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1991 Ford Mustang LX
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Discussion Starter #1
Just noticed this when installing the transmission. The motor seems to be about 1/2” leaning towards the passenger side. The transmission crossmember didn’t line up with the mounting bracket so i had to shift it a little bit towards the driver side but it was a side to side movement not a rotation. Shifter looks pretty damn level if you look down at it in the driver seat. I’ve removed the motor mount nuts and lifted the engine several times and also did this with the trans crossmember unbolted. And can’t get it level.

-new engine
-new maximum motor sports k member
-new prothane motor mounts (R&L sided only go on one way)
-stiffler trans crossmember
-prothane trans mount


Any tips would be great. Here’s a pic and as you can see with the oil pan it’s off. It’s a 1/4 bubble with a leave off towards the passenger side.

1066939
 

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Do you have other motor mounts that you could put back in and check to see if its level? Is all hardware tightened down like the k member hardware? I doubt the MM K member is at fault
 

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1991 Ford Mustang LX
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Discussion Starter #3
Do you have other motor mounts that you could put back in and check to see if its level?
I don’t unfortunately. These I think where like $155 and really trying to prevent buying new ones to see if the issue is still there. But if I cant figure out what’s going on then I’m certainly going to buy new ones
 

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I went with the Energy Suspension poly mounts because they keep the motor at or around stock height. The Prothane mounts lift the motor 1/2 inch.
 
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Can you measure the thickness of both motor mounts and see if they are the same? Is this on a stock engine block or aftermarket?
 

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I want to say they don’t usually sit perfectly level from side to side. You can always use a washer and shim one side if it bothers you.
 

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Is the engine rotated within the k-member, or is it squarely set in?

if it sits squarely in the k-member, its possible one frame rail is higher than the other?
 

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1991 Ford Mustang LX
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Discussion Starter #8 (Edited)
Can you measure the thickness of both motor mounts and see if they are the same? Is this on a stock engine block or aftermarket?
[/QUOTE
both mounts are the exact same 2.5” thick.

this is a boss 351 ford crate motor. Completely loss for words why it’s off so much. Not sure if I should shim the passenger side st this point. I’m think the frame has to be bent or something. I’d leave it if there is no long term effect on it.
 

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1991 Ford Mustang LX
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Discussion Starter #10
Is the engine rotated within the k-member, or is it squarely set in?

if it sits squarely in the k-member, its possible one frame rail is higher than the other?
That’s what I’m thinking at this point.

not sure if it matters it’s sitting like that or if I have to shim it. I guess I’m only concerned on it cause I am not sure if it’s safe to leave it
 

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start measuring

I would like to know the root cause, if it were my car.
 

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I would want to know too. That engine is significantly off so any tweak in the front frame rails should be noticeable.

the engine mount have a locating pin on each mount. I know you said yoube verified the mounts are on the correct side, but can you clearly see the mounts locating pin in its slot?
 

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Its the engine mounts. We have told Prothane several times that they are built wrong, but they don't care. They raise the engine a significant amount. It wouldn't surprise me at all if they also raised the engine different heights on each side of the car. Send them back and get some Energy Suspension mounts.
 

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1991 Ford Mustang LX
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Discussion Starter #14
I would want to know too. That engine is significantly off so any tweak in the front frame rails should be noticeable.

the engine mount have a locating pin on each mount. I know you said yoube verified the mounts are on the correct side, but can you clearly see the mounts locating pin in its slot?
To be upfront there isn’t a locating pin on thise. Maybe they are defective. I saw that most do have them. One only has a hole the size of a pencil but all you can see is the rubber. It’s not like a physical pin.

if you were me and it was off this much would you shim? And if not and it truly is the frame rails is this a project you simply just abandon?
 

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Discussion Starter #16
Its the engine mounts. We have told Prothane several times that they are built wrong, but they don't care. They raise the engine a significant amount. It wouldn't surprise me at all if they also raised the engine different heights on each side of the car. Send them back and get some Energy Suspension mounts.
You talking these?
1066967
 

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Yup, I just got a set myself. Nice pieces. I got them on Amazon for about $20 cheaper

I would just double check however that the prothane mounts are installed evenly on both sides. In other words one stud seated further down in the slot than the other side. I noticed without the locating pins on mine, there’s a lot of room for the mount to slide up and down on the mm k-member. The locating pins stop that. Not sure how it works on the prothane mounts without them

72488789-2844-4A4E-B5B4-BCBBDED07A47.jpeg
 

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No, I'm talking about these:


Just kidding. They are the exact same part. Look at my signature and then look at my link for an explanation. We sell a LOT of Prothane bushings, but we don't sell their engine mounts because of these problems.

It won't be difficult to determine if there is a problem with the frame rails or k-member on your car. Just Make sure that the distance from the top of each front fender arch to the ground is that same height. Then measure from symmetric locations on the frame rail to the ground on each side of the car. If these are the same, then the frame rail is fine. Then measure from the TOP of the engine mount slot in the k-member to the ground on each side. This may be tricky to do. If these measurements are identical, then the k-member is almost definitely fine. Also measure from the bottom of the engine block mounting bosses to the ground on each side of the car. If these heights are different, then the problem must be the engine mounts.
 

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1991 Ford Mustang LX
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Discussion Starter #19
I appreciate all the info and responses. Makes me feel a lot better switching from Chevy to Ford, should have years ago. These mounts must be **** then. Mine aren’t even seated fully on the k member like what was linked. Either they sent me the wrong ones, packaged wrong or these are just plain old ****.

1066971
1066972


as you can see these aren’t even fully on the K member and they are pegged out on the bolt so I can’t slid them down any to level. I’m getting new ones unless someone says otherwise
 

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Discussion Starter #20
No, I'm talking about these:


Just kidding. They are the exact same part. Look at my signature and then look at my link for an explanation. We sell a LOT of Prothane bushings, but we don't sell their engine mounts because of these problems.

It won't be difficult to determine if there is a problem with the frame rails or k-member on your car. Just Make sure that the distance from the top of each front fender arch to the ground is that same height. Then measure from symmetric locations on the frame rail to the ground on each side of the car. If these are the same, then the frame rail is fine. Then measure from the TOP of the engine mount slot in the k-member to the ground on each side. This may be tricky to do. If these measurements are identical, then the k-member is almost definitely fine. Also measure from the bottom of the engine block mounting bosses to the ground on each side of the car. If these heights are different, then the problem must be the engine mounts.
wow, well thank you for the response. You guys make great products think I dropped about 7k with you guys during the beginning stages of Covid till now and your team did a great job getting parts out with being short handed. Might have to pick your brain on what to do with my sway bar I just got from you guys. Hits the damn oil pan.

Thanks again for the response
 
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