sheared woodruff key on crank pulley

[Robert Mangas]

Due to a design issue, this type of problem is quite common on the early 
first generation Miata.  Since it's been known for so long, the solution is 
pretty well developed (in part by a loctite engineer)

Page with pictures:

http://www.rivercityroad.com/garage/crank/crankfix1.html

Forum topic with good description of process/products by "Softop", the 
aforementioned Loctite employee (about 3/4 of the way down, dated Aug 10 
2000) and further discussion of the method of action of these products (Aug 
11 '00)

http://www.miataforum.com/ubb/ultimatebb.php?ubb=get_topic;f=27;t=000018

  Many have used this fix to avert huge repair bills.

Best of luck,
Robert



>From: "AV8oR" <zpavelic at comcast.net>
>Reply-To: zpavelic at comcast.net
>To: "Quattro at Audifans.Com" <quattro at audifans.com>
>Subject: sheared woodruff key on crank pulley
>Date: Tue, 30 Dec 2003 21:36:40 -0500
>
>Hi guys!
>
>Patient: 1987 4KQ w/ 152K on it.
>Project: Timing Belt (now Timing Belt from Hell)
>
>Looking at the harmonic balancer I noticed that the driving belt
>sprocket (timing belt) had a sheared woodruff key.
>After further inspection of the crank, I also noticed that its notch was
>damaged (about a 1/4" of the left wall is chipped away)
>(the previous owner explained, " it has intermittent compression - it
>doesn't run" )
>The harmonic balancer was definitely loose due to an improperly torqued
>CRANK BOLT!
>
>Today I found another Driving Belt Sprocket.
>
>My question is - can I just use the new Driving Belt Sprocket w/ the
>intact Woodruff Key on the slightly damaged crank or do I have to get
>a new crank? Are there any alternatives (like building up the wall with
>J B Weld or a real weld)?
>
>[ All this after I broke the Idler Pulley Bolt off and I had to remove
>the oil pump, pan and sub frame to get to it.
>... oooh I had to reinstall the Cam and Crank Seal twice because the
>casings were bent to hell and damaged from
>the previous installation - SIGH ]
>
>Any pointers and recommendations are greatly appreciated!
>TIA & a Happy New Year!
>
>Zaf
>
>PS: Can't believe that I spent Christmas Eve and Day Working on this
>thing.
>         One less 4KQ in the Junkyard!
>_______________________________________________
>quattro mailing list
>quattro at audifans.com
>http://www.audifans.com/mailman/listinfo/quattro

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