Treasure Coast Miata

Loctite Fix for the early (1990-1991) Miata Engine

by Harry Sue





Parts needed



A. The Crankshaft Assembly

At the lower front of your engine, the crankshaft pulley does the work of spinning your alternator and water pump. If your car has air conditioning or power steering, this pulley spins those accessories too.


If we open up the front engine cover, we see that the above pulley is attached to a gear on the crankshaft. that also turns the timing belt and camshafts..



The miata crankshaft failure is very simple in nature. It starts if the crank bolt gets loose!

More info on


B. The failure

The gear is aligned with a key to the crankshaft. If the bolt comes loose, the gear be free to wear away at the keyway. Here are three examples. ranging from mild wear to a catastrophic failure.
And as the keyway wears, the position of the gear changes, which affects the alignment of the timing belt. As a result, the camshaft timing becomes retarded. As the keyway wears further, the timing becomes more retarded, and the engine has less power. The loss of power is a gradual process, so most owners don't notice it until the car becomes very slow. If ignored, the nose of the crankshaft can break off.

What to Do if It Fails?

  • Replace the crankshaft. A robust fix. Probably a $3000 bill comes with that.
  • Replace with a used engine. Also a robust fix . $600-2500, depending on who does the labor
  • Weld the crankshaft to repair the gap. Perhaps weld the gear in place. Some risk of failure. $ 100-700, depending on who does the labor.
  • Try the Loctite Fix described in this web site. Some risk of failure. $ 50-700, depending on who does the labor.

No one guarantees this Loctite Fix will work on your car. That's why there is a risk of wasting time and energy. If you are a do-it-yourselfer though, it may be worth your effort.



I can be reached with the user name hsue
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Listing an email address attracts too much spam, so you'll have to type both parts and add the "@".

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