I received this from another member: SVTCOBRA

Please tell me that when your 181mm shereed the keyway on the crank that you didnt have to get the whole crank pulled out and that all you did was relpace the keyway. i hv the 185mm and it tore the keyway off yesterday

I believe that he intended to replace the KEY, which can be done if the keyslot is not augered out or deformed to be loose.

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Greetings: Iam copying this for the forum, so that all can hear my actions and answer to svtcobra.

I had my engine hit high intake temp and the motor cut power, which at about 6000 revs, caused the engine to loose power suddenly and do a nose dive. The pully inerta forced the key ( shear key) to shear off and strip out a portion of the keyway on the crankshaft as the engine violently slowed. The now loose-flying pulley bent my crank, opened the oil pan with a nick, squashed the water pump, and MISSED all the radiator fins.

I used force and a dial indicator to straighten the snout of the crank, replaced the water pump, belt, and such to get the car running.

The crank was in the car and I am crazy ( only on days ending in Y) but decided to not pull the crank. I recut the keyway in the crank and widened it to allow me to use a longer FULL length key that was wider. I used carbide dremel bits to cut the keyway and a special file that I made to make a clean square key-slot in the crank. Thankfully pulley position is not important to the operation of the motor and I did not care if it was advanced or retarded a degree or two.

Please use a new crank bolt as they stretch and are torqued to allow full retention of the pulley. However the pulley was not to rotate on the crank in any case, the key was to prevent this. I have a serious key now, as my 185 mm pulley has larger than stock loading on the crank, Iam feeling covered now. THat was a year ago, and many races too.

Enjoy, Woody

 

What? I hate trying to read what was typed on a cell phone. I'd be nervous with a jury rigged keyway. And crushed with a buggered up one. I love my lowly Code 3. May it live forever.

Les

 

if im reading it right les woody had a keyway shear and thats how he fixed it . he was relaying the info to the member who sheared his keyway after his "mechanic" installed the bolt with an impact wrench instead of properly torquing the bolt
LONG LIVE MY C3!!

 

Gosh Woody! I was wondering where you'd been. You need to get off the honey pot so we can understand what's going on.

Les

 

I might as well bring this up here.......
I bought and old 181 pulley, haven't installed it yet BUT, the instructions call for heating the center hub to over 200 degrees F in an oven then sliding it on the cold crankshaft. To me this would indicate a press fit. I have not heard of anybody else even mentioning this step. I can't see how a piece of keystock could hold 8 pounds of pulley inertia.

 

im not exactly sure if the same values apply to the v6 pulleys but on mbworld in the s/c v8 engines the torque values are ranging from 200 ft/lbs to 275 ft/lbs plus 90*. this is a huge amount of torque that ensures the bolt will not come loose .
maybe jake can chime in as to the proper torque need for the 181,185 pulleys they sell or rob for the 178

 

Sure, you get a bit of friction value there, but with slightly different thermal expansion/contraction values(crank & pulley hub), it's definitely the key that does the job. That being said, and being as though I will be installing a 181 this summer (and this shearing business is scaring the heII out of me), do we need (and can we get) a stronger bullet proof key(stock size of course)? Woody made it sound as though all of us w/ larger crank pulleys should have a stronger key. Titanium anyone?

 

Well I guess I'll just have to dissagree on this one. We'll see......

 

Which part do you not agree about? I was sort of agreeing with you. If I 100% agreed with you then we'd both be wrong. LOL.

 

Stronger keys are possible, and in some applications the key is to shear to save the machine. In our cars the key appears to me to be an alignment and securing mechanism intended to hold the pulley from slipping.. Remember that mine did its thing only when the motor went into a violent shut down as a result of high IAT onset.

THis is the reason that I did all the changes and upgrades to the cooling systems, ie the super cooler and stat redesign cause Iam driving mine hard doing autocross at full power for most of a minute-----less if I learn how to follow the course better..

I dont have any heat related issues now even in the summer races or at summit point doing 20 minute course runs. Enjoy, Woody

 

Woody, Did you custom machine a larger key, or use the next size larger off the shelf? And what grade metal is this that is used, or that you used?

 

I have had the 181 pulley on the Aero since LET first sold them....there were no instructions about heating and installing...I did have to send the first on back as it WAS too small to fit on the crank shaft by a couple of thousandths.... the replacement slipped right on like it should and has not given me a bit of problems since...... except for making my rear tires wear out faster....

The torque spec for the crank bolt is 148 pounds + 90 degrees...I used blue loctite on it also...

 

When you buy the 181 pulley kit from Eurocharged, does it come with a new "Key" for the keyway? Or do we get a new one at the M.B. dealer? Sorry for all the questions today.

 

Mine didn't come from EC.... it also didn't come with a new key... I re-used the factory key...

I may pull it off to check/replace the oil seal and if I do I will get a new key to install...

 

I got a key off the shelf and made the slot in the crank to fit it closely and opened the slot on the pulley so that it was the same width.

Our key was a semi circle and short. I have a square one that is mostly the full length of the pulley, but its not something I would do again cause of the fitting and measuring...................I bought a factory key to know the size of the stocker and went from there. Dont go there if you can and I suggest using the locktight BLUE also. Woody

 

Funny, I must have got a rev1.

from the LET Motorsports Crank Pulley Install Instructions:

Could that melt the oil seal LOL??