Howard wrote:

Someone mentioned the need for a thrust bearing on direct drive
installation......

    I'd like to know how this has been handled.....   The pieces I have
laying around including an e-shaft and some end housings show no evidence of
any provision at all for thrust.....     Every other engine I've ever dealt
with had some sort of thrust bearing to keep things in line.   What does
Mazda do for thrust?..... what provisions have been made in direct drive
setups???

                H.W.

There are a series of spacers and a sandwiched thrust plate that bolts to
the front of the e-shaft. Needle bearings are used.

Paul Lamar

charles.harbert wrote:

Howard, the 13B internal thrust bearing is a relatively small needle bearing
(Torrington type), except for the late model turbo (and 20B)which use a much
large size. Dave Atkins had one come apart which forced a rebuild of the engine
which was determined to be from the helical gear load from the Ross gearbox. He
has seen this in other similar setups. There's a fix for it (including
installing the later larger thrust bearing). Other people have successfully (so
far) run direct drive, but I believe that could be marginal based upon the
hp/thrust being developed.

The Mazda engine does not produce any end thrust, but the clutch pressure plate
does when you disengage the clutch. I haven't tried to calculate the thrust from
the clutch compared to the thrust from a prop absorbing up to 200 hp. I think
that you'd also need to know the continuous hp rating at 6K rpm for the Mazda
Torrrington thrust bearing. My guess is that it's not adequate for the job, but
if your thinking about doing this, I think you need to calculate it.

 
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