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LeighWebber 04-10-2019 07:25

Engine trunnion mount to allow lifting rear of engine
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I have pulled my 4JH2-TE from my Columbia 43 and have it in my home garage for a rebuild. I have a Walter V-drive and a Velvet Drive transmission. I am sending the V-drive in for a rebuild, and am replacing the Velvet Drive with a ZF 45 (much lighter, and a perfect replacement fit). When I pulled the engine, it was impossible to remove the V-drive and tranny without first lifting the engine. There is a large frame a few inches forward of the V-Drive making it impossible to pull the V-drive or tranny unless you lift the engine first. Obviously, reinstallation will present the same problem.

I saw a Youtube video of a transmission replacement in a ski boat. The engine had a trunnion mount that allowed the engine to be rotated up so that the transmission was accessible without lifting the entire engine. I want to put in something similar in my boat. Explaining this is a bit tricky because I have a V-drive. When I use the terms "forward end" and "aft end" I am referring to the boat-wise orientation. So the forward end of the engine is where the transmission sticks out. When I use "front of the engine" and "back of the engine" I am referring to the engine-wise orientation. The transmission attaches to the back of the engine, which is at the forward end.

OK -- so what I want is a swivel arrangement for the engine foot/mount at the front of the engine (aft end). The idea is that with the engine installed, I can lift the back of the engine (forward end) up simply by unbolting the prop shaft coupling, removing the nuts on the two engine mounts at the back of the engine (forward end), then lifting. The swivel foot/mount arrangement on the two mounts at the front (aft end) of the engine will allow the engine to rotate in the vertical plane without removing the mounting nuts. I can then remove the V-drive or transmission -- or get at the stern tube, packing gland, etc. very easily. Of course I must first detach the gearshift linkage and throttle linkage cables (and make sure my fuel lines have enough slack).

If you have ever worked on a V-drive sailboat, you will know how difficult it is to reach the packing gland: it's right under the engine, and almost impossible to work on. This trunnion arrangement would solve that problem.

Attached is a screen shot from the Youtube video showing the trunnion (ignore the pink circle). Anyone know where I can get these?

DougR 04-10-2019 13:35

Re: Engine trunnion mount to allow lifting rear of engine
Inboard gasoline engine manufacturers have been using these type trunnion mounts since the dawn of time....companies like Mercruiser, Volvo, Crusader, Marine Power, etc.

Try going to "" where you can get the trunnion itself. Finding the engine side bracket for your 4JH could be more of a challenge, but maybe they have something which you can adapt.

Good Luck,

skipperpete 05-10-2019 01:27

Re: Engine trunnion mount to allow lifting rear of engine
It sounds like a great idea, servicing the vee drive and stern gland would be a breeze. Do you have a lot of overhead clearance to hoist into? As DougR said . The trunnion mounts are available and they came as standard on some 4/236 and 6/354 Perkins engines. You might have to invent something that inhibits the transverse movement of the whole shebang or expect to do a re alignment after each lift cycle but apart from that I think it's a winner.

FPNC 08-10-2019 08:39

Re: Engine trunnion mount to allow lifting rear of engine
You might want to rethink converting to the ZF 45C. The Velvet Drive 1:1 is much more robust gear and can be completely rebuilt at a very low cost. It is rare to see one that needs more than seals and clutch discs.

LeighWebber 08-10-2019 11:03

Re: Engine trunnion mount to allow lifting rear of engine
I'll look into rebuilding the Velvet Drive myself. This thing is very heavy, and the shipping cost to and from a rebuilder plus the rebuild charge might exceed the cost of the ZF.

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