Jump to content
Strawberry Orange Banana Lime Leaf Slate Sky Blueberry Grape Watermelon Chocolate Marble
Strawberry Orange Banana Lime Leaf Slate Sky Blueberry Grape Watermelon Chocolate Marble
seasurveys

BMC 2.2 rear engine mountings

Featured Posts

Someone might know:  I have to raise the rear of the engine for shaft line up as it has dropped about 5mm. Engine is BMC Commander 2.2. The rear engine mountings are right angle brackets bolted to the bell housing. These lay on the timber bearer. There is a stud protruding with a nut on. The nut has been removed. The protruding stud seems to  pass through some form of metalastic bush.  There are shims beneath the base of the bracket on top of the bearer. All OK so far.  I am unable to raise the engine as it seems that the  protruding stud is seized in the matalastic bush. There are also three small 1/4" studs with nuts  located around the  base of the bracket circling the  centre main stud.

It would be extremely difficult to remove the  bracket at this time to investigate how it is made, does anyone know the purpose of the three small studs surrounding the centre bolt & am I correct in thinking the centre stud p[asses right through the  mounting & the engine should just lift off the stud & allowing  more shims to be placed under the bracket. It does seem there are two bases to the bracket but full access is a bit difficult to confirm. The photos  show various views but really good access is limited. It is the original design mounting & has not been altered, just cannot work out  the design to enable me to focus on freeing the correct part.

IMG_20181010_133010.jpg

IMG_20181010_132920.jpg

IMG_20181010_133031.jpg

IMG_20181010_132946.jpg

Share this post


Link to post
Share on other sites

The 'studs' are the end of bolts that hold the metalastick bush to the bottom of the engine foot. It has a flange with three holes in it

 

Richard

Share this post


Link to post
Share on other sites

Thanks Richard, I am assuming that the large stud in the middle is  a coachscrew with a threaded end passing right through the  bush and screwed into the timber bearer, so the  core of the metalistic bush is temporarily siezed onto the shank of the main holding bolt or coachscrew. In that case the shims have to be fitted  under the metalistic bush plate which is  secured to the base of the engine bracket. That seems to have made things clearer. Now all I have to do is somehow break the sieze between the holding down stud and the core of the bush.

Thanks.

Share this post


Link to post
Share on other sites
5 minutes ago, seasurveys said:

Thanks Richard, I am assuming that the large stud in the middle is  a coachscrew with a threaded end passing right through the  bush and screwed into the timber bearer, so the  core of the metalistic bush is temporarily siezed onto the shank of the main holding bolt or coachscrew. In that case the shims have to be fitted  under the metalistic bush plate which is  secured to the base of the engine bracket. That seems to have made things clearer. Now all I have to do is somehow break the sieze between the holding down stud and the core of the bush.

Thanks.

 

Most of those I found with a wood thread in the bearer were as you say a coach screw but coach screws do not normally have a nut on top so I think they are lengths of studding.

 

On the fleet we found that eventually coach screws pulled out of wooden beds and did if far quicker on GRP beds with a core of goodness knows what type of wood or paper so we drilled the bed to the size of a length of scrap shaft, drilled and tapped the shaft across its diameter and the screwed the studding or a bolt into the length of shaft that then sat through the bed at the centre or below of possible. I have also seen beds slotted with a  piece of thick plate threaded for a stud. Both methods give a fra firmer and stroner method of securing the mount.

 

I have a horrible feeling that type of mount is no longer available.

 

If you do manage to free the stud you can often fit a thick "washer" onto the stud before you drop the engine back down. The ID is the stud size and the OD will be the size of the flange at the bottom of the centre section of the mount. I suspect that you will find the the three special "thin headed" bolts the hold the mount to the foot have been eating away at the engine bed where the rubber in the bush has collapsed.

 

I also fear the simplest way out of this may be to plate the large hole in the foot (once the mount is removed) and mount it rigidly. Typically there would be no more that 1/4" gap between the bottom of the foot and the bed. If I am right about these mounts no being available now I hope someone knows a better way of dealing with it.

 

For goodness sake do not get too boisterous with the centre part of the mount because if you break the rubber's bond to either of the two metal parts the mount will have had it.

 

 

 

Share this post


Link to post
Share on other sites
20 minutes ago, Tony Brooks said:

 

 

I have a horrible feeling that type of mount is no longer available.

 

Indeed

 

I think I'd pull the engine upwards against the mount, then take a hacksaw to the bolt. Once it is apart, you can sort out the remains

 

Richard

Share this post


Link to post
Share on other sites

Thanks both,  I had thought that ultimately it would be easier to solid mount the rear end but could not fully understand how the mounting had been designed as the area is a bit cluttered and over painted. Lifting the engine is the problem at the moment because the  holding down bolt is, I think, well screwed into the timber bearer but also siezed in the bush core so cannot separate the two. However. Now I know which bits should separate I can work more selectively 

Thanks again.

Share this post


Link to post
Share on other sites

A dose of phosphoric acid, like Jenolite, may assist in separating the stud from the inner bush given a bit of time. There was a time when we used battery acid but its a bit difficult to get rid of.

Share this post


Link to post
Share on other sites

Coincidentally I did try phosphoric acid a day or so ago but probably was too impatient because I was uncertain as to which part had siezed. I will try again, make a sealed bath around the bolt. Thanks, just confirms that it is a good idea worth trying again.

Share this post


Link to post
Share on other sites

Thanks...I will give it another go as at the moment I cannot get the engine off the hold down bolt  bush core and cannot get the bolt out of the wood. Could try heat but I bit too risky in close proximity to timber hull structure.

Share this post


Link to post
Share on other sites
33 minutes ago, seasurveys said:

Thanks...I will give it another go as at the moment I cannot get the engine off the hold down bolt  bush core and cannot get the bolt out of the wood. Could try heat but I bit too risky in close proximity to timber hull structure.

That's why I suggested sawing through the bolt. You are at a point where you are going to have to destroy something

 

If you break the leg, you're in big trouble

If you burn out the rubber mount (which otherwise looks OK) they are unobtainable)

If you damage the bearer, you are into some extensive repair

Cut the bolt - or drill it out of the rubber mount

 

Richard

Edited by RLWP

Share this post


Link to post
Share on other sites

Although tedious drilling the bolt might heat it enough to break the rust.

 

Another alternative to give you more room would be to remove the three larger bolts holding the foot to the engine or the three little nuts holding the mount to the foot but you will probably have to grind down a spanner to fit under the foot and hold the heads of the small set screws. In both cases you could then lift the engine while leaving the mounts on the studs. Once the engine is out of the way you would have much better access. Also once the outer part of the mount or mount and engine foot is free to rotate you could grip the top of the metal tube the stud goes through and try to twist it free without  risking  tearing the rubber or its bonds to the steel.

 

As the inner tube part has a flange on the bottom that is almost certainly sitting hard don on the bed plus three screw heads between the outside and that flange that have probably settled into the wooden bed I suspect cutting the bolt may be difficult and impossible without also cutting the bed.

 

The photos seem to show angle iron sat on top of the timber and if so the studs may be tapped and welded into the angle iron and the iron bolted or screwed into the bed from the inside of the beds . If so another alternative would be to free the iron and lift the whole thing, engine and bed, as an assembly. Once the iron was clear of the bed a very large hammer and brass drift on the top of the stud (nut loosely on first) may drive the stud out of the mount. Note - the problems we had keeping coach screws in wooden beds eventually lead to us screwing 1/2" plate to the beds on new engien installs and securing then to the beds with coach screws the once fitted were removed and GRP resin poured down the holes and the screws refitted. They never came loose again. The   studs were threaded into the steel. If we had problems I can't see why others would not and come up with a similar solution.

Share this post


Link to post
Share on other sites

Thanks all, all ideas much appreciated. The bracket rests directly on the timber bearer, there is not enough clearance between the base of the metalistic bush and bracket to saw it off and although heat would help, the area is bounded by timber and fuel lines so a bit of a risky last resort. Now I understand how the bearer is designed that helps enormously.

Thanks again.

Share this post


Link to post
Share on other sites
40 minutes ago, seasurveys said:

Thanks all, all ideas much appreciated. The bracket rests directly on the timber bearer, there is not enough clearance between the base of the metalistic bush and bracket to saw it off and although heat would help, the area is bounded by timber and fuel lines so a bit of a risky last resort. Now I understand how the bearer is designed that helps enormously.

Thanks again.

 

Sorry to disagree, it might appear to now but originally the flange at the bottom of the centre part of mount would have held the bracket maybe 3/8" clear of the bed and the heads of the tree small set screws holding the mount to the bracket would be about 3/8" clear of the bed. If you supported the weight of the back of the engine and gearbox the engine and bracket would lift by deforming the rubber bush back to something like its original state so you could get under the bracket BUT If the flange on the bottom of the mount is not sitting on steel I forecast it will have worked itself into the wood which pretty much makes it difficult to just saw the stud off under the bush.

 

Here is a cross section of the mount.

 

BMC foott.jpg

Edited by Tony Brooks
  • Greenie 1

Share this post


Link to post
Share on other sites

I have been trying to understand what the line as indicated by the red arrow actually is. This is what makes me think it might be metal over a wooden bed but it might be a strip of wood over a metal bed. While studying the photo I realised that the rubber is well proud of the top of the mount's outer shell (yellow arrow) so I suspect the mount has had it. The bonding between parts may have failed/weakened or the rubber softened allowing the engine to drop.

 

 

Real BMC foot.jpg

Edited by Tony Brooks

Share this post


Link to post
Share on other sites

Further thought on freeing the stud. If you can lift the back of the engine enough to get a punch or flattened cold chisel under the bracket applying force to the flange at the boottom of the inner part of the mount might shock it free. Bit hard to do in situ. but possible.

Share this post


Link to post
Share on other sites

Hi Tony

 

thanks for the drawing, do you think the drawing is actually the way the mounting is designed as it obviously impacts upon the best way of attending to the problem. The bearer is timber without any steel tapping plate or top. Your red arrow is highlighting  the edge of a form of sole boarding that is attached to the side of the bearer to  act as a support for  the battery box that is standing on the sole as can just be seen on the left hand side. Your yellow arrow is the outer shell of the bush and not the rubber insert.  the rubber insert is just below the level of the core & outer shell & looks to be OK. I am hoping that I can get the core to free off from the through bolt with enough thought. The area is not  heavily corroded although it may look it as I can see the top or the core tube is clean, the trouble is that it does have a moderate length of bolt that it can seize up on.

 

John

Share this post


Link to post
Share on other sites

I am absolutely sure that diagram is correct, maybe not dimensionally as it was drawn from memory, and maybe the odd chamfer is missing but it is certainly how these mounts are. I know because I ran a fleet of boats with BMC 1.5s and 2.2s in the 70s and the shortcomings of the mount  are engraved on my mind.

 

If you can grip the top of the core tube you could try twisting it in both directions a very small amount, enough to stretch/compress the rubber but not enough to tear it or break the bond to the metal. That metal tube has maybe 3mm walls. However I would still favour lifting the engine to try to get a punch onto the bottom of the core tube. The flange is perhaps  1/4" thick so you are not likely to damage it much and even if you do a file would soon sort it out.

 

Whatever way you try it if you are to remove the mount either the engine will have to be lifted clear or the engine feet/brackets freed from the engine so they can be lifted clear of the stud. As we don't know how the stud is secured at the lower end I don't think there is much point in trying to remove it at this stage.

 

Maybe the inner sleeve flange has glued itself to the bed with paint so a good shock might break it free.

Edited by Tony Brooks

Share this post


Link to post
Share on other sites

Thanks Tony, your information is of enormous value, particularly the diagram. I will try creating a sealed bath around the core & filling with a mild acid (used phosphoric for a few hours but was reticent to experiment further as I did not know which part should be freed off.) This time I will leave for a day or two before getting more brutal with it.  Thanks again     John

Share this post


Link to post
Share on other sites

If its rust it will be between the stud and the inner steel core but at the moment you can't twist the inner core very much for fear of destroying the rubber insert so if you can grip the top of the steel core and can  support the engine and undo  the  screws that hold the bracket to the engine or the small screws that hold the mount to the bracket you could twist it without  risking the rubber. Personally I would be more inclined to try penetrating oil but would take great care to keep it off the rubber.

 

If the inner core is stuck to the bed it will probably free if you just lever the bracket (engine foot) off the bed but disconnect the shaft first.

 

 

Share this post


Link to post
Share on other sites

Thanks Tony. Left it with some  penetrating oil yesterday so who knows but if that does not work I'll try the mid acid.  I might have to figure out a way of supporting the engine/gearbox whilst  removing the bracket from the engine. Trouble is the weight is quite substantial & it means  probably fabricating something to rest on the bearers  and sling under the gearbox in the meantime. There are more difficult problems in the world so I will sort it eventually. Thanks for your advice.  Just in case you ever need  the favour returned in an area that you  might not be fully familiar with, this is my website.  www,seasurveys.co,.uk .   The engine is fitted in the  boat  Dalrymple on the right hand column so you know the type of boat

 

John

Edited by seasurveys
hyperlink

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.