Timing Belt?'s

Hi all. As you can tell, I'm uber new in here and the questions I have will be flowing until get a better idea of what I'm into here. I inheirited the car from my dad, its a '91. We just drove back from California to home in Pennsylvania. The car has 89,000 miles on it and its the original timing belt. It is also the short nose crank. I was going to take it to my local shop and have it replaced, but I don't want to make the mechanic sound stupid and show him the tech article on the proper way to do this, or should I do this myself? Does anyone have any tips? I really don't want the engine messed up. Then I'll have to drop in a small block V8 and there goes the fuel economy.

Print the article and take it with you. Just ask him if he's aware of the crankshaft problem on the early miadas.. He'll say he knows about it, then you say 'oh, then you don't need this', and put it in the car. then he will read the article when no one is looking.

JetBote said:

Hi all. As you can tell, I'm uber new in here and the questions I have will be flowing until get a better idea of what I'm into here. I inheirited the car from my dad, its a '91. We just drove back from California to home in Pennsylvania. The car has 89,000 miles on it and its the original timing belt. It is also the short nose crank. I was going to take it to my local shop and have it replaced, but I don't want to make the mechanic sound stupid and show him the tech article on the proper way to do this, or should I do this myself? Does anyone have any tips? I really don't want the engine messed up. Then I'll have to drop in a small block V8 and there goes the fuel economy.

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I am new here too but you ask a very important question. I used to work on Miatas quite a bit (www.rspeed.net) and very familiar with your situation. The best news you can have at this point at 89,000 miles is that it is the original timing belt (with your short crank). If not, you run the risk of making something worse as it is bound to fail if not installed with the update crank key. See if you can find out by giving your VIN to your local Mazda dealer for history on your car. If you have original belt and the crank has not been touched - you have a great opportunity to keep this 91 healthy for years to come.



While you talk to the Mazda dealer - ask about their 60K service (this is typical timing belt service) service - have them fax you what is done at 60k and whaat parts are replaced. Ask about the ala carte timing belt service as well - what is done and will they upgrade your crank with the appropriate fix. Consider having that water pump checked as well.

Now go to your mechanic and sit down for a small conversation about timing belt service - you need to show him what Mazda specs at the timing belt change (your dealer can give you this). You really need a 90k - but a full 60k service will get your 91 into great shape.

Check out the RSpeed service plans - we based these service on the Factory spec with factory parts and will give you what should be done:
http://www.rspeed.net/miata/item.asp?dept=9&cat=20&prod=699-000

Depending on how much $$$ you have - be very careful on getting a "deal" on such an *important* service - especially on the short crank problem.

Make sure you read up as well here: http://miata.net/garage/crankshaft.html

My recommendation - take it to the dealer (so you can get the warranty on the repair) or a Mazda specific shop - one that knows about the short crank issue and does not need to be educated.

Keep us posted.

Blue Potato has it right.

If you are mechanically inclined, I'd say go for it yourself. You might learn a thing or two. If you do attempt to do the work yourself, replace the woodruff key (as already stated), the crank timing cog, front main seal, and water pump. The FMS and WP aren't necessary, but just a good bit of preventative maintenance. Be sure the crank bolt is torqued to 80-87 lb-ft, use blue loctite on the bolt and key, and you should be good. Removing the radiator will yield quite a bit of room to work. I've completed the entire process in less than two hours.