Motor mount mod

[DamnHippie]

I've heard of people welding chain onto their motor mounts so that if the rubber part fails it limits how far the engine can jump. Since I tore a mount last year (and am sure to tear them again in the future) and I have a bunch laying around right now, it seemed like a good time to play with this idea.

I dunno how others have done it, but I know my goals were:

- No metal-on-metal contact when everything is working right.
- No new rattles (I HATE rattles and squeaks).

What I came up with is this:

http://img180.imageshack.us/img180/617/1002855qq7.jpg

http://img180.imageshack.us/img180/2461/1002856qc2.jpg

The top link is a partial link of 1/4" chain. The bottom and middle links are 3/8" chain. I used the two different sizes just to get things spaced and lined up the way I wanted. The middle link is very lightly tacked to the top link, and the mount can move quite a bit and the bottom link just waggles around in the space inside the center link.

If the rubber ever tears the bottom link will slam against the bottom of the middle link, which will break the tack welds, then the middle link is gonna start rattling. It'll be like an alarm that the mount broke (although the vibration when you get on the gas and it's the metal holding the engine down should be a strong clue too).

Oh, here's another interesting thing: the motor mounts for a qx4 and a frontier are different. The frontier one is WAY beefier. I was using the qx4 mounts to play with then when I went to duplicate the effort I liked onto a frontier mount I had to rethink it a bit because the top part is shaped differently. (But you could use qx4 mounts in a frontier and vice versa if you needed to, I think.) The metal part of the qx4 mount is 3/16", the frontier is 1/4".

http://img72.imageshack.us/img72/8442/1002857hj1.jpg

[Nissanclay]

I need to do that mod.

[tmorgan4]

Wow, didn't realize the engine mounts were different. Was there any difference in the rubber section or just the metal?

I need to post up pictures of my mounts. I can't tell where the rubber *should* be connected and it looks like one or both of them are partway torn. I guess that would explain the extra drivetrain movement.

And isn't the chain used to actually KEEP the mount from tearing by limiting it, rather than just hold it in place once it tears?

Looks good!

[Ryan Gee]

Keeps it from overextending... Crawler gears eat engine mounts.

Awesome! Your welds are looking good!

[tmorgan4]

How much are these to replace BTW? Probably best to not go with cheap aftermarket ones.

[Packman5280]

the ones for my pathy were $85, from ABC in AZ. not sure about the newer ones.

[DamnHippie]

I think I paid $80 at Pinnacle Nissan. I love Pinnacle, their customer service rules. On Monday the harmonic balancer I ordered arrived, and it was in a factory-sealed box and it was broken -- a big chunk was chipped out of the edge (and no pieces were in the box, they packed it broken at the factory). I called Pinnacle and the guy actually cursed that we had just missed UPS by 5 minutes and a replacement wouldn't go out until the next morning. So he said he'd send it 2nd-day for free to make sure I had it before the weekend.

[DamnHippie]

My goal wasn't to keep the mounts from tearing, just to limit the damage when they do tear. I think there's enough free movement (3/8 - 7/16") before the links engage that it'll be torn before I get metal-on-metal contact. Which is fine, I don't mind replacing a motor mount every year or two, I just don't want all the damage I got last time -- I was muscling over an obstacle when it tore, and the engine jumped so far that the fan destroyed the upper shround and the ends of the fan blades.

In addition to the front motor mounts, be sure to check the rear one (aka the transmission mount). If you wheel much it'll probably be torn, and there's almost no way to tell that short of removing it. I tried the wiggle-test with a pry bar and it didn't seem torn, but (in trying to elmiinate a driveline vibration) I removed it and it was clear then that it was torn almost completely in two. I picked up a couple replacements from 89 Pathfinders at pull-n-save for $6 each. Be sure you get replacements off a 4x4 pathy/fronty/x, the mounts off a 2wd are much lighter weight and would tear on the first rock you tried to climb.

For vehicles that aren't wheeled, even old mounts are usually in good shape. If you get junkyard parts for the front mounts, try to get the passenger side, they get compressed rather than stretched, so they're never torn.