Guidance on First Timing Belt Change

Okay, so following the discovery that the water pump on the Miata is kaput (a week before a track day), I decided to change my timing belt and water pump. I'm about 1/3 of the way through the job, with most of the disassembly done, but still waiting on parts. Car is a '94, so 1.8 engine.

I'm running into one thing that I'm not finding in the literature about doing this job. I've removed the lower drive pulley, and there is a metal guard attached to the crank timing pulley. (please forgive horrible cell-phone pick with grease smudge):

That guard does not want to come off easily. I haven't gotten too aggressive prying or bashing, because I don't want to bugger anything up. I'm guessing it's just a bit rusted on. Do I just hit it with some WD-40, and let that soak in? I'm thinking I'll rent a claw puller from Kragen, since I can get the seal puller I need there too.

Also, given the amount of crud, it looks like the front main seal is definitely bad. Are there any weird tricks to getting to it? The literature makes it sound like I just remove the woodruff key, and the pulley should just slide off. Is removing the key that simple and straightforward? Just pull on it with some pliers?

Also, any suggestions on safely cleaning the grime from this part of the engine?

Thanks folks. Let me just tell you in advance, how much you rock.

Don't use WD-40, get some penetrating oil. The guard (I forget the rear name) should come off easily. You're probably going to have some fun getting the crank pulley off as well if everything else is this goobered up.

Keith wrote: Don't use WD-40, get some penetrating oil. The guard (I forget the rear name) should come off easily. You're probably going to have some fun getting the crank pulley off as well if everything else is this goobered up.

Thanks.

Will it be possible for me to use the 4 bolts that held the drive pulley on to attach something easier to pull on when I'm ready to pull the crank pulley off?

Anything in particular I should or should not do as far as pulling the key out?

My best is advice is to know and understand the 'correct procedure' for timing the engine. No hoodoo voodoo and clamping of spanners on the cams. Just knowing that it is right the first time is a good feeling.

The pulleys are made of powdered metal that is pressed into a form, like an aspirin. Don't pry on it with much force. Don't as how I know.

If it is really stuck on there, the car may have had the loctite fix for a worn keyway in the past. Hit the crank nose with a MAPP torch for 10-15 seconds and see if it comes off.

Just like a brake drum, it might take a couple whacks with a rubber mallet to free it up.

Otherwise, prepare for a few swear words. I do about two timing belt jobs a day. Some of them are super-simple and straightforward. Others are a multi-day, multi-profanity endeavor that requires specialty tools and vague instructions that usually don't completely cover the real procedures. Be prepared for a little logic and problem-solving. My best piece of advice is to make sure the "drive" side of the belt (the one that gets pulled by the crank pulley, so driver's side) is without slack as well as between the pulleys. Install that side first, then go around the rest of the stuff. Make sure that the slack is on the not-driven side, that way when you tighten it with the tensioner, it won't pull the sprockets off the mark. The nice thing is that the tensioner is automatic on that one. To take it off, loosen the center bolt, pry the tensioner out of the way and retighten the bolt. Once the new belt is on, loosen that tensioner bolt to let it apply and turn the engine over twice by hand without letting it go counter clockwise. If your timing marks line up again, tighten that tensioner and you're done.

That's all I remember from the 1.8, but if you need more details, I think I can still hack into Alldata.

I don't think this issue is a loctite fix. I'm just trying to get the guard off the pulley first. I'll tackle the pulley after I figure out that.

I need a rubber mallet. Hell, might as well invest in one.

Curtis, thanks for the tip about starting with the driven side. Fortunately the current belt is intact, in good condition, and hasn't slipped. I was planning to use the trick of marking it with a dab of paint or whiteout at the top of each pulley.

Excellent idea. I use a white grease pencil just because I happen to have one.

I hate timing belt changes

I used a 3-jaw puller to get mine off. VERY little force and it just popped off! My advice is to make a simple device to hold the crank still whle everythingn is assembled/bolted. I made mine out of 3/16 steel. I'd give you mine but it's for a 1.6L.

Salanis, just so you know, your cams will both shift on you and throw the gears out a tooth or two as soon as you release tension on that belt. I was not ready for this and it made putting the car back together a bit scary (who would know if I was off by a tooth?) Remember to mark each gear, and be precise!

Keith recommends using binder clips in his book to hold the belt onto the correct teeth when you are installing it too. This is good advice and might help you if you don't feel like you can get it to go together Curtis's way. I did it without researching it too much first, so I didn't get all these nice tips.

Do yourself a favor. Replace the berkeleying belt while you're in there. Even if it is in good shape.

I've never had the guide plate stick to the crank pulley before, so I'm going to guess it's going to come off easy.

With regards to tensioning the Miata motor, it's easy. Loosen the bolt off as Curtis says then turn the engine 1 5/6 turns. There's a mark on the crank to show you the correct location. Now tighten the bolt to lock the tensioner in place. Turn it the remaining 1/6 turn and voila, all the marks should be perfectly lined up. Before you tension the belt, they will be off very slightly. But not by a full tooth.

I don't see the point in marking the belt. The first time you turn the engine over to check alignment, your marks will be off. There are marks on the cam gears and the crank already, just use those. Remember, if you're off by a full tooth it's going to be obvious.

Replace the crank seal while you are in there, and use the proper $10 seal tool to seat it. Trust me, tried to cheap my way out of it when I had my miata and had to do it all over again.

With that said, I can now change a miata timing belt, water pump, and crank seal in about 1-1.5 hours start to finish.

Got that guide plate off easy. Let a shot of penetrating oil sink in for a bit, and gave it a few taps with a hammer. Then it wiggled free easily. The woodruff key slipped out at the same time too; so that isn't going to be a problem later.

Fortunately I will have a second pair of hands to help keep the cam gears aligned.

I guess I'm a bit confused about the mechanics of timing belt alignment. I was under the impression that you need to maintain the same number of teeth distant between all the pulleys. I guess, it doesn't matter the number of teeth between the cam pulleys and the crank pulley. The pulleys need to be in the correct positions relative to each other, and that means a certain number of teeth between cam pulleys. But I guess it doesn't matter the teeth between the cams and crank, as long as you maintain tension...? Or does it?

And where does one get the proper tool for seating the main seal (that definitely needs to be replaced)? I was just planning to use a socket to push it into place.

There will be a correct number of teeth between each of the gears, cam and crank - but why bother counting? Use the marks on all the gears. You don't need a helper to hold the cam gears, the exhaust cam stays in place on its own. For the intake cam, put a wrench on the flat on the camshaft and that makes it easy to put the cam in the correct location.

So, here's how you align a Miata timing belt. It's all you need to align a Miata timing belt. There are a number of weird techniques developed by Miata owners whose anal retentive tendencies outweigh their mechanical abilities and who thus make things as complex as possible. Ignore those.

1. Set the crank to TDC using the marker on the crank, with the cam gears aligned so the E and I (on the intake and exhaust cams respectively) line up with the markings on the front of the head. Alternately, use the I and E marks and set them to 12 o'clock. Because the cams turn at half the speed of the crank, you may have to rotate it one more time to get everything in this configuration.

2. Loosen off the tensioner bolt, pull the tensioner back, use the bolt to lock it in place for minimum tension.

3. Remove the old timing belt.

4. Use a wrench to hold the intake cam in place (it's going to want to advance a tooth) and put the new belt in place.

5. Turn the engine over two times. Double-check your cam alignment. It's going to be a hair off, but not by a full tooth. To confirm, ask yourself if it would be better aligned if the marks were one tooth over. If so, pull the belt off and install it again, doing a better job of wrangling that intake cam

6. Loosen the bolt on the tensioner so the spring pulls it in. Rotate the crank 1 5/6 turns, lining the notch in the crank pulley with the indicator on the block.

7. Tighten the tensioner bolt to lock it in place.

8. Turn the engine another 1/6 turn to TDC and triple-check the cam alignment. It should be dead nuts perfect.

Tool for installing the seal: http://www.flyinmiata.com/index.php?deptid=&parentid=&stocknumber=35-60000%20%20BIG%20NOSE

Or use a socket

Ya. That's the thingy:

Front seal installer

Sorry, it's actually more like $23 - not $10 as I originally stated.

Keith wrote: There are a number of weird techniques developed by Miata owners whose anal retentive tendencies outweigh their mechanical abilities and who thus make things as complex as possible. Ignore those.

Seriously, where were you when I got my miata 3 years ago? I had suspected it previously, and it was cemented during my recent timing belt change. I marked my old belt with whiteout, I held the cams in place with wrenches and a c-clamp ("Oh, hey what a nifty trick!"). Guess what? All that just made it harder and more stressful. There are marks for the cam pulleys, marks for the crank pulley and the Haynes manual details all of this and the proper procedure.

I'm disenfranchised with miata.net, in short.

Well, I did write this a few years back

The garage articles on Miata.net were written by amateurs. Some are fantastic, some are not. Kinda like Wikipedia :) If you have improvements to suggest, contact Miata.net.

PB is your friend. WD-40 is for displacing water.

Trust in Keith. He's the man when it comes to Miatas.

Well, I have Keith's book. I'm just biding time until UPS delivers the parts. I'm also going to replace the pulleys and water pump.

I presume both of those tasks happen while I have the old belt off. (I can double check with the book.)

Yup.

I gather that I'm supposed to put a bit of silicone sealant around the gasket for the water pump, and at the 90* bends on the valve cover gasket. Is there any particular type of silicone I should or should not use? We have a tube of some copper fleck silicone gasket sealant. I presume that will work for the job.

I always wondered... they go to great lengths to engineer certain things, like timing marks, keyways, and self-adjusting tensioners. I always wanted to see cam sprockets with holes that line up with a threaded boss on the head or block. That way you could line it up, thread in a bolt to hold it in place, and not worry about needing five hands to hold cams, align marks, and put a belt on at the same time.

what about cam gear holders? snap-on or mac sells them, obviously they only work with DOHC motors as they fit between the gears, but they are well worth the money. get everything set, put the holder in place, and start working...

Dunno about the Miata cams (never done one) but on a 907 Lotus the cam gears are close enough together that I have used two short pieces of 3/4" wide steel, drill a 5/16" hole through the middle and use a bolt and wing nut to keep the pulleys from moving. You install this BEFORE loosening the belt tensioner- turn the engine till all the marks line up, install the tool, then loosen the tensioner. That's pretty essential on the 9xx motor because it IS an interference engine and if the timing belt tension is released and the cam is in the right (wrong?) spot, the valve spring pressure can turn the cam and possibly bend a valve. I did the same thing with George Walton's Cosworth Vega for the same reason. AFAIK the MeOtter is not interference.

curtis73, some engines actually are done that way. Honda H22? (Accord 4 bangers) have a plug on the back of the engine which you remove before taking the belt off; you line up all the marks then stick a screwdriver or?? through the hole, this keeps the balance shaft from turning when you take the belt off. Of course, remove the screwdriver before trying to turn the motor. Quad 4's (yeah I know it's a chain!) have a special tool which is a pin set on a cable, you turn the various gears till the holes in the gears line up with the holes in the rear timing cover, stick the pins in the holes and then install the chain.

There's also a VW? motor with hexes machined on the cams, you turn the cams till the hex is pointing the right way, then you drop a special tool (which is only a plate with matching hex cutouts) over the hexes and that holds the cams in place while the belt is installed.

Well, managed to get everything put together and running today... and had a mondo oil leak. Pulled off the valve cover and a couple of shields and... yup... the intake cam seal that gave me a bit of trouble had oil pouring out from around it. So I get to buy a new seal and do most of the job all over again. I'm trying to figure out how little I can get away with doing. I think maybe take apart enough to release the tensioner pulley, clip the timing belt on the cam gears, and just pull the intake pulley and seal.

Also, my dad and I had a little bit of confusion with aligning the intake cam. Didn't look like it was aligned quite right, but was pretty sure that it would have been worse if we moved it another tooth. The top was tilted in a bit from center. I gather that's not abnormal. Didn't test drive the car to see if it was down on power, due to the oil leak.