Modern-day Miura

[Steve Hamilton]

Hi Joel

Fingers crossed 🤞 I also hope it fits!

Sure looks good

Steve

[Gojeep]

That is some fine engineering and machining there.

[Superleggera]

Definitely share a picture (or a few) of the transaxle bolted to the Coyote engine as a standalone assembly if possible to showcase for visual reference.

This would NOT fit in an actual Miura but your iteration has a much better chance than the original.

[cliffrod]

That transaxle is something I've really been anxious to see. It sure looks great.

Looking forward to seeing it in your car.

[heinke]

...Drumroll please...

Now to the big question: will that big, wide V8 engine and it’s transaxle fit in that tightly constrained chassis engine compartment?

I decided to use the core engine for the first trial fit exercise because it had already been prepared to accept the transaxle. After some head scratching to work out the needed mid-air engine hoist gymnastics to drop the assembly in there, IT FITS!!





BUT…as I anticipated, there are fitment issues that will need to be addressed:

1. Insufficient CV/axle clearance under frame rail

2. Engine when in mid-air during installation will not clear the main cabin bodywork (when the bodywork is actually in place) and a risky engine/transaxle assembly rotation from horizontal was required in mid-air to get the transaxle to clear a cross member.

3. Insufficient clearance between damper pulley and frame rail. Core engine has single belt damper pulley that cleared fine but Coyote has a 2 belt damper pulley that will not.

Here are pictures that show the clearance issues.







The root cause of the CV/axle being too high is that the engine/transaxle assembly will need to be located 3 inches higher than originally planned to provide clearance where the transaxle sits directly above the drivers side rear lower A arm front pivot point on the chassis. The upper A arm pivot limits the side to side placement (thus the dampener clearance issue) and the lower A arm pivot limits the vertical placement.





If we’d have done a full CAD design of powertrain and chassis together, we probably would have foreseen these clearance issues. But at the major component level, this project is closer to back of the napkin engineering, so these issues come to light during trial assembly exercises. Not to worry, I have a workable answer for each of these issues.

1. Re-angle or re-clock if you will the transaxle final drive case relative to the transmission. In other words, if you think of the transmission output shaft as center pivot on a clock face and the inner CV/axle center as the pointer on a clock hand, shift the clock so it reads more like 7 o’clock rather than the 8:30 position it’s currently at. Pete Aardema (transaxle designer) and I think this is doable but more to come I’m sure as it unfolds. A side effect of re-clocking the transaxle is that it reduces the front to back length of the engine/transaxle assembly by about 1 inch such that the engine can be moved rearward from firewall by that amount. When the distance from the valve cover to seatback is about 4 inches, every inch counts!

2. Convert the chassis rear cross member from being “fixed” to chassis and make it a bolt in removable crossmember. Installing the engine separate from the transaxle is a non-starter given the tight clearances on all 4 sides of the assembly. But once the cross member is removed; the engine/transaxle assembly can be lowered into the engine compartment in a straight vertical line thus not hitting the cabin bodywork. Once engine installed, re-install the cross member and full chassis strength is restored.

3. Rework the engine accessory drive belt to a single serpentine belt instead of a 2 belt system. As used in the 2017 Mustang GT, the Coyote engine has a belt that drives only the A/C compressor and a second belt that drives water pump and alternator. Power steering must be electronic as there’s no P/S pump on the engine. I should be able to redesign this into a single belt system such that a shorter damper pulley can be used.

There’s my plan anyway. This project is never boring

[123pugsy]

Figuring and ciphering how to get stuff in is always a fun part of a project.
Looks good with a power plant in there though.

[Jaroslav]

Joel perfect job ....
Note: If you used a different timing chain, you would save space.

[Gojeep]

I'm glad you are thinking ahead with installing and removing the engine. Too many times frames are built around the drivetrain never thinking of how to ever get it out later on!
I have seen brand newly painted customs have an early engine failure and the whole body had to be removed to get it out!

[heinke]

Originally Posted by 123pugsy

Figuring and ciphering how to get stuff in is always a fun part of a project.
Looks good with a power plant in there though.

I have a feeling the fitment issue fun is just starting. I do agree that the engine looks great in there. Just think what it will look like with an 8 stack Weber EFI setup

Originally Posted by Jaroslav

Joel perfect job ....
Note: If you used a different timing chain, you would save space.

I used a bunch of chain for the mid-air rotation gymnastics. Maybe it would have been easier if part of that was timing chain I'll be glad when a hook and single chain will be all that's required.

Originally Posted by Gojeep

I'm glad you are thinking ahead with installing and removing the engine. Too many times frames are built around the drivetrain never thinking of how to ever get it out later on!
I have seen brand newly painted customs have an early engine failure and the whole body had to be removed to get it out!

I've been at this hobby long enough to know that the engine/trans never goes in just once. I always plan for at least a half dozen iterations for engine install and removal before all the kinks are worked out.

[123pugsy]

I think you'll be a lot more than half dozen. I did eight ins and outs putting a simple LS into an El Camino.
You should keep track, just for giggles.