ericdwong

For those of you who have the P/R motor mounts, you know how much vibration those things caused. Being as I am semi luxo and semi performance oriented, I wanted to stiffen the motor mounts to reduce some of the slop and flop. I had these in for about a week exchanged them for new ones and then decided to get rid of them. They didn't fit on the car and were almost impossible to get on and off. The vibration, noise and harshness was just too great. I was prompted to get the P/R mounts because I broke my stock rear mount on the crossmember.

I had this idea before, but just could not think of an appropriate material to "fill" the motor mount with. Then I came across this site (maybe it was somebody here) http://www.geocities.com/CapeCanaver...-r/mounts.html (cut n paste it). I got the 80 Durometer Shore A polyurethane resin which is a 2 part mix from http://www.mcmaster.com part number 8644K11. It is about $20 for enough to do many motor mounts. Very interesting stuff indeed. The base and activater are both liquid by themselves, but when you mix it, it turns hard. For those of you who don't know what Durometer is its a hardness measuring scale. This is a relative scale comparing the different "Shores." from the McMaster supply web page, so you can see about where 80 Shore A stands.



In the mean time, I had tried to fill the existing lower 2 mounts on my car with polyurethane roof flashing sealant from home depot for $2 a tube. My attempt was also to fix my busted mount. This stuff proved to be no good at all. It didn't adhere to the rubber and a few weeks later I find my rear mount leaking casue the inside never dried despite curing for nearly a month. WHen I drive around, theres so much flop on the on and off of the throttle. And, there is alot of clutch chatter making the car uncomfortable, and it sounded like somethin was banging around in the engine bay.

I bought a brand new rear motor mount from Nissan and prepped it for $70 from the local dealer (NOT the one who gave me a $#!t fit before). When I got the mount, I noticed that there was a pocket of something that was jelly like beneath the rubber above the "open" area that I was going to fill. This would not be good for what I wanted it to do, so I took a knife and gashed it open thinking it was an air bubble. Boy was I wrong as a ton of liquid came gashing out. I cleaned it all out with brake cleaner. I dried the entire unit and then ductaped sealed one side of the mount. Then, I took the polyurethane, and mixed it 2 parts base to 1 part activater by weight using my parent's postal scale (accurate to .01 of an oz). I waited maybe 15 minutes or so until the polyurethane had the right thick consistency that was pourable (like thick syrup), but would not leak out of the duct tape. I poured it all in, making sure to get rid of any air bubbles I could by ramming a screw driver into the loose rubber. I let it cure for 3 days under artificial heat. The results looked really good. The polyurethane was black, smooth, consistent, and hard.

So today, I removed my old mounts by dropping the entire crossmember, and the rear one was toast indeed. It wasnt doing a thing at all, it was so bad I could move the bushing sleeve with my finger. I put the new motor mount on and then put everything back together.

Word of advice when doing motor mount projects-do not tighten down any of the mounting bolts or nuts until AFTER everything is situated in the right place cause you'll need the few mm's of play. Also- support the motor with a jack and be sure to use jackstands. To get to the rear motor mount's rear bolt, unbolt the driver's wheel and get together about 2-3 feet of extensions for a socket. Then stick a 17mm socket in there to undo the thru bolt. If its stuck, get some kind of pivot point. Also, take off the front splash gaurds to save you from alot of swearing.

So, once I put the motor mount in, I started the car. There was a tiny bit of a shock, but nothing like the P/R mounts would do when the motor kicks over (if you got P/R's, you know what I'm talkin about). I put the car in reverse to back the car out of the garage, as I slowly let off the clutch, I immediately noticed that there was NO clutch chatter!! It was smooth! The car was still at high idle, so I didnt know if the car was gonna vibrate or not. After some driving around, warming up the car, there isnt as much flop in the drivetrain. THe car chirps 3rd gear pretty consistently now. Sitting at a stoplight produced something unexpected. The car actually felt QUIETER then it did before at idle!! This is probably now because the motor has all the support it needs, instead of with that busted mount putting a strain on all the others. But the best part was that it had zero vibration. That was my biggest concern. Car felt almost like a new car.

I still can get wheel hop if I hit it just right. This is probably cause I only toughened up one of the mounts, and I'm still on a stock SE suspension.

I'm going to the drags strip tomorrow night. I hope I wont break anything, but it should be interesting. That rear mount should definately not break now, as there is no room for the rubber to move to. As for the other mounts, I definately plan to do them, but only one at a time to see what happens with vibration. My next candidate will be the front torque strap mount near the radiator. Fortunately the "caulk" i put in that one didnt adhere to the rubber well at all and I'll be able to clean it out.

Overall, I consider this project to be a complete success. I'm really happy with the result.

Jeff92se

iTrader: (82)

Nice write up. I'll stickie it and maybe someone will incorporate it into a faq later.

Check you Pm also

BriGuyMax

iTrader: (1)

nice write up eric! I'll have to try this myself....

did I hear someone say "sticky"???

dwapenyi

iTrader: (3)

Man Eric, you certainly do play hard, McD's trays comes to mind but you also work hard Good job.

DW

pocketrocket

iTrader: (1)

I agree, your effort deserves to put you in the sticky!

I think you're starting to love your Nissan again

Did you resolve the rust at the sunroof issue? You had me paranoid after your post, so I looked at mine after going to the carwash. I found a little scuff, couldn't figure out if it was rust breaking through or just an uneven weld spot, so I'm going to attack it with some anti-rust and silicone.

xHypex

iTrader: (1)

Great writeup indeed. I'd seen that DIY page, but I've never worked with engine mounts or polyurethane before so I decided against it. Now we have an alternative to stock mounts and the PR mounts too! The only question I have is would it be ok to reuse your old mounts or would new ones be recommended? My mounts aren't broken, but I feel that they may be weaker because of my wheel hop :/ Also are there any pages that deal with removing engine mounts? I'm still making my way up the DIY ladder
-hype

OriginalMadMax

A long time ago I wrote up the "$.02" engine mount project, which was to cut a section of rubber hose and squeeze it through the gap in the rubber motor mount. It actually worked pretty well to cut engine movement. I could immediately tell because my stick shift wasn't rocking back and forth from throttle input.

Well, I finally got the PR mounts. The rear went in just fine, but I had trouble with the front not fitting (holes didn't line up well). I contacted PR and they sent me another, then another. I finally enlarged one of the holes on one to get the bolt through, and then sent my stock unit back to them so they could check their jig. Hopefully the next one they send will be a perfect match. Meanwhile I have a couple of extras I'll sell cheap (less than Eric spent for making his) that will work if you grind a bit.

IMHO, replacing even one engine mount (we're just talking front and rear, since those are the ones that affect wheel hop) will make a difference, and it won't be as rough as doing both. When I did the $.02 fix, I only did the front, and I could tell the difference.

blueghost75

I like the idea of getting rid of the vibrations, and the transmission jerky thing when you move your foot off of the gas. I may give the $.02 project a try, as long as it is not too hard.

OriginalMadMax

This is as easy as it gets. Cut a piece of rubber hose as long as the mount is wide. Use the hardest rubber you can get through there, which probably is not the hardest hose; it will have to collapse flat. It may not have given me all the potential of the PR mount, but it was pretty darn good!

blueghost75

unfortunatly, as of right now, I don't even know where to look for a motor mount. I will whip out my haynes manual and pop the hood and start tooking when I next get a chance. I should be able to figure it out real quick

Nismo87SE

Here are pics of my homemade urethane mounts.

Erock

Eric,

On this motor mount project... did you actually cut open all the motor mounts and pour out the liquid? Or did you just fill the small gaps with the polyurethane? I am kind of weary of cutting open the mounts without knowing exactly what to do, but I have them both out and ready to go!!! I just need a little help in this area. Please be as detailed as posible, I am waiting with baited breathe.

Thanks,
Eric

ericdwong

The area above the gap in the motor mount, there is a "bubble" of what appears like jelly under the rubber. This is actually liquid. What I did was use a knife and gash this part open in order to pour out the liquid. Then I used some brake cleaner and waited for it to dry. I stuck a large flat head screwdriver in tehre to hold the opening open. Then, with one side of the motor mount sealed with ductape, I poured in the polyurethane mixture while it was in a thickened liquid state. Using that screwdriver, I made sure that all the air was worked out of the mount. Then, just let the thing set for the next 3 days or so and you'll have yourself the mount. I still have only done one, and am going to do one at a time, to observe changes in performance and vibration. Next on my list is the front torque strap.

Matt93SE

iTrader: (44)

I would highly recommend waiting more than 3 days on the urethane to cure, unless you've got it in the oven he whole time. I failed to wait long enough making some on my car, and the urethance "sagged" a bit and I had a 1/2" of play in the mount where the shaft had shoved itself through the rubber form the weight of the engine.

the fix was simply to put my OEM mount back on (I had an extra), then fill the hole with urethane and let it set up again..

that was on my GXE auto, and it even made a huge difference in driveability of that car. there were a few small vibrations at idle, but nothing horrible. it didn't feel like a Ford Tempo or anything, but it wasn't the silky smoothness I was used to from my car.
If I shifted to neutral, it was so smooth that I couldn't even tell the engine was running without looking at the tach.

ericdwong

Ahh yes, this is why it works so well with sticks. If the clutch is engaged, or you are in neutral, either way theres no torque converter to idle up against, so no vibration.

Nismo87SE

I noticed the samething in my maxima. I did the engine mounts one weekend and did the tranny mounts about 3 weeks later. With the engine mounts it reduced the vibration some and there wasn't any flop anymore. However once I did the tranny mounts man the car idled like it was brand new. I couldn't even feel that the car was on it so smooth in park or neutral. Not to mention I could feel the shifts, now there weren't hard shifts, its hard to explain. Actually I believe you can feel the pause inbetween shifts would be more accurate, since my 87 max had the stock VB the slushbox shifts were more noticable.

OriginalMadMax

What trani mounts did you put in? Haven't heard about these before.

Nismo87SE

Mine were homemade urethane mounts. I had pics but I have no where to host them.

ericdwong

I finally got around to filling the remaining 3 motor mounts left. This would be the front torque strap, and both upper mounts. The quantity of urethane provided was perfect in doing all 4 mounts. Anyway, I was afraid that all 4 mounts would vibrate the car like crazy. So yesterday was the test. I put all 4 mounts in. They fit in very well, no forcing needed whatsoever. The motor was solidly in place, it did not want to move at all. I started her up, and it was still smooth as can be. Not even that jolt from startup when the motor kicks over. I drove around, and its wonderful, it significantly cut down that imfamous flop and slop of the Maxima drive train. There is still some play, but thats most likely from other things including the unlowered 70,000 mile stock suspension. Best of all, at 500 RPM idle the car feels smooth, without vibration, and still feels refined. Taking off the clutch chatter has been minimized as well. Driving is pretty interesting, the car feels much more planted and connected with the road, with no harsh side effects. Too bad I have my OEM Y pipe on the car right now, so I can't enjoy the full potential of the car.

I can still get wheel hop if I hit it just right with the clutch, but its much more controlled then before. Hopefully lowering the car, and/or those Radius Bars will be the ticket. Cause my car did it even with the zero engine movement P/R poly mounts. Otherwise for the $20 or so I spent for this, and the time needed it was completely worth it.

ericdwong

I was having a horrible time before I solidified the mounts in the rain with my car's setup. It would hop like crazy at the upper range of the RPMs in 1st gear and also if I banged 2nd gear hard. Well no more! Today it rained so I went and had some fun in the parking lot of the high school just to see if my motor mounts cured the wheel hop. Yup. The car will spin both wheels in the rain without wheel hop! I'm very happy.

xHypex

iTrader: (1)

Eric I know you already mentioned that you used artificial heat on your first engine mount, but how much downtime would be required to cure the engine mounts correctly. My engine mounts seem to be in pretty good condition, but I don't think I can have too much downtime this summer because I will need my car. I considered buying new engine mounts to let them cure for a while and then installing them, but if I can avoid this I'd like to since OEM engine mounts aren't exactly cheap. Also do you think it's worth it to treat all 4 engine mounts, or would the front and rear accomplish about the same thing?
-hype

OriginalMadMax

Cattman and PR just went with the front/rear mounts since that is the major axis of movement. Frankly, when I did my $.02 fix on the front mount alone, that took care of about 80%+ of the excess movement.

Eric - now that you know you can spin both wheels in the rain without hop, one word - Quaife!

ericdwong

Hehe, artificial heat was my fancy way of saying using a 100 watt or so incandescent bulb in close proximity to the mount. Since the mounts are black and the urethane is also black it soaks up the heat well. The downtime will be 3-5 days to do it properly. I'd go all the way to treat all 4 mounts, only because 1) you get enough material to do it and 2) it didnt worsen the ride or idle any and 3) with only doing the lower 2 mounts, the engine still has a tendency to twist transversly being the way it is mounted, and seeing how the transmission is at one end with a huge driveshaft on the other.

ericdwong

Yea that was _the_ most time consuming and expensive mod I have done to date on any car. It was worth it though. Now, my pet peeve is any car that does not have some sort of LSD/ATB differential.

KWheelzSB

iTrader: (1)

At least 1 of my mounts is bad, so considering doing this. . .


1) After a decent amount of time (a month or more), have you noticed any sagging of the polyurethane material around the mounting bolt sleeves?

(I want to be sure the "80A" McMaster-CARR stuff has been holding it's shape, and if it isn't, maybe I'll use the next harder compound ["94A"], or make sure I give it an extra amount of time to cure)

2) Does anyone know what the Durometer rating is for the polyurethane compound used in the Place Racing mounts?

3) If you had to do it over, would you get the 94A compound?

4) I have a 5-speed: would you anticipate any problem with removing & treating one mount at a time, and driving the car very gently while it is out & the poly is curing? (Car is my daily-driver, so I need it).

Thanks in advance to all!

ericdwong

Originally posted by KWheelzSB
At least 1 of my mounts is bad, so considering doing this. . .


1) After a decent amount of time (a month or more), have you noticed any sagging of the polyurethane material around the mounting bolt sleeves?

(I want to be sure the "80A" McMaster-CARR stuff has been holding it's shape, and if it isn't, maybe I'll use the next harder compound ["94A"], or make sure I give it an extra amount of time to cure)


No sagging that I know of. This stuff is rated for temperture extremes so under the hood temps shouldnt be a problem.


2) Does anyone know what the Durometer rating is for the polyurethane compound used in the Place Racing mounts?

Felt like 90 or so to me. That stuff was super hard.


3) If you had to do it over, would you get the 94A compound?

Probably not, unless you wouldnt mind the possibility of increased vibration.

4) I have a 5-speed: would you anticipate any problem with removing & treating one mount at a time, and driving the car very gently while it is out & the poly is curing? (Car is my daily-driver, so I need it).


I would not recommend doing this. At the bare minimum let the things cure for at least 2 days.

KWheelzSB

iTrader: (1)

Thanks for taking the time to reply, Eric - much appreciated!

ericdwong

I responded to your PM's but your mailbox was full.

dmbmaxima2k2

iTrader: (1)

just ordered 2lbs of the poly and 4 motor mounts. i hope to start an exchange program for 2k2's with this too.

matty

iTrader: (54)

Anyone else succesfully fill there mounts with this poly stuff from McMaster Carr ?? Im odered three new mounts..tranny, front and back, and Im probably going to fill the front and the back only...anyone else do it, Vibrations, clutch chatter ??

-Matt

BEJAY1

iTrader: (19)

Just finished mine. Wanted to add some advice to the original thread. Seal up the backside of the mount real well with whatever tape you use. I used clear packing tape and didn't have a good enough seal in some places. The stuff ran out while I was pouring and working it into the crevices. Wound up having to tape more while it was still liquid - what a mess. Would suggest after mixing the McMaster stuff let it sit for like 20-30 min (was 60deg at the time) so it just starts to thicken. That way it'll still flow but won't run out as easy. Finished product looks good and cleans off easy though.

matty

iTrader: (54)

I did 3 of my mounts about a year ago. Both engine mounts, and trans mount. Well a year down the road both engine mounts are good and the tran mount has fallen apart..the rubber fell out and thats it. I did it the same as the other 2, but i dont know what happened

emmas97

ok i am thinkin of tryin this on my max, does anyone know how these hold up to more torque and hp? i have a 3.5 bottom end and jwt cams so im pushing somewhere near 300 hp and i just want to know if these will survive the abuse and stuff like that. also when you order it, is the hardener and activator under the same part number? any input would be greatly appreciated. thanks

Matt93SE

iTrader: (44)

I've had some poly filled ones in my car for a couple years. they hold up to severe abuse and track use with 200hp, so they should be fine for 300hp as well..

when you order it, it will come as a "kit" with the resin, mixing stick, and the hardener all in a box.

Sprint

iTrader: (10)

its up and running? got pics?

emmas97

no pics yet...it looks virtually the same but you can have some pics anyway when we get around to takin any.... we will have to borrow someone else's digital.....and it runs awesome, no problems yet.... the clutch cant hold enough power tho, so there goes more cash that i dont have....

skeelo34

iTrader: (4)

I've done them....work pretty well without much noise inside the car.....

Sprint

iTrader: (10)

oooohhhhhhhhhhhhh your Robs girl

emmas97

yes i am the lucky one

ThurzNite

iTrader: (13)

if i use the whole can and hardener, can i fill all 3 mounts?

Jae