MTFCA Forum

Came across this in a series of technical articles from Cimorelli's Model T Digital Library
Interesting - open for pro's & con's

Yes.., a very good idea and it was used on TT's.

Hank

One problem with any flexible rear motor mount scheme on the Model T chassis is that there is not enough material in the upper frame flange to allow for enlarging the bolt hole. Any significant flex or movement of the top bolt here would thus tend to wear the hole out bigger due to normal engine vibration or on a vehicle that is driven hard, or over rough ground. Henry Lee's solution looks to be about as good as can be devised with a stock frame.

The front engine/spring mount is also a problem area on vehicles that are driven hard, with cracked crossmembers being all too common. Some method of introducing additional controlled flexure at the front engine mount would be a good idea, subject to the same caveats.

Keep in mind that the rear engine mounting arrangement is also a primary frame structural crossmember and that it has a major role in securing and in locating both the front and rear axle. The front engine mount has a major role in locating and securing the front spring and axle assembly.

My car came to me without wood blocks and with stock bolts holding the ears to the frame. I added wood blocks, installed as directed, with the cross bolts just snug. I believe that it made a slight improvement in the car's handling. Vibration was the same, or slightly less noticeable.

I would not want to do anything to enlarge the bolt hole in the top frame flange at the rear motor mount unless something was done to take a portion the strain off the frame at that point, and to allow for some kind of bushing to prevent the bolt from sawing at the frame flange.

With a car that is routinely driven over rough ground, it is especially important that the cross bolt on a stock motor mount with wood blocks in place not be tightened excessively. They must be just snug, about finger tight plus one or two turns, and on a car in rough service, finger-tight less a couple of turns would probably be a good idea.

Agree with Pat.

Found over the years it's hard to improve on Henry's engineering.

As for that spring on top, and the comment at fracture point 'A' in that sketch, have found most times crankcase arms are busted at the top, where all the stress is found. Putting only one bolt and a small radius rod ball cap spring there, and no wood block or side bolt allowing the arm to pull away, wouldn't stop fractures like these:







Service Bulletin of May 1925 did say that Ford TT discontinued the wood block 3083 and side bolt 3073 in attempt to reduce crankcase arm fracture on low speed trucks over very rough roads. However the top bolt , 3074C, used only on the trucks is longer, as the TT frame is thicker, so maybe they figured it would be ok. Remember, just a few months later the new Improved Car was introduced and used the bolts to hogshead, and the braces to the crankcase arm upper, so TT trucks then got that advantage.


As for the T, using the wood block and the side bolt must help. Of course the Improved Car method is better. But, lots of earlier aftermarket pieces abounded, and still do today, to aid in the strength of Ford's 3-point suspension of the engine.

In my case, my '17 touring car had both rear mount ears broken off, and the bolt on repair brackets installed. The wood blocks are missing. If or when the time comes to remove the engine my plan was to replace the broken arms with new, riveting them to the pan. In the meantime I got two new blocks from Langs which I intend to install with the repair brackets that are currently on the car.
Now I see an alternate method with no blocks, but with springs on the upper bolt, and no side bolts.
In your collective opinions, should I install the wood blocks? Or should I leave the blocks and side bolts out, and install a longer bolt with a spring?
Thanks, Maury Dean

A potential problem with the bolt & spring method is the fact that such an arrangement will allow the motor mount to wear into the top of the frame, since it will shift constantly when the motor is running due to vibration and the frame flexing as the vehicle moves. The flanges on the motor mounts may also cut notches in the inboard edge of the upper frame flange. You don't want any kind of wear on the frame itself, either at the bolt hole in the upper flange or on the top surface of the flange. I've seen old frames with deep wear from loose motor mounts rubbing on the top of the frame. You don't want anything to weaken what is already a weak point, and if wear is present, you don't want to add to it. An enlarged motor mount bolt hole in the frame flange, or notches at the edge of the flange, are likely to lead to a broken frame. A weakened frame is also more likely to sag.

Look very closely at the photos please, a soft metal such as aluminum or a rubber pad works great! Been doing it for 30 years plus.., no wear period.Those whom tighten up your bolts will always have broken ears, common physics kicks in on the trinity suspension where as two different frame rails (planes) are bending in different directions. Look to at the wooden blocks, they have aluminum tubing installed to compensate wood shrinking.

Enough said, sorry for helping,

Hank

I was referring to the picture in the first post in this thread, showing a mount with the wood block and cross bolt deleted and a spring added to the motor mount bolt.

Ted Ashman's tinkering tips right side main pic
Is the way I like and used only addition is I put think rubber between the pan and frame.
I can say if you don't the orginal way all 4 bolts figure tight