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joesurf79

Miata BP Valve Clearance Questions

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During the Maintenace-A-Palooza on my Miata last week, I checked the valve clearances while the motor was out. Several of them are out of spec 1-2 thousandths one was 3 thousandths, all of the deviation to the loose side of spec, so no concerns like burning a valve. This is a '99 motor with the solid lifters and shims. There's a tiny bit of ticking, but it feels like it pulls strong. To adjust them, I'd need to pull the cams, measure shims, play shuffle-the-shims where possible to minimize new shim ordering, wait for the new shims, install the cams, double check, and repeat if there are any problems...blah.

I'm sure the super competitive SM guys are on top of their clearances, but would the miata track rats care about 1-2 thousandths? on the intake side, that's like 25% of the spec clearance...

I've looked around online for the special tool that Mazda sold that would allow shim removal with cams in place, but good luck finding one. Shims seem hard to find. Anyone have a bead on where to get the special tool and or the valve shims? Anyone willing to rent (with a deposit) an internet rando like me the special shim tool if you have one?

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If I had to guess, most 99-00 owners have never and will never check their valve clearances. They're never out of spec if you don't measure them lol. 

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I checked clearances once. Like yours, they were very close. My math was that the risk of pulling cams and such was higher than running them barely out of spec, so I didn't do anything. I really like having adjusters on the Hondas.

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Honda made it easy. a 10mm, a flathead, and 30 minutes and you're back in Soichiro's good graces. The only easier way is hydraulic lifters.

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I just called Mazda Motorsports and inquired about it while I was getting my account updated.  Dan said they regularly sell the shims and they have them in stock at Mazda.

Vs the effort required to measure, chart, mix n match all the shims, you might just buy the three you need and move on with life.  They're less than $10/each.  $30 in parts isn't worth all the downtime to me...

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1 hour ago, Matt93SE said:

I just called Mazda Motorsports and inquired about it while I was getting my account updated.  Dan said they regularly sell the shims and they have them in stock at Mazda.

Vs the effort required to measure, chart, mix n match all the shims, you might just buy the three you need and move on with life.  They're less than $10/each.  $30 in parts isn't worth all the downtime to me...

Looks like I'm signing up with Mazda Motorsports now!

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