motor mount bolts

[brant]

I plan to install new Vetus motor mounts, but the boat is in Mexico and I'm in San Diego, so I have to go to the boat fully equipped to do the work.  I understand that the new mounts will require different sized lag bolts: can someone tell me what size are the originals, and what size should the new ones be?

[Ken Juul]

I don't know, if someone doesn't respond, try doing a search.  This has been discussed in the last month or so.  Not sure if bolt length was mentioned or not.

[Jeff Tancock]

I replaced the mounts this year. The way they came from Vetus was fine. Use your old lag bolts to secure the new mounts. You will likely need a rat tail file to enlarge the size of the opening in the new mounts for your present lag bolts so you can align the engine to the shaft properly. You may find that one or more of the old lag bolts has lost their grip (stripped). That means getting longer lag bolts or filling in the holes with something. Email me if you need any tips or reasurance.

[John Gardner]

I think the need to use shorter bolts depends on your luck to some extent.  I too replaced my engine mounts this winter, and I was able to use the original bolts in about half the holes;  the other holes weren't drilled deep enough, and as I am sure you realize you will not be able to drill the holes deeper while the engine is in place.  I would go prepared to put shorter bolts in all the holes and see what luck you have - the bolts cost pennies.

[Craig Illman]

My existing lag bolts were 3/8 x 2-1/2". I've purchased eight 3/8 x 2" bolts for when I do the remainning mounts in a couple weeks.

Craig

[Bob K]

I went through this last weekend.   The Vetus mounts required bolts 1/2" shorter than original.  Being impatient, I cut the 1/2" off with a cutoff wheel on a dremel tool.  Leaves a flat bottom bolt.  Not elegant, and not optimal, but it got the job done.  If you don't know the original bolt size, go buy an assortment of bolts in 1/2" increments so you are absolutely prepared.  You cannot force the original bolts the extra 1/2" into the holes - I tried!!  And yes, Vetus mount holes must be widened.  I used my Dremel with a grinder tip - it trashed the tip, but did the job.   

I removed the old mounts by cutting the bolts with a sawzall, and then raising the engine slightly - I did not have to remove the exhaust riser from the manifiold, but I did disconnect the hump hose at the muffler.  I installed the new mounts by removing the bolt from eachmount (at home in a vise), and then reattaching once the mount was installed.   

By the way, this job took a lot more time than I anticipated from reading earlier posts.  I did not know about the shorter bolts, and that added time.  I also didn't widen the Vetus mount holes enough and had to remove the front mounts and redo them.  I hope this helps your job go easier....
Bob

[Craig Illman]

Thanks, I'll remember to throw my Dremel in the car and probably try to pick up a spare bit or two.

Craig

[Gary]

I've been following this thread on motor mount bolts with interest because I have one bolt that is close to being stripped.  The repair recommended in the mesaage board search is to use epoxy lightly on the stripped wood hole and then to use bolts 1/2" longer.  If this is the repair for a stripped hole why do the Vetus Mounts need a 1/2" shorter lag bolt and why do some find it impossible to use the longer lag bolt wiyh Vetus Mounts.

Ron, I hope you'll weigh in on this one as it was your message/repair suggestion for a stripped motor mount hole that I was going to follow for my repair.

[Ron Hill]

Brant : The previous posts are correct on the lag bolt length.  You'll find that some of the longer bolts (2 1/2")can be used so I'd take down 4 of the shorter (2") bolts.
The only reason that you will have to elongate the holes in the Vetus mounts is IF the old mounts were installed in a cocked (side ways) position.   It all depends how the factory was doing the day your engine was installed!!  If the existing lag bolts are centered in the engine bed you're OK.  Make sure that you have lock washers and COAT the old holes with 5 min epoxy (for a better grip, but let dry 1 hr before installing the lag bolts!) The forward engine mount bolts have had raw water and oil (starboard side) dripped on them and the port side has had oil from changing the filter dripped on them.  Oil is what killed the rubber in the old mounts!! 

Why not join the C34IA and get access to the Tech note that have all of this written up.   

[David Sanner]

Not sure about the stripped holes... maybe that's due to rot and half inch longer bolts will work but when I swapped
out my mounts I found the existing lag bolts are just too thick to screw that extra 1/2 inch into the solid stringers. 
Maybe you could force them in but you run the risk of damaging the 'threads' that are already there.

Ron's suggestion on what was going on at the factory that day sounds about right.  Some of us may have
holes that were drilled a bit deeper and can handle a longer bolt but that didn't seem to work for me.

I wound with another solution, I used some stainless nuts I had lying around to work as a thick washer.
Maybe I'll someday I'll get shorter bolts... maybe.

[Ron Hill]

Guys : The biggest problem with the factory that I've encountered over the years is that the workers were using the wrong tools to tighten items. 
They weren't using an electric screwdriver, but drills that didn't have a torque brake.  That's why most of the lag bolts (holes) and nuts are all striped.  Some on the engine bed and most on the head floor installation.  You'll find that same thing if you remove the teak for refinishing - the holes are stripped!! 
That's what happened (my guess) in the early C34 production when you're sending 350 to 400 boats out the door every year! 
A thought