The silver Miata

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Dave_G
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Re: The silver Miata

Post by Dave_G »

jcollins914 wrote: If you end up needing an engine hoist, let me know, and you can borrow mine and a truck to get it there & back if need be too. The motor mounts should be pretty easy to change; you MIGHT not even need a hoist. I've never tried to just change a mount w/out one though, as the task has always been coupled w/ engine/transmission removal projects.
Thanks Jeff! I don't think I'll need one, though. According to two sources, including the Enthusiast's Repair Manual, the job can be done by jacking up from below with a piece of wood under the oil pan, without having to remove the engine entirely.

The next step is figuring out what kind of new bushings I want for the front control arms. Replacing with stock bushings would be cheapest and easiest, but I might want to go with something stiffer, and potentially faster. I've already ordered offset bushings for the upper control arms so I can get more than 1.9° of camber.
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'90 Miata (summer fun)
'91 BMW 325iX (winter fun) oo=[][]=oo
'04 Mazda 6s wagon (family fun)
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Dave_G
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Re: The silver Miata

Post by Dave_G »

Now that the car is straight, the pieces are going back on. First up: the bent lower control arm.
Out with the old, in with the new:
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I decided to go with the popular Energy Suspension polyurethane bushings for the LCA, so the right one came off too to get matching bushings. The new LCA on the left side made the old one on the right side look terrible, so that one got cleaned up and finished with a shiny new coat of paint. I also added the Zerk fittings for easy greasing when the polyurethane bushings inevitably start squeaking:
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While I was messing around with the lower control arms, might as well get new bushings for the upper arms too. These are the cool offset Delrin bushings from ISC Racing. Yay, negative camber!
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I hit a little snag with bolting on the left UCA, when it turned out the the long pivot bolt holding it to the car was very slightly bent, causing the arm to bind when the bold was torqued. A new bolt is on order.
Dave GuertinImage
'90 Miata (summer fun)
'91 BMW 325iX (winter fun) oo=[][]=oo
'04 Mazda 6s wagon (family fun)
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Dave_G
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Re: The silver Miata

Post by Dave_G »

Dang, if it ain't one thing, it's another. Tonight I was bolting everything back together, and when I got to the inner tie rod. I discovered that my new replacement tie rod didn't fit. It had the wrong threads. Turns out I ordered one for manual steering by mistake. :mad:

Then when I turned to getting the control arms all buttoned up, I couldn't get the holes around the lower ball joint to match up, and when I finally did, the ball joint was swivelling at a very peculiar angle. Turns out the lower ball joint was bent, another casualty that I overlooked amidst all the other carnage (the rubber boot has been cut away here):
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I'm not surprised, given that the wheel was hit hard enough to bend the lower control arm, and the ball joint is in between. Oh well. At least it's a bolt-on piece.

On a brighter note, I did get the new competition motor mounts installed tonight, which should help alleviate the problems I've been having with the 2-3 shift going up the hill at NHMS. Nothing like wrecking a car to create an excuse to upgrade parts. :P
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'90 Miata (summer fun)
'91 BMW 325iX (winter fun) oo=[][]=oo
'04 Mazda 6s wagon (family fun)
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Rabbit Farmer
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Re: The silver Miata

Post by Rabbit Farmer »

My limited experience (one car) with a car that has been in an accident, there is more broken/bent parts that it seems by taking an general overview at the beginning of the project.
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Dave_G
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Re: The silver Miata

Post by Dave_G »

Rabbit Farmer wrote:My limited experience (one car) with a car that has been in an accident, there is more broken/bent parts that it seems by taking an general overview at the beginning of the project.
You speak the truth. The first surprise was the broken motor mount. The second one was the lower ball joint. If there's going to be a third surprise, it'll be the steering knuckle. It looks OK, but then so did the ball joint. So far the steering knuckle and the upper control arm (and the upper ball joint connecting them) are the only original pieces left in the left front suspension.
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'90 Miata (summer fun)
'91 BMW 325iX (winter fun) oo=[][]=oo
'04 Mazda 6s wagon (family fun)
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lawdogg
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Re: The silver Miata

Post by lawdogg »

Dave, mind talking real quick about running those offset bushings?

I've only ever driven MacPherson strut type setups and my Miata is the first dual A-arm config I've had. I've been wondering about the camber profile of the Miata's geometry ... any good articles? Or just a quick & dirty rundown?

In any event, glad to see progress even though I'm a little late to the party ...
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Dave_G
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Re: The silver Miata

Post by Dave_G »

lawdogg wrote:Dave, mind talking real quick about running those offset bushings?

I've only ever driven MacPherson strut type setups and my Miata is the first dual A-arm config I've had. I've been wondering about the camber profile of the Miata's geometry ... any good articles? Or just a quick & dirty rundown?
Well, I still haven't driven on those bushings, so I don't have much to say in the way of a review. But the idea is to bring the upper control arms in a little to gain more negative camber. In general, the Miata suspension is a thing of beauty, and is adjustable eight ways to Sunday with the eccentric bolts in the lower arms. To adjust camber and caster (and toe in the rear), you just adjust those eccentric bolts. But even with the lower arms adjusted all the way out, the maximum possible camber is still less than 2°. That's more than fine for a street driven car, but on the track I want closer to 3°, and the only way to get that is with offset bushings.

I'd say it isn't really worth it unless you've got things all apart anyway. Until now I've driven many track miles with 1.9° of camber in the front (the most I could get), and it has been fine. But I'm still looking forward to seeing how the tires behave next season with more camber.

BTW, the two best ways to get more camber in a Miata without replacing the bushings are to a) lower the car (while still staying off the bump stops); and b) replace the eccentric bolts with new ones.

The best place to get more info on Miata suspensions is at miata.net. Here's a good place to start: http://www.miata.net/garage/garagehandling.html. It's also worth picking up a copy of the Enthusiast's Manual if you don't already have one.
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'90 Miata (summer fun)
'91 BMW 325iX (winter fun) oo=[][]=oo
'04 Mazda 6s wagon (family fun)
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Dave_G
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Re: The silver Miata

Post by Dave_G »

Almost done! The Miata came out of winter hibernation last weekend, and if my luck holds, it will be able to make the autocross this weekend. It's currently at the body shop getting the new fender and headlight cover painted, then assuming that goes to schedule, it's off to get aligned Friday morning. With its completely rebuilt front suspension, it is seriously out of whack until it gets aligned. When I drove it to the body shop yesterday, the pre-alignment handling was, well, "interesting." :shock:
Dave GuertinImage
'90 Miata (summer fun)
'91 BMW 325iX (winter fun) oo=[][]=oo
'04 Mazda 6s wagon (family fun)
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