MEP 002/003 Motor mounts

[Scoobyshep]

Is anyone else having problems with the motor mounts/engine supports failing? My 003 6 of the 8 rubber bushings have delaminated to the point where the inner bushing was taking the load. after several days of searching online, i only found 2 sets in the bay of E and they were more than I was willing to pay for replacements. If anyone is interested, I did come up with an alternative repair, I was able to fix all 4 for about $25

 

[Chainbreaker]

I don't have an immediate need but you never know with me having 4 units to maintain.

So, what was your fix? Pictures?

 

[Light in the Dark]

I haven't had too many air cooled sets come through my hands, but I have never seen an issue with any of the mounts. The forum is always welcoming good info though on upgrades and fixes that aren't always 'by the book'.

 

[Scoobyshep]

I found some rubber bushings, 2 inch OD x 1 inch thick. the down side was the hole was only 1/2 inch. I had to drill the hole out to 7/8 inch (an electricians 1/2 inch holesaw works well). Press the spacer into the bushing and reassemble. It took me about an hour to rebuild all 4 mounts(the one behind the fuel tank being the most difficult).

Bushings https://www.amazon.com/gp/product/B07NKSKVVV/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

 

[Ray70]

Good work Scoobyshep. I've run across a few 003's with broken mounts. I think it's probably due to "Agressive handling" and the additional weight of the 4 cyl. motor, It's a pretty poor design, relying heavily on the adhesion of the rubber to the metal outer rings.
I've repaired a couple by fabricating plastic bushings to replace the rubber. It worked fine on the "smooth" running 003's but I suspect these "solid" mounts would cause additional vibration on an 002' so I like your rubber bushing solution better, especially for an 002.

 

[Guyfang]

The bushings, on ALL gen sets, are something that NEVER get changed, unless broken. For all the hoo-haw concerning RESET, its not a part changed. And it should be, on high hour/age gen sets. I was told by a CECOM rep, to always look for cracked bushing on the TQG's. He told me applying silicone grease to them prevented cracking. Its a combination of age, vibration, and normal deterioration of rubber products exposed to air, heat other elements. The makeup of the bushings is different from machine to machine. For instance, the MEP-802 and MEP-803 gen sets, do NOT use the same bushings. Different hardness of materials.

The 002A and 003A do use the same bushings. BUT, the 002A has some extra "bumpers" to help control the vibrations from beating the skid to death.

I once found a gen set in a corner, (this was before RESET) a MEP-802A. It had four completely failed bushings. The centrifugal force of the fan, forced the engine to the right, and main gen to the left, when the last bushing failed. The engine pressed on/rested on, the optima battery. It wore a hole in the battery case, and shorted out the battery. The fan chewed up the fan guard, and some other metal odds and ends. Lots of other damaged. The set was fixable. But no one wanted to wait months, maybe years, for the parts to come in. Many damaged parts had no NSN, and could only be ordered using a 1348-6, "Non NSN" requisition. Without CECOM direct intervention, this set would never have been repaired. So the bushings are important, but seldom looked at.

 

[Chainbreaker]

Its a shame they don't seem to mfg a 2" OD x 7/8" ID x 1" thick rubber bushing . I did several searches and found one but it was 2" thick vs the 1" thickness required. Attempting to cut the thickness down accurately would be tricky considering its rubber with a lot of friction/drag. Thus drilling out the 1/2" ID to 7/8" Id is most likely more practical but requires 4x drilling vs 2x cutting.

 

[Scoobyshep]

Yea. I spent hours searching, drilling the ID out wasnt too horrible to do. Slow cut speed and a drill press make it easy.

Sent from my SM-G973U using Tapatalk

 

[NY Tom]

McMaster Carr has this. Which is 2" OD x 1" ID x 1" Long and costs a little over $7 each.

You could fabricate an inner bushing from 1" OD x 7/8" ID stainless tubing 12" of which is about $20.00.

Then press it in to the rubber.

Would that work? If the stainless bushing was 1" long would it prevent the movement you need?

I haven't seen how the bushing works but can make these easily and the bushing could be less than 1" long if all it needs to do is locate. Hate drilling or cutting rubber.

 

[Scoobyshep]

McMaster Carr has this. Which is 2" OD x 1" ID x 1" Long and costs a little over $7 each.

You could fabricate an inner bushing from 1" OD x 7/8" ID stainless tubing 12" of which is about $20.00.

Then press it in to the rubber.

Would that work? If the stainless bushing was 1" long would it prevent the movement you need?

I haven't seen how the bushing works but can make these easily and the bushing could be less than 1" long if all it needs to do is locate. Hate drilling or cutting rubber.

It can work, the only problem that my have is getting the spacer pressed into the tubing. at 7/8 inch the spacer was still a tight fit.

More than one way to defur this particular feline.

 

[NY Tom]

Ok perfect. What are the dimensions of the spacer? Knowing that I can look for a spacer that will fit the rubber ID and the original spacer ID and length. No need for the tubing.

 

[Scoobyshep]

Ok perfect. What are the dimensions of the spacer? Knowing that I can look for a spacer that will fit the rubber ID and the original spacer ID and length. No need for the tubing.

Measured at .8765 inch. The spacer is longer but the motor mounts are conical in the inside, so the bushing is much shorter than the spacer. OD dimensions of the spacer may vary as it is coated in rubber.

 

[NY Tom]

OK aluminum tubing is available at 0.884 on the ID. Should work it's corrosion resistant but the grade is not listed.

Probably easier to just make a new spacer if the old one still has rubber on it etc.

Make the spacer OD 1.000" and the length and ID whatever is the original.

 

[Scoobyshep]

OK aluminum tubing is available at 0.884 on the ID. Should work it's corrosion resistant but the grade is not listed.

Probably easier to just make a new spacer if the old one still has rubber on it etc.

Make the spacer OD 1.000" and the length and ID whatever is the original.

Yep, Many ways to fix this.

 

[Ray70]

Not that I have tried it personally but where I work we buy precision ground rubber rollers. The manufacturer takes the aluminum core, molds on the 80D rubber then freezes them and grinds the OD to precision tolerances.
Drilling cutting and machining rubber really sucks. I wonder if freezing would work for these processes as well. However I don't think your home fridge will work. Might need dry ice or liquid nitrogen, which will pretty much negate that option.

 

[NY Tom]

I wish I could see how these mounts work. I would like to be able to help someone out by making up a set to try.

Without knowing if the bond from bushing to rubber is really important hard to say.

If the motor is just sitting on the rubber and the bushing and spacer only keep it in place then it might be OK.

If somehow the strength of the rubber bond to the bushing is supporting the motor then maybe not. Based on the original post it sounded like it might work.

 

[Ray70]

Maybe we can get you pics. On the 002 / 003 the bond is the ONLY thing keeping the motor and gen sitting correctly because the mounts are sideways so the weight is in a shearing action trying to shear the rubber off the metal housing.
Being that the housing is hollow, once the bond breaks the motor falls about 3/4" until the center aluminum bushing hits the inside top of the metal housing and the steel casting of the other half of the mount.
The weight is no pushing down on the rubber mounts, it's all sideways.
A picture will be worth GOLD to understanding it!

 

[Ray70]

here you go...

 

[Scoobyshep]

maybe this will help

 

[Ray70]

Ah, yes! When the rubber adhesion of #17 fails, #20 falls down until it hits #19 and the engine now sits crooked.
Still works and runs fine, just looks wrong because it's crooked.