Cam bolt

Phil Dyer · Post by **Phil Dyer** » Fri Aug 24, 2001 10:43 pm

I read somewhere recently that early MX5s, like before mid 1992, have a
smaller bolt that is worth replacing when you do the cam belt. Can someone
point me back to where I read this?
Phil

Gary Morrison · Post by **Gary Morrison** » Sat Aug 25, 2001 9:40 am

Phil,

Got to www.miata.net and have a look for tech info there. They have an article
on the camshaft issue. Its the camshaft nose itself that is smaller though,
not just the bolt. Changing the bolt won't make any difference.

Gary

Post by **zorruno** » Sat Aug 25, 2001 12:20 pm

also there has been plenty of discussion on this list. Go to
http://www.mx5club.org.nz/search/ and search for crank.

Fletcher... hows that article that you didn't promise to write

H.

Keith Cook · Post by **Keith Cook** » Sat Aug 25, 2001 2:49 pm

I've just scared myself silly by reading http://www.miata.net/garage/crankshaft.html . How many failures have there been among club members does anyone know? I know of one 'cos my son checked this car (low price and replacement engine) out when he was buying the one I have now but have there been others in NZ?

From badcat@xtra.co.nz Fri Apr 27 15:46:33 2007
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Date: Sat, 25 Aug 2001 16:06:57 +1200
Subject: Re: Cam bolt
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i've just been through this - relaced the engine a couple of months ago
after 3 attempts of diagnosis by my (now) ex mechanic.
if anyone needs first hand info - email me.
Advanced Autos
http://www.advan.co.nz/
by the way were absolutely INCREDIBLE with finding a new (17,00K) engine -
fitting and sorting me out in 3 days.
by far the best service i've ever had from an auto company.
andrew is the service manager - and just brilliant.
love this car.
ken

[...]

Fletcher Blades · Post by **Fletcher Blades** » Sun Aug 26, 2001 12:08 pm

The latest thoughts on avoiding this issue do include replacing the bolt.

Some years ago, it got around that improper re-assembly of the crank/key/bolt
assembly was responsible for the majority of failures, and one suggestion was
just leave it alone. You only need to remove the bolt if you are replacing the
oil-seal, and most of them aren't leaking at 100k.

More experience, and a large number of "un-touched" bolts failing has revealed
the "don't touch it" advice to be faulty.

Today's advice is that the bolt is undersized for its task, and stretches with
age. And the best way to avoid the problem is to replace the bolt with a new
one at time of cam-belt change.

It goes without saying, that you must reassemble is correctly (The key has a
chamfer and only fits properly one way around), and to torque the bolt
correctly. (80 foot-pounds).

All this advice ONLY applies to the small- cranknose/bolt assembly on the 89
to mid 91 cars before the redesign with the larger bolt.

If you go to www.miataforum.com click on the 1990-97 forum and search on
"crankshaft" you will be inundated with reading on the subject.

For what its worth, Lance Schall, the author of the info at www.miata.net
garage section has just this week admitted that the five year old article is a
little out of date, and he will be updating it soon. Nothing in that info is
wrong, its just hasn't been updated with this later info about replacing the
bolt, and a few other things that have been learnt in the mean-time.

Fletch.

P.S. Both myself and Larry Young were in the "don't touch it" camp when we did
our cam-belts, and have both since had the failure occur...

Keith Cook · Post by **Keith Cook** » Sun Aug 26, 2001 4:28 pm

He updated his article last week! Unfortunately the mechanic who replaced my
belts 3 weeks ago was also in the "don't touch it" camp. Woe is me!

Gary Morrison · Post by **Gary Morrison** » Sun Aug 26, 2001 7:03 pm

Oops, my info must be out of date. Sorry...

Michael Donovan · Post by **Michael Donovan** » Sat Sep 01, 2001 12:38 pm

Hi Fletcher and all.
Did my cam belt a few weeks ago and as the Crank/cam bolt was so so tight I
left it. Though I had purchased a new bolt and Key before beginning. Just
going through the emails sorting them out and saw this subject reappear. I
found a link on the net to a (I Think) Locktite page that gives a reccomended
procedure for doing the bolt, and sealing it with locktite to spread the load
more around more of the area of the bolt etc. I didn't really want to undo the
bolt as my only method would have been the long handle wedged on the ground
and useing the starter motor to loosen it, and I thought this might cause more
harm than good. What do you reckon, there is not the slightest descernable
play/slack or anything with me bolt pulley that I can see. Even got a new
pulley as well.
Any advise appreciated
Mike

brett havill · Post by **brett havill** » Mon Sep 03, 2001 1:33 am

hey there my new email is bsiakl@amcom.co.nz talk to you soon

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