'Morefun' and I were at Lime Rock yesterday with the Porsche Club of America. I think we were the only non P-cars running besides one other BMW 330.
Was a great time , but for this one incident. http://members.tripod.com/ghmyc_1m/lrppca2.wmv

Yes, belts do break, and when they do, it's more then just replacing it. As you can here on the video, that tensioner pulley slams down on the crank pulley, and if you have an aluminum crank pulley, as I do, then there is damage to deal with.

Dear Alta, I need a new 3%! Arrrggggg.....

This is were running performance parts starts to cost. Not only do I need to bring a spare belt to the track, but I now need to carry along a spare crank pulley.

This is how it happened. HEAR the warning
This is my second lightweight crank pulley from Alta. My first was stock dia. One day I heard a squealing when the motor was warming up. Found that it was the crank pulley and that the bolt had loosened up and the pulley had started to back out. Fixed it in time and never had another problem.
Now I am running the 3%. Remembering what happened with the first pulley, I made sure that I was extra careful with this install. Ran one track day and all was good after two hours of track time. Yesterday was a different story though as you can see. After being towed in and doing the inspection I found the same thing, a totally loose bolt with the crank pulley back out about 1/2"!
The tensioner pulley slammed down into the crank pulley, basically destroying it. I was though able to repair it enough to run the rest of the three 30 min runs and drive it home.

 

Well, you did state it correctly at the end of the video. That sucks man... hearing those pulleys and the belt grinding made me cringe

 

Bummer! Glad you were able to continue running. Guess I never mentioned that I always bring an extra belt. Jacques has had that problem twice. He's now very careful to shift before the red line, forgot where. What size is your reduction pulley?

Great vid!

 

There should be a relatively easy way to 'mod' the tensioner via the 'belt change tab' (the piece that passes through the spring that you use to hold the tensioner in the open position when changing the belt) to keep the tensioner from dropping onto the crank pulley when the belt breaks. I realize that this is even more of an issue with larger crank pulleys since these two pieces are closer to kissing range than stock.

With the crank pulley bolt constantly loosening itself: Does this appear to be caused by dissimilar metal expansion/contraction during heat/cold or possibly from harmonics shaking it loose? Does the stock and Alta pulley use a keyway (I havent messed with the crank pulley yet, so I am not sure here)?

Bummer on having this happen repeatedly to you.

 

-15% SC and +3% crank. I use the JCW belt, but can actually use the stock S belt now. Had a spare with me and tools so it was an easy fix until I saw the pulley damage. I screwdriver and a ladies emery board cleaned it up good enough ..
It was the debate in my head that was the toughest issue. Do I use this belt just to get home or do I chance running it at the track and then get home ... . Hey, I came to play right ...

 

There is and there is an company in England I believe that has one. I had just been talking with Alta about them doing one also a couple of weeks ago. They seemed to think it was a good idea. Just a bit to late for me ...
I agree and it's my thinking also. I think the aluminum heats and expands and it gets loose. I will now use RED loctight on that bolt, not to mention a lock washer.

 

You definately PUSH that car ... I LOVE IT !!!

That course, Lime Rock looks to have a lot of bumpy terrain, vibrate/knock your pulley loose ?

There is a tensioner, sold overseas

 

Careful with the red stuff. I've busted bolts trying to remove them with that stuff applied. Even with heat!

Sounds to me that this could be helped a bit too by using a thick 'belleville washer'. These are dished washers that act as springs. Care must be used to find a belleville that remains 'dished' at the torque level found on the crank bolt. This will allow 'give' as the parts expand and contract without causing the bolt to see much more than it's typical clamping force. In other words, it lets things move around if they have to without letting anything get loose (or too tight, this is also key).

 

How did you install it? This is the first I have heard about the pulley trying to come off. You used lock-tight and torqued the bolt down right? (to 85 ft. lbs) With the pulley working it’s way out it would put a lot of stress on the belt.

 

http://www.gtt.uk.com/parts3.asp

 

Sorry to hear about your problem with the pulley and belt. Nice driving! I enjoyed seeing you blow by the porsches... Thanks for sharing!

 

Yes, That is it, anyone had one installed ??? Do tell , is it hard to insatll ?

ONASLED: Where did you get your splitter-brake duct cooler piece ?

Phil

 

IMO, you shouldn't HAVE to use locktite on something like a crank pulley. The factory didn't see the need.

 

That was a great video, right till the failure :( Man I would give anything to live near a real track like that. The closest Tampa has a crappy go-cart track :( I couldn't even get out of 2nd gear! A real track experience with a Mini would start lightening my wallet FAST!

 

...... at that point i just wanted to get trough the day. i would have welded it, but ....

 

Sad story but great vid! LRP was my first track day experience ever ... sigh. :smile:

 

Yes the factory did use a locktite on the crank bolt. when you take it out it has left over blue paste on it.

 

Let me second Bear's caution about red loctite. Even with heat that stuff can be unbelievably tenacious.

Is there any way of safety wiring that bolt? Even if you just drill the head through the flats and safety wire it to one of the spokes of the crank pulley it might keep it from backing out.

I'd probably go that direction before I went with the red loctite.

 

If a bolt is properly torqued and blue (medium strength) Loctite is applied, and still backs out, there is a physical problem. Either the bolt has stretched, the threads on either the bolt of hole are damaged, something is not positioned/aligned correctly, or there is excessive vibration. Many bolts are one-time-use only for these reasons, perhaps this is one of them?

 

Guilty as charged..... this is most certainly the problem as I somehow had the wrong specs on this and only torqued it to 55 lbs!

 

Yeah the torque spec is 85 ft. lbs. I am sure that will help a lot. I have found that a good way to keep the motor from spinning around too much during torque is to have a buddy hold a large flat head screwdriver between a spoke and one of the “nubs” (nub: small metal bump) on the front cover. It gives it a positive stop to make sure you have a good torque and keeps from over stretching the belt. Good luck!:smile:

 

God do i wanna take a ride in onasled's car!!! hey dude how far are you from White Plains, NY?

 

myminiparts.com offers -

Product ID: TSB
Tensioner Stop Bar.

Details

MyMini Tensioner Stop Bar

Price: $20.00

 

Now that looks promising. Anyone have any experience with something like this?

 

One great video except for the crunching sounds.