Ford V8 Discussion Discussion relating to getting the most out of your Ford-based V8 Miata's engine

347 Motor Mount Issues

Old 02-25-2015, 02:00 PM
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Default 347 Motor Mount Issues

Hello All:

Need a little advice here. I am doing some engine clearance checks on my '93 Miata 347 conversion. I have the front sub-frame loosely bolted under the motor. The spacers from Martins kit are in place, then the block to motor mount plate, then the rubber motor mount, then Martin's modified Miata sub-frame. The steering rack is right up against the oilpan and the motor mount bolts still need to be tightened. I am estimating I need about an inch of spacers put in.

Am I missing something?

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Old 02-25-2015, 02:38 PM
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Flipping this to the Ford section for a better chance of our Ford pros seeing it. You might want to page through the Ford section too as I see lots of threads with motor mounts or clearance in the titles.

Of course if you had a build thread....
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Old 02-25-2015, 02:52 PM
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I think that I ended up using a couple of washers along with the spacers. I also ground down part of the boss on the rack & pinion & part of the racks mounting bracket. Those spacers look like the ones that I recommended to Martin when I did my build years ago, & are actually front caliper slide inserts off of a RWD GM car. You will not really be able to tell much about your clearance issue until you have the transmission attached & it resting on the installed crossmember. A lot of clearance can be obtained by raising or lowering the transmission at its mount. I would suggest that you clearance the rack & pinion stuff while it is easy to get to. You can always add a washer or 2 to the mounts after the unit is installed in the car. Others have shimmed down the sub-frame, but that is for underhood clearance.
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Old 02-25-2015, 08:24 PM
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This is what I did to my steering rack. Turned out to be more than needed but all is working fine.

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Did the oil pan need additional depth to clear the stroker crank? May need additional washers for spacing as tbone said. He also mentioned making the spacing adjustments once it is in the car and the trans mount is mocked up. This is when you can tweak things as needed. Like pinion angles relative to engine angle, etc.

I would add that the engine (at least in my car) has a bit of a tilt downward toward the back of the car. My shifter flange ring (Pro 5.0) that has the two bolts in it for over shift protection is about flush with the top of the tunnel so I did not want it any higher. The tilt made it necessary to have the front spacers on the engine block slightly longer than the rear spacers otherwise it would crush and stretch at the same time the motor mounts.

Bottom line, you will be tweaking the engine/trans mounting (front, back, sideways, up, down) several times until you get it where you want it.

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Old 02-26-2015, 06:54 AM
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You better add a aluminum bloc (same size of your rubber mount) Or you can uses a non power steering rack that a lot smaller like a did.
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Old 02-26-2015, 11:43 AM
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I agree with the grinding down of the rack. You'll also have to move the powersteering hard line a little by loosening it, rotating it a few degrees and then bolting it back down.

On all of my builds I ended up using the spacers plus a few washers on each bolt.

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Old 02-26-2015, 12:20 PM
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Thanks for the tips, Martin emailed me with pretty much the same info. It just looks way off right now. I was going to try the install the engine/trans from the bottom but, it sounds like for fitment issues, it might be easier to drop it in and shim it at that point.

I was going to put washers between the frame and sub-frame. Give me another 1/8 of an inch to play with. As for the crank to oilpan clearance I have about 3/16ths of an inch. The depth of the oil pan from the block to the modified section is a hair over 3 1/2 inches.

I'm probably just panicking, I'll hope for the best.

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