Motor mount failing

#1

I think I have a motor mount failing and am looking for input from smart folks. Assuming I’m understanding what I’m seeing, I have a couple ~ 1.5" thick yellow plastic bushings that I think are aftermarket motor mounts. The one on the passenger side is near the exhaust. It looks like heat and compression have caused it to fail. It is “mushing” out such that it’s origonal donut shape is very distorted and it’s lost ~1/3rd of it’s thickness.

Questions.

  1. Cause of failure? Might there be an underlying issue that cause premature failure. My car has about the equiv of half a race season on it, and on that motor mount. Seems like it ought to have lasted longer than that.

  2. Should I care? Maybe the heat of the exhaust commonly damages the passenger side engine mount and maybe losing a third of it’s thickness is no big deal. A little hard to imagine, but what the hell do I know?

Thanks guys, -S

#2

The stock passenger side motor mount had a heat shield that covered the mount so it would not melt. This part was probably discarded when the new mounts where installed. You want to replace that mount, and find a stock heat shield, or fab your own to keep it from melting again. Don’t run the motor mount if it is not the same thickness as the other one.

#3

Thanks for the info.

Do I need to replace both motor mounts to ensure that both have the same compressive characteristics, or can I just replace one and assume that they will be mismatched somewhat?

Is part # 10 at the below link the heatshield at issue?

http://www.realoem.com/bmw/showparts.do?model=1413&mospid=47322&btnr=11_0073&hg=11&fg=10

Thanks a lot,
-Scott

#4

Yes, #10.

You can just replace one if need be.

I have a spare heat sheild for the passenger motor mount that I can bring to RA if you can wait that long. It only needs two small bolts/nuts to install, just make sure you have the piece that it attaches to.

#5

Yes, you do care. If the mounts fail, the motor can rock forward and the mechanical fan (if there still is one), will rock forward on hard braking (10a at Road Atlanta) right into the lower radiator hose and cut a hole into it. In the same vein, do yourself a favor “while you’re in there” and put poly tranny mounts in as well if they aren’t already. Will help locate the shifter points for you.

Like Haynie (87isman?) said, just buy/make the heat shield.

My guess is that the yellow ones are Ireland mounts. FYI.

#6

Here is a picture of my failed IE.

#7

The latest issue of Grassroots Motorsports has a little write up about this in their Spec E30 project.

#8

You guys really kicked ass on answering my questions from every angle. My tranny mounts were replaced so I went ahead and bought a motor mount from Ireland, and found the heatshield components at Strictly German. Y’all are a credit to your race.

And goddamned fast too.

155MPH, thanks, but I wanted to get this wrapped up before 22-24Feb at Roebling. I figure I owe you a couple beers for making the offer tho.

#9

Ranger wrote:

Pardon the thread hijack :silly:

You’re going to be out at Roebling for the CCA event coming up?
John and I will be out there too, as well as Don Stevens - we’ll have to try to catch up with you. With 3 spec e30 cars there, we can start our own “compound” in the paddock :cheer:
It’s our first time out to Roebling - always fun to learn a new track! We need a little seat time there before we try to come out and play with the rest of the folks…

Natalie

#10

natblack wrote:

[quote]Ranger wrote:

Pardon the thread hijack :silly:

You’re going to be out at Roebling for the CCA event coming up?
John and I will be out there too, as well as Don Stevens - we’ll have to try to catch up with you. With 3 spec e30 cars there, we can start our own “compound” in the paddock :cheer:
It’s our first time out to Roebling - always fun to learn a new track! We need a little seat time there before we try to come out and play with the rest of the folks…

Natalie[/quote]

Cool, I’ll be there Fri-Sun. SpecE30 area is near turn 3. Turn left after entering the paddock area. Can’t hang out in the evening much tho. Gotta get home so I can keep the divorce lawyer at bay. Come for the Friday Seat-Time event if you can. More track time/dollar with them.

#11

I run in PRO3 here in the Northwest, and there has been a discussion lately on engine mounts. It has recently been brought up that our rules call for no change from stock, with a stay rod allowed. This was news to many, since like me, most are running aftermarket mounts.

I’m curious what the SpecE30 rules are?

Scott

#12

motor mount bushing material cannot be solid and must be the same height as the oem mount.

#13

FWIW, i’m using the AKG 75D poly motor/tranny mounts and they told me i don’t need the heat sheilds, the material should hold up fine… shrug

#14

I’m running the same ones - but with heat shields. I didn’t see where in the rules I could remove them…unless they are part of the exhaust or motor mount install required it. I’m sure one could argue either one.