Cheap 100mm-100.25mm Pistons
Posted: Sun Nov 29, 2020 9:08 pm
Had my eyes on these as a “Maybe” piston for some time, and a few months ago, I decided to pull the trigger on a set. Here are the factory specs:
99,5mm bore STD
Hypereutectic
30mm compression height (100s) - the heights may shrink a bit as bore increases
About 600g with piston, pin, clips, and rings, bare piston was 430g
Small end width between bosses - about 25mm
1.2x1.2x2.0 rings
24mm pins
There a slight dome on the pistons that is about .090” tall
I calculated the approximate piston speed that they see in the Hemi 5.7 they come out of, and 6,500-7,500 is fine with most of our small strokes up to around 82mm.
Oh, and price! They’re currently around $315 for eight piston assemblies! I split the price with a Norwegian friend, and sent some after I machined them for some Pauter rods.
K. Now you’ll need to need to widen the area between the pin bosses. An aftermarket T4 rod is too wide to slip all the way down. T1 just barely fits, but still needs more sideplay to avoid issues. It’s a fairly easy job. Clamp them down, use a radiused endmill and gave myself 2mm clearance.
Barrels are expensive, unless you have some old Birals, or can machine your own Deutzes. If you can, great!
IMPORTANT: 99,5 is standard. You’ll need at least .50mm oversized. You also need to buy Enginetech brand, as only these come with slip-in pins instead of press-fit. Enginetech is the only brand that I found with clips.
https://www.ebay.com/itm/Chrysler-Dodge ... 3430070870
99,5mm bore STD
Hypereutectic
30mm compression height (100s) - the heights may shrink a bit as bore increases
About 600g with piston, pin, clips, and rings, bare piston was 430g
Small end width between bosses - about 25mm
1.2x1.2x2.0 rings
24mm pins
There a slight dome on the pistons that is about .090” tall
I calculated the approximate piston speed that they see in the Hemi 5.7 they come out of, and 6,500-7,500 is fine with most of our small strokes up to around 82mm.
Oh, and price! They’re currently around $315 for eight piston assemblies! I split the price with a Norwegian friend, and sent some after I machined them for some Pauter rods.
K. Now you’ll need to need to widen the area between the pin bosses. An aftermarket T4 rod is too wide to slip all the way down. T1 just barely fits, but still needs more sideplay to avoid issues. It’s a fairly easy job. Clamp them down, use a radiused endmill and gave myself 2mm clearance.
Barrels are expensive, unless you have some old Birals, or can machine your own Deutzes. If you can, great!
IMPORTANT: 99,5 is standard. You’ll need at least .50mm oversized. You also need to buy Enginetech brand, as only these come with slip-in pins instead of press-fit. Enginetech is the only brand that I found with clips.
https://www.ebay.com/itm/Chrysler-Dodge ... 3430070870
