Exocet Part 4: Cleaning & Engine Leakdown

Posted: January 13, 2014 in Racing

I tried to do a thorough job of steamcleaning and failed miserably. I followed the instructions and soaked the dirtiest areas of the chassis with a 4 part water / 1 part Simple Green solution and tried my best but it did not do anything at all. Just not enough spray / pressure coming out to clean off heavy dirt and grime. So I waited until a day got above 40 degrees and started up the power washer. Again a treatment of Simple Green and bang the chassis was clean in no time. I did be quite careful around the electronics.

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Dirty rear end

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Dirty front end

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Dirty engine

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Cleaner after powerwash but now needs some rust treatment on a-arms and some fresh black paint.

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Cleaned up the rear end and did some light sanding of the surface rust on the rear subframe. Also note I added a 3rd car stand as the chassis was sagging a little.

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Some anti rust coating primer sprayed on will chemically bond with the rust and stop it. Will paint it next.

While that is going on I got some new stuff from OG Racing and Mazda USA (late presents to myself).

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Fresh oil and gear lube, water wetter, some Hawk DTC pads, an electrical cutoff switch, battery through panel (no hole when running positive line through chassis) and my favorite – carbon fiber ignition panel with 2 accessory switches. Thanks OG Racing!

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Mazda came through with some comp motor and differential mounts, plug wires, NGK plugs, shifter bushing and ss clutch line.

Adding Front Extended Studs at home as they are easy to install. Also checked over all the hubs for wheel bearing issues and no play so the hubs are solid. I can’t do the rear studs as you have to pull the hub in order to get them in (extended studs won’t clear the housing).

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Longer extended wheel studs to allow for spacers and run wider track.

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Installed in the front.

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Pulled off all calipers to check sliders – pads were hardly worn and rotors were brand new (just coated with surface rust). Will reuse the calipers and rotors but put in Hawk pads.

Leakdown Test on the Donor Car’s Engine. Picked up a used leakdown tester so that I can check the donor car’s engine. One thing to note on a Miata is to find TDC easily. Seems the Miata Enthusiast’s Manual and the Interweb say sticking a long cylindrical object to sit on top of the piston is the best method. So this long screwdriver with a very flat edge did the job.

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Speedway Leakdown Tester I got off Ebay for cheap.

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Long enough and fits in the sparkplug hole and can’t fall in.

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There’s TDC (try to turn the crank so that it sits right at the middle so it won’t try to push the cylinder down when you apply the air). Also remove all the spark plugs in other 3 cylinders to make it easy to turn the engine over.

So the leakdown results:

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Cylinder 1: 0% leakdown – and I can hear air going into the coolant passages so a blown headgasket.

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Cylinder 2: Again the same issue so I’m assume air is escaping into the coolant and past into the other cylinders. Will have to pull the head and look at it for other damage.

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Cylinder 3: Better with running 60 psi and according to the leakdown tester 20% leakage.

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Cylinder 4: Even better but a loss nonetheless.

When I bought the car it did start and run and didn’t make bad noises when we revved it. I however bought a 2nd engine that I got locally that is supposed to be a good runner (sitting on a movers dolly in my garage and it is in much cleaner condition). I’m going to run a leakdown on it and if it passes then I’ll install that one instead. If not then I’ll gauge the condition of both then decide which one to rebuild.  It’s only time and money right?

  1. linuxd00d says:

    I’m trying to decide on the Mazda Comp diff mounts vs the ones that would come in an Energy Suspension poly bushings kit. I’m having a hard time finding a good comparison between the two, and complaints about NVH in street miatas don’t really apply to my intended use case (track exocet). What made you decide on the Mazda mounts?
    BTW, sorry for the flood of questions. You just seem to know a lot about miatas, and I’m following in your exocet footsteps 🙂

    • I’m not certain of comparos either but since Mazdaspeed is a major help in my build I went with their comp mounts b/c I can get them at dealer cost being a racer with them. Plus with mounts you want some give to reduce stress and the more solid the mount the more vibration is let through which can fatigue other items that are not meant for such vibration.

      No problem on the questions – keep ’em coming. Good to know my info is helpful to others.

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