jaball77

Got some bad news on the car today. I took it over to Stuart at Just Miata in St Pete to have a timing belt and clutch done, and it turns out there's something pretty seriously wrong with the timing belt pulley/crank nose area. Apparently the keyway is pretty badly worn. Worn enough that there's play on both sides of the key - enough that it would affect the timing and possibly "Cause a very bad situation" in Stu's words... So it needs a new crank.

It's something I couldn't really see when I bought the car. I knew the crank pulley was wobbling a little, but without tearing it off there was no way to tell why. So I gambled and lost.

On the bright side, the car was only $2500, and some of the labor from the other work I was gonna have done anyway will overlap, so it's not going to cost me THAT much more. But still... The shop is pretty backed up, so the car probably won't be ready for Brooksville on 3/13.

oilleak

Well known problem on early miata cranks - lots of info on miata.net
Stu knows his stuff.

Loren

Bummer, but it's definitely a well-known Miata problem that you should have known about. You didn't do enough homework before you went shopping! The crank pulley visibly wobbling is an obvious sign of the problem.

But... before you go spending $2000 to have Stuart put a new crank in the car... you have options.

1. Go search Miata.net for info on the various fixes that have been successfully done for this problem. Everything from filling the keyway with JB Weld to loctite to outright WELDING the pulley in place. (obviously, that last one is a bit extreme, but with a fresh water pump and timing belt, you'd very likely get another 80k miles on it... plenty of time to source a new engine and have it ready)

2. Find a salvage 1.6 and spend a day swapping it. Complete engine should cost you between maybe $400 and $800.

3. Find a 1.8 and swap it in... might affect what class you can compete in, but Flyin' Miata makes a kit that has almost everything you need to do the swap. A 1.8 engine with the 1.6 gearing is pretty fun.

Boxy Rocket

Bummer. Although in the short term this hangs things up, in the long run its a chance to really build up a motor as you want it. The good thing about those mazda engines is you have lots of options. Plan it out and build a screamer ...

mofugga

it already has a 1.8 in it

PseudoRealityX

Loren, it's a '94 A package. It's not a well known problem on the BP's built after about '93. Jason just happened to get an early engine it seems. Even by 92, the Protege had the big nose cranks on their BP's.

Loren

Interesting. Sorry about that. Short nose crank failure on a Miata just immediately made me think 1.6 because that's all it applies to... pre-92 1.6's. All of the Miata 1.8's have the big nose crank. This problem must have been caused by improper assembly or something.

Or, did Stuart actually take the thing apart yet? Maybe it's just a bad pulley?

oilleak

Opps - that's my fault - I'd thought it was a '90 1.6L

jaball77

Oh he's taken it apart all right, haha! It was glued/epoxied/rigged on there to the point that he had to cut off a bolt to get the timing belt pulley off... We discussed the JB Weld/Quickmetal/welding option and he really didn't feel comfortable doing it.

We also discussed the junkyard motor option, and he didn't sound too excited about it, and I hadn't seriously considered it... The up-side is that I could find a younger/lower mileage motor (the current one has 108k). The down-side is that it's not guaranteed to be in better shape than the current one, and I'd still want to do the PM on it (clutch/tb/wp/etc). So it would probably add 4-500 on top of what I'm already paying for the work...

He said that the motor actually looked pretty good in spite of the visible problems. I asked him what he'd do if it was his wife's car and he said he'd replace the crank.


Like I said, I gambled and I probably shouldn't have. But hind-sight is 20/20. The car is mine now, and there's nothing I can do to change that. I actually talked to Stu on the phone the afternoon I bought the car and told him about the crank pulley wobbling. He said it could be something serious, or it could be an easy fix... I was betting on the easy fix. :-/