Reverse rotation D16

So, has anyone actually done it? (Yeah, yeah, I know, the D16 already is reverse rotation. Knuckleheads.).

I know that reverse rotation versions of stock motors are common in marine applications.

Issues that come to mind: Mirror image camshaft, easy enough.with $$$ Oil pump? dunno, depends on the gerotor configuration. Timing belt tensioner would have to be on the other side. Distributor: Megasquirt Starter: Re-polarize a stock unit, or reposition the brush carrier.

Why bother?

Lightweight, high output, universally supported RWD motor replacement.in LBC, Locost, etc.

Carter

Would the tensioner have to be swapped? I don't know the D16, but on the Miata the tensioner is locked down after it's found its happy place.

Keith wrote: Would the tensioner have to be swapped? I don't know the D16, but on the Miata the tensioner is locked down after it's found its happy place.

Belts usually have tension on both sides so I don't think it would?

If it was a chain on the other hand....

A plain belt requires a lot of tension because it transfers force via the friction developed between the pulley sheave(s) and the belt surface, so max energy is proportional to the tensile force. Toothed belts transfer the force via the mechanical engagement of the teeth elements on the belt and pulley, and max energy is limited by the strength/durability of the engaging elements. In theory, a toothed belt will run with zero pre-tension, but from a practical standpoint, enough tension is applied to compensate for the small amount of stretch, and to control belt whip at high speed. Many business machines use toothed belts without any tensioning mechanisms when the forces are moderate, depending on the spacing of the elements and the size of the belt to be within spec.

it's a fairly interesting idea.. but I think you ran into the problem.. the timing belt. From the few I have done, the belt seems to "pull" directly from the cam(s) to the crank with the tensioner on the "slack" side as it goes from the crank, past the tensioner, and to the cam(s).

I am not sure the tensioner would like to be taking the forces of acceleration in that manner.

As far as I know though, most marine engines are pushrods for a reason

Is the D16 tensioner always active? ie, is there a spring that's always under tension to put pressure on the belt?

The reason I'm asking is that's not how it works on a Miata engine. In that case, you set the crank to a particular position with the tensioner free to move, then lock the tensioner down in that spot, essentially turning it into an idler pulley. Once this is done, there's no more movement and it wouldn't matter which way you spin the engine.

A few years ago, there was an article about doing exactly this so a guy could get an early Elise road legal. Now it seems most Elise conversions are done with the Honda motor still turning the way its designers intended.

This thread mentions someone who has already done it:

http://www.honda-tech.com/showthread.php?t=2346260

This article was referenced in that thread.

http://www.turbomagazine.com/features/0106tur_apexi_drag_racing_acura_integra/index.html

IIRC, the D16 tensioner is supposed to be locked down too, so you may not have to move it.

mad_machine wrote: As far as I know though, most marine engines are pushrods for a reason

Yeah, displacement.

I appreciate the info folks.

It appears that the project is possible, but not simple.

Note the dry sump system on the Apexi Acura, and the way the external oil pump is driven by the cam belt. That takes care of two problems at the same time!

Lacking a good supply of Rover K motors on this side of the pond, the D16 could fill that role if a suitable conversion kit were made available.

Carter

Appleseed wrote:

mad_machine wrote: As far as I know though, most marine engines are pushrods for a reason

Yeah, displacement.

depends on the engine. I have seen 4 cylinders used in I/O boats.. they were pushrod engines too.