M35B Engine Mount Allen Bolts

[Stu Jackson]

An interesting and useful heads-up from the C36 Forum:

 http://www.c36ia.com/forums/showthread.php?t=579&goto=nextoldest

[Ron Hill]

Stu : Thanks for the heads up ?  
I went to the C36 site and read the narrative, but was blocked from seeing the picture.  I tried to setup a new account, but was unsuccessful (just to see the picture) so I gave up.
 
I have the parts book on the M35B engine and it looks to me like the M10 x 1.25 x 20 DIN7991 cap screw was not installed properly by the factory when the engine was put together.  These cap screw are on the under side of the engine mount bracket and should have had "Locktite"/thread sealant, so they wouldn't back out.  You can also make a "slippage mark" on them (like I've described in numerious Mainsheet articles) to insure -at a glance that they are inplace .

I'll guess that the only way to really check that cap screw for tightness is to use a metric M10 Allen (hex head) wrench.
 
A few thoughts/observations.  

[Stu Jackson]

Here's the picture.  The issue is a loose allen bolt on the underside of mount.

[Ken Juul]

It's hard to tell from the picture.  On the upper bolts you may be able to get a socket with a short extension on a rachet to tighten them.  May need to add a flex joint between the socket and extension if the ridge on the mount interfers.  For the lower bolts needing an allen wrench I would recommend using an allen wrench socket and and a short extension.  The sockets are available at Sears, Lowes, Snap On or most auto parts stores with a good to tool selection

[Stu Jackson]

Here's the text of the message.  Thanks to Pete Taylor who has a 2005 C36 in Australia.

During my regular engine compartment check I found a bolt lying under the oil pan. On closer inspection I was surprised to find it was one of the 4 countersunk allen key setscrews that hold the engine mount bracket to the engine block. (This is the assembly bolted to the engine block upon which sit the flexible engine mounts). See photo. They are very difficult to tighten due to limited access and limited pressure you can apply to a short allen key.

I was however more concerned to find that two of the four 17 mm bolts, which are above the setscrews and also fix the brackets, were also loose. On very close inspection it was obvious that the block has been moving slightly against the starboard bracket.

The problem is that there is very limited access to the general area but more importantly there is virtually no access to the bolts as there has only been a small slot made in the bracket to allow the bolt to be inserted.

It is not possible to fit a socket spanner in there and I will have to grind down a ring spanner to get it into the slot, Even then there will be limited room to move the spanner. Thus I doubt whether I will be able to really tighten them.

I will do the best I can and apply a thread lock compound.

It seems to me a poor design feature and the reason they are loose is that it was difficult to access during assembly of the motor.

It might be worthwhile to check yours as my engine has only done 150 hours.

[Ron Hill]

Guys : As I mentioned above, check the cap screws for tighteness and put a slippage mark on them.  Then a simple visual check will let you know - if all is OK or if they are backing out! 

[Peter Taylor]

Gentlemen my apologies for not posting on the C34 site - I feel rather shameful!!

Just a clarification - all 4 Allen key cap screws were loose. It is possible to access these but they lie close to the engine mount base and I don't think a socket with an Allen key extension will fit. I will however get one and try -  thanks for the suggestion Ken.
Also there is some (very slight) oil seepage around these so I am not sure how to clean the threads well enough to get thread lock compound to work. Your hint to mark them is a good one - thanks Ron.

Finally the real concern is the upper four 17 mm bolts. Not capscrews as shown in the parts list Ron.

I would be grateful if anyone can suggest a method of tightening these.
As I mentioned I have a 17 mm ring spanner which I plan to grind the circumference to enable it to fit in the square access hole.
Then I will need to grind some "meat" off the spanner shaft to allow some movement.

As I said it was only with very close inspection I noticed the problem.


Peter Taylor
Altair 2005 C36 Mk11
Melbourne Australia

[Ron Hill]

Peter : My only suggestion on getting the cap screw holes oil free is to use some lacquer thinner with a "Q" tip to clean them out.  Then you want to use "medium" grade lock tight, to keep the screws in place.

On tightening the 17mm bolts, is to sacrifice a socket by grinding it so it'll fit.  Not too sure about the torque specs, but again some medium grade "Locktight" - if they are also loose.  
You might contact Westerbeke and ask them the same questions and see what they say.  The timing may also be a bit of bad luck, but check as your engine has a 5 year warrentee.  A few thoughts

[Peter Taylor]

Thanks again Ron - I will try the Q tip and I planned to contact Westerbeke to enquire how they assembled the mounts.
Peter

[billandalita]

A few days ago day I found an allen-head bolt lying underneath the engine oil pan.  Like the thread I am replying to, this bolt is used to attach the forward starboard engine mount flange to the engine.  The engine mount is attached to this flange.  This flange is in turn attached to the engine by two allen head bolts and two hex headed bolts.  Upon examination, the other three bolts attaching the flange to the engine were also loose which means the engine was not securely attached to the forward starboard engine mount.  All other engine mount bolts were tight.  Initially I thought this must be an isolated case; that is until I discovered on this website that the exact same thing happened to at least several other Catalinas.   By the way, as noted in the thread below, it is very difficlut to tighten the two hex bolts.  You will have to grind down a standard socket to fit; or, I found a socket made for impact wrenches that was 3/4 deep with a wobble connection inside the socket.  This barely allowed me to securely tighten the hex bolts with a 3/8 drive socket wrench. 

My C-34 MII is a 2002 year model with an M35B engine having 443 engine hours.  I really can't understand why this is happening, but obviously this can be a serious problem; and perhaps we should all be inspecting these engine mount flange bolts periodically.  I haven't yet applied Lock Tight to the bolt threads as suggesed in this thread, but intend to so as soon as I return to the boat.

The story continues:  Probably as a result of increased engine vibration caused by the loosened bracket, I also found the mounting brackets holding the heat exchanger to the engine had broken the solder joints.  The heat exchanger is now at the local radiator repair shop being repaired.  Bill Small, Williamsburg, VA