I have decided to make some urethane motor mounts for my car while. I basically made them just like they are described in this thread.. https://www.rx7club.com/forum/showth...5&pagenumber=3

I am also going to add some 60 shore urethane and a 1/8" steel washer to the bottom to try to absorb some of the vibrations.

Here is a pic of the mounts themselves


Here is a pic of the 60 shore and washers.

 

where did you find the 3 inch urathane rods? and how much did they cost you?

are you keeping the band? i read that the other guy tossed them

P.S. very nice

 

I used the same stuff as Damian did, part #8695K653
at mcmaster carr.

I thought about not using the straps, but I really don't see what harm they do, and along the same lines I don't see what good they would do with this design. I think it is really up to you whether you use it.

 

ok i read the other post. let me outline what i understand the process to be.

-cut the main portions 2.1" & 2.3"
-use a 3" long bolt to hold it all together.
-on the bottom side of the engine cradle, you can used either a drilled hockey puck or a 1" piece of urethane in order to reduce "pull vibration"

and that is the whole nine yards?

could you use a .75" piece of urethane on the bottom(this would allow you to use one 6" rod instead of buying a longer 12")

 

I used 1/2" thick 60 shore for the washers under the bolts. I figure the little softer material will offer a little more dampaning. I think that 1/2 the thickest you would want, any thicker and it is going to stick below the car.

A 3" bolt will not be long enough, you will need a 3-1/2 without the extra rubber, or a 4" if you add the 60 shore like I did.

 

thanks for the help and for the great pics.

 

What are your thoughts on possibly going with 60 Durometer bar?

Cheers,
David

 

how about making a bunch of these for those of us that don't have the time or skill and saving us some money on mounts while making yourself some extra $$ at the same time?

 

I think that the 60 durometer is to soft for the actuall mount. It is about the same as a car tire, I think it would flex to much side to side.

 

I wouldn't be against it, How much would you be willing to pay for this setup? If there is enough interest, I would do it.

 

..... tips its hat to you. Good going.

 

Great post. I only have some questions:

Is this the length? This means the left and right motor mounts are not of same size?

What should be the diameter of this bar?

 

i would probably have used a much bigger urethane washer, the ones i run are about 1" thick, anad about twice the size of that, you want it to mold around the subframe, most of the driver's side force is exerted on that piece

just my $.02

 

i tried 60, it's about the same as stock, a torque brace would still benefit you

with 80-90shore, torque brace is unnecessary

 

Only if you have one of the aluminum mounts and one of the cast iron pieces. The aluminum mount is thiner then the cast iron mount. If you have two of the cast iron one the length should be 2.1" or so.

 

Great Job, I will be undertaking this project soon as well.

 

what diameter are the bolts? M10, M11, or M12?

 

Most people have been using 3/8" bolts, which are about equivilant to M10.

 

I poured my own, with the stock parts, melted away the rubber in a fireplace, the built a cylinder out of a thin sheet of aluminium and the poured the polyurathane solution into the cup (I had help)...

The question that I'd like an answer to is, how do you like 'em !?

Performance wise I love mine, no more sifter movement, during wot, but there is a significant amount of vibration below 2k rpm... that is transferred to the frame... unavoidable I suppose, but do you think the trade off was worth it !?

 

I have a solution for the vibration. Feel free to try it since I don't know when my car will be running. It's pretty simple really. Cut some "Dynamat" circles and stick them to the bottom of the mounts. If you need more then do some patches in between the the car body and the motor cradle (whatever it's called).

 

I don't know if anyone has addressed this but if you look at the stock motor mounts, the bolt that attaches to the mount itself is independent of the bolt that sticks out of the rubber. I see everyone is just using one bolt. Is there a problem in doing this?

 

Yes in the stock mounts it acts like

L
T

kind of like that except they're two "T" one upside wown one right side up, and the t is really a round plate with a bolt on it, and they sit opposite of eachother with some of the suspension material in-between... to "isloate" vibrations...

The ones I made are stock, just with new suspension material used. The ones with a bolt trough will most likely be barsher since metal is harmonious, as in transmits vibrations. But as I don't have both, I can only speak of my method...

 

Update time- I have the car running and have had a chance to test out the mounts. I have to agree with everyone about the vibration being noticeable under 2000 rpm's. Get the car above 2000 rpm’s and you can hardly tell, it is baby smooth to me. I haven’t had a chance to beat on the car yet since it isn't tuned. I will give more feedback later. All and all I am very happy with the mounts and don't have any intention of removing them. I think that the benefits outweigh the negatives. Oh and it sure beats buying on of those pointless torque braces.

 

That is a great idea. What durometer is you urethane? How is the bond between the urethane and the stock mount? This would be my only concern with this style, all the motor's force is pulling up on the one mount. How long have you had them on the car? How are they holding up? I am sure there is less vibration with your method, but I would be curious to see how much less.

 

The torque brace is not useless. I have urethane mounts and a torque brace. You basically gave the answer to why. The engine is still pulling in one direction. The torque brace give you bracing from a different direction within the bay.

By the way after about 2k miles the urethane mounts soften up and you can't feel any vibrations.

Chris