NB1 Timing Belt

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NB1 Miata

Timing Belt


The first thing I needed to do my Miata SE was to figure out how to do the timing belt maintenance. I read all the threads I could find on this before I began and am glad I did. I found Miata.net and the garage section has instructions with pictures showing how to do the belt replacement. They all recommend replacing the camshaft and crankshaft seals, the water pump and the valve cover seal.

This is the link I used to access their instructions: http://www.miata.net/garage/timingbelt.html.

I also found this site http://revlimiter.net/blog/2009/09/nb-miata-timing-belt-change/ that had a few different ideas.

I used some ideas from both sites but I followed the Miata.net Garage instructions most of the way.

Securing Parts:

I live in a rural area and must have all the correct parts for any project I start...unless I want to wait for them while the vehicle is out of commission. So, I did as the Miata.net instructions suggested and gathered the parts before starting. I found a kit that included all the parts needed at R Speed: http://www.rspeed.net/R_Speed_Timing_Belt_Kit_Miata_1990_2005_1_6L_1_8L_p/nab-72007.htm. I have used this timing belt kit on two of the Miatas with success. They arrived in just two days.

I am going to go ahead and include this now, but it was after the first two timing belt replacements that I found this out. It only makes sense if you need enough parts to make the shipping from several locations work out. I found that I can source the parts separately and save some money. These are the parts I ordered from several different sites. It takes longer for these to arrive since they are shipped from different places but if you have the time it can be worth the wait.

I ordered these parts for my 2000 Miata SE from Rock Auto http://www.rockauto.com/ . The timing belt kit only includes the belt and the tensioner and idler bearing.

· (1 ea.) VS50569R Valve Cover Gasket

· (1 ea.) 42134 Water Pump

· (1 ea.) TCK179 Timing Belt Component Kit

· (1 ea.) 710355 Crankshaft Seal

· (2 ea.) 223420 Camshaft Seals

I ordered these parts from The Mazda Parts Center http://mazdapartscenter.com/parts/. This is a dealer site that sells OEM parts online. Again, I was also ordering other parts to offset the additional shipping charges, this may not be the best solution for your needs. I really like the OEM metal gasket instead of a paper gasket so I ordered the water pump gaskets here. If the water snout is left attached (it does not need to be removed to replace the timing belt) and is not leaking the O-Ring is not needed. But, if the O-Ring is a concern, this would be the time to replace it.

· (1 ea.) B6PF15116 Water Pump Gasket

· (1 ea.) B61P15106A Water Snout O-Ring

These parts are what I ordered and may not fit your application. These vendors will assist you if you wish.

I needed some non-standard tools. The Miata.net Garage shows how to use a large washer and piece of steel to make a tool to hold the crankshaft while the crankshaft bolt is removed and installed. I needed a tool like this. Several places sell this tool, but I decided to make one.

I got large washer and a piece of 2” flat steel from a hardware store. I used the timing plate for a template, marked and drilled the attachment and alignment holes as shown in the Miata.net Garage instructions. I temporarily bolted the washer onto the crankshaft and positioned the flat steel so I could leave the crankshaft at TDC with the steel rising up above the engine at about 11 o’clock. I marked the washer where the arm should be welded, removed it and welded the two parts together. I have used this tool now on four occasions and it has worked OK each time. The flat steel did bend on the last bolt removal, but a hammer persuaded it to straighten out and the bolt finally was removed.

Vendor Links

The Parts Group

I made a crankshaft pulley boss puller out of a scrap piece of 1/4" steel plate. Again I used the timing plate to mark the holes and drilled them out on the drill press. To use it I put two or all four of the bolts through the holes with the plate against the end of the crankshaft. Most of the pulley bosses have come loose when I tightened two opposite bolts a little at the time. On one I had to use all four bolts to get it moving.

I used a 1/16” drill to make one hole in each of the seals and then used a drywall screw into the hole for a puller. My claw hammer then could pull them easily. The camshaft seals can be removed by removing the end cap, but these must be torqued properly afterward. I did this on one and it worked also.

My son made me this. It would be a complete seal removal kit if he had included the 1/16" drill.

Always the comedian! Maybe I won't loose the screw?

I bought a 1-1/4" PVC coupler at the hardware store to make a seal driver to install the crankshaft seal. The seal O.D. is 2” and it goes onto a 1.5” O.D. shaft so the coupler must be able to fit over the shaft and close to the 2” O.D. I cut the coupler just at the divider in the middle to make one end a little thicker. It worked great. I don’t remember where I got the tip, or idea, but it works. I could have used a large socket, or bought a crankshaft seal installer.

Another tool I found useful was a paint marker. I used it to mark the old belt and timing gears and to mark the belt and crankshaft gear before removing the belt. Then it was easy to line up the new belt and mark it so it was installed with the same number of teeth between the marks onto the gears.

Caution: the marks made on the outside of the belt must be transferred to the new belt on the side that will face outward. If the marks are made by placing the belts front to front then when the new belt is turned around to install it, the marks will not be in the correct position. Don’t ask how I figured that out.

Replacing the Belt:

Now that I was ready to start I had to overcome my fear that something would break if I touched it. The engine compartment looked too complicated for me to remember where everything went back. So, I was timid at first about removing or disconnecting anything. I followed the instructions I found at Miata.net Garage on what to remove when and how and also how and when to re-install each part.

I was pleased with the outcome and only had to do a few of the steps twice on the first timing belt replacement. I have found that the more I work on these cars the simpler everything has become.