Print

Please login or register.

[Bill Shreeves]

Rock & Roll!

Or, replace it with a Twin Disc TMC-40 as I am and it is only 4mm (>3/16") longer and 1/4 of the price of a ZF10 ($1259 vs. $5000 on CD).  I'm mid project right now, having removed the exhaust riser and heat exchanger, drained coolant form the motor, and removed the alternator and wiring from the motor.

I'll report back when I've successfully swapped the gearbox and relocated the heat exchanger.

Patches

[Stu Jackson]

Ron, If I recall it was an 1" longer.  Do you really think that would make that much of a difference?

Bill,

Yes, because of the clearance required between the prop and the rudder.

[Noah]

As well as (possibly) violating the “rule” that the prop should be no farther than 1in. behind the strut.

[Ron Hill]

Guys : I agree with Noah " rule of thumb - the prop should be one shaft diameter behind the strut".

A thought

[Patches]

Well...change of plans.

The decision to go with a new transmission was based on the assumption that the motor was good to go for another few seasons (at least).  I take extremely good care of my motor, and have added much new while its been on my watch.  It ran super reliably, didn't smoke, and--until recently--didn't leak any oil.  It has approximately 2500 hours since new in 1990.  Even so, the new leaking was toward the back of the engine, relatively minor, and the oil level never got to the level where I was adding new oil between changes (roughly every 65-75 hours).

So, I'd purchased a bunch of things in preparation for the tranny swap:  new motor mounts, hanger bolts and nuts to secure them, and damper plate.  I also fabricated a new mount for the heat exchanger out of 1/4" aluminum angle stock to hang from the underside of the rear berth, and purchased the new hoses to make the extra run from the engine.

We pulled the engine on Wednesday to replace the transmission and placed it on the galley floor.  We'd prepared the area with some plywood and drop cloths.  After removing the bell housing, we saw some oil on the inside suggesting the need for a new rear seal. No biggie.  But my mechanic, a very experienced guy, showed me how there was "end play" in the main shaft which would require a much more significant rebuild to remedy.  In his view, putting in a new seal would be--at best-- temporary and the leaking would be back within a matter of time.

So, time to choose.  I could do "half a re-power (transmission only and assorted shorter term fixes like the rear real)", get through the upcoming charter season, and decide to re-power a year from now.  Or, I could do a "full re-power" and pull the engine only once, start the charter season a little later, and be done with it.

Like many others facing this choice, I thought about rebuilding to get several more years out of the (otherwise) super reliable motor.  I LOVE that motor for its ease of maintenance and reliability.  But, it is 32 years young now and I'll be keeping the boat for a while as part of the business.  I'd already decided that in the event of a re-power it would be a new Beta 25, to the exclusion of the M25 XPB or a 3 cylinder Yanmar.

So, I ordered a new Beta 25 which I'm told will be shipped in "March."  I hope so.  In the meantime I'll be able to make many of the preparations in the engine bay pending its arrival. 

I'll also be selling a couple of the items I recently purchased for the original M25xp, like the Compass Marine 105 amp small frame alternator which I added as part of my electrical upgrade 2 years ago, as well as some spares.  So, check the "parts and pieces" classified if you need something for your M25xp.  I don't think I'm going to part it out, preferring to sell it as a complete motor with the original alternator.

Patches