which is already a reverse rotation compared to the Model-A/B pump. The V-8 pump will then be turning correctly.

As far as the distributor is concerned, consider using an electronic unit for better performance and just modify the centrifugal advance if so equipped.
 
Benson said:
Yes my brother's 38 foot has twin 140 HP Volvos and they turn opposite.

I think that the P-38 twin fighter engines turned opposite also to counteract the torque. More of a problem with an airplane on take off so the plane did not pull to one side under full power.
Click to expand...






The P38 is one of the very few airplanes with counter-rotating engines. The early models were problematic and adding a backward spinning engine made them more user friendly.
 
The easiest way would be either a custom cam or end-for-ending a stock one. A V8 pump then would be easy to do but I would do something to hold the dist. drive gear down. In a stock setup those gears thrust the drive downward, keeping it stable. Too much heat through those 2 ports would be a big concern, especially on a street driven car. I've seen this done on race engines but have not been impressed by the performance.
 
Tom Wesenberg said:
Boats with twin in board engines often have one turn the opposite of the other for better balance. I have an older tri-hull with a single Volvo engine that turns backwards of a Volvo car engine.
Click to expand...





Wasn't your Volvo engine made by GM ? All Volvo Penta 4 cyl engines I've seen were the GM engine.
 
Bill Kenz built what was called a Reverse Cam Model A Engine that included with a Miller OHV. The Cam (and everything else) turned the same direction, only it reversed the intake and exhaust ports to allow four ports for intake and only two for exhaust. It would have allowed for overlap of intake on cam timing, but I would think some restriction (and maybe heat issues) with only two exhaust ports.

This concept was also used with V-60 Ford Engines in Midget Race Cars in the 40s-50s.

Bill Kenz was much more innovative and smarter than me, and since the concept was also used in other applications, there must have been some benefit.

Another thought, if the engine rotation was reversed, the transmission would work fine, but you would have to the reverse the rear-end in the housing, or you would have one forward gear, and three reverse.
 
One forgotten point here- The A block has the cylinder bore centerlines offset 0.125" from the crank centerline. This was done to improve the rod angle during the power stroke. The result is unequal piston acceleration forces on the up/down strokes.

Reversing the rotation of an A (or any engine with offset bore centerlines) will turn that beneficial offset into a penalty. Increased rod angularity and severe piston side thrust during the power stroke will be the first result. To make things worse, the primary I-4 design imbalance will make that long stroke A shake even more with the reversed up/down piston velocity profiles.
 
The original question was, "to attain REVERSE FLOW",
not reverse rotation. That means swapping intake and exhaust ports.
All that needs to be done is make a billet cam with rearranged lobes.
All parts rotate in the original direction.
Of course the carbs and headers need to be swapped.
 
Pete, your right about him asking about reverse flow, but to reverse the cam would involve having the engine run in reverse, his post is a little confusing, reading it as is it sounds like he wants to reverse rotation, maybe he will come back and explain more clearly what he intends or wants to do
 
This is hearsay, I never flew one, but I've been told the hot fighter planes (single engine) would flip right over from engine torque if you "Got on it" on takeoff.
Terry

Patrick L. said:
The P38 is one of the very few airplanes with counter-rotating engines. The early models were problematic and adding a backward spinning engine made them more user friendly.
Click to expand...
 
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