Sunday, April 3, 2011

Changing Engine Mounts

Capt. Kyle at work changing engine mounts.
Saturday Mike, Bob, and I changed Donnybrook's engine mounts!  The goal is to decrease noise and vibration and increase overall comfort on the inevitable long motoring that is part of cruising on Lake Michigan.  We'll find out at launch in May if the goal was met.

This was a relatively easy job.  Physical flexibility accessing the rear engine mounts was an asset.  Patience getting to the tougher bolts and aligning the engine was important.

The EXCELLENT article by Ron Hill on the Catalina 34 International's project Wiki, Changing Engine Mounts, and other advice on the C34IA Main Message Board made planning easy.

Back of the engine showing the disconnected
coupler and rear engine mounts.
The red object is my Globe Drivesaver

After reading everything I could find on the C34 International Association site, I decided on Vetus K50 mounts in the front and K75 in the rear as several other Catalina 34 owners have done.  Based on other's experience, K50 mounts all around--although within Vetus' specifications for the Universal M25xp--seem too soft for the engine and may cause excessive engine movement.  Placing K75s in the rear will keep the prop shaft centered in the tube and the K50s in the front will help keep the engine run as quiet as possible.  I ordered the mounts from Jamestown Distributors.  Mounts were $65.41 a piece with free shipping (free discount code fship50).  I ordered at lunch Tuesday and received them Thursday.

A 2x4 across the companion way with
Mike looking on.
The mast is off the boat so using the boom as Stu did wasn't an option.  Instead, I used a 2x4 across the companion way and I used my backstay adjuster for the block and tackle.  We were only lifting half of the M25xp's 300 pounds so weight wasn't a concern and this layout made it possible to raise and lower the engine from inside the boat.  Instead of using a bridal as Stu did, we used the engine lift points.  There are two, one for the front and one for the back.  They're slightly off center but worked fine.
Front of the engine lifted and ready
to remove the front mounts.

The only additional information I can add to the Wiki is:
  1. The mounting studs on the Vetus are about half an inch longer than the original.  This means you have to raise the engine slightly more to insert the new mounts.
  2. Put the top nut and washer on the front, starboard engine mount before you lower then engine.  I didn't have enough clearance to put it on with the engine lowered.
  3. Watch the exhaust riser clearance as you raise the back of the engine.  There is room to take the rear mounts off with the rear raised as high as it'll go, but I had to remove the lag nuts first so I could twist them off.  
  4. The engine moves on the mounts A LOT more with the shaft disconnected.  I tested movement with the shaft disconnected and was concerned about excessive movement until I reconnected the shaft.
  5. Be careful with the silicone used on the lag bolts.  The silicone makes everything it touches very slippery.
Total time for us was about 5 hours on the boat and included laying out all tools and equipment and one trip to the ship's store for shorter lag blots.

I'd replaced engine mounts on my previous boat (S2 9.2A) so I had some experience.  Changing mounts on the Catalina 34 is more difficult because of access to the rear mounts, but still relatively easy.  Patience to work in a cramped space while loosing and tightening bolts one or two ratchet clicks at a time is key.

UPDATED 6/14:  Final engine alignment was a bear!  See Engine Mount Epilogue for details on final alignment.  All is well.  Again, patience is key.

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