'99 Miata Camshaft Confusion!

With the help of a couple friends, I figured out why my new '99 head was making such a racket. It's got the wrong exhaust cam in it. I got the '99 head from a friend of mine. It's been in storage for over 10 years and its exact history is a little fuzzy. It came completely assembled but the cams were just loosely held in the journals with the bearing cap bolts finger tight. As seen much earlier in this blog, I took it apart and lapped the valves, checked the bottom surface for straightness, and put it back together.

What I've been hearing since I first started it up was what sounded like excessive valve lash. It was quite loud so I knew something wasn't right. I had checked all the clearances when I installed the head and they were pretty good. If anything a couple of them were on the tight side, not loose. Nevertheless, I figured I had screwed something up so this morning I popped the valve cover off and measured the clearances. None were above the maximum spec, but a couple were below the minimum, so I fired up my spreadsheet and plugged in all the numbers and identified 4 shims I could swap with each other that would bring everything within the factory specs. I was able to get the shims out without completely taking out the cams or having to re-do the timing. If you loosen the bearing caps and rotate the engine you can sneak the shims out from under the cam without removing the timing belt.

I was very glad to get the clearances better adjusted. Most of the valves are in the bottom half of the range. Alas, the noise was unchanged, so I put out a mayday to some gearhead buddies. One of them asked if I was sure I was using the right cams because the cams for NA and NBs have a different profile due to (or at least coincident with) the change to solid lifters in '99. I just used the cams that came with the head, but I realized that I took it on faith that they were the right cams.

From Solomiata.com:

Note the NB cam on the left has a more rounded profile, while the cam on the right from an NA is more pointy.

So, I pulled the valve cover off again and held a cam from a '96 next to the cam installed in my '99 head. They look the same to me. It was starting to make sense.

Next to the intake cam in my '99 head: The known '96 cam looks a little more pointy compared to the intake cam in my '99 head, as would be expected.

To seal the deal, I spotted the marking on the intake cam, BP4W, which is indeed the correct intake cam for the head. On the exhaust cam is BP06, which is an NA cam. Bzzt. Wrong cam. So I'll be ordering up an NB exhaust cam and I'm debating whether to also order the BP5A (aka Mazdaspeed cam) for the intake side. Would be easy to swap it out as long as I'm in there swappin'. Hope this helps save someone some trouble sometime. Never assume!

Refurb Results!

The car is pretty much done! I'm just taking care of details at this point. I still have to wet sand and polish the whole car to correct some flaws in the paint. I'll try to document that as I go. I'm also going to revisit the valve adjustment. The car runs like a scalded cat, but the valves are noisier than I think they should be. I just want to check it again and try to get the clearances down to the bottom half of the specs. This is the downside of getting rid of the Hydraulic Lash Adjusters from the '94 head.
 

Here's the car on its first outing! The hood is still unpolished after wet sanding but you can't see it too much in this picture. The Reptile Red paint really pops in the sunlight. It's insanely red!

The engine money-shot.

This shot shows the color in more normal lighting.

I replaced the instrument lighting with LEDs. This doesn't make a huge difference except the needles are now white instead of green.

This came in the brown truck the other day.

It replaced the 12 year old MOMO Champion that was getting quite ratty. I love the red stitching and will probably mimic that on the seat upholstery when I do that.

Painting Miata, Part 4

So here's the end of the first day of painting. I got three coats on the car. The first coat looked like crap because I hadn't got my technique down yet. The second coat made things a lot better and the paint was starting to flow out better and look glossy. After the second coat I sanded down some small nibs with 600 grit wet sandpaper and cleaned the gun before spraying a third coat. I didn't get the sprayer adjusted just right after I put it back together and it was putting down a lot more paint than before. I got greedy, because it was flowing out so nicely and looking really good, and I ended up with a few small sags that I will have to go back and fix.
 

The hood is really hard because it's difficult to reach all the way to the middle and keep the gun at a constant angle and velocity.

This is the paint. It's called Reptile Red and it's a bit brighter than the Mazda Classic Red, but definitely in the same family. It's a 3:1 mix so they sell you 3/4 of a gallon and then you add 1/4 of the activator. If you were going to spray the whole gallon all at once you could just dump the activator in the can with the paint and go. Once you do that, though, you only have about 2 hours until it starts to gel.

Next I have to fix the sags and then I can spray clear. It still looks kinda "raw" and probably won't all come together until the clear is on and cured and I can really give it a good buffing with the random orbit polisher.

Painting Miata, Part 3

This weekend I started spraying paint. Since the car is mostly stripped down, the job of masking is pretty minimal. This photo shows the car more or less ready to shoot with primer.

Safety first! Painting involves some pretty nasty solvents and particulates in the air. Proper protection of lungs and skin is essential.

This is as far as I got the first day. I was having trouble with my HVLP spray gun and decided to stop and make a couple improvements to my air system. I installed a bigger air regulator and a new inline filter. It seemed to do the trick once I learned how to set the gun up right and I got much better results.

Primer before sanding.

Parts.

So this is where I left off tonight. The primer is all sprayed and I've gone over the whole car with 400 grit dry paper. Before next weekend I have to wet sand the whole car with 600 grit and then I'll be ready to spray color and clear.

Painting a Miata, part 2

The paint prep continues. The entire car has been sanded with 400-grit and some small dings on the passenger side filled. I also filled the hole in the trunk from the spoiler mount, and the two holes in the nose from the emblem. I plan to leave the emblem off.

Next weekend I'm going to give it another going-over just to make sure the surface is fully scuffed and everything is smooth, and then I'll be ready to spray the urethane primer. I figure a whole day to mask it and spray the first coat of primer. I'll be doing the door sills as well.

This dent was very wavy and very hard to fill in. It had low spots as well as high spots. It will probably be visible once the paint is on but I don't think anyone will notice it unless I point it out. It feels pretty smooth when you run your hand over it, but it is detectable.

Painting a Miata, part 1

I started sanding the body today. I'm using sanding pads with 400 grit dry sandpaper. Once I hit the paint with sandpaper I passed the point of no return. I have to paint this car now!
I do plan to remove the door handles, by the way.

This panel has two real nice little dents in it. They happened years ago and I've neglected to do anything about it. I'm very happy to get these fixed. Here they are after I sanded them down to bare metal so the body filler will stick.

I got this stuff from Eastwood. It comes with a tube of hardener. You mix the hardener in at a 2% proportion. After that you have about 3 minutes to get it in place. Forget about making it pretty and smooth. Just get it on there and 15 minutes later you can sand it down smooth.

It took 3 applications to build the material up high enough that I could sand it down level. Interesting how each dent had high spots surrounding it. It's level now as I can't feel any deviation at all when I run my hand over the filler. The primer-filler and paint coats should make it disappear completely.

This was as far as I got today. I did the driver door, left rear quarter, and the trunk lid. Next weekend I'll continue around the rest of the car, then probably go over it again completely before I spray primer-filler. I'm wiping down between sanding passes with a product called Pre to keep the dust down and hopefully avoid any contamination that would create fisheyes or pinholes. We shall see if it works.

Final details on the cooling system.

So today I installed the Koyorad radiator in the Miata and got the rest of the coolant hoses installed. I also finalized the routing of the fuel lines and got everything tidied up and zip-tied in place. The engine compartment is really looking proper now.

Old vs. New. While the old coolant pipe would probably work, leaving it in place would bug me because it's pretty corroded after 18 years of service. Replacing it with new resets the clock which is one of my main goals in this project.

Stant 10227 radiator cap fits the Koyorad (or any other Miata radiator).

So this is it for the mechanical stuff for a while. The next few posts will be about the paint and body work. We'll get back to the engine when I'm ready to start it.

Koyorad 37mm Aluminum Radiator

Got this in from Good-Win Racing today. Nicely packaged to arrive safely.

Beautifully made, very light, and should perform well. The Miata cooling fans will bolt right up. I'll install it this weekend and get the cooling system buttoned up.

Engine install details

I found the issue with my transmission not wanting to mate to the engine. It was my fault. Using the transmission jack, I got the transmission perfectly lined up with the engine block, threaded all the bellhousing bolts in by hand and proceeded to tighten them down thinking that would just pull things together easily. It would have worked if the splines on the clutch disk and the transmission input shaft happened to be lined up or at least pretty close to lined up. Unfortunately, they were exactly NOT lined up and the slow compression by the bolts drawing things together just crushed the splines and made it impossible for them to engage the input shaft. I can probably clean up the splines with a file and salvage this clutch disk but I didn't have time to do that now. I threw the old clutch disk in since it showed very little wear anyway. It's got a good 80-100k miles in it still.

 

A quick clean up of the starter. Wire brushed it and hit it with some chassis black. I replaced the mounting bolts with new ones.

The Power Plant Frame was nasty dirty from the oil leak so I pulled it out and cleaned it up. Having it out made maneuvering the transmission back into place a bit easier, too.

I had sort of underestimated the amount of work involved in getting the engine fully dressed and everything hooked back up. I spent a whole day and a half doing just that. I installed the starter, A/C compressor, PCV hoses, belts, brake booster lines, clutch slave, Power Plant Frame, exhaust header, O2 sensor, and fuel pressure reference sensor. I still have to install the radiator (ordered a new all-aluminum KOYO 37mm radiator) and associated hoses, plus the heater hoses but I'll do that when the radiator gets here.

Using the '99 head and intake manifold leaves nowhere to mount the PRC solenoid valve, so I relocated it to where the carbon canister was. It has to be within reach of the wiring harness and it has two vacuum connections so it has to be in this general neighborhood. Hopefully it won't matter that it's vertical instead of horizontal. This valve helps the engine start under hot-restart conditions and doesn't do anything most of the time.

Finally, I filled the transmission with Amsoil MTG 75W-90 gear oil. It's very easy with a proper pump.

Installing the Miata Engine.

Today I installed the flywheel and clutch and dropped the engine in the car. But first...

Here's my method for getting seals out. First I drill a small hole in the middle of the seal. The top of the seal is metal underneath the rubber so it's quite hard.

Then I screw a screw into the hole, being careful not to drive it too deep. It just needs to thread in a couple turns.

Then grab the screw with pliers or vise-grips and pull.

Viola! This one was really easy. Smaller seals like the cam seals can be more stubborn and sometimes you have to put in two screws so you can pull from two sides.

Here's the F1 Racing chromoly flywheel just before being bolted down. It weighs about 11 pounds so should be a nice performance enhancer.

The holes for the pressure plate bolts were threaded wrong! The factory bolts are M8x1.0 while the flywheel is threaded for M8x1.25. Of course they don't tell you that so when I started to bolt on the pressure plate I was met with resistance. I got all six screws about halfway in before I decided something was not right and pulled them out. I went to the hardware store and bought new bolts.

I was going to plan a tech day with some friends to help me install the engine, but my time has been so limited lately I had to just forge ahead whenever I could and ended up doing it by myself. Flying the engine on the crane into the engine bay was not too hard. It just took me about 15 minutes to maneuver it into place. I wasn't able to finish bolting up the transmission due to a complication. Usually the engine and transmission will mate up and go together pretty easily. Sometimes they fight a little bit but with some finessing, they will eventually pop together and from there it's easy to bolt them down. Today though they never got friendly with each other. I got the bellhousing bolts about halfway in and was met with extreme resistance. The transmission and engine are still a good 3/4 of an inch apart and the bolts just don't want to go any farther. I'm afraid I'm going to bend the transmission input shaft so I desisted for today and will start over next weekend. Something isn't mating up right and I'm not sure why. I've seen this before, though, and I'm confident I can sort it out next weekend.

I'm glad it's back in its place!

All put up for the night.

Engine details

I was a little premature in declaring the motor 'done'. In reality there were still a few tasks to take care of. I wanted to get as much done as possible while the engine is out of the car because it's so much easier to work while the engine is on a stand.

I installed the alternator and all the accessory brackets today. After I did it I realized I will have to take the belt back off and remove the balancer so I can use my crankshaft locking tool while I torque the flywheel bolts.

The new Mazda Competition engine mounts are assembled and I bolted them to the engine. I cleaned them up and painted them with Chassis Black. The competition mounts are a harder durometer than the stock ones, but not as hard as some urethane mounts on the market. I still need this car to be reasonable on the street.

The transmission is all set. I replaced both the front and rear seals and painted it with Aluma-Blast from Eastwood. That is one amazing product. It makes aluminum stuff look like new, or even better.

I painted the engine compartment black. I think the shiny new motor will really shine in front of it. The camera flash makes every little flaw pop out but I think once the engine is in and in normal light it will look fine. I just didn't want to remove the brake lines or master cylinder, or any of the A/C lines, so I masked them off the best I could and let the chips fall where they may.

This is a good shot of the Aluma-blast finish on the valve cover.