Ford Lehman Velvet Drive Starboard

[MVDarlin]

My starboard transmission on my 1982 120 Ford Lehman runs hotter than the port side. I know it has a planetary gear to reverse rotation. Has anyone else noticed this? Is there anything I can do to reduce temp? Should I be concerned?

 

[diver dave]

I would get some data from an IR gun. Just before and just after the xmission oil cooler. On both engines.

 

[jleonard]

My starboard transmission on my 1982 120 Ford Lehman runs hotter than the port side. I know it has a planetary gear to reverse rotation. Has anyone else noticed this? Is there anything I can do to reduce temp? Should I be concerned?

"Hotter" doesn't mean much until you have some numbers as stated above.

 

[kchace]

I check the temps of my VDs about every 2 hrs when cruising (along with a number of other items in the ER). They are always within a few degrees of each other. Depending on water temp, usually in the 135-145 range.

IMO if there is a marked difference in running temps between your 2 transmissions I would certainly investigate. The likely cause is a partially clogged oil cooler. A less likely but other possible and very bad cause could be that the clutches are slipping.

BTW Velvet Drives do NOT use a planetary to reverse rotation. The trans with reverse rotation has an idler gear that goes between the Ring Gear and the Drive Gear causing reverse rotation. This is also where the reduction ratio occurs. In non reverse rotation units, the Drive Gear contacts the Ring Gear directly. The planetary section is used for reverse only and is locked up in forward.

Ken

 

[C lectric]

How much hotter specifically? What do they actually operate at?

Most gears can operate at up to about 180oF without a problem. Still should not be pushed though.

In many cases heating is caused by the gear oil cooler getting clogged in the raw water side with salt deposits , maybe some weed or vegetation that gets past the sea strainer and of course old zinc pieces that break off. They can block some of the tubes.

Get them cleaned, both of them. In most systems as they clog that also reduces the seawater passing through to the engine heat exchanger so if they are clogging it has other consequences than just to the gearbox.
Remove them to a good radiator shop.

And by the way the cleaners such as Barnacle Buster or Rydlyme, will not do much to vegetation clogging.

 

[catalinajack]

New oil coolers cost about $140. Their useful life is 2,500 hours according to Brian Smith at American Diesel. Sure, you can have oil coolers , and heat exchangers,, cleaned and pressure-tested but what you won't know and a test cannot determine is how close to failure it is. Tested okay today and installed and pressurized tomorrow and it could fail. Consider replacing if they are known to be old with unknown hours and certainly replace if in excess of 2,500 hours. I changed everything on my pair of Lehman 120s, four oil coolers and two heat exchangers as I had no idea of their age. They likely still had a lot of life in them but I did not want to be in some remote Canadian anchorage (Great Loop) and suffer a cooling issue and having to run on one engine for a LOT of my miles all the time worrying about the other engine crapping out. With all new, this boat is good for another ten or more years.