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| Forged pistons/pins - group buy - Pistons ordered on 1/31/24 https://slantsix.org/forum/viewtopic.php?t=67301 |
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| Author: | Dart270 [ Fri Jun 16, 2023 1:22 pm ] |
| Post subject: | Forged pistons/pins - group buy - Pistons ordered on 1/31/24 |
Dear Slant Sixers, One of our racers has a contact with a big piston company and can do a group buy of pistons/pins. I am asking if there is interest in this. If we can get about 5-6 sets together, this would work. Details: Forged pistons from "Icon" which is part of the same company as Silv-O-Lite and Keith Black All sets need to be the same bore. We are proposing 3.485" (88.5 mm) to fit about any application and old or already bored block. We might go as small as 3.464" (88 mm). Thin ring pack like on modern import and a package that is readily available (1-1.2 mm top and 2nd rings, etc) Made for 225 rods, so similar compression height to stock Small pop up (dome) that can easily be milled off if you want low compression Cost would be around $500 shipped for a set of 6 Basically, these would be drop in replacements for a stock 225 rotating/reciprocating assembly, but but would be significantly lighter and stronger than a stock piston and with modern rings. This avoids aftermarket rods or hard-to-find 198 rods. Please feel free to ask questions. Thanks and all the best, Lou |
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| Author: | Badvert65 [ Fri Jun 16, 2023 3:29 pm ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
I'd be on board for a set, I'd prefer the largest bore size I could get. I'd rather have flat tops with valve knotches, but I would go with whatever is in the group buy. Count me in for one set. Any chance we could also get light weight pins? -Matt |
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| Author: | Rick Covalt [ Fri Jun 16, 2023 5:48 pm ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
Lou, I know this does not help much, but I would be a maybe? I honestly am running that bore size right now and would be more inclined if it was a bigger bore? But I will think about this and let you know. Do we have an estimate of where this will put the compression ratio out of the box? |
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| Author: | Greg Ondayko [ Fri Jun 16, 2023 7:08 pm ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
I like the 88.5mm Bore. 89mm would be a good 2nd option, but the 88.5mm is probably the best all around size. Would there be any opportunity to get these after the initial buy again if one wanted more sets? Greg |
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| Author: | DadTruck [ Fri Jun 16, 2023 8:42 pm ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
Lou, Would the piston pins be non floating stock or have provision for a piston pin retaining clip? And would the piston ring spacing be modeled after the stock piston or is the plan to modernize that also? |
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| Author: | Dart270 [ Sat Jun 17, 2023 9:13 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
Thanks, everyone. My guess is we'll have enough to do this if all of us here buy at least one set. Given the recent inflation of parts+labor prices, this sounds pretty cheap to me. Answers: John 1) I'll have to ask about floating or fixed pin. 2) I assume modern ring pack spacing, but I'll ask. Greg 3) This is probably a one shot deal. The guys doing it want like 5-6 sets, and they need like 6 more sets to do a group buy. I doubt we can get this many (12 sets) together again any time soon, but who knows. I bet there would be a few extra sets that one could buy after the fact, since most of us do not use these things right away and some buy spares... Rick 4) I believe the target static CR with stock 225 rods and block is around 10:1 but I will ask. Milling block/head can get you much more, and milling the bump off the top of the piston would get you something like 8.5:1, I believe is the idea. Matt 5) Sounds great, thanks! Will ask about light pin. I bet it will be lighter than stock, but probably not super light. I'll ask about valve notches in the bump too. Thanks again and keep 'em coming! Lou |
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| Author: | Greg Ondayko [ Sat Jun 17, 2023 9:19 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
It would be nice if they could add that part # to their catalog, and I would assume they would have the CAD / CNC File on hand to make more.. Then a person could contact them and get them made later if needed for $900-$1000 as a custom order. Thanks for the work here. Will like to know about the pin style as John had asked. Light pin is better for me. Floating Pins will require Modification of the OE rods correct? |
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| Author: | SlantSixDan [ Sat Jun 17, 2023 9:41 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
Quote: Made for 225 rods, so similar compression height to stock (…) This avoids aftermarket rods or hard-to-find 198 rods. I can't tell if I'm under- or overthinking, but how does a piston like this 'avoid' 198 or aftermarket (longer) connecting rods? If you want to improve the rod:stroke ratio to get those benefits—increased dwell time at TDC and BDC; reduced side-loading, etc—how does this piston give those benefits without a longer rod?Also: cam-ground? Offset pin? |
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| Author: | Rick Covalt [ Sat Jun 17, 2023 12:27 pm ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
This gives folks a lighter forged piston and good ring set without having to buy rods and bumps the compression. Forged 225 rods are plenty strong and the long rod benefits may be real but they are not huge in the big scheme of things. Just my opinion of course. |
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| Author: | kesteb [ Sat Jun 17, 2023 1:54 pm ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
What are the advantages of these pistons on something like this: https://www.summitracing.com/parts/uem-1718-std |
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| Author: | Rick Covalt [ Sat Jun 17, 2023 4:55 pm ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
These are forged, and should suffer more abuse. Thinner ring package. |
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| Author: | Greg Ondayko [ Sun Jun 18, 2023 4:56 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
The pistons kesteb linked look very tall and heavy. These *should* be lighter as well, with a more efficent ring package . |
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| Author: | Dart270 [ Mon Jun 19, 2023 3:20 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
Thanks again for the feedback folks. Rick and Greg answered most of the questions from Dan and Kesteb well. PLENTY of really fast motors have been built with std 225 rods. I will ask about offset pin and cam ground, and if the pistons can be ordered one-off later at a higher price. Any gain you might see with 198 vs. 225 rods will be smaller than what you can get by doing a little more head porting or choosing your cam well, or degreeing your cam at the right spot, or adding a bit more CR, or... Keep em coming, Lou |
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| Author: | Charrlie_S [ Mon Jun 19, 2023 3:47 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
I suggest having them with floating stock dia pins. That way they could be used with press fit rods, or floated. Gives a choice. The pistons should definetly be "pin fitted". Also the only purpose of the offset pin is to make the piston run quieter (especially when cold). Don't think this would be desired with these pistons. Just my opinion, and I doubt I would be in the market for a set at this point in my life. PS: The only difference in the piston/pin for floated/pressed is for floated the pin must be short enough so the piston pin bore has enough room for the lock grooves, and the piston requires the grooves. And the rod small end needs to be honed larger for pin clearance (with or without a bushing) and a oil hole drilled in the rod small end. Any auto machine shop can do the modification while reconditions/balancing the rods. When using in a press fit application, same as stock, and just leave the pin locks out of the piston. |
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| Author: | volaredon [ Mon Jun 19, 2023 5:52 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
To be worth it, they would have to have taller than stock (or at least taller than standard "rebuilder grade") compression height. .being 0.185" in the hole even after block shave is ridiculous. If I hadn't had my block shaved as much as I had my pistons would have come out 0.215" in the hole. Which is even more ridiculous. Especially being how hard 198 rods are to find and everyone doesn't have the money for K1, Molnar, etc. |
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