1st Gen R53 Cooper S Most liked posts in thread: Help: grinding noise when accelerating hard....

Possibility 1:
The upper pass side engine mount will not make noise in and of itself when it goes bad. However, it can allow the top of the engine to move rearward enough for your exhaust to smack the top of the gusset (i.e. the X) on the X-brace.

This can sound like a vibration, I am sure sure I would characterize it as a grinding noise though. The TSW/WMW Poly engine mount will cure this issue.

Simple test.....Remove the X-brace. The front bolts are supposed to be one time use, but I use them a few times before I get new. (44lbs +90deg) The rear ones are 74lbs. Also, inspect the top side of the X-brace when removed, do you see a little spot in the paint where it looks like something (i.e. your header) has been beating on it?

BTW, at rest, what is the clearance between the bottom of your header/cat and the X-brace at the closest point?
And how many miles on your OEM passenger side mount?

Possibility 2:
Brakes? I was thinking this one more when you indicated the noise was always after a dead stop and so I was considering the chance of a dragging pad or sticking caliper piston. I am not so strong here since you indicated you also get this from 20mph. Easy to check though with wheel removal.

 

If you only have 1/8" clearance that just is not enough.

Make sure that forward catback mount is supporting the exhaust properly.

As mentioned earlier you can add a small spacer on the rearward mounting points of the X_brace, and even grind away a small portion of the X-brace exactly where the exhaust is touching to no ill effect.

I would personally not grind-on or beat-on the cat itself. the core of the cat it very brittle and you could easily break it up with a little trauma. You could also grind through the thin walls or introduce a weak point that will fail sometime in the future.

Good Luck and congrats on the new power.

Oh and common Isopropyl Alcohol is the perfect solvent for the old dried on motor mount hydraulic fluid. Strong enough to dissolve this stuff, yet not so strong it will harm any paint or dry out any rubber it may contact. You still will need some agitation though, a small plastic bristled brush on the rough surfaces and any rag or even a paper towel wet with the alcohol on smooth surfaces will do the trick.

 

Where's the grinding coming from? If you can't hear it with the hood open and the car idling, I'd be inclined to look at the suspension rubbing. The car's going to lean back pretty hard when you get on the gas, so it may not necessarily be engine related.

 

Grab the engine (not running) and rock it front to back. You might have an engine mount that went bad. This may allow more engine rotation than normal during heavy acceleration.

 

The steam is normal with supercharged MINI's... Water gets into the engine bay through the scoop, and evaporates on various hot surfaces...

Many supercharged "S" owners learn to enjoy the "dragon's breath" coming from the scoop after a wash!

_Dave_

 

For the steam, I got steam after getting a lot of water in the radiator vanes, such as when I spray the radiator to get bugs off. It took awhile after the wash for the engine to get hot enough to create steam.

For the grinding noise;
Trying to rock the engine by hand would be a good idea.
Your X-Brace might be rubbing on the exhaust.
Another place to check, is the rear sway bar and end links to make sure they are not rubbing on the trailing arm.

 

This is less likely but check your Catalytic converter. I had one come apart on me and I thought my engine had a terminal issue. Its gonna vary a little but it will tend to sound like small pebbles in a tin can (or a hollow grinding) and it will happen most noticeably under hard acceleration at first. It will get worse.

The other thing is that a cat-con shouldn't do that unless you are running rich. So, that is a sign of a problem in the engine.

Good luck.

Sent from my Droid using Tapatalk

 

Like I said. It's un-likely. However, if you are within tolerances for running rich and doing it consistantly then it can still happen. It's not an overnight process. It's just an item to knock off your list of potential issues.

 

There are pictures in the forum that shows failed engine mounts. When they go, they do leak a black goo.

 

My money's on mini_racer's possibility 1.

CheckersSD, you mentioned a gap between the dampener body and rubber pad of 1/4" - that's usually the case when it fails. If you enjoy the stiffness of the x-brace, go with the TSW/WMW poly engine mount. It's pretty noisy when you first install it, but it'll break in after a couple hundred miles and you won't notice any more vibration.

I installed a catback exhaust and had to use 10 washers on the rear exhaust hanger on one side of the car to get the tips to line up right. After I installed the new engine mount, I had a horrible rattling sound and the tips hung to the right, so I took all the washers out. Problem solved. I was surprised how far the engine mount put the exhaust out of alignment. I don't have an x-brace, but I'd imagine if the clearance is tight, that could be the cause of your grinding.