Originally Posted by Mach929
(Post 190019)
does anyone make hypereutectic pistons for the miata, from the reading i've done these would bridge the gap between stock cast pistons and fancy loose fitting forged ones.
Sam, I didn't open the thread you linked, but I assume it concerns cylinder wear and piston slap? I don't think it's really a big deal anymore. However, Mach and Mark do make a good point. OEM pistons, with a ceramic coated dome, and upgraded and moly coated skirts would make nice pistons. |
Originally Posted by Mach929
(Post 190019)
does anyone make hypereutectic pistons for the miata, from the reading i've done these would bridge the gap between stock cast pistons and fancy loose fitting forged ones.
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oh didn't know that....oops.
what does mitsu use in their 4g63 motors? |
Thanks Ben... I love that idea.
Looks like Topline Pistons with the treatment and Toga Rings, plus Belfab Rods and one of the better "rebuild" kits is what I want. I'll have my shop get the block ready and see if they can't source the kit plus ARP main/head bolts. That stuff plus a head rebuild and I'll be set. Pistons: $136 Coating: $100 Rings: $109 Belfab Rods: $315 (via eBay) Rebuild Kits: $250-$400 (depending on level, but the Topline rebuild kits also seem to include pistons and rings... more research needed). ARP Head/Main studs: $130/$100 New Valvetrain: $200 (can't find one anywhere, but the FM one is $388, so figuring halfprice of that is more likely. So, depending on whether the Pistons/Rings I want are included in the rebuild kit, I'm sitting at about $1200 in parts. How much is the block work going to cost. Shawn said the head rebuild should be about $200 in labor... so another few hundred for the block work and a few more if I wanted them to do the rebuild? Bottom line is I'm into this thing for around $1800 with a little slop included? Does that sound right? |
Originally Posted by Markp
(Post 189996)
Sam, the weakest part of the stock motor is the rods. Get the Belfabs. Cheap insurance.
Though new to the turbo end of the Miata world, word from Corky is that in his experience, the rods are the weak link as far as engine internals go. Additionally, if budget allows, valves and port matching is money well spent. - L |
I don't think that OS valves are warranted at 200 hp. Not that they'd hurt, but on a budget build of this magnatude, I'd leave them out in favor of putting the $ elsewhere. Reason being, OS valves make a % difference, and on low power they don't do too much. On a 300+ hp motor, I'd agree with ya.
Sam, I think you're on the right track, but I don't think you've got enough $ in the pot to cover everything. I'd be REALLY suprised if you got out that cheap. What are you estimating for machine labor? I think you'll be in it for a 4 digit number, the first number being a 2, and the second number being between 1 and 5 depending on what's up with your head. I also think you should check into adjustable cam gears, as there will never be a better time to put them in. |
I hate to threadjack, but oversized pistons vs stock...I'll need to do a rebuild soon I think...and wont both require the block to be bored anyway?
If I was wanting ~250...which isn't far off from sam's goal...are the larger pistons needed or just highly recommended? Assuming I needed to replace some burnt valves...I didn't see an answer to sam's question about oversized valves. (cost difference on something different in the head vs replacing stock stuff) |
Originally Posted by Ben
(Post 189850)
You're probably looking at $2000 or so on a mild shortblock with budget forged internals and machine shop labor, with your own assembly.
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I was figuring on around $400 for the work on the block and the shop actually doing the re-assembly... and another $200 for headwork. So I thought around $600 total for labor. Is that reasonable?
But I am really confused about what exactly is included in the "rebuild" kits as far as the quality of the product. I'm gonna have to makes some phone calls tomorrow. We'll use the Topline kits as an example. The kit comes with pistons... but I've budgeted an extra $136 for pistons. The kit also comes with rings, but I assume the $109 for the Toga pistons are in addition to the kit price. The RPMMachine website quotes a longblock for $1120 and I'll guess $200 for shipping. I need to see if the quality of parts in their stock longblocks are good enough. But if I can have them build a motor with the better rings, have them coat the pistons, and install better rods for less than I can have it done locally, then I've got more thinking to do. And the valvetrain will remain stock. |
screw the rebuild kit, headwork & arp studs.
pull the pistons, get the block honed. slap your new guys in, reuse all your old componets and your new headgasket. call it a day :) get that shit running again! |
...says the guy who's had a half dozen motors in his car.
He's got a running motor, and a busted motor. Sam, throw in the running motor and put $200/month away to build the bad one up. That's pretty much what I've been doing on my motor build project: going forward at around 1 item per month, or jumping when a good deal hits. |
Damn you both!!! It's like trying to choose which side of the Force I want to be on.
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Those who got the CAT (belfab, 949) rods, what did you do about bearings? Do they come with bearings or do you reuse your old ones or do you source from third party? I really would be against reusing my old ones...what do new bearings run and which to get?
I've been following this thread closely and didnt want to crap on it, but this sort of interests me since i'm seriously considering to go ahead and get these rods already for my motor build. |
Originally Posted by samnavy
(Post 190112)
Damn you both!!! It's like trying to choose which side of the Force I want to be on.
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Originally Posted by Mach929
(Post 190019)
does anyone make hypereutectic pistons for the miata, from the reading i've done these would bridge the gap between stock cast pistons and fancy loose fitting forged ones.
Mark |
are rings and ringlands going out as fast as honda's?...i know that the rods are weak but what about guys with 323 gtx rods?...what about piston coats?...do they last?...just various questions for mild oem builds!!!
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Originally Posted by samnavy
(Post 190112)
Damn you both!!! It's like trying to choose which side of the Force I want to be on.
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Originally Posted by Ben
(Post 190107)
Sam, throw in the running motor and put $200/month away to build the bad one up. That's pretty much what I've been doing on my motor build project: going forward at around 1 item per month, or jumping when a good deal hits.
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I'm doing the same thing, just got a cheap ass block back together so I can do something with the spare one sitting on my garage floor. However, I'll still cheap out and use belfab rods and "oem" pistons with a .20" overbore :)
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I'm going with the cheap rods and some JE forged overbore pistons. I'll probably have the pistons ceramic coated. The JE's don't cost much more than oe pistons + rings, and will hold up better in the event of any nasty detonation.
And Tom, I gaurantee you I won't be buying anything else for a good long while. So have at it... :bigtu: |
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