How to Mount a Motor

It has been an insanely busy week working on the car but also incredibly productive. My goal was to get the motor and transmission mounted in the car so I can finally take them off of the hoist. I can happily say that with some help from friends, my goal was successfully accomplished last night.

 

The project started off with AWR Racing Mazda Miata engine mounts that I purchased off of Mike. They’re a rock solid construction, utilizing 3/16″ steel plate and polyurethane bushings to keep the motor in check during spirited driving. Originally, I designed my own mounts in SolidWorks but I later opted for the modification of these mounts as it was a much cheaper, quicker and easier route.

 

I made a quick trip to metal supermarkets to purchase some more plate for the arms and landing pads for the mounts, as well as some 3/8″ ID pipe for sleeves that will more accurately locate the bolts that will keep the pads on the frame. Measure, measure, clamp, cut, measure, remove burrs as required, blend. Landing pads are done.

 

I really cant stress enough that having the right tools for the job is essential. It takes so much pain out of the process as you’re not fiddling around with incorrect tools to “make them work”. Having proper metrology equipment works wonders, even if it is just the basic stuff.
Having a clean and well organized shop also makes for a much easier job – tools are clean and accessible, there’s flat surfaces to work on and you aren’t always bathing yourself in the typical oil and metal shaving bath that you normally get in a shop. Overall, it’s just more rewarding.

 

Patience goes a long way too – spending the time to make accurate measurements and references that you can later work off of. I marked the pads to locate the mount itself that will soon be welded on, hole positions that account for interference from the bushing and mount geometry and any area that needed notching to make room for the lower a-arm shims.

 

The motor and transmission were in and out of the car several times at this point. I positioned the motor in the car exactly where I wanted it to sit, line up the mounts on the frame, scribbled some lines down with marker and refine from there. The more accurate the mounts are located at this point, the easier life will be when welding and drilling starts. I used some electrical tape to hold things together to rough out the new required geometry.

 

 

 

 

Arts and crafts comes into play here – cutting out some cardboard out of an old beer case. I started off by cutting out a cardboard rectangle to get the extents of the mount, from the face of the plate mounted to the motor, to the outside edge of the bushing. I roughed out the rest with a marker and refined the shape from there. After the cardboard is all cut up, tracing it out on the 3/16″ plate is easy. Running a marker around the outside of the bushing helps locate the hole that will need to be drilled in the arms later down the road.

 

 

 

 

 

 

 

The night after I cut the rough blanks, Mike and John came over to the shop to help me continue. Mike helped cut and shape the new arms into what they are now, in which case they look fabulous. It was great having them both over; having friends to enjoy beers with and each others company is always great. They had a hockey game to go to so while they spent their time on the ice I spent my time with a blending wheel to get the shape of the arms finalized. I drilled a hole though all four arms and clamped them all together to keep all the arms true to one another. Using a bolt through the drilled hole allows for accurate location through all four arms. Once John and Mike came back, the fun continued. My parents also came in to drop off an extension cord that we needed for the tig welder, and I am hugely thankful for this.

 

 

We were at the shop until 3:30am that night.

 

 

My dad was kind enough to pick up some argon for us to use to weld at the very last minute. Without him picking up a new tank, none of this would have been possible. Quite some time ago already, my dad also taught me the basics in tig welding. I haven’t been able to practice his lessons enough, but his teaching was definitely critical to the whole process. Mike gave me a refresher as I worked away as well, his help was also essential.

 

 

Really, I can’t take credit for a lot of the work here. It was really Mike that did most of the welding on these. His welds look awesome, and they’re strong enough to hold way more than a Miata motor. Thanks for all of the hard work, late nights and awesome craftsmanship behind these – I have you to thank for most of it. With one mount welded and positioned, it was time to put the motor back in, measure up where we stand and locate the arms on the next mount.

 

 

The past few days have been a blur, I’ve literally been going non stop. Other than tonight, every single night after work has been spent at the shop working away, usually until midnight. It’s hard when you have to wake up at 5:30am the next morning, but it’s worth it. Especially now. After welding everything together, we ended up actually melting the polyurethane bushings that were installed in the AWR mounts. The bushings that Mike had purchased were 90 (A?) durometer which are classified as race-only. As I’m not going to be racing with this car for most of the driving, I will be opting for softer 70A durometer bushings.
The process of locating and welding was repeated for the passengers side. One note that I would like to mention for the bushings – I have been in contact with Tony at AWR Racing for purchasing new bushings. Absolutely great guy to talk to, and what is even more interesting is that he was working on the same swap for a project of his own that used a TR-6 chassis. Gorgeous car, fantastic project and just a pleasure to chat with. He even covered a miscalculation on shipping charges for the new bushings as his own contribution to my project. I just wanted to extend a huge thank you to Tony at AWR for the generosity and the support in my project, it’s greatly appreciated! Go check out their online store, they have a lot of neat stuff available for many platforms! http://www.awrracing.com/

 

 

 

After the welding was complete, Mike and I bolted the new mounts onto the motor and positioned them on the frame. The measuring, careful fabrication and a whole lot of luck played out hugely in our favour. We sat the motor down on the frame with the new mounts and just like that we were done. The only thing that was left to do at this point was to grab our beers, grab some chairs and have a cheers at our success. We did just that.

 

 

I went back to the shop last night to finalize the positioning of the mounts on the frame. This consisted of drilling holes straight through the frame and welding sleeves into these holes to allow for accurate location of the bolts going through the pad. This also helps to alleviate some compression stresses that would have otherwise been on the frame. Instead, the sleeve is taking the load rather than the flats of the frame. I welded the sleeves in, blended them down and bolted the mounts in. I left the car with a completely secured power plant. I had a big smile too.

 

I will be adding in a rib on each motor mount to minimize any movement and to strengthen them up. I will also be taking them home for a proper sandblasting and finishing job – they’ll look brand new once I’m done with them.
I also want to extend a massive thank you to anyone following my blog as well. I am officially over 5000 views which in my eyes is massive! Thank you! I’ll try to stay on top of this project as much as possible to keep everyone entertained! Stay tuned!
– Sean

One Comment Add yours

  1. Unknown says:

    Great Blog! I have been putting a mazda engine in a much modified triumph herald for, well, the past 10 years or so. I too was going to use AWR poly mounts- having seen this however, I am absolutely going to copy your mounts- These are much better! Your description of the build is quite detailed already- and I could sit (squat) down and do a bit of Cardboard Aided Design- but on the off chance, do you still have sketches or templates of the plates? Also, are you on the FB? You can find me under Rust Buckit,Cheers, Arlo

    Like

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s