[TOM RENZO]

here is the piston specks on the midnighters pistons.http://i600.photobucket.com/albums/t...TCMOTOR020.jpg

Sealed Power
Piston number L2455F
Dome depth (negative).100
Material forged aluminum alloy
Piston diameter (size) 3.81625
Bore of engine 3.81975
Piston to wall clearance .0035 @ 70*F
App compression ratio (static) 8-1
Pins pressed
Piston face to deck clearance (piston drop) .015

I think these modified pistons should work OK. I have done this before with good luck to other pistons. It took me a tun of hours for setup and final machining. These pistons are obsolete according to Seal Power diamond still makes a turbo piston for the 2.3. They cost app $350.00 a set. They are exact replacements for the 2.3. The Seal Power L2500F pistons are also obsolete. If you are building a 2.3 pistons are up their in price. I used to run the 2455 on big cam motors with stock CR of 9-1. But this motor i want to run 28-30 LBS of boost. Thought you would like to have the specks.

[b_chandler]

Good stuff.

Do the Sealed Power pistons have metric or standard ring land sizes? The factory turbo pistons had metric ring land sizes and metric sized rings. I was going to jump on the bandwagon and buy the rings everyone else buys for the Sealed Power pistons that are supposed to be the same as the factory rings. Diamond machines the piston ring lands in inches rather than mm. After taking some measurements and doing some standard to metric conversions I found that the metric rings aren't an exact fit for a standard ring land. The oil control ring pack is really tight by the numbers (no real fit test data). I ended up buying a different set of Sealed Power rings that were of the same composition but were standard measurement rather than metric.

Sealed Power Part Number R-10515-xx (xx=cyl. oversize in thousanths)

I've got a set of +.030 Diamonds hanging off of Crower Sportsman Rods waiting to go in my Turbo motor. I've got everything to put the bottom end together for mock up to check clearances. I need to get my fat carcass out there and get that done.

[TOM RENZO]

Ok chandler here is the scoop on the rings

TOP 5/64 MOLLY
SECOND 5/64 chrome
OIL chrime normal tension 3/16
SP# E-441K-1.00MM +.040

DUDE sportsmen rods far out THE BEST MAN

:b igthumbsup

[b_chandler]

So the 441K's are in inches? Son of a... I swear somewhere (and I want to say either Summit or Sealed Power's website) that they were measured in mm.

I still think I'm okay on the rings. Worst that can happen is that I'm wrong, and I've been there before.

[TOM RENZO]

Chandler mike up the ring lands on your pistons and see what they read. You can do it with a vernia. Whose pistons are you using??? If memory serves me the stock 2.3 had 5/64-5/64-3/16. Check it out and repost. You can also check the clearance with a ring and feeler gauge. This will tell you your land clearance. Land clearance should be .0008-.0011. Back space shouls be .020 negative or better. Hope this helps TOM

[b_chandler]

Here's the info I got from Summit regarding the Speed Pro rings

Brand
Sealed PowerManufacturer's Part Number
ZE441KPart Type
Piston RingsProduct Line
Sealed Power Performance Piston Ring SetsSummit Racing Part Number
SLP-E-441K

Bore (in)
3.779 in.Bore (mm)95.987mm
Top Ring Thickness 2.0mm
Second Ring Thickness 2.0mm
Oil Ring Thickness 4.76mm
Oil Ring Tension Standard
Top Ring Material Iron
Top Ring Facing Material Moly
Second Ring Material Iron
Second Ring Facing Material Cast iron
Oil Ring Material Stainless steel



I know the bore size is wrong on these. It's the part number and ring thickness that's important here. The pistons I have are Diamond PN29000 advertised as having 5/64 5/64 3/16 ring lands.

Now if you do the math (and I may be splitting hairs here) but 5/64" works out to 1.98mm. Here's where a shrug and "eh, close enough" usually gets tossed in. But hey, if we're going to round off numbers, why measure with mics and calipers? Looks like the 2.0mm ring in a 5/64 land is gonna be a little tight clearance-wise. It'll fit, but the land clearance is gonna be out of spec. If ring land clearance should be .0008-.0011 inches, and you just installed a ring that was .0008 " (.02mm)thinner or thicker (depending on which way you go) You're out of spec as soon as you remove the ring pliers. Am I being anal? maybe. But blueprinting is blueprinting.

I was mistaken earlier, when I said the oil rings wouldn't fit. In fact, the oil rings are actually closer between the two ring sets than the compression rings.

Here's the ring package I ended up with.

Brand
Sealed PowerManufacturer's Part Number
ZR1051530Part Type
Piston RingsProduct Line
Sealed Power Standard Gap Plasma-Moly Piston Ring SetsSummit Racing Part Number
SLP-R-10515-30

Bore (in)3.810 in.
Bore (mm)96.774mm
Top Ring Thickness 5/64 in.
Second Ring Thickness 5/64 in.
Oil Ring Thickness 3/16 in.
Oil Ring Tension Standard
Top Ring Material Iron
Top Ring Facing Material Plasma-moly
Second Ring Material Iron
Second Ring Facing Material Cast iron
Oil Ring Material Stainless steel


Sorry for the long post

[TOM RENZO]

Sounds good the best way to check believe it or not is with a feeler gauge for the land clearance normally .0008-.0011. The bore is up to the machine shop and the piston specks. Normally wall clearance is .0035-.0050 for forged units at 70*. I think you are golden. Man i hate the metric system YUCKIE DUCKIE. Tom

[b_chandler]

The machine shop that did the block work had the pistons in hand when they finished the bores. They came back numbered for each cylinder. All I need to do is check the land clearance and the ring gap before I drop them in.

I agree that the rings I have will do the trick. When I sat down to order them, that's when I ran into all of the metric crap and kinda panicked a little. I finally took a deep breath and went looking for a set of rings that were made of the material I wanted and would fit my pistons (or at least were measured by the same unit of measure).

I think when I get home from work tomorrow I may start mocking things up and checking clearances. It'll give me something to do before dinner.

[TOM RENZO]

Sounds good and if you have to open those ring gaps GO EASY DUDE. Good luck and i know it will be done right. Keep a build sheet for future reference. Take some photos DUDE. Love to see your build its going to be AWSUM. Do you have everything you need?? Dont forget the plastigauge in two colors. I used to put two colors on each journal to compair clearances. Believe it or not its real accurate.TOM