Frame Width at Front Engine Mount

[RichardL]

Hey, guys. If you've got a minute I could use your thoughts on this.

The total width for my front engine mount plates attached to the crankcase is 3".  My frame is about 0.055" too narrow. I tried mildly spreading the frame but it just sprung back. I figured I'd try a little more force to see how much it would take to get it to stay the right width due to plastic deformation of the tubes. Before going very far I heard a loud snapping sound. After a mild heart attack and inspection of all the possible stress points, I've concluded the sound was the mount tube (I don't know the correct name for the piece the stud slides through) slipping against the thread of my spreader. Figured I better ask for advice before I really hurt something. It seems to me the weakest weld points when spreading the frame at the engine mount would be the mount tube itself, or at the small cross piece where the steering damper anchor plate attaches.

So, the question is, should I be trying to go for a bend in the tubes that permanently opens up the frame about 0.060", or should I spread it while fitting the engine and just let it clamp back?

Thanks in advance for your thoughts on this.

Richard L. 

[Alex kettle]

I had a mild heart attack reading that bit about the “ loud snapping sound”. God knows what you must have been through.  Those more enlightened might come up with a better suggestion but how about taking a bit off the inside of the lugs or bosses to make it fit with a grinder dare I say it. Just a thought 

[RichardL]

Alex,

That sounds disturbingly like the recommended solution for my zero end-float problem. I'll do that unless I hear that spreading is a good idea.

Richard L.

[muskrat]

G'day Richard.
First make a very good inspection of all points/joints/welds/cracked paint. You must be 100% sure there's no damage.
Our frames have been through a lot in 60 odd years so a little deformity is expected. My Cafe frame needs a little prying to get the front mounts in, probably the same amount as yours. I wouldn't try to bend the tubes.
Cheers

[chaterlea25]

Hi Richard,
How does the lower mounting measure up? there are spacers to account for in that measurement
Find a straight edge and sit it against the down tubes front and sides to see if there is any damage

If I were to tweak the frame I would not use a stud on those welded mountings  a diamond car jack against the tubes will not strain those welded on tubes

The dimensioned  frame drawings are on the site somewhere or in the service sheets

John

[RichardL]

Musky,

Thank you for waking me up. I was wrong. It's serious. The first cross tube is fractured. What a stupid effing thing to do. I had no idea the tubing was that brittle. I know a very good welder whom I'm sure can fix it, but I could cry. Aside from welding, it's the dismantling, the powder-coat repair, the waiting and the money.  What a mistake!

John,

I know you wrote something while I was working on this. I'll read it in a minute if I can stop cussing myself long enough.

Richard L. 

[Alex kettle]

Bugger. I feel your pain.  Hope you have it sorted soon

[Swarfcut]

   It would take a lot of force to crack a frame tube, that looks more like an overlooked fatigue crack or a previously weakened area that was just ready to let go. Is that a dent in the tube from accident damage? It could  be the source of the original misalignment.

 The bad news is that  beautiful cosmetic skin deep finish has a minor blemish.

 The good news is a welded frame is easy to fix, and with that tube floating, realigning the major frame tubes will be easy.  I'd go with Musky's sound advice and check every tube and joint, particularly the front down tubes, and if serious spreading the tubes is required, spread the force rather than use point areas of contact to avoid deforming the tubes. Threaded bar through the engine mount lugs can hold the frame tubes aligned for welding. Also when all is back together it will be unseen, only you will know....

   A quick measure on a '54 frame for the top front mount lugs shows the inner faces 89mm apart. For the lowers its 100mm. Not saying this is gospel, but that's how my bare frame stacks up. Lower mounts have a small spacer 42 4071 each side to accommodate the outward flare of the front down tubes compared to the vertical faces of the front engine mounting plates. There should be spacer tubes welded into one of the front mounts.

 Better to find the problem  in the workshop than on the highway.

 Swarfy.

 Additional.. I'll be looking closely at that tube on my frame !

 Additional...89mm quoted is not correct for an undamaged/unmolested frame. See my later post.

[Jules]

I agree with Swarfy Richard, although its hard to see the crack clearly in your pic, its doesnt look "fresh" somehow....

[Greybeard]

Oh Richard, that's heartbreaking. Did you upset a gypsy? 

[chaterlea25]

Hi Richard,
In my head I had the position of the welded and forged lugs on the down tube mixed up 
Either way a different issue has now come to light 
I am trying to make out from the photo where on the frame the crack is? Is it the cross tube under the gearbox ?

Sending the frame off for blasting and powder coating / paint has an inherent flaw in that it is unlikely that the frame will be examined for damage after blasting
I would always want to examine the frame after its been blasted

John

[RichardL]

Thanks, all.

I plan to respond to all your kind help and comments, but a bit jammed with work right now.


Richard L.

[RDfella]

Richard - I take it that crack is in the front crosstube / engine mount? Might have been accelerated by loose engine mounting bolts or an engine with worn mains vibrating badly.
However, welding that will pull the front tubes a little closer together and I understand they're already a tad tight. My advice would be to push those tubes apart to spec + 1/16" so that when the weld is done they're near as posible where they should be.

[Peter in Aus]

Yes have a good look at the frame after sand blasting and before painting, the last one I did I found a crack in the frame that I did not know about. lucky for me.

[Clive54bsa]

Does this help?