• From: Elverson, PA
  • Registered: 2017-08-15
  • Posts: 1,135

Topic: 2 quick '90 NA Miata questions:

1. Should I put anything on the crankshaft before putting on the crankshaft gear? (like oil, standard grease, neverseize, brake pad high temp grease)

(Next time I'll buy a 'puller', but I'm looking for best practices, and I'm definitely NOT a mechanic, so I really don't know about this. Any help would be appreciated; I'm doing this Saturday morning (tomorrow). I finally have everything together, and time to finish (I hope) timing belt and water pump on '90 NA Miata (all day Saturday if necessary).)

This was the result of me trying to pry off the gear (I did a LOT of cleaning in that general area):
https://i.postimg.cc/Kv9kkd1s/20240325-185220.jpg
.


2. Do these plugs suggest a problem? (_other than_ it was WAY TOO LONG since the plugs were changed in this car)
https://i.postimg.cc/pdwKLbgw/20240325-144653.jpg
.

  • Zacks
  • Ripened Lemon
  • Offline
  • Registered: 2022-10-17
  • Posts: 112

Re: 2 quick '90 NA Miata questions:

Plug 3 looks like arc tracing.likely needs new plug wires.

I don't think service manual calls for anything on crank but I've used a thin coat of anti-seize with no problems many times on personal cars I expect to need tobtear back down...

  • From: Elverson, PA
  • Registered: 2017-08-15
  • Posts: 1,135

Re: 2 quick '90 NA Miata questions:

Zacks - thanks! That's on the list now.

To review: it looks like this car sat for 5 years, with _maybe_ 500 miles over that time - or maybe none. It had an oil change the previous year before it was auctioned, and an inspection.

Lots of rust on the pulleys from sitting. A new battery, wipers, tires, and a few lights and electrical work, and it's passed inspection twice. I haven't yet touched anything else, until the water pump leaked; that's why I'm doing the timing belt now, also.

In the back of my mind I'm thinking of someone who told me about deposits on plugs (again, NOT a mechanic); I think I heard - a long time ago - that mineral deposits on plugs might indicate a head gasket problem. I'm hoping that's not the case here, but I am worried about it. There's no water in the oil that I can see, which is good.

And with this, I'll be going to sleep trying to remember the last time I changed plugs and wires on _my own_ vehicle rather than a friend's (I'll update this when I remember).

  • From: Camarillo, CA
  • Registered: 2021-03-26
  • Posts: 386

Re: 2 quick '90 NA Miata questions:

1) I've gone both ways and haven't had an issue... usually after the first time I'm doing the job frequently enough to where the cog gear doesn't seize, but antiseize wouldn't hurt if you don't plan on doing the belt for the next decade.

I'm assuming that you know of the short nose crank issues on the first couple years of 1.6's? Make sure you use blue loctite on the crank bolt and torque it to spec. Most of these failures are because people just send that crank bolt with a couple ugga-duggas and it loosens up, leaving the key to take all the shear load rather than the static friction taking the load, applied by the crank bolt.

2) Plugs look OK for a miata, just old. As mentioned I'd throw plugs+wires at it and you'll be good.

Full Ass Racing
#455 Piñata Miata - 1990 Miata
#735 BMDollhÜr 7Turdy5i - 1990 735i

5 Reply by Lemon_Newton-Metre (edited by Lemon_Newton-Metre 2024-04-09 06:59 AM)

  • From: Elverson, PA
  • Registered: 2017-08-15
  • Posts: 1,135

Re: 2 quick '90 NA Miata questions:

duthehustle93 - thanks! And timely, as some 'elder care' issues delayed me, so I'll be getting to this in the morning.

I hadn't read about the blue-dot (242) Loctite on the bolt; so that's new and useful.

And yes, this is a short nose crank, and it looks like the epoxy thing was done, based on discoloration on the end of the crankshaft.

So, with my custom crankshaft tool, I'll be able to get good torque on the bolt.

And with this back together, I think I'll be doing the timing belt again in 3 years or so.

////////
[edit]:
I made my own, which I think is an improvement on the original; but then again, I only have the one NA type; and yes, there are bolt holes, just no bolts for the pics:

https://i.postimg.cc/FHVDnxBt/20240322-072600.jpg

https://i.postimg.cc/8CywTzGt/20240322-072614.jpg