The Triumph Dolomite Club - Discussion Forum

On page 9 of the April – May 2020 edition of Dolly Mixtures you will find an article titled “Further notes on engine mountings” if you read this you will read that Chris Witor had manufactured some Sprint poly engine mounts but having produced them he was advised that they should have an offset so he is having to get his mould modified. I do not know how Chris came to produce the batch of Sprint mounts and who he has been dealing with. I only got involved when Steve Waldenberg told me that Chris Whitor had asked him to take out a planned news flash which was due to go in the next edition of Dolly Mixture’s that he had produced poly Sprint engine mounts because the ones he had produced did not have an offset. I do not know how much offset Chris is building into his Sprint mounts.

I contacted Chris and ask him if he also proposed to produce Dolomite OHV engine mounts. The outcome was I took a number of OHV mounts down to him in March and he measured the hardness of the rubber and asked me to confirm that they also needed to have an offset. To do this I raised the issue on this discussion board on the 22nd March and the outcome was that I advised Chris that an offset of 10mm was needed for the OHV mounts. How this decision was reached will be covered in the next edition of Dolly Mixture. When Chris measured the hardness of the rubber mounts we found that some we harder than the others so we believe we know the hardness of both the 1500 engine mount, part number 149934 and the softer OHV engine mounts, part number 158016.

I do not know the current situation in respect to Chris Witor’s Sprint or OHV engine mount production.

Richard the old one wrote: ↑Sat May 09, 2020 7:20 pm On page 9 of the April – May 2020 edition of Dolly Mixtures you will find an article titled “Further notes on engine mountings”

Thanks Richard,
sorry, I haven't got round to reading the latest Dolly Mixture yet, but I will.

Superflex are an Australian company and Chris Witor became their European distributor
and from a few years ago, he has become both their European manufacturer and distributor.
His first contact with Superflex would have been on one of his trips to procure T2000 parts?




Ian.

I've been having a play too creating a new type of engine mount as the new ones I had from Rimmers literally fell apart after a few miles.

I've created a new mtg plate to mount a Land Rover engine mount and drilled a hole in the std Sprint engine brkt.

All pretty simple and if it works out ok I plan to sell them as a better alternative to the std ones.





I'll look at the near side one in due course.

Please let me know your thoughts.

In respect to the manufacture of poly OHV engine mounts - Chris Witor advised me that he has given a machine shop the go ahead to make the tooling today and that the mould should be ready in 3 weeks so samples should be available in 4-5 weeks.

shaunroche wrote: ↑Sun May 10, 2020 3:04 pm I've been having a play too creating a new type of engine mount as the new ones I had from Rimmers literally fell apart after a few miles.

I've created a new mtg plate to mount a Land Rover engine mount and drilled a hole in the std Sprint engine brkt.

All pretty simple and if it works out ok I plan to sell them as a better alternative to the std ones.





I'll look at the near side one in due course.

Please let me know your thoughts.

That should work, at least better than the pattern originals.

But it still doesn't cure the design fault that sets the mount horizontal and thereby subject to vertical shear loads it was never designed for. Best practice calls for no more than 45 degrees from perpendicular. I'm still thinking about that one as it needs a cure that doesn't involve modifying the subframe!

Steve

Good point Steve, leave it with me!

...and thereby subject to vertical shear loads it was never designed for.

I disagree, I expect it was categorically designed to resist the sheer forces involved. What it wasn't designed for was the cars surviving beyond the then design life of what, 5 years? Maybe 10 years maximum?

The company I spoke to in Birmingham which makes mounts told me that correctly bonded rubber to metal joints can withstand multiple tons of shear and the rubber should be expected to tear before it releases itself from the metal to which it is attached. Unfortunately they didn't make the after market offer currently available which was evidently procured on a 'can you make something that looks like this' basis, with little care or understanding for expected function.

Carledo wrote: ↑Thu May 14, 2020 9:39 pm I'm still thinking about that one as it needs a cure that doesn't involve modifying the subframe!

I have made a prototype that Steve.
The mount is turned 90 degrees, said mount is for a Jaguar XJ6.
It is the way a lot of engine mounts are nowadays.

If you are interested I can post a photo?


(As an aside, I notice you can get Land Rover mounts which look very similar to an XJ6 one
for 1/4 or even 1/6 of the Jag price!)



Ian.

xvivalve wrote: ↑Thu May 14, 2020 11:30 pm

...and thereby subject to vertical shear loads it was never designed for.

I disagree, I expect it was categorically designed to resist the sheer forces involved. What it wasn't designed for was the cars surviving beyond the then design life of what, 5 years? Maybe 10 years maximum?

The company I spoke to in Birmingham which makes mounts told me that correctly bonded rubber to metal joints can withstand multiple tons of shear and the rubber should be expected to tear before it releases itself from the metal to which it is attached. Unfortunately they didn't make the after market offer currently available which was evidently procured on a 'can you make something that looks like this' basis, with little care or understanding for expected function.

I disagree with your disagree! As far as i'm concerned, bad practice is bad practice and the engineer who let that particular bit slip through should have been shot! I suspect that somewhere in prototype development, the horizontal mount got slapped in to get it moving and somehow never got modified out. I won't say i've NEVER seen another mount like this, GT6 mounts hang in a similar but not quite so obviously perilous fashion. (A vertical blade in a vertical U section with the gap filled with rubber, but even there, the vertical U gets narrower towards the bottom which largely stops them dropping out when they fail) And the old 1500PCF Ford mounts were only slightly better, being at around 15 degrees from horizontal. ISTR those used to break for a hobby and dump the sump on the crossmember too. Those cases aside, most manufacturers make gravity work FOR them and use the rubber in a compression setting. It lasts longer and is more foolproof, even if in 2 pieces, the engine's weight will keep it in more or less the right place! Though i've seen some rather alarming results from torque reaction in cases of broken compression mounts!

AND the LR (or Jag) mount was emphatically NOT designed to carry these loads. At all. Ever.

I don't doubt that the better made OE mounts coped better with their natural disadvantage. But they just aren't available any more!

Real world, we need to design a better solution! I gather Ian might have done so! Lets see it Ian!

Steve

Carledo wrote: ↑Fri May 15, 2020 8:18 pm Real world, we need to design a better solution! I gather Ian might have done so! Lets see it Ian!

My attempt is a simple cradle to hold a Jaguar XJ6 mounting.....




From the XJ6 mount I removed a little from each side (which took a while with a hacksaw).
For the cradle I used an angle with gussets at each end and, for additional stiffening, an upstand under the front.
Also, I welded the fixing bolts to the cradle for easier fitting/removal.

Once I put the engine back in to my car I will be able to make the arm to attach this to the engine.


The XJ6 mount feels slightly stiffer than the Sprint ones.
I went for this because it is designed to support the heavy XK engine.
Another (rather expensive) option for this cradle is Mazda MX5 (mark one) but this has a much softer compound than the Sprint mount.

If a Land Rover mount can be used for this, you are looking at under £10 cost in materials.....



Ian.

sprint95m wrote: ↑Sat May 16, 2020 10:43 am
From the XJ6 mount I removed a little from each side (which took a while with a hacksaw).
For the cradle I used an angle with gussets at each end and, for additional stiffening, an upstand under the front.
Also, I welded the fixing bolts to the cradle for easier fitting/removal.

Once I put the engine back in to my car I will be able to make the arm to attach this to the engine.


The XJ6 mount feels slightly stiffer than the Sprint ones.
I went for this because it is designed to support the heavy XK engine.
Another (rather expensive) option for this cradle is Mazda MX5 (mark one) but this has a much softer compound than the Sprint mount.

If a Land Rover mount can be used for this, you are looking at under £10 cost in materials.....



Ian.

Ian, may I make a suggestion? you probably want the metal top plate of the mount to be cut back a little more than the rubber, so that you don't get solid contact to the cradle. I think you will get some sideways movement.

Thanks Clive.
I had thought of that sideways travel as being a probability, so I intend using one of these:

a rubber exhaust hanger, sandwiched between the mounting and the cradle.


thanks,
Ian.

sprint95m wrote: ↑Sat May 16, 2020 10:43 am

Carledo wrote: ↑Fri May 15, 2020 8:18 pm Real world, we need to design a better solution! I gather Ian might have done so! Lets see it Ian!

My attempt is a simple cradle to hold a Jaguar XJ6 mounting.....




From the XJ6 mount I removed a little from each side (which took a while with a hacksaw).
For the cradle I used an angle with gussets at each end and, for additional stiffening, an upstand under the front.
Also, I welded the fixing bolts to the cradle for easier fitting/removal.

Once I put the engine back in to my car I will be able to make the arm to attach this to the engine.


The XJ6 mount feels slightly stiffer than the Sprint ones.
I went for this because it is designed to support the heavy XK engine.
Another (rather expensive) option for this cradle is Mazda MX5 (mark one) but this has a much softer compound than the Sprint mount.

If a Land Rover mount can be used for this, you are looking at under £10 cost in materials.....

Ian.

Nice one! Can't wait to see the engine side bit now, do you think you will modify the original, or start from scratch and the 4 holes in the block?

By my reckoning, this should almost eliminate the need for the clumsy afterthought that is the steady bar!

Steve

Carledo wrote: ↑Sat May 16, 2020 4:25 pm Nice one! Can't wait to see the engine side bit now, do you think you will modify the original, or start from scratch and the 4 holes in the block?

By my reckoning, this should almost eliminate the need for the clumsy afterthought that is the steady bar!

Steve

Still thinking about it, Steve.

None of the local workshops are open presently so I can't buy any offcuts of steel,
therefore it is a case of making do with what I have lying around here,
so it is likely that the Sprint bracket will be modified, I expect.



For the nearside it is feasible to use an XJ6 mount, although I am minded to try the cheaper Land Rover mounting
(because I can get one from Car Builder Solutions with my next order).
I was going to fit an engine steady bar but you have made me think I should try without first.


thanks,
Ian

sprint95m wrote: ↑Sat May 16, 2020 9:22 pm

Carledo wrote: ↑Sat May 16, 2020 4:25 pm Nice one! Can't wait to see the engine side bit now, do you think you will modify the original, or start from scratch and the 4 holes in the block?

By my reckoning, this should almost eliminate the need for the clumsy afterthought that is the steady bar!

Steve

Still thinking about it, Steve.

None of the local workshops are open presently so I can't buy any offcuts of steel,
therefore it is a case of making do with what I have lying around here,
so it is likely that the Sprint bracket will be modified, I expect.



For the nearside it is feasible to use an XJ6 mount, although I am minded to try the cheaper Land Rover mounting
(because I can get one from Car Builder Solutions with my next order).
I was going to fit an engine steady bar but you have made me think I should try without first.


thanks,
Ian

The N/S mount is not the problem that the O/S is, the angle is near enough OK. I reckon Shaun's solution with the LR mount would work there.

As you might guess, I have quite a lot of steel offcuts here, 2mm, 3mm a bit of 4mm, some 2mm 50x25 box, L section etc. Want a care package?

Steve