Motor Mount Experiment - Picture Intensive
#1
Banned
Thread Starter
Motor Mount Experiment - Picture Intensive
I recently installed new mounts only to learn that they could be defective.
https://rennlist.com/forums/928-foru...-opinions.html
The engine height may have been acceptable but I feared they may be hollow and continue to sink so out they came. When I tapped on them they indeed did sound hollow. I could stick a wire way down into each of the four “vent” holes in both mounts. The next step was to measure the cavity.
I dropped them in a pail of water until no more bubbles came out. They held about 6 ounces of water each.
I then performed some “compression” tests.
104 pounds (all I have) yielded 1/4" compression.
Adding 50 or 60 pounds yielded 5/8” compression.
I got some of this stuff. http://www.shopmaninc.com/moldmaking.html (No affiliation, just what I got).
It’s easiest to mix if you pour the thick into the thin. I mixed only enough for one at a time.
It was too thick to go through the funnel so I had to pour it free hand. Glad I only mixed enough for one as it was barely flowing by the time the mount was full.
Another test showed less than 1/4" compression.
The pan was about 1/2" lower than the cross member. Now they are nearly even.
There was about 1/2" pan to cross member clearance. Now there is about 7/8”.
The hooks also show about a 3/8” gain.
Am I safe to run these?
Thanks in advance for any feedback.
https://rennlist.com/forums/928-foru...-opinions.html
The engine height may have been acceptable but I feared they may be hollow and continue to sink so out they came. When I tapped on them they indeed did sound hollow. I could stick a wire way down into each of the four “vent” holes in both mounts. The next step was to measure the cavity.
I dropped them in a pail of water until no more bubbles came out. They held about 6 ounces of water each.
I then performed some “compression” tests.
104 pounds (all I have) yielded 1/4" compression.
Adding 50 or 60 pounds yielded 5/8” compression.
I got some of this stuff. http://www.shopmaninc.com/moldmaking.html (No affiliation, just what I got).
It’s easiest to mix if you pour the thick into the thin. I mixed only enough for one at a time.
It was too thick to go through the funnel so I had to pour it free hand. Glad I only mixed enough for one as it was barely flowing by the time the mount was full.
Another test showed less than 1/4" compression.
The pan was about 1/2" lower than the cross member. Now they are nearly even.
There was about 1/2" pan to cross member clearance. Now there is about 7/8”.
The hooks also show about a 3/8” gain.
Am I safe to run these?
Thanks in advance for any feedback.
#2
Rennlist Member
Wow, now I know my mounts are bad.
#3
Chronic Tool Dropper
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I suspect that the mounts need to provide a certain amount of flexibility if you want any more than just getting the engine up higher. Adding a relatively rigid/non-compressible filler to the mount may or may not give you the flexibility you desire. Even if it's there now, no clue on how the filler will break down over time with multiple flexes from normal vibration.
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I'm a big fan of hydraulic mounts. I replaced mine with genuine P mounts before the Ford mounts were identified as possible replacements. Maybe next time I'll look at the aftermarket hydraulics, but the hollow rubber ones will likely not get used. The hydraulic mounts provde a certain amount ofmotion damping that a 'solid' rubber or hollow mount will never achieve. IMO, the excellent ride qualities and passenger comfort are compromised too much.
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I'm a big fan of hydraulic mounts. I replaced mine with genuine P mounts before the Ford mounts were identified as possible replacements. Maybe next time I'll look at the aftermarket hydraulics, but the hollow rubber ones will likely not get used. The hydraulic mounts provde a certain amount ofmotion damping that a 'solid' rubber or hollow mount will never achieve. IMO, the excellent ride qualities and passenger comfort are compromised too much.
#4
Under the Lift
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Safe? You appropriately labelled this an experiment. Keep us posted.
You found a six ounce cavity that had an opening large enough to drip rubber through and put a funnel snout into it? Amazing. The ones I have from Roger have no such "vent" holes. Your initial load test is interesting in that the first 100 lbs yielded 1/4" but adding just another 60 lbs more than doubled that. Egad. Looks like your rubber fill added a lot of support, but, as dr. bob said, who knows how durable it is?
You found a six ounce cavity that had an opening large enough to drip rubber through and put a funnel snout into it? Amazing. The ones I have from Roger have no such "vent" holes. Your initial load test is interesting in that the first 100 lbs yielded 1/4" but adding just another 60 lbs more than doubled that. Egad. Looks like your rubber fill added a lot of support, but, as dr. bob said, who knows how durable it is?
#5
I was a poor student in College and this was one my first DYIs on my Nissan Maxima. http://www.saabcentral.com/forums/sh...d.php?t=102450
Have you tested the polyurethane and see how soft it is? Depending on the softness it may work just fine.
Have you tested the polyurethane and see how soft it is? Depending on the softness it may work just fine.
#6
Banned
Thread Starter
The rubber I used is quite durable. I’ve playing with a 1.5” diameter X 3/16” thick piece since I poured them on 5-14-10. I have folded it onto itself a few thousand times and can see absolutely no sign of degradation or fatigue.
#7
Banned
Thread Starter
I was a poor student in College and this was one my first DYIs on my Nissan Maxima. http://www.saabcentral.com/forums/sh...d.php?t=102450
Have you tested the polyurethane and see how soft it is? Depending on the softness it may work just fine.
Have you tested the polyurethane and see how soft it is? Depending on the softness it may work just fine.
They have different durometer compounds available. I used Shore 60. It is about like a pencil eraser.
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#8
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Thread Starter
I am not too concern with how the rubber will hold up, I think it will be fine. And, if everyone has been satisfied with the “feel” of the solid mounts (the good ones that is) I think I will be happy with the “feel” of these after being filled with this stuff.
The one concern I do have is if they will hold together. If you look at these two photos you should be able to see how these mounts are (supposed to be) held together. The hollow one in the photo is missing the “hook” (circled area) that holds it together.
If this rubber is merely filler and isn’t “bonded” to the original rubber, the mounts could theoretically “pull apart”.
The one concern I do have is if they will hold together. If you look at these two photos you should be able to see how these mounts are (supposed to be) held together. The hollow one in the photo is missing the “hook” (circled area) that holds it together.
If this rubber is merely filler and isn’t “bonded” to the original rubber, the mounts could theoretically “pull apart”.