Passanger side mount -PITA

[chromguy]

re 87 era mounts
I like several others have more engine at idle vibration than we want/need. There appears to lots of misinformation out there as I searched this and other forums. My factory mount was installed like "^" which is what most people recommend. At that point, I felt I was still being tenderized for a pig roast. So I needed a different view on the problem. Here is a picture of the "V" in the opposite position from RockAuto.

I collected up my seven passanger mounts (Mopar,polybushings and ukn) and guess what??? The pipe through the rubber is positioned in different three places by over 1/2". WTF. So I read Gary D. statement on Dodge Garage

Mount mistake number two- The passenger side mount is directional as well. See the arrow? The insert has been installed upside down. Engine is now ----ed way up in the air AND vibrating like crazy. Just great for the axles. Also there was 2 1/4 thick washers under the mount when you took it off- put them back. Chrysler figured out that they could minimize torque steer by having them there..

Makes sense to me that engine level is the important thing to watch here. I measured the distance from the flats on the body (where the mount bolts to) to the centre of the bolt that goes through the mount itself and is rigid mounted to the engine. I lowered both the Sundance and CSX with centre of the bolt at or lower than the body mounting flange and both were better than before, vibration wise. Just for fun, I measured this distance on a newer style liquid mount I removed from a 91 RS Shadow, the distance was 1/4" lower between the mounting flange and the bolt centre but I am unsure if Ma Mopar changed the flange height on the 91+ body.

What is the optimum distance?

[Johnny]

In this photo...its upside down.

[Johnny]

Also my mounts are usually used without the spacers. The mount from the factory sagged, so their bandaid was adding spacer to get the engine back to level.

[chromguy]

In this photo...its upside down.

Yes but that would place the hole above the body flange unless it sags a ton. My car would then act like Elvis.
I will experiment more with hole position vs shaking

[Johnny]

It will vibrate MORE with it upside down...... metal to metal contact.....

[chromguy]

It will vibrate MORE with it upside down...... metal to metal contact.....

Which surfaces are metal to metal contact in this config?

[GLHNSLHT2]

The big lip under the center bolt hole in the mount you pictured is metal. MP mounts have 2 of those lips (top and bottom) on the same side to stop the engine from sagging.

The V of the mount is supposed to support the weight and vibration of the engine.

Do not base measurements off of later mounts. They changed the other 2 mounts to make up for any differences in 1 mount.

Get the mount installed correctly. Get the engine level with or without the spacers.

Also check the front mount.

What are you running for mounts at all the locations?

[4 l-bodies]

Miles,
What I have found is the factory mount (when new) works great. As noted, they sag. You can sort of tell how much they have dropped by looking at clearance between top of motor mount insert and motor mount bracket. When new they will have like 1.5" clearance. When well sagged, you can't fit your fingers between the two. I've seen them even touching.
The MP mounts are a harder durometer rubber, and will introduce more vibration into vehicle. I have been told the MP mounts were actually OEM parts that tested and failed (too hard) factory mounts. Then DC/MP marketed them as performance mounts! The aftermarket rubber mounts from Anchor and etc. are also much harder duromater than the OEM mount. I removed one early poly mount from Johnny because of too much vibration for my tastes. I believe he softened them up in later mounts.
You might want to check all your other mounts and see how they line up. I just installed a powertrain in a friends GLHS and after installing a poly front mount, the rear dog bone (a555 rod shifted) had WAY to much preload in it. What I needed was either an adjustable dogbone, or to extend the length of the dogbone. I ended up cutting the dogbone in half and extending it around 9/16" with a piece of 3/8' rod. When done I could either unbolt front or rear mount and after loosening nuts I could take either bolt off with finger pressure only. Zero preload on either front or rear mount. That vehicle had zero vibration at idle or at speed.
Todd

[jonnymopar]

The sad truth is, after this many years, no one really makes factory fit-form-function parts for these cars anymore. Companies like Anchor will give you something to stop your engine from hitting the ground, and that's about it. I consider myself fortunate that the vibration doesn't bother me because homemade mounts and Johnny's mounts are the only ways I ever got my engine to sit where it's supposed to, reliably, for any length of time.

Engine alignment and leveling are key, but that only gets you so far when you're dealing with junk parts to begin with. I have found that the Anchor mounts do soften up a little bit after a a bit of use. Comfort gets better, but now the leveling that you worked so hard to get dead-nuts is probably off by that point.

I have been told the MP mounts were actually OEM parts that tested and failed (too hard) factory mounts. Then DC/MP marketed them as performance mounts!

Just like the factory injectors that flowed a tad too much magically became +20's!

[Dr. Johny Dodge]

+1 the mount is pictured upside down
easy tell is the bit that sticks out of the box structure of the mount - seen in this pic at the bottom
- that should be at the top ( the part wityh the two nubs on the sides)

only turbo cars had the shims under the mount - any other nonturbo car , someone's added them

non turbo cars have a notable tilt of the valvecover towards the passenger side
the shims change this in the turbo cars thus our turbo valve cover should appear level

the late model mounts used a different flange welded to the frame to fit the new mount , thus the late model and earlier versions don't interchange

the real early versions differ yet again

I have seen the hard MP front mount give differing degrees of vibration in different cars
(comparing a buddy's to my own both with the mp front mount)

if you're having leveling issues with the mount turned the correct side up , check the trans mount

and always make sure the through bolt that attached the isolator to the rad cradle is centered in the witness markleft by the bolt washers on the bracket on the rad cradle

you don't have to go far from that witness mark before you start blowing the guts outta the c/v joints
in my buddy's case it was the second left turn after replacing the c/v joint that had blown out on the way home from the shop that installed the mount - without alligning the bolt and witness marks

[Dr. Johny Dodge]

I have wondered about filling the mounts with liquid aluminum body filler ...

also , the J body lebaron converts from 87-9 used mounts that were modifyed to include a strut like damper at both the passenger side and trans mounts

these dampers when found in good condition are very stiff unlike the ones used for the bobble bracket

also , 87-9 K cars and vans with the 520 trans used a dog bone L body style bobble bracket that also used a different mount to attach to the 520's diff

keep in mind the bobble bracket is intended to prevent engine / trans rotation when in reverse
it's ment to prevent the diff from lifting and changing the driveshaft angles

[chromguy]

Also check the front mount.

What are you running for mounts at all the locations?

Currently I am used the original stock mounts from 1987 on the rear, left and right. Approx. three years ago I changed all the mounts to Poly from Johnny, the vibration was super crazy. Johnny was very supportive but it was still too much vibration so I returned back to the factory mounts. Earlier this year I replaced the front mount, the vibration level was acceptable, but when I replaced the passenger side the vibrations was unacceptable. Visual inspection of the MTX mount looked OK as mounted on the car but I can inspect closer this weekend.
My main point is I have many different mounts that will place the engine in a different orientation. It appears you simply cannot just change the mount and you are good to go.
Thank you to everyone for your help/suggestions.

[chromguy]

Miles,
What I have found is the factory mount (when new) works great. As noted, they sag. You can sort of tell how much they have dropped by looking at clearance between top of motor mount insert and motor mount bracket. When new they will have like 1.5" clearance. When well sagged, you can't fit your fingers between the two. I've seen them even touching.
Todd

Thanks Todd,
my passenger side is original and has "sagged" to approx 1/2" but was like that when I purchased in 87. Yes perhaps my MTX side has sagged as well, the engine is level btw. All the 87 style mounts I have are very different and none have the pipe in a position that can allow more than approx 3/4" of an inch without turning the mount upside down. Both my Sundance and CSX are the same in this regards.
Currently the Sundance DD vibration level is acceptable but I would like to better understand the root issues here before these fail.

- - - Updated - - -

I consider myself fortunate that the vibration doesn't bother me because homemade mounts and Johnny's mounts are the only ways I ever got my engine to sit where it's supposed to, reliably, for any length of time.

Thank you for your thoughts, do you have any details on your homemade mounts you are willing to share?

[chromguy]

and always make sure the through bolt that attached the isolator to the rad cradle is centered in the witness mark left by the bolt washers on the bracket on the rad cradle

Thanks Johny for the tip.

[Dr. Johny Dodge]

if the 87 mounts you have all differ I'd think they simply have varying degrees of mileage and sag happening

1/2 inch of sag would have me checking the c/v joints are not hitting the crossmember or control arms

I'd think a pair of new mopar mounts would solve the issue as they're probably just to old and soft with a 1/2 of sag now

I've only ever used the stock side mounts and a MP front mount insert with great results in my modest builds (and the 87 K bobble brkt)

[jonnymopar]

Thank you for your thoughts, do you have any details on your homemade mounts you are willing to share?

I was still in high school when I did this, so set your expectations accordingly. Hey, you asked.

I took a broken mount and torched all the rubber out so I was left with the outer shell and the steel tube through the center. I then took two hockey pucks and bonded them back to back with epoxy, letting them cure for a couple days. That gave me the thickness I needed for the mount. Next, I cut a square block out of it that was just large enough where it couldn't fit into the mount's shell. Using a belt sander, I slowly shaped it by hand until it got to the point where I could press it into the shell using an arbor press. I pressed it in and bolted it to the car. (congrats to anyone still reading this post, by the way)

Jacking the engine up as far toward the crank pulley as I could, I brought it up so it was level, then made a mark on the mount where the center tube needed to be drilled (it's questionable whether this actually worked because while the jack is lifting the engine, it's also relieving weight from the car itself, allowing it to rise). Once it was marked, I yanked it out of the car and drilled it to a press-fit diameter for the tube. Finally, once I was happy with the overall fit, I coated all mating surfaces with epoxy, pressed it all together, and cured it for several days. That engine never moved or sagged again, but it was difficult to see out of the rearview at certain RPMs.

Shortly after, I ended up doing the exact same thing for the front mount, except I didn't need to press it in because the shell has a cut on one side. The design of the trans mount doesn't really lend itself to this method, so I just filled the voids in the mount with 3M windshield sealant. The damn tube of sealant cost me more than the other two mounts combined. For reasons I don't understand, vibrations seemed to *lessen* once I had two ultra-firm mounts instead of just one.

I don't recommend this method for anyone that's sensitive to NVH, or anyone else in general.

[GLHNSLHT2]

Miles,
The MP mounts are a harder durometer rubber, and will introduce more vibration into vehicle. I have been told the MP mounts were actually OEM parts that tested and failed (too hard) factory mounts. Then DC/MP marketed them as performance mounts!

I too have heard that story but after having a stock mount and an MP mount in each hand I don't believe it. Why? If you look at the stock mount in the original post you see the cradle that the center bolt boss is sitting in at the bottom of the mount as pictured. Stock mounts have one of these cradles on each side. MP's do not. They have cradles on the same side, top and bottom. So as the mount sags the bracket hits the bottom cradle and stops any more sagging and also limits total sag. Clearly they are a different design.

You might want to check all your other mounts and see how they line up. I just installed a powertrain in a friends GLHS and after installing a poly front mount, the rear dog bone (a555 rod shifted) had WAY to much preload in it. What I needed was either an adjustable dogbone, or to extend the length of the dogbone. I ended up cutting the dogbone in half and extending it around 9/16" with a piece of 3/8' rod. When done I could either unbolt front or rear mount and after loosening nuts I could take either bolt off with finger pressure only. Zero preload on either front or rear mount. That vehicle had zero vibration at idle or at speed.
Todd

Yep done right with no preload and the vibes won't transfer to the car. It's too bad PB doesn't make adjustable poly dog-bones. I ended up making my own.









I just hope I have enough "rubber" in the mount to keep the vibes down.

also , 87-9 K cars and vans with the 520 trans used a dog bone L body style bobble bracket that also used a different mount to attach to the 520's diff

I wouldn't say "style" I'd say exact piece. See the above pipe of the installed adjustable dog bone for a pic of the 520 Lbody dog bone bracket pulled from an 88 caravan mounted to my 523 trans in my SL.

Currently I am used the original stock mounts from 1987 on the rear, left and right. Approx. three years ago I changed all the mounts to Poly from Johnny, the vibration was super crazy. Johnny was very supportive but it was still too much vibration so I returned back to the factory mounts. Earlier this year I replaced the front mount, the vibration level was acceptable, but when I replaced the passenger side the vibrations was unacceptable. Visual inspection of the MTX mount looked OK as mounted on the car but I can inspect closer this weekend.
My main point is I have many different mounts that will place the engine in a different orientation. It appears you simply cannot just change the mount and you are good to go.
Thank you to everyone for your help/suggestions.

On my 5spd cars I run an MP pass side mount, a stock trans mount with a wood filler in the gap to prevent sag (bought this way and it works great), a modified PB front/rad mount, and a semi-solid bobble strut. With the stockish side mounts that supports the weight of the engine and keeps vibrations down. The modified PB front mount had it's center hole filled and re-drilled to allow the motor to rock fwd as much as possible. The semi-solid "bobble strut" is a 1" galvanized pipe with a cap on top. I drill a hole through the center of the cap and install a 3/8" shoulder bolt with a shoulder long enough to hold a small energy supspension strut rod bushing on either side of the trans bracket. Then with the other 3 mounts locating the motor I drill a hole through the pipe sideways at the bottom and mount it to the kframe tabs. So it's solid to the car and slightly bushed at the motor. I just barely snug up the bushings so there is no movement but not super tight so vibration is transferred. Vibration isn't any worse than stock, the motor doesn't rock back and forth so power transfer is instant.

I tried a PB pass mount without spacers to keep the engine level with the above setup and my rear view mirror looked like it was going to vibe off the windshield. So back to the MP on that side.

My auto cars I run the PB pass and an MP front and stock drivers side with the wood insert. Vibration was similar to stock


Sounds like you have your mounts just about figured out. A stock pass mount should have the washers installed. If you put a PB mount in you take the washers out. So those 2 mounts are going to have holes in different locations. Are you comparing used mounts as well?

[chromguy]

Sounds like you have your mounts just about figured out. A stock pass mount should have the washers installed. If you put a PB mount in you take the washers out. So those 2 mounts are going to have holes in different locations. Are you comparing used mounts as well?

Thank you for the info. i am starting to get a better idea on the mounts. It is OK for now. Yes I am comparing used but not abused mounts
PS nice work on the aluminum dogbone!

[Johnny]

I wish I knew what you do that causes vibration with my mounts.
I have installed many into many different cars and it has not caused vibration.
Why? Or is it a car with vibration no matter what mounts are installed?

[chromguy]

I wish I knew what you do that causes vibration with my mounts.
I have installed many into many different cars and it has not caused vibration.
Why? Or is it a car with vibration no matter what mounts are installed?

Perhaps I just have a special untapped talent!!!

As a FYI, CSX #432 shakes even more! and someone else installed these. But this one has a huge threaded rod on the back, a similar idea to your rear adjustable mount. Since the car is not on the road yet I have not attempted to adjust.