[carnage] Savington throws a rod, hilarity ensues - Page 5 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 03-04-2009, 11:43 AM   #81
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I agree, check the runout. IIRC just because it is a '99 and is in the VIN range does not necessarily mean it has the wrong throwout bearing. If you are pulling the oil pan then you may be able to measure the clearance directly with a feeler gauge.
Thrust bearing. Just to clarify. You have the right location though.
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Old 03-04-2009, 11:51 AM   #82
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Right. My bad
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Old 03-04-2009, 11:51 AM   #83
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I'm curious now.

Wrist pins I can understand; those take some finessing. But main bearings? You need a torque wrench, some plasti-gauge, a dial indicator and a prybar for endplay, and...?
Depends on your definition of "right". Having a machine shop background, we usually don't make assumptions when building an engine. IE-ASSuming that all the main bearings bores (that the actual bearing resides in) are on size and perfectly inline with one another when the caps are torqued down. Or ASSuming that the bearings are crushed just right (not too much (bearing deforms), not too little (spins a bearing)) when the caps are torqued down.

IE-if sav took it to a shop, they'd verify the bores for the main bearings are within an acceptable range of true. They'd check the surface finish of the crank and mike it out to determine if it needs to be ground. If it's good then they'll order the correct size bearings for each bore and journal. Then when assembling they'll measure the crush in the bearing and make the correct* adjustments to get that right. Then they'd break out their snap gauge and check for any out or roundness after the bearings are installed and torqued. All that before putting the crank in to check for clearance with plastigage.

If sav can't hone a cylinder, I doubt he needs to be spec'ing out the bottom end of his engine. Leave good enough alone there. But since he's doing the rods he'll have to at least plastigage the big end of the rods and adjust or order new bearings accordingly.
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Old 03-04-2009, 02:34 PM   #84
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Pat, by your theory, every motor out there needs to be torn down and professionally checked. The other option, remember, is to slap it in blind and see what happens; I don't think a 96,000 miles motor needs to have the main bearings line-bored or the crank ground. That's a slippery slope, and probably the reason motor builds cost so damn much. I probably could hone a cylinder, and if I had someone standing next to me critiquing my work, I'd be comfy, but I'll just as soon pay that someone $25 to do it themselves so I know it's perfect. Bearings are cheap enough I could buy a couple different options and use the one that fits.

Joe, as far as wrist pins go, I've heard some of the rods need to be honed out to fit them. I assume the same shop that hones the cylinders can handle something like that. I did add new circlips to my list.
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Old 03-04-2009, 02:41 PM   #85
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Pat, by your theory, every motor out there needs to be torn down and professionally checked. The other option, remember, is to slap it in blind and see what happens; I don't think a 96,000 miles motor needs to have the main bearings line-bored or the crank ground. That's a slippery slope, and probably the reason motor builds cost so damn much. I probably could hone a cylinder, and if I had someone standing next to me critiquing my work, I'd be comfy, but I'll just as soon pay that someone $25 to do it themselves so I know it's perfect. Bearings are cheap enough I could buy a couple different options and use the one that fits.

Joe, as far as wrist pins go, I've heard some of the rods need to be honed out to fit them. I assume the same shop that hones the cylinders can handle something like that. I did add new circlips to my list.
It's not quite as simple as trying them out and seeing what fits. That's why I said "If you don't know what you're doing, you'll probably **** something up or at minimum, make it worse than it was before you fixed/improved it."
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Old 03-04-2009, 03:19 PM   #86
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You need to either:

a) let someone that knows how to do this build it.
b) slow down, get a couple books on building engines, read up, talk to some people that do this kind of thing, buy the tools needed, and do it yourself.
c) put a stock engine in your car and drive it, build one on the side.

I suggest c because it gets you going now and you'll have time to learn and possibly build your own engine down the road. Nothing wrong with paying a machinist that knows their **** to build an engine though. There's a lot of little stuff that goes into building an engine. Specs are huge as working clearances change when you change the power and RPM the engine will operate at. And knowing which end of spec to error on is equally important. You build a new motor to tight end of factory spec on piston/cylinder clearance and put it on a race track and it will seize up if it doesn't detonate and destroy itself first.
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Old 03-04-2009, 03:25 PM   #87
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enjoy the math if you have these tools. If you don't then don't worry about measuring **** and just bolt it together. It will probably hold.
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Old 03-04-2009, 04:25 PM   #88
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As long as everything is within factory specs when you assemble it, it shouldnt be an issue. I say just build it. Its far too early in my build to know how I did, but I did everything myself and its been doing great so far. Ive been pretty tough on it n/a for the last 1200 miles. We shall see if I eat **** when I put boost to it.
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Old 03-04-2009, 05:09 PM   #89
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On the one hand I built a 1978 Honda motor a very long time ago with little knowledge and a shop manual. It was my first engine. I had a shop do the machining, but I did the ring gaps, plastigaging, final assy etc. myself and that motor held together fine. It was a tough little bastard, high compression, Weber carburetor, run hard as a DD for years with no problems, but it was NA. So that experience says you will be OK.

On the other hand when I just had my motor built, the machine shop (a good one) checked the crush and the bearings were not right, lots of runout. If I had just plastigaged them I may not have caught it. And this motor is going to be producing almost 3X stock power levels. So that experience says pay the machine shop to check the details.

I say it all comes down to your personal risk-versus-cost-versus-time comfort area. Mine this time was spend more money, have less risk of failure, and avoid the time needed for another engine swap. You might be willing to go low budget with more risk.
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Old 03-05-2009, 02:02 AM   #90
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I think rods are out of my reach right now. After pricing out labor and parts, including a head gasket, TB, WP, etc. it ends up being damn near a thousand bucks and I just don't have it. I just spent $150 or so on fittings and tools to upgrade the oil/water lines and $700 for the motor itself so the rods are going to have to wait.

Since I'm going to build the motor soon, I'm going to leave EVERYTHING alone. No timing belt, no water pump, no nothing. It'll get a reroute, oil/water lines, and go right back into the car. I'll start amassing parts (rods, possibly pistons?, maintenance items) immediately and the motor will come back out in a couple of months to get everything installed.
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Old 03-05-2009, 02:07 AM   #91
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Good decision, but take an extra belt to the track...I always have a spare. go low-comp.
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Old 03-05-2009, 02:12 AM   #92
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nice inline 6 behind the civic mmotor man :P
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Old 03-05-2009, 11:14 AM   #93
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nice inline 6 behind the civic mmotor man :P
endyne is the most bad *** naturally aspirated engine shop on earth. I've done a couple track events where they've run a 275whp, 1800lb crx w/225's, and a gloriously frightening s2k.
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