Doing the cambelt on my 2002 1.8 sport today, I had a swine of a job getting the crankshaft ancillary pully off. Did some browsing on our wonderful site, and ended up taking the boss off complete with the pully…Hurray !
When I tried to set TDC with the timing marks by turning the crankshaft bolt, I realised that the woodruff key had come out with the boss, and the crankshaft was turning independently of the cambelt drive pully ! Durrrrrrrrrrrrrr
Am I right in thinking that simply putting the woodruff key back in will be OK?
Can I get the engine timing out by 180 degrees ?
I dont think I can as the crankshaft has to turn twice to the cam shafts one revolution.
Its been a long day and paranoia is setting in. Can someone help me sleep tonight and tell me I haven’t really messed up !
Not sure what you have done but timing is not an issue.
With the cam belt off, cam and crank move independently so you just need to synchronise the timing using the marks on cam and crank and refit the belt.
Many thanks guys ! I will sleep better for knowing !
I am Ok with the timing marks etc, as its the third time I have done an MX5 cambelt.
The stuck pully has taxed me this time though.
Once I removed the pully and boss in one piece, it was simple enough to separate the two with a drift ( socket on extension bar ) for re-installation.
It will enable me to use the crankshaft locking tool I have bought, and along with the threadlock, torque it correctly.
I will have to straighten the cam sensor plate though as I distorted it slightly with all the prying with screwdrivers etc trying to get the pully off !
The woodruff key has slight taper on one side only, and one end only, and this must be positioned in towards the engine block the taper sits in to the sloped groove in the crank itself.If this is not fitted correctly it can cause crank wobble as although bolt it tight the pulley may not be fully seated/home.The taper is very slight but noticeable if checked
I have not been able to get the crank pulley off a Mk2 or MK2.5 with just the little M6 bolts out. Only with the full crank bolt off. To much rust there by now.
That’s the crank sensor plate Richard. If it doesn’t straighten out perfectly with no damage, buy another one. Clearance to the crank sensor has small tolerance.
It would be a real shame if you had to take all this apart again to replace this part. Can’t see it available at MX5parts but surely available cheapish somewhere.
I’m sure you did this, but may I note that after a cam belt change, it always pays to turn the engine by a couple of full rotations by hand to check that there are no piston/valve clashes before you try to start the engine.
I remember getting in a mess with the timing with the the first belt I did. Expected my tippex marks on the belt to line up again after rotation - bit of a head scratching moment.
I would say it gets easier on subsequent belt changes but also easier to forget to do stuff.
Very impressed Lffsam. And as previously commented, great to see the forum operate as it should.
Mind you, I thought part of the beauty of an MX5 is that they use cam chains instead of belts. (I have an '06 2.0i sport)
Of course I’m probably showing my total ignorance here. It’s not as if I would or could tackle such job anyway!
Just the MK3(2005) on MX5 cars have a timing chain.
All MK1 - MK2.5 cars 1989 - 2005 have a cam belt. Not all bad news through as all the engines on these cars are non interference. This is rare in modern engines but basically means that if the cam belt slips badly or snaps and the cam and crank timing go haywire, pistons will not impact valves and the engine will not become scrap:-)
I don’t think anyone would call a cambelt / waterpump change on an MX5 an easy job. Aside from the expected work involved, once all the covers are off there is often other damage that needs repair or parts that require replacement. It is also a good opportunity for the proud owner to clean all the oil and dirt off parts that haven’t seen the light of day for a year or two.
Pleased to have been able to successfully complete this job several times now but always see it as a daunting task and respect every owner prepared to have a go.