Bore size question
#1
Bore size question
I was measuring the block bore yesterday and got:
Piston 1
X 3.327in (84.51mm)
Y 3.327in (84.51mm)
Piston 2
X 3.327in (84.51mm)
Y 3.326in (84.48mm)
Piston 3
X 3.327in (84.51mm)
Y 3.326in (84.48mm)
Piston 4
X 3.327in (84.51mm)
Y 3.327in (84.51mm)
Do you guys recommend that I should bore the block? If so, what size? If not, what size pistons should I use and what brand?
Piston 1
X 3.327in (84.51mm)
Y 3.327in (84.51mm)
Piston 2
X 3.327in (84.51mm)
Y 3.326in (84.48mm)
Piston 3
X 3.327in (84.51mm)
Y 3.326in (84.48mm)
Piston 4
X 3.327in (84.51mm)
Y 3.327in (84.51mm)
Do you guys recommend that I should bore the block? If so, what size? If not, what size pistons should I use and what brand?
#2
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You're already 1.5mm over stock. AFAIK there isn't much more meat left to bore. Some people go to 85.0mm, but that's it.
If you get 84.5mm pistons you have .01mm (0.004") clearance that's not too bad. In fact that's what I asked my machine shop to do for me. So if the cylinder walls look good remove glazing, slap in new pistons and go.
But I'd definitely wait for one of the more experienced guys to weigh in too.
If you get 84.5mm pistons you have .01mm (0.004") clearance that's not too bad. In fact that's what I asked my machine shop to do for me. So if the cylinder walls look good remove glazing, slap in new pistons and go.
But I'd definitely wait for one of the more experienced guys to weigh in too.
#4
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Sorry- made a mistake in my earlier post. I usually get the numbers right, but the order of magnitude wrong. 0.004" is 0.1mm, not 0.01mm!
You're sitting almost exactly at 84.50mm. You want your bore to be 0.05mm to 0.1mm larger than your piston- depending on your manufacturer's specs and your application.
If your bores look good, buy some 84.5mm pistons, measure them and then have the block machined to fit. If they need to remove less than 0.1mm, my guess would be that honing would be sufficient.
You're sitting almost exactly at 84.50mm. You want your bore to be 0.05mm to 0.1mm larger than your piston- depending on your manufacturer's specs and your application.
If your bores look good, buy some 84.5mm pistons, measure them and then have the block machined to fit. If they need to remove less than 0.1mm, my guess would be that honing would be sufficient.
#9
Got a set of pistons and rings for sale if you are going with 9.5 comp ratio
https://www.miataturbo.net/showthrea...82#post1046782
https://www.miataturbo.net/showthrea...82#post1046782
#11
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Got a set of pistons and rings for sale if you are going with 9.5 comp ratio
New Supertech pistons pins and rings set - Miata Turbo Forum - Turbo Kitten is watching you test compression.
New Supertech pistons pins and rings set - Miata Turbo Forum - Turbo Kitten is watching you test compression.
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