99 Miata Engine Swap

Posted by Zachary Visker on

Ken originally brought his beautiful 99 NB1 in this winter to do a clutch swap. After doing it successfully and doing a basic inspection we noticed that the crank pulley was very wobbly. During a test drive, the car just felt really doggy. Using a timing light we determined the timing was off 5 degrees. Assuming the timing and crank were related we requested to do a timing belt change. 

After digging into it we determined there was some severe damage to the crank. We determined that the last tech reused the woodruff key which seemed to be damaged already which just made the crank damage worse. Here is what we say after removing the timing belt boss. There should be about 5mm more of the woodruff key. 

Here you can see even if the key was able to be removed there was already a lot of play/damage to the crank nose. At this point Ken had to decide in rebuilding the engine with a new crank or putting int a used lower mileage engine. 

I informed Ken that we can find a low mileage engine from a parts car that would be much more cost effective having a low mileage engine installed instead of having a crank installed. So we decided to pull the engine. I don't like to brag about fast work, but that was the fastest time I have pulled an engine/trans solo.

After a few monthes, we finally got a donor! It was out 99 NB1 Auto part out. This engine only had 80k miles on it and ran great. Then paired with an automatic transmission means that this engine never was able to be abused due to the depressing automatic. 

Before removed we did a compression test and come with great numbers with 180 +/- 10 across all 4 cylinders. With very minimal leaks this was a very good clean engine to start with. 

Now it's on the stand all fluids are drained it was time to start to break it down. Not much to show on the breakdown but everything comes off with minimal cleaning needed before we painted everything. The inside of the valvetrain you can really tell the condition of the engine. Zero oil staining means this car was maintained well.

During our dismantle, it became obvious this engine was recently serviced with everything we were planning to do. But unknown to the brand of seals we decide to replace everything. Once the entire motor was dismantled it was time to paint some of the components before reinstalling.

At this point, we finished most of the new component install. This included:

  • Oil Pan Seals
  • Front Crank Seal
  • Rear Crank Seal
  • Cam Seals
  • Valve Cover Gasket
  • Spark Plugs
  • Water Pump
  • Timing Belt
  • Timing Tensioner/Idler
  • Woodruff Key
  • Crankshaft Bolt(Loctite)
  • Water Neck Seal
  • Front/Rear Thermostat Seals
  • Intake Manifold Gasket
  • Water Lines

Everything was painted, sealed, torqued on the external of the engine. We also transferred the new clutch from the old engine to this one. Once it was bolted we mated the transmission to the engine and was ready to install. 

Once the engine was in we bolted the mounts and PPF to the transmission. The harness was ready to reinstall and bolt in the exhaust. We also did some additional work which included:

  • Exhaust Manifold Gasket
  • Exhaust Flange Seal
  • Engine Oil
  • Coolant
  • Transmission Fluid
  • PCV Valve

Now the engine was in it was time to start it up, right up with no hesitation, after bleeding all the air out of the cooling system we were ready for a test drive. Taking it easy to let the clutch break-in, it was immediately obvious that this is how an NB1 is supposed to drive. 

After monthes of waiting for a donor and tons of detail work to make it presentable. Ken finally got to pick up his Miata. Before I could come outside to greet him he was already in the car and started it up and popped the hood. The reason I paint these engine and detail them is see the excitement of the customer. It turned in a sucky engine swap into a great experience for both MiataSource and Ken.

Hope you enjoy your new engine Ken!

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