Please critique my solid motor mounts I made

Dusterbd13 wrote: I just wasn't happy with the hybrid mustang convertible mounts, so I pulled them out and chucked them in the scrap bin. I figured I could create sold mounts that did what I want them to do cheaper and better than making the rubber ones work. I also wanted to give a fair whack at making things fit better. So, consider these mounts version two. Please give feedback on them, as there's something I don't like and I cant figure out what. the constraints were simple: light, strong, removable, and as small as possible. So I used the motor mount brackets from the lincoln as the base. They fit the block, and had a bolt through design. Figured it was a good start. So now it was off to build motor mounts. On the passengers side, I got all fancy. This mount will be loaded primarily in compression, so I wanted it to be strong in that plane. Used a few inches of scrap 16 gauge 1x1 square tube that I found out back in the scrap pile. Welded a 3/8 nut in one end, and made a rough guesstimate for height. Also, cut the top of the t short enough to leave room for two fender washers so the engine would stay locked in place on the bolt. [URL=http://s54.photobucket.com/user/dusterbd13/media/amc/20161015_183432_zps3fwoivef.jpg.html][/URL] Drivers side, I was much more concerned about tension. So I used again a few inches of the 16 gauge and fender washers, as well as the last little bit of the 2x2 angle iron from the trans crossmember. [URL=http://s54.photobucket.com/user/dusterbd13/media/amc/20161015_184009_zps9sxsk0wa.jpg.html][/URL] These were made all in the car so I knew they would fit. Not a comfortable welding position. [URL=http://s54.photobucket.com/user/dusterbd13/media/amc/20161015_183435_zpsxwraollh.jpg.html][/URL]

I'm no expert on metallurgy, but I think I would add some gussets to the passenger side mount.

For the driver's side, it's hard to tell from these pictures, but it appears the entire load of the engine is being supported by the welds. That doesn't give me warm, fuzzy feelings.

Since all of the engine vibrations and torque will not be absorbed by the rubber isolators and will get transmitted through the mounts to the chassis, I'd over-build the sh1t out of them.

I'd strongly advise against building all-metal engine mounts. Those will rattle the tooth fillings out of your head and the nuts off of every bolt on the car. Even the most serious purpose-built race cars have a little rubber or urethane between the engine and chassis. People who build their own race-grade engine mounts typically use large generic off-the-shelf bushings and build around those.

Even solid urethane engine mounts can be harsh even by racing standards, all-metal mounts will be a paint shaker with wheels.

In reply to GameboyRMH:

A lot of BMW 3 series racecars, including 3 I've built and raced use solid aluminum engine and trans mounts. For sprint length races they are awesome. They make accel and decel immediate with no wind-up slop whatsoever. Anything that uses glue fails so solid metal is reliable. Solid nylon is probably better. For anything less than an all-out sprint car though I agree with you. Including anything that is racing for more than 45 minutes because it does vibrate and fatigue things loose at an alarming rate.

OP, the driver's side mount... box or gusset the angle iron.

If those square tubes are supported solely by the weld - make sure it's a good one all the way around and not just spotted on the flats.

I'm with Gameboy on this. Unless a car is going to be used for drag racing only I definitely would have something soft in the mounts. I've not experimented with different materials to give advice on what to use, but i've been in solid mounted cars. It's no place you want to be.

One more thing to consider: by making them solid, your engine is now a stressed member. That doesn't look like a motorcycle engine, so it's probably not designed to be as such.

Quick design check: If the weld were not there, would the engine be supported? For example a load sitting centered on top of a "T" would be stable without the upright welded to the crossbar. If the load is off to one side and the weld were not there, then it would fail.

I cant really tell much from the pictures you posted.

If I took the welds out, engine would fall until it crushes the oil pan.

also, this is a full blown race car with a Ford 302 and an automatic. C prepared is the goal.

Simon, upon thinking about it during lunch and rereading the comments, I think the plan is to scrap these as well and try again while adding something to absorb some vibration.

Hey does the 3m window weld work? Would that provide him with some cushion?

A company called E36V8 has been selling 302 mounts for V8 swaps into E36 chassis for a while now. They have gone through a progression of heavier and heavier mounts, because each generation had problems with deforming over time. And these are designed for urethane motor mounting units, not block-to-bracket.

What I'm seeing in your photos looks to me like something lighter than the design they started with a few generations back. BUT I emphasize here that I'm just looking at a couple internet photos and I could be 100% wrong.

Trackmouse wrote: Hey does the 3m window weld work? Would that provide him with some cushion?

It dries into urethane, so yes you can use this to make your own urethane mounts. More commonly used to turn factory rubber mounts into mostly-solid-urethane mounts.

I did it. They've been holding up just fine for like 10 years now.

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Hopefully you don't want them to be too pretty....

Also, they need like a week to cure, depending on how thick it has to be.