# Another Motor Mount Question



## madderscience (Jun 28, 2008)

If the motor housing is cast iron, I'd mount it right side up. Cast iron can be pretty brittle and I'm not sure I'd want 250lbs (just guessing on the weight based on diameter) of motor hanging from those bolts. If its forged steel, its probably safe to mount upside down.

Exactly how old is that motor anyway? From the looks of it (brass nameplate and all), not later than 1950s. Do you think it can handle the RPMs you are going to want to put out? Can the insulation handle the voltages you will be running? Seems like something slightly more modern might be a good idea. Just a random worry.


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## Guest (May 17, 2010)

Just googled Morrison electricar as I am sure you have and found some interesting stuff. Maybe you could find someone restoring a Morrison lory or milk float and get enough money to put towards a newer more efficient motor for your car. I mean you have been working hard at finding parts for your conversion but to cut corners on something as important as the motor could make all that work for naught.


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## Woodsmith (Jun 5, 2008)

It probably is quite old, that I don't mind and Jim Husted seems to think it will be ok, just keeping it to around 3600rpm max and up to 156V tops.

I will probably be looking at 120-144V as the original was 72-96V. 3600rpm would be about right at that voltage in the original vehicle too. Though it may not be the most efficient, it would probably run forever like that.

I'm not looking for a sporty performance either so I am happy to play with it and get it in the car to see. I like the challenge.

One day it may even get rewound, if needed, for a different project.

The foot seems to be steel welded to a steel frame but I shall work on the basis of it being right way up. I guess I should worry about what stripped the threads in the first place.


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## piotrsko (Dec 9, 2007)

just stuff some thread inserts into a oversize tapped hole per the instructions and you are back to original (actually better than original). brand names in USof A: helicoil, threadserst, permacoil......


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## ngrimm (Oct 19, 2007)

Just looking at the way a big block ice hangs on an engine stand with smaller bolts than what than your motor mount uses makes me think you could mount it anyway direction you want. I remember looking at the bolts that anchor the Space Needle in Seattle to the pad before I rode up to the top. You wonder how something that small could possibly hold but apparently they do.


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## Woodsmith (Jun 5, 2008)

For static loading I could suspend the motor from a single M8 8.8 high tensile bolt. I doubt it would hold if the motor was bounced a bit though.

Granted 4 M16x1.5 bolts would be able to support the weight and high tensile 8.8 or 12.9 would manage easily. I am planning on buying Helicoil as I think their coils are also high tensile. I just hope the metal I put them in will be strong enough. I have to do it either way as the threads are stripped in the holes.

I guess I am thinking 'failsafe' in the back of my mind. Upside down would be easiest by a long way, but with a battery pack over it I wouldn't be able to check the bolts are still secure without removing some cells.

Right way up would be more metal but the motor wouldn't fall off if bolts worked loose.


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## piotrsko (Dec 9, 2007)

two more helicoil comments: a properly installed helicoil should fail the attaching bolt before it pulls out. they also make locking inserts with a odd wind on the coil for locking purposes.

how about upside down with a safety strap wrapped about the circumference and mounted to something really strong. Then you're just using the 4 bolts for anti torque.


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## EVfun (Mar 14, 2010)

Wow Piotrsko, I just stepped back into this thread to suggest exactly what you just said. Mount it the easiest way and add a steel strap to two around the motor. 

Another thought is to just drill the holes oversize and thread to a larger size. Either 18mm or 20mm should work. I admit, 3/4-16 was the thought running through my head


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## Coley (Jul 26, 2007)

I would just drill and tap them larger without the helicoils. 

No need to retain the standard size hole, if making a mount for it.


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## Woodsmith (Jun 5, 2008)

piotrsko said:


> two more helicoil comments: a properly installed helicoil should fail the attaching bolt before it pulls out. they also make locking inserts with a odd wind on the coil for locking purposes.
> 
> how about upside down with a safety strap wrapped about the circumference and mounted to something really strong. Then you're just using the 4 bolts for anti torque.





EVfun said:


> Wow Piotrsko, I just stepped back into this thread to suggest exactly what you just said. Mount it the easiest way and add a steel strap to two around the motor.
> 
> Another thought is to just drill the holes oversize and thread to a larger size. Either 18mm or 20mm should work. I admit, 3/4-16 was the thought running through my head





Coley said:


> I would just drill and tap them larger without the helicoils.
> 
> No need to retain the standard size hole, if making a mount for it.


All good points.

I will need to think about these. It comes down to economy of tooling, what I need to buy and how useful it would be in the longer term.

M20x2 taps would be useful as I have a sack full of M20x80 bolts. I would prefer a finer thread as there isn't that much depth of steel in the mounts. I'd need to buy the drill as well though.

The motor frame is too heavy to go on my drill press so I would need to either rig up something or drill by hand.

In addition I will need to incorporate the foot mount into the adaptor plate as the DE cap mountings are too small to support the motor that way so this will get a little complicated.


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## toddshotrods (Feb 10, 2009)

Pretty sure that Major said the in the Random Motor Questions thread that the cases are steel, not cast iron. If I remember correctly, he said they're cut from steel tubing and machined. It should be on the first page or so, if you want to verify. I asked questions about developing lighter cases, which naturally led to discussions about the materials.

I would build the mount so that the weight is sitting on it, not hanging from it. One, it is inherently stronger. Two, it's good design and engineering. In the event that a bolt did work itself loose, you would have to remove your battery packs just to check/tighten them. That sounds like the kind of crap manufacturers do that mechanics _love_ so much. The hanging mount is friendly for manufacturing, probably not so much for service. You'll also gain an inch or so clearance above the motor for batteries or whatever. Should also make installation easier with the mount under the motor because you can sit it on the mount and get everything lined up and fastened, without trying to support the weight of the motor while doing so.

I just had visions of servicing your conversion, mumbling, "what the h#!! !"


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## Woodsmith (Jun 5, 2008)

toddshotrods said:


> Pretty sure that Major said the in the Random Motor Questions thread that the cases are steel, not cast iron. If I remember correctly, he said they're cut from steel tubing and machined. It should be on the first page or so, if you want to verify. I asked questions about developing lighter cases, which naturally led to discussions about the materials.
> 
> I would build the mount so that the weight is sitting on it, not hanging from it. One, it is inherently stronger. Two, it's good design and engineering. In the event that a bolt did work itself loose, you would have to remove your battery packs just to check/tighten them. That sounds like the kind of crap manufacturers do that mechanics _love_ so much. The hanging mount is friendly for manufacturing, probably not so much for service. You'll also gain an inch or so clearance above the motor for batteries or whatever. Should also make installation easier with the mount under the motor because you can sit it on the mount and get everything lined up and fastened, without trying to support the weight of the motor while doing so.
> 
> I just had visions of servicing your conversion, mumbling, "what the h#!! !"


Yes, from an engineering point it is better, that would have been my prefered option. I need to work out how to get metal from the foot to the mount that sits above the CE cap.
There is very little room to go around the back of the CE and it is snug around the sides. That is the basis for wondering about hanging it upside down.

The foot at the bottom may also force me, not just to use better engineering but to more easily tie the foot to the bell housing from below. The weight of the motor and any flex would compress the motor against the adaptor plate. If the foot was on top and I tied into the bell housing from above then the weight of the motor would pull it away from the adaptor plate with flex.

The whole thing would need to be fully assembled with mounts before it can be put in the car so above or below wouldn't save anything in that.



As an aside, with flange mounted motors of this size and weight, what size and number of bolts would normally be used to hold the DE cap to the the motor frame to make it strong enough to be flange mounted?


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## toddshotrods (Feb 10, 2009)

Woodsmith said:


> ...As an aside, with flange mounted motors of this size and weight, what size and number of bolts would normally be used to hold the DE cap to the the motor frame to make it strong enough to be flange mounted?


My GE has six .375" bolts in a symetrical pattern holding the DE cap on. The difference is the motor mount uses separate bolts that thread into the (steel/iron?) DE cap; there are nine .375" bolts in an assymetrical pattern for this. Eric (my machinist) is an engineer (Ph.D) and didn't seem to have any issues with the size or number of bolts on either. I don't know if that helps but figured hearing what others have could be a good reference in figuring out what you need.


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## Woodsmith (Jun 5, 2008)

That would be about the same as six M10 bolts taking the weight. 
Hmmmm, unless the DE cap is very deep they would be the ones taking the bulk of the loading rather then the 9 mounting bolts.

You can almost hear a plan developing....


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## Woodsmith (Jun 5, 2008)

OK, here's the plan.

The DE cap of my 12" motor is retained by six 5/16"unc bolts.









I can, if I am careful, tap out the threaded holes in the steel frame to M10x1.25 and then bore the holes in the DE cap to 10mm.

I have the M10x1.25x90mm cylinder head bolts from the old ICE I removed. They have 12 point socket heads.

I could use them to bolt through from the adaptor plate, through the DE cap into the steel motor frame. I would only have 15mm of thread engaging but I could counter bore the 19mm adaptor plate to make it 20mm of thread.

So, any reason why that would not be a good idea?


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## toddshotrods (Feb 10, 2009)

Woodsmith said:


> ...So, any reason why that would not be a good idea?


When you say, if you're careful, how close does that mean you're coming to the outside wall of the case? I don't think I would be too concerned about anything else. If you were pushing for high performance I would think more threaded depth in the case, and not counterboring the plate, but for a daily transportation it should be okay.

You still have 14mm of adapter thickness, and relatively strong boltsholding it all together. Any indication on the cylinder head bolts of how much thread length was engaged on the ICE?


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## Woodsmith (Jun 5, 2008)

toddshotrods said:


> When you say, if you're careful, how close does that mean you're coming to the outside wall of the case? I don't think I would be too concerned about anything else. If you were pushing for high performance I would think more threaded depth in the case, and not counterboring the plate, but for a daily transportation it should be okay.


If I carefully ream out and tap the threads could be within a mm of the inner surface of the case.



toddshotrods said:


> You still have 14mm of adapter thickness, and relatively strong boltsholding it all together. Any indication on the cylinder head bolts of how much thread length was engaged on the ICE?


I think the bolts were only engaged about 10-15mm in the head from what I remember.

I could get longer bolts later if the plan works.


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## toddshotrods (Feb 10, 2009)

I actually see one potential problem. These six bolts are supporting the weight of the motor, holding it in alignment, and also providing some resistance to the torque. If there were a recess that positively locked the pieces together it would isolate the bolts. Maybe with the foot mount the torque won't be a huge factor, but the problem is that it's your motor case that you're gambling with.

I think he's been extremely busy with work, but if I see Eric this week I can show him the pics, explain it, and get an engineer's perspective on it. My guess is his eyes will dart from component to component looking for what carries what loads, then he'll cringe, because he'll see what places would light up bright red in an FEA. The 1mm of material would likely be the main one.

Is your DE cap made so that it locks positively in the case? In other words, is the weight of the motor (when horizontal) on the bolts or on the cap? If so, and if you can precisely bore the holes for the 10mm bolts, you should be able take some of the tension off of the threads. If the cap can float at all on the DE, the threads will carry all the stress of keeping it aligned.


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## Woodsmith (Jun 5, 2008)

The DE cap is fitted into a rebate on the case and so locks in tight.

I have thought about rotating the cap 90deg then moving the holes outwards a mm when I open up the holes in the cap. I can then drill new threaded holes a little further from the edge.

I suppose I could make a steel DE cap....


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## toddshotrods (Feb 10, 2009)

Woodsmith said:


> The DE cap is fitted into a rebate on the case and so locks in tight...


That's good.



Woodsmith said:


> ...I have thought about rotating the cap 90deg then moving the holes outwards a mm when I open up the holes in the cap. I can then drill new threaded holes a little further from the edge...


If you're willing to do that a better solution might be to put six hardened steel pins in between them and use the original six bolts to compress. You'll have the cap carrying the weight, the pins resisting the torque, and the bolts keeping everything locked together. Everything has an isolated function. The integrity of the case should be least affected because the pins will be pressed in.


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## Woodsmith (Jun 5, 2008)

The only place for the bolts would be where the existing ones are now through the full thickness posts on the cap. The same six bolts would need to handle the weight and the compression of the components together.

I could add pins. Or I could add short 5/16" bolts in the cap openings into the origonal holes in the case.


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## electromet (Oct 20, 2009)

Woody,

I thought you were going to use the large lugs on the case to support the weight of the motor on or under a crossmember. If that's the case, the six bolts coupled with dowel pins should be plenty to resist the torque. Am I missig something?


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## Woodsmith (Jun 5, 2008)

electromet said:


> Woody,
> 
> I thought you were going to use the large lugs on the case to support the weight of the motor on or under a crossmember. If that's the case, the six bolts coupled with dowel pins should be plenty to resist the torque. Am I missig something?


Not really missing anything.

I could make a crossmember that would relieve the DE cap of any load but that would add a lot of weight to an already weighty motor.
I am looking to see how much of the combination of loads can be taken by the DE cap bolts.

Another option would be to make the adaptor plate from steel and make it a part of the motor frame with most of the loads taken by the foot mount and only location to be taken my the DE cap.
That could be as much work as making a steel DE cap that can take all the load.


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## toddshotrods (Feb 10, 2009)

I suggested pins because they are more precise than bolts. What about six pins between the bolts in the motor case, and then six more in the DE cap. Everything is locked together and stress and forces are carried and counteracted by proper measures. Again, the bolts are just a clamping mechanism.

If you decide to fabricate a new DE cap, make it replace the adapter as well.


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## electromet (Oct 20, 2009)

Woody,

I don't know what the subframe looks like in your engine bay, but a properly gusseted crossmember could be welded up out of .120 wall rectangular tubing and maybe a piece of 1/4" steel plate for the motor mount. I'll bet you could keep it under 10 kg. It just seems like a much more secure method to deal with the weight of the motor. I fear you're asking your marginally engineered DE cap to do too many things to expect it to all of the things well. Just my $.02 worth.


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## Woodsmith (Jun 5, 2008)

toddshotrods said:


> If you decide to fabricate a new DE cap, make it replace the adapter as well.


Yep, that would make it simpler. It would require machining that would need to be paid for though so if I do that I might as well do it well and pay for accuracy.



electromet said:


> Woody,
> 
> I don't know what the subframe looks like in your engine bay, but a properly gusseted crossmember could be welded up out of .120 wall rectangular tubing and maybe a piece of 1/4" steel plate for the motor mount. I'll bet you could keep it under 10 kg. It just seems like a much more secure method to deal with the weight of the motor. I fear you're asking your marginally engineered DE cap to do too many things to expect it to all of the things well. Just my $.02 worth.


The nearest subframe in the car is too far back to help the motor and I'd rather it was rubber mounted on the original mounts.

I could assemble it all and then build a frame that links three of the four mounts together and provide a sturdy platform for the motor foot mount.


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## electromet (Oct 20, 2009)

Woodsmith said:


> I could assemble it all and then build a frame that links three of the four mounts together and provide a sturdy platform for the motor foot mount.


Woody,

If you're talking about fabricating a mount that attaches to three of the stock ICE chassis mounts with rubber bushings, that should work well. I just don't think you want to cantilever the weight of that motor off the bellhousing and the CE cap. If you can get the three chassis mounts to bear the majority of the weight, the DE cap will just have to deal with holding the motor and tranny in alignment. 

So, what's the holdup? Let's see some sparks fly!


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## toddshotrods (Feb 10, 2009)

electromet said:


> ... I just don't think you want to cantilever the weight of that motor off the bellhousing and the CE cap. If you can get the three chassis mounts to bear the majority of the weight, the DE cap will just have to deal with holding the motor and tranny in alignment...


I don't think he was planning to do that. If I remember correctly, he is making a foot mount that will connect to the original ICE chassis mount location. Tha will support the bulk of the weight. This was more about six bolts doing triple duty holding the assembly together, helping counter the torque reaction, and supporting the weight in that area that isn't directly supported by the foot mount. It wouldn't be much weight, but the factory DE cap bolts are 5/16", and would be even longer than stock to catch the adapter plate.

The question was about drilling and tapping the holes in the case to 10mm, which would leave on 1mm wall thickness between the inside of the case and the threads. Any stress in in that area, whether from torque or weight would be concentrated on the threaded areas of the bolts and motor case. We were toying with ideas to isolate torque, weight, and tension.


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## electromet (Oct 20, 2009)

Thanks for the clarification, Todd. Those big bosses on the bottom of the casing should be able to carry a ton, and with proper triangulation in the crossmember, all the torque should be controllable without having to transfer it through the DE screws and dowels. I might suggest polyurethane motor mounts, if they're available for the MR2, to take as much slop out of the equation as possible.


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## Jimdear2 (Oct 12, 2008)

Woodsmith said:


> I could assemble it all and then build a frame that links three of the four mounts together and provide a sturdy platform for the motor foot mount.


Woody,

I think you are on the right track with this Idea. 

Get your motor and trans on the bench.
Get the trans and motor concentric and mounted.
Then build, a cradle that ties and supports motor and trans together and supports same in the original motor mounts.
In the long run I think this is the KISS way to get your components installed.

Jim


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## toddshotrods (Feb 10, 2009)

Even though that foot mount is going to be strong there is still the issue of how the transmission is connected to it. Especially using rubber mounts to locate them in the chassis. Rubber, or even poly to a lesser degree, allows the components to move. Under the stress of a moving vehicle, on less than perfect roads, and with a fair amount of torque being transferred from motor to transmission, what prevents them from moving in different directions is a critical issue.


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## Jimdear2 (Oct 12, 2008)

Todd,

Sorry, I was not clear in my suggestions. 

What I suggested is that the motor and transaxle first be brought into concentric alignment on the bench by using the current DE cap with an adapter plate as Woody has previously described doing, this being done on the bench so there is no strain on the end cap or bolts.

While the assembly is still on the bench build a cradle that bolts solidly to the transmission and motor. Then set the transmission on its normal rubber mounts, supporting the cradle on a suitable jack, add to the cradle any necessary structure to attach it to the existing vehicle motor mount points.

The cradle should eliminate any bending stress or torque reaction between the motor and transaxle. Building the cradle on the bench should allow the construction without causing any mis alignment


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## TigerNut (Dec 18, 2009)

The only function of the DE cap on the motor (in its original application) was to hold the end bearing, to resist radial loads and resist some minor thrust loads, right? To help with that, the end cap is registered on the motor case and the 5/16" bolts just hold things in place.

In the EV application, there will be negligible radial load, and no thrust load, but there will be a major torque coupling between the transmission and the engine, depending on how the engine and transmission are mounted in the vehicle. Since the transmission includes the final drive, the torque at the wheels will be coupled into the chassis through the engine and transmission mounting. This could be over 1000 foot-pounds depending on what gear the transmission is in.

Because of all that, I think that the long-term bombproof solution would be to make a new endplate that serves as the bearing carrier for the motor, while matching the transmission bellhousing pattern, and integrally including the motor case registration features. To properly resist the torque between the motor case and the transmission you should have at least a couple of 3/8" dowel pins, similar to what the original transmission to engine interface had.
What if you attach extra mounting ears to the motor case around the drive end, either by welding a flange around the DE or by drilling and threading some holes in the case so that you can attach some flying buttresses?


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## toddshotrods (Feb 10, 2009)

Jimdear2 said:


> Todd,
> 
> Sorry, I was not clear in my suggestions...


You were clear, and I agree with you. My post was still tossing ideas back and forth with elecromet. It ended up being posted after your post and not before it (after his last post on page 3) because I was watching Sunday's episode of the Simpsons on Hulu, and typing during commercials! 

If Woody builds the cradle it would support Big Ben and the London Bridge without a millimeter of distortion!  Personally, I would probably violate the KISS principle and have a big hunk of aluminum in the CNC being whittled down into a new DE cap with bellhousing pattern, dowel pin locations, etc, after spending 100 hours in CAD designing it. The cradle could accomplish the same thing, and actually be in the vehicle while I was still staring at my computer screen.


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## TigerNut (Dec 18, 2009)

toddshotrods said:


> Personally, I would probably violate the KISS principle and have a big hunk of aluminum in the CNC being whittled down into a new DE cap with bellhousing pattern, dowel pin locations, etc, after spending 100 hours in CAD designing it. The cradle could accomplish the same thing, and actually be in the vehicle while I was still staring at my computer screen.


I have a couple of pieces of 12 x 2.5 x 16" 6061-T6 waiting for a special project... sometimes going to Metal Supermarket is BAD. Shipping to England would be pricey though.
I think that it would be effective and more in line with Woody's tools to fabricate the DE cap out of several pieces of steel or alumin(i)um. The individual parts can be welded or bolted and pinned together as appropriate. What I think is the limiting factor is how well the DE hardware can be coupled to the motor case, and that more than the six 5/16 (or even 10mm) bolts are going to be necessary in order for it to last.


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## Jimdear2 (Oct 12, 2008)

toddshotrods said:


> If Woody builds the cradle it would support Big Ben and the London Bridge without a millimeter of distortion!


Todd,
You've noticed that too. Nothing wrong with overbuilding something, I do it all the time on my tractors. Problem is, I'm weight limited so I end up cutting here and snipping there and of course, when I'm done it looks like crap. 



toddshotrods said:


> Personally, I would probably violate the KISS principle and have a big hunk of aluminum in the CNC being whittled down into a new DE cap with bellhousing pattern, dowel pin locations, etc, after spending 100 hours in CAD designing it. The cradle could accomplish the same thing, and actually be in the vehicle while I was still staring at my computer screen.


There are times when KISS be damned, your stuff is purdy. Of course if I did it your way, with my lack of formal technical training, I would still be building my first tractor.
Jim


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## toddshotrods (Feb 10, 2009)

TigerNut said:


> I have a couple of pieces of 12 x 2.5 x 16" 6061-T6 waiting for a special project... Shipping to England would be pricey though...


Aren't we on the same continent? I'll PM you my address.  J/k, I have been fighting the temptation to snag a couple pieces a tad bigger (13") and start whittling that forced-air system.



Jimdear2 said:


> ...There are times when KISS be damned, your stuff is purdy. Of course if I did it your way, with my lack of formal technical training, I would still be building my first tractor.
> Jim


Thanks!  My formal training consists of never being able to accept that I can't do anything I want to do. Superman complex. I started doing CAD because a guy took too long to answer my email about designing a part for me. 

"KISS be damned" has it's drawbacks, for sure. My motor would have been in the Inhaler by now and, instead of winning auctions on Ebay for parts I really didn't need, I would probably have it working - if I had done it by hand and not by computer. But then the experience wouldn't be as sweet - for me, it's all about the journey.


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## electromet (Oct 20, 2009)

TigerNut said:


> To properly resist the torque between the motor case and the transmission you should have at least a couple of 3/8" dowel pins, similar to what the original transmission to engine interface had.
> What if you attach extra mounting ears to the motor case around the drive end, either by welding a flange around the DE or by drilling and threading some holes in the case so that you can attach some flying buttresses?


I like this idea. Given torque available, I'd be inclined to have it professionally welded, however.


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## Woodsmith (Jun 5, 2008)

LOL

I step into to work for a moment and you all get chatting without me.

Yep, I want as strong a connection between the DE of the motor and the adpator plate and the transmission bell housing first. That will get and maintain shaft alignment and be the most direct location for transmitting torque.

I will then make a set of cradle parts.
One part will bolt to the motor foot.
Another will bridge under the transmission to join the front and rear mount brackets together.
That will then join to the foot mount.
From the foot mount it will either wrap around the motor frame or rise up the CE to the RHS engine mount.
That forms a cradle.

I will then brace the cradle back to the bell housing bolts and back over the top of the motor to the RHS mount.
That should triangulate the cradle and prevent flex.
It should also provide a bearing mount for the drive shaft.

The mounting points will then have the original rubber mounts back to the car frame.

Much of it will need to be bolted together so that it can be re-assembled in the car and also to reduce any stresses caused by welding the whole cradle.

Then when the price of steel goes up because of my buying potential I will resell the whole lot back and clear a significant part of the national debt!

Seriously though, to save money I will try and figure a way to make it out of what I have without it all being 4"x2"x1/4" box.

All this will have to wait though.
I have spent most of this week suffering exhaustion. I still have student work to assess at college, a stage to finish building and a theatre show to run all next week before I can even think about any heavy work.
I also want to fit in a break but I don't think I find the time.


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