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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 [ Mon Jun 19, 2023 7:13 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
There would be a dome in the piston to give ~ 10:1 CR. You can mill the dome off if you want flattops for boost, etc. Compression height would be close to stock (to get around 0.185" in hole with no block shave). We might go for 0.170" in the hole for a bit more of a bump. Thanks for the info on offset pin. I would say no to that, and I expect that is what my contact is thinking (centered pin). Personally, I see no reason to float the pins. I have done all my motors except one with pressed pins and have had zero problems and made up to 260 HP NA and 380 HP boosted and redline to 6000+. Or, maybe could someone explain the (substantial and hopefully documented) gain for floating pins in a Slant 6? All of this said, we could do what Charlie says and allow for press or floating. Lou |
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| Author: | Valleyant [ Mon Jun 19, 2023 7:49 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
Whats the time frame on these? I am interested in a set. I like not having to deck the block for that compression ratio and not to mention the benefits of the construction and modern rings. Do I just add myself to this thread? Thank you for your time! |
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| Author: | Dart270 [ Mon Jun 19, 2023 7:57 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
Great! Just adding to this thread is enough. I am not sure of timeframe, but I'm guessing late summer or more likely fall? Please pass the word around! We may get more of a discount if more folks sign up. Lou |
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| Author: | Charrlie_S [ Mon Jun 19, 2023 8:01 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
Quote: Personally, I see no reason to float the pins. I have done all my motors except one with pressed pins and have had zero problems and made up to 260 HP NA and 380 HP boosted and redline to 6000+. Or, maybe could someone explain the (substantial and hopefully documented) gain for floating pins in a Slant 6? All of this said, we could do what Charlie says and allow for press or floating. Lou Also, say you assemble the pistons, rods, crank, block to check deck for CR. Then find you need to mill the top of the piston. That is a lot harder to do, with the piston on the rod, and risky to press them off. Or how about you find you need more piston to valve clearance. Easier to cut bigger notches if the piston is off the rod. If these are "racing" pistons, I don't think it would cost much or any more to have the pistons set up for floating pins. Mainly jut lock grooves in the pin hole. |
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| Author: | Dart270 [ Mon Jun 19, 2023 8:24 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
OK, sounds good, Charlie. Thanks a bunch for explaining. Will ask and contemplate. Lou |
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| Author: | StrokerScamp [ Mon Jun 19, 2023 9:07 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
Quote: 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? Also, I am interested in a set. Depending on the timing, I might could shake it out of the budget. I can't promise anything, but the interest is certainly there. |
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| Author: | Warhammer [ Mon Jun 19, 2023 10:33 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
Quote: There would be a dome in the piston to give ~ 10:1 CR. You can mill the dome off if you want flattops for boost, etc. Compression height would be close to stock (to get around 0.185" in hole with no block shave). We might go for 0.170" in the hole for a bit more of a bump.
You want full floating. Pressed pins stress the rod ends, also remove the seizure safety. There is a less friction gain, and we all know that friction robs HP.
Thanks for the info on offset pin. I would say no to that, and I expect that is what my contact is thinking (centered pin). Personally, I see no reason to float the pins. I have done all my motors except one with pressed pins and have had zero problems and made up to 260 HP NA and 380 HP boosted and redline to 6000+. Or, maybe could someone explain the (substantial and hopefully documented) gain for floating pins in a Slant 6? All of this said, we could do what Charlie says and allow for press or floating. Lou |
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| Author: | wvenable [ Mon Jun 19, 2023 12:31 pm ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
Thanks for putting this out there Lou. I may be interested as well. |
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| Author: | vitamindart [ Mon Jun 19, 2023 1:30 pm ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
if they are floating and the dome can be milled to lower the compression Im interested. 9ish to one is about as crazy as I want to get in my boosted application. better rings, lighter and better materials all sound great. |
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| Author: | volaredon [ Mon Jun 19, 2023 4:05 pm ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
How much difference might it make by making different oversized optional? I tend to go only enough on a given rebuild to square things up, and straighten the bore. Whatever the engine needs and no more |
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| Author: | CNC-Dude [ Mon Jun 19, 2023 4:21 pm ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
The material the pistons are forged from is a consideration also. Only 2618 is recommended for boost and high compression, 4032 is not! So make sure you choose the correct material and everyone is on board for either N/A or boosted builds or you may end up being disappointed if you get the wrong material.... |
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| Author: | Charrlie_S [ Mon Jun 19, 2023 5:44 pm ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
I put a link over at "for a bodies only" |
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| Author: | Dart270 [ Tue Jun 20, 2023 3:24 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
Thanks, everyone. There will only be one size offered. Otherwise we need 78 or more pistons to do another size. Will check on other things too. I will not handle anything on FABO, so if folks from there who are not on here want a set, someone here would need to vet them (vouch for them being able to pay) and collect orders. Thanks. Lou |
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| Author: | joesnow [ Tue Jun 20, 2023 11:28 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
I still have 2 sets of 198 rods, so i think i will pass.. Thanks Lou |
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| Author: | Dart270 [ Wed Jun 21, 2023 3:46 am ] |
| Post subject: | Re: Interest in forged pistons/pins - possible group buy |
Hi Folks, Here is what I am seeing from those on this thread, as far as interest: I want a set: (Definition - I definitely have money to spend and will guarantee I can pay the money when the pistons are made. I am prepared to pay a deposit at the point we make the order.) 1) Lou 2) Greg 3) Valleyant 4) Matt 5) Vitamindart 6) rich_mc 7) Mark C or Bryce Gill or Rodney or someone else at Knoxville on 7/8 (sounded very definite, but now I can't recall who exactly!) I might want a set: 1) Rick 2) Wayne 3) Strokerscamp 4) Stan 5) Andrew 6) Killer6 Please let me know if you are not represented accurately on this list. Thanks! Lou |
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