Aluminum motor mounts

[Nthe11s]

bmw also has very little body flex. They tend to be designed very rigid.

The ford's I own, they flex a bit more than the bmw's and other german designs. The germans like to alloy, what kind of aluminum do they use?

4.6 v8 is very smooth in the delivery of power, at least mine is in my svt. course, I can get the body to flex, launch or twisties...

Strip launch's will put instant stress and twist in a body in ways a road car will never see unless it's bouncing off a wall.

Not good, not bad, just a bit different...

If it is not a proven design , I'd put a safety chain/strap on it to keep it from eating other parts up if it decides to let loose.

Just my opinion.

yes, for the test i will have it chained or straped. i will update with pic and results soon.
Thanks Rich

[Fishy Jim]

Trstek, I'm not sure what alloy they use, but you're right - the whole rear suspension and sub frame on my e39 is aluminum, as are the front suspension arms.

What I was getting at in the other post was that the thickness of the plate was getting excessive and that it still didn't provide the rigidity to counter the flexes the engine will induce on it. Boxing the section would eliminate the issue.

[Flyingpig]

First Ill say Im not familiar with the 4.6 or the body youre using.

If youre going to use solid mounts forget making your own like that and use motor plates. These are simply flat plates bolted to the front of the block and bell housing. They are ultra simple and you can usually get a universal design which you can trim for your specific application. You will have to add shim material between the flywheel and converter to insure proper engagment to the pump.

Should you doubt the integrity of the simple design keep in mind that is what is used on those 6000 horsepower fire breathing nitro cars. My digger uses the same thing even tho its only an 8 second car. Working on the car is faster as the engine can stay put as you pull the trans and vice versa. Having the mounts in the middle of the block will require supporting one end of the parts that stay in the car. Installation and removal will go much smoother as you wont be reaching into a dark hole trying to get a bolt started.

[pro70z28]

I agree with the motor plate/mid plate idea.

IMHO I wouldn't use shims on the converter though. I'd have the correct extended mounting pads welded on the converter by the manufacturer.

[H80N]

Fishy Jim
had you done a (bmw) v8 conversion in your e30?
thanks
Heiti

[turboglenn]

I"ve made some aluminum mounts on a few cars in the past (mainly hi-po 4 and 6 cyl apps) And one thing that tends to be prevelant in all of them is the "ovaling" of the main bolt hole on your standard type of mounts where the main bolt joins the 2 pieces together.

If possible use either steel or some 7075 inserted as a "sleeve" for the main bolt to keep it from ovaling and make sure it runs the full length of the bolt. Basically you would be using the steel/7075 in place of where teh rubber isolater is with it's sleeve for the main bolt to help the mount last longer.

I would agree with most others about staying away from AL for motor mounts, Personally i would use some stainless on them unless you area dead set on AL. 6061 and 3105 are going to be your only heat treatable and weldable alloys if you do go with AL

An engine plate of 6061 + 2 mounts towards teh rear would probably be the optimal setup IMO.

[Fishy Jim]

Nope, just did the conforti chip, a few things to the intake and exhaust, pretty much replaced the whole suspension with racing stuff (including lower rear end gears), and shaved a lot of excess weight. SCCA wouldn't let me run in anything but modified class. So I just drove the heck out of it on the street.

I'm not sure what I would think of the 4.4L in that small of a car. It's pretty potent in the 4000# 540. I'd love to get my hands on a M5 version of my car, I don't really care for the new ones styling. Right now I just have eibach anti-sway's and 40 series 18" rubber. I'm torn between replacing the shocks and springs and just cutting a coil or two off the stock springs. I like the ride quality, but I'd like it to be a little lower and not so squishy in corners.

[Blackbird455]

Smooth delivery or violent delivery, I still wouldnt use aluminum. The last Pontiac 455 I built had a habit of destroying mounts. we solved that by bolting a chain to the front of the cyl head, and leaving about 1/2 " of slack in it. My point is this though, I saw the aluminum mounts on a few "fast" cars and if there is one place that I would spend a few extra pounds it is on the mounts. I agree that the 7075 machined mounts would be tough, but have you priced a chunk of that lately? You could make 10 sets of mounts in half the time out of stainless for 1/3 the price. And you cannot just reheat the 6061 to get the strength back, it is a delicate controlled process, that involves pre-heating and time @ precise temperature.