I’ve noticed the crack pulley (8 slot) doesn’t appear to be running true, is this the start of LWSC problems?
It doesn’t appear to be loose (the pulley or the bolt).
Whats the best course of action?
DTI the pulley then a belt change and inspect the crank, refit and hope it straightens up?
Is there any aftermarket pulleys available with a tighten tolerance, or ones I can machine to suit?
What torque is required to tighten the crank bolt? Sorry I have no manual for the car 
this might have to change!
Other than this worry I love the car!
Cheers,
Dave
G’day Dave
It’s sometimes difficult to tell if the pulley is loose with all the belts under tension, i would slacken all the adjusters and then see if you can move the pulley. Another check before doing that is to have a look at the timing, if the key has broken the crank moves in the pulley and takes the timing with it. Standard on an MX5 is 10 before TDC, but might have been adjusted to 14. Standard torques for most bits are in the General FAQs, here’s a link to the torque tables
Has the performance deteriorated at all? Often with pulley failure the car performs badly to about 4kRPM and then goes ok.
Several people have had problems with cranks on newer cars, and it has, in most cases, needed a strip down of the pulley to identify the problem. Good luck with the checks and let me know how you get on
Thanks Geoff,
I’ve not noticed power dropping off, but I’ve not had it that long. It doesn’t perform bad under 4K, but 4K is when it seems to be on cam.
I’m going to wash it on my way home, then park it up untill the weekend, when I can check it over and report back.
Well I didn’nt have time at the weekend, but I had the afternoon off and braved the wind and showers to strip the pulley off.
I am no expert in these matters, all I noticed was the key was loose (in and out, not side to side in the slot), i popped a little thread sealer on it and gently tapped it further into the key way.
I cleaned the pulley and crank nose then reassembled, with thread lock on the bolt, and thats about as far as I got, forgot to borrow a torque wrench and I’m not conviced it’s anywhere near tight enough as there is so much back lash in the engine (got it in 5th with the hand brake on). Pulley didn’t seem loose, had to pull it on with the bolt
Took a few bad pictures, see below.
There was a small patch of rust on the crank shaft and on the inside of the pulley bore, I am guessing this is because there is or has been a gap there, ie the pulley doesn’t or didn’t sit right.
I guess I’ll just have to see whats it’s like when it’s back together, unless anyone can spot something obviously wrong!
Fingers crossed it’s ok!
From what you’ve written it all seems normal. Torque for the bolt is 160Nm.
I’m a little concerned about torqueing up the crank bolt a significant time after originally tightening it.
The loctite you used is designed to harden in the absence of air, so, soon after you originally tightened it, it set, providing a vibration proof fixing. When you apply the torque wrench at a later time two things happen, the loctite bond is broken, and, more importantly the loctite remaining in the threads changes the frictional feature of the bolt/crank.
I know it’s a pain, but I would be inclined to remove the bolt, clean the threads and reapply loctite before retightening the bolt with a torque wrench.
Good Luck
Thanks for your input chaps and fingers crossed it’s all ok now.
Removed bolt, clean, thread lock applied, torqued properly, new belts and everything seems to be good, not belt noise I was getting before etc.
It is once again a joy to drive! [:D]