Motor mounts compressed to under 1mm of clearance after only 8 months/6K miles…

…but why?
I replaced my ‘03 360’s motor mounts last year due to what I felt were excessive vibrations in the cabin.
That was 8 months / and 6,000 miles ago. The cabin vibrations have recently returned. I can also see the exhaust tips on the drivers side vibrating much more than the passengers side. I checked them today, and the drivers side mount has less than 1mm clearance on the back side, and only just 2mm on the front. The passengers side has just over 2mm on the front, and just under 2mm on the back side. I’ll include pictures.

What could cause mounts to collapse down this far so quickly? Everything was torqued correctly, but I can’t remember if I torqued once the engine and car were fully settled on the ground, but I *believe* I did.

They were new OEM mounts from a forum supporter.

What gives?
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I can’t see any cracks. My basis for concern is that the cabin vibrations have returned. They dissipated when I first replaced them last July, but have since recently returned. That’s the only connection I can make. The trans bushing was also replaced with the 430 unit 2 years ago.

 

I had assumed that once the rubber blocks contacted the base plates, they would transmit extra vibrations through the chassis, and therefore, cabin.

 

Good. I replaced it in early 22

 

At this point I don’t think I’ll dig any further, based on Brian’s input. I was basing it on internal cabin vibrations, which led me to replace them in the first place (on top of the age of the previous replacement, roughly 10 years). The vibrations quelled immediately upon the last replacement. Now they’re back, seemingly out of the blue. if anyone has any ideas, I’d gladly check!

 

I had actually considered doing an ECU/TB reset, just to see. Easy enough and worth a shot.
I didn’t think that would’ve been necessary at this time, because I just got the 360Trev tune about 4 months and 2,000 miles ago, which concluded with an ECU reset. There were no new vibrations present after the tune. They didn’t begin to present themselves until the last week or two. I did install new coils a month or two ago without doing a reset or tb relearn. I did them as part of the prerequisites Trev likes to have done when installing a tune: plugs, MAF’s, coils, primary 02’s. The coils were the only thing that didn’t arrive before the tune was installed. Perhaps not doing a relearn after the coils were installed affected the ECU’s? Either way, easy enough to do.

 

Collegeboy is correct; Tubi heat-shielded headers, 200 cell sport cats, and Capristo Twin Sound cat-back. I always leave the engine lid open whenever I get home from a drive to dissipate heat, but not so much when parking out in public, for many obvious reasons.

 

Smart. Very nice. Did you ever start a thread on making it? Which materials, etc?

 

Can you post a link, or at least share the name of the heat shielding product you used? It looks like the same stuff used in the OEM 430 heat shielding I installed over the trans bushing when I replaced it.

 

Agreed, and I’ve thought about that possibility too. The cams were timed at the second to last belt service, but this last belt service I did myself as a lock-and-swap. That was last May. The vibrations did not present themselves any more after the belts. It was running as nice and smoothly as before. The vibrations improved with the mount replacement in the July following, and have started to creep back over the last few weeks. I’ve often considered inquiring to local Indy’s about having the cams timed, but it’s pretty far down on my list. I pulled data from the Autel 2 months ago after seeing someone else’s post about cam timing. I’m the first to admit I’m out of my depth on this subject matter, but the figures I got were:
“Camshaft and engine fase angle” were 650.688*C on one bank, and 651.594*C on the other bank.
“Cross inlet/exhaust cross value” was 32*F for both banks.
“Camshaft Cross Factor” was 0 for both.
Again, I have little to no understanding of what these numbers translate to, expect for that I believe the fase angles are both low?

 

I’ll be trying that on Friday as soon as I’m done with work for the week!