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NA

Cam Cover Replacement

John Seegers
JESFromRIC

This is not a step-by-step but an add-on to what is already offered here and at “The Garage” so be sure to read the others and you may want to look at a service manual too.

IMPORTANT! One of the other “directions” in The Garage has an image showing the wrong place to apply silicone! You place silicone where the cam bumps meet the plane of the engine areas. You will have 4 spots in the front and 2 in the back just next to the oil dipstick.

I strongly recommend wearing a good headlamp while doing most of this. The more light you have the less likely it is that you will leave something behind that you don’t want to. You do not want old caked grease and who knows what else getting in your top end.

I spent about an hour pre-cleaning the cover before I ever loosened a single bolt. I used “industrial strength” citrus degreaser, a small brush and plenty of rags. Work around the cover as much as possible until all loose and caked grease is removed. I followed the cleaning with a good blast from an air nozzle from my little home compressor.

I loosened the cover bolts using a 3/8” drive socket attachment in my cordless drill. Obviously you could use anything but that made very short work of loosening the bolts.

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Image shows the coil and where the two bolts pass through it and in to the cover. They attach the coil to the cover they do not hold the cover. It is a snug fit to the bolt head but I pulled them using an ordinary open-end wrench.

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You DO NOT loosen any bolt(s) past where the cam passes through the rear of the cover! Be sure you can see what you are doing so you will know which ones to avoid. If you have loosened everything from the front going back the cover will lift up even with the coil bolts in place.

The breather hose was sort of stuck on so I ended up pulling the entire hose assembly off so I could work on it on the bench without risking any damage. I taped the hose clamp and hose retainer clamps in place so they would not fall off or get lost. The hose to the PCV did pop off the valve quite easily.

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Image shows the breather hose clamps in place. In case you forgot to note it the shorter screw goes on the left, the longer on the right when facing the engine as if you were working on it. Well, I'm pretty sure that is how they go.

Only then did I pull the cover, set it aside and carefully covered the open cams with a clean plastic bag just in case.

Then I went about pulling the old gasket, working off the breather hose, pulling out the PCV valve, removing the oil fill cap and removing the wire guides.

Then I set the entire cover in a large plastic tub (just big enough that it fit) and poured an entire bottle of the degreaser on it. I let it soak, worked it with a stiff brush, let it soak and worked it with a toothbrush – repeat – repeat – repeat until clean. Clean is still a relative term here since it was permanently stained.

Then I took it out back and hit it with the pressure washer. Just your garden-variety home pressure washer (not a mechanics one). I sprayed until clean and then hit it with 409. Then sprayed again, again and again until I was satisfied that I had removed every trace of degreaser, grease, soap and dirt. This left the cover in perfect readiness for painting and for the gasket installation.

I let the cover set about four hours and then taped off the PCV valve grommet, the breather tube, oil fill opening and I even chose to tape off the raised Mazda logo. Taping off the Mazda logo was about an hour job using blue painters tape, an X-Acto knife and a magnifier. If you have a roller from sound insulation use it to impress the tape. Then I hit it with NAPA self-etching primer and let it sit overnight.

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In the morning I hit it with the high-temp engine paint in red as shown. Waited for about four hours and then peeled back the tape, NICE! In the meantime I had let the oil fill cap and wire guides soak overnight in a mix of 409 and dishwashing liquid so with a little rag work and a few Q-Tips they came out looking good.

Now it was time to hit the car again… I had a large stack of clean cloths ready to begin wiping down the gasket area on the engine. I probably spent about an hour plus wiping, wiping, wiping and working the corners to get them clean and free from old silicone. I used a small screwdriver wrapped around the point of a rag and I even used my Dremel and about 6 polishing points to get in the corners where the silicone will go. The last “mechanic” did not appear to have done a very good job.

I used Permatex black “ultra oil resistant” silicone gasket maker. I have since started using "Right Stuff" gasket maker instead.

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Image shows you where you will run the silicone in the front of the engine.

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Image shows you where you will run the silicone at the back of the engine.

I had three torque wrenches (1/2, 3/8, 1/4) but none covered the range necessary. So it was off to Sears for me. Yes, Sears had one so I am good to go on 55 inch pounds of torque. No guessing here! 55 inch pounds is, in my opinion, not something we are used to feeling or sensing, 55 foot pounds yes, inch pounds no. I found the torque diagram from “The Garage” was from a confusing perspective so I used the one from the MX-5 Miata Enthusiasts Workshop Manual.

Don’t forget to re-plug the wires around the coil and double check everything is back in place. I did not like the way the old wires looked so I also chose to install new plugs and new wires. I found the openings or “female” coil plugs on the coil to be quite fouled up from what I am guessing was overuse of “electric compound”. I waited until everything was back together before blasting out the spark plug holes. I am not sure when it would be best to this but it made the most sense to me to do it after reassembly. Here is the after picture.

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