we`ve built 91mm stroke engines with 74.5mm bores
we`ve built 86mm stroke with 74.7mm bores
we commonly build 84mm stroke with 73mm bores
i`ve been working on a 5-main, 91mm stroke & 75mm bore 20v power unit
not sure i`ll ever get it finished tho
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| strokers https://www.ausmini.com/forums/viewtopic.php?f=2&t=91829 |
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| Author: | justfanginaround [ Sun Feb 14, 2016 8:12 am ] |
| Post subject: | strokers |
what the biggest stroke you can run in an a series ? how much stroke can you get out of a 1505 big journal crank with offset grinding ? how much stroke can you get from a 1505 with welding then offset grinding ? worth my time / money of am i better off grabbing a "big" crank from pomgolia ? |
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| Author: | TheMiniMan [ Sun Feb 14, 2016 8:24 am ] |
| Post subject: | Re: strokers |
we`ve built 91mm stroke engines with 74.5mm bores we`ve built 86mm stroke with 74.7mm bores we commonly build 84mm stroke with 73mm bores i`ve been working on a 5-main, 91mm stroke & 75mm bore 20v power unit not sure i`ll ever get it finished tho |
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| Author: | IndigoBlueCooperS [ Sun Feb 14, 2016 1:55 pm ] |
| Post subject: | Re: strokers |
Hi Matt, What do you have in the way of cranks for or with an 84mm stroke? I am after one, but I don't have a crank to start with. |
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| Author: | timmy201 [ Sun Feb 14, 2016 2:05 pm ] |
| Post subject: | Re: strokers |
You can get new ones in 84 + 86mm http://www.minispares.com/product/Classic/C-AEG497.aspx http://www.med-engineering.co.uk/produc ... rankshafts |
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| Author: | IndigoBlueCooperS [ Sun Feb 14, 2016 3:56 pm ] |
| Post subject: | Re: strokers |
Yes, they look the goods, but my budget is half that. |
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| Author: | TK [ Sun Feb 14, 2016 9:41 pm ] |
| Post subject: | Re: strokers |
Use the 1505 and some 080 small journal big end bearings. OK so 080 are all gone so use 060 |
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| Author: | TheMiniMan [ Tue Feb 16, 2016 4:35 pm ] |
| Post subject: | Re: strokers |
i still have a couple of sets of .080 unders,,, but they`re mine , all mine i tells ya insert mad evil laughter here-> Matt |
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| Author: | drmini in aust [ Fri Feb 19, 2016 8:35 pm ] |
| Post subject: | Re: strokers |
I got 84.3mm stroke out of a std 1505 crank, and using std bearings. But the cost adds up with stroking these big journal cranks- $200 extra for stroking, $300 or more to wedge it due to the poor counterweighting, $100 (est) for balancing. For a road motor is it worth it? (edit) these days I prefer a stock small journal crank, M1100S or Cooper S.
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| Author: | awdmoke [ Sat Feb 20, 2016 2:28 am ] |
| Post subject: | Re: strokers |
Hmmm, yes! What else is Monet good for if you can't enjoy it? |
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| Author: | TheMiniMan [ Sat Feb 20, 2016 9:01 am ] |
| Post subject: | Re: strokers |
We grind them offset to 2thou over std size then balance them (& i`ll tell you why we balance them now in a min) then we harden them (Nitriding) then we grind them true (straight) both b/e & mains & then balance them again. (generally this 2nd balance very little has to be done, if any at all. the reason why we (my dad) has always done the strokers this way is because he was always a firm believer in that if you grind it down offset, "close" to where you want the crank to end up at (size-wise) then most of the metal that has to come off the thing is done early in the process,,, then when it`s balanced obviously more metal comes off it so then , in the hardening process, they grow & bend & do all sorts of wonderful things,,, so when you grind it true, (both mains & big ends), often that little bend from hardening gets ground out of it so the crank ends up straight & true with the last grind process... this way the balancing that was done early & the first grind done before balancing, the crank needs only very little metal taken off it in the last balance process,,, this leavs as thick & as even "Crust" of hardening throughout the whole length/width of the crank. if you can get what i mean? most guys have a crank ground, hardened (if at all) & then just simply linished to final size on the journals,,, & then balanced (if at all) so in this way the crank can be bent, & the hardening crust has been broken (usually) a little deep in places... it breaks that hardening crust. my dad always said to do the extra processes --> do it his way i`ve kept doing strokers this way since forever & so far we havn`t had any broken cranks but i do know a few of dads old customers who have argued about the cost & didn`t want to do it "His-way" & funny enough their cranks broke,,, i could name & shame here but i won`t anyways, just a story about dads mini crank metalurgy process
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| Author: | TheMiniMan [ Sat Feb 20, 2016 9:31 am ] |
| Post subject: | Re: strokers |
But hey... i`m at the stage with these cranks now where i`m thinking new is going to be far better than some sh!tty 30 or 40 year old fatigued & mucked with crank that you have now idea what treatment it`s had over those years so many have even crack-test`d up okbut after fitting & building & driving for a short time have still gone clunk. so ,,, the large journal (std/std) cranks that i have here i will keep for myself (sorry it sounds greedy i know) but we still have a few old ReadSpeed delivery van stroker cranks here & i still have 2x 86mm (1510cc) stroker cranks, plus a 060 under stroker so i`m ok with cranks for myself & my mates, we have spares to keep us going for the next how-ever long,,, but the rest of the 2nd hand cranks that we have are simply that,,, 2nd hand undersize, need work done & are use-able after spending time & money,,, but they`re not std/std "S" or std/std Large journals , no. i probably value the large journal std/std cranks a bit higher than the average mini guy but again only because we know what to do to them, we do it dads way, & they`re fine & dandy ,,, but they`re getting very very hard to find now so the cost becomes pretty high compared to what they used to be. ok,,, end of crapola about cranks carry on
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