Popular Post Roman Posted November 23, 2023 Author Popular Post Posted November 23, 2023 What is also cool, is that someone asked me if I could send them a file for the ITB adapter. Sure. So they had some CNCd And they've also made some 14.9:1 pistons. How good! And this is all going in a tube framed EP80 time attack car for a European hillclimb or autocross or something series. It still looks like cams are the bottleneck though, but it will be interesting to see how it goes with the higher CR and presumably some race gas. 20 3 Quote
igor Posted November 23, 2023 Posted November 23, 2023 2 hours ago, Roman said: 14.9:1 Almost sounds like a diesel engine compression ratio. As a comparison the spec sheet for my tractor says 16:1 compression. Quote
RUNAMUCK Posted November 23, 2023 Posted November 23, 2023 Remember way way back i shared with you a page with some "rule of thumb" formulas? And you ran the sums, and they said cast piston go BOOM? Is there any galling on whats left of the the pin boss? The last motor i destructively tested to failure had nasty galling on the gudgeon pins. And another piston was stiff on its pin too. Datsun motor go bang too. 1 Quote
deankdx Posted November 23, 2023 Posted November 23, 2023 10 hours ago, Roman said: And this is all going in a tube framed EP80 time attack car for a European hillclimb or autocross or something series. It still looks like cams are the bottleneck though, but it will be interesting to see how it goes with the higher CR and presumably some race gas. please link us with any youtube story about this thing when it gets going, so we can continue our story of 9000+ rpm 1NZs 4 Quote
VitesseEFI Posted November 23, 2023 Posted November 23, 2023 15 hours ago, RUNAMUCK said: And you ran the sums, and they said cast piston go BOOM? Is there any galling on whats left of the the pin boss? The last motor i destructively tested to failure had nasty galling on the gudgeon pins. And another piston was stiff on its pin too. Datsun motor go bang too. Cast piston go BOOM indeed. I agree with the failure analysis. Curious on dye-pen results. Also curious about galling on pin bosses, plus whether the relevant BE shell/crank pin looks any different from the others. Plain old material failure of cast piston seems entirely reasonable given the, errr, circumstances and history, and that is what the fracture surface looks like. Any reason why that piston should have been hotter than the others, or just hotter that day? Presumably the top of the rod and gudgeon pin escaped through the hole it made, chased the oil filter housing out into the wide world and remains uncaptured ? Quote
Roman Posted November 24, 2023 Author Posted November 24, 2023 I had another good look over everything last night, and I couldnt see any issues. All of the piston pins move freely no problem. Even on the cylinder that went kaboom, the remaining end of the rod swings around on the crank no prob. No signs of any cracking or anything else on the remaining 3 that I can see. But yeah need a dye test to know for sure. 21 hours ago, RUNAMUCK said: Remember way way back i shared with you a page with some "rule of thumb" formulas? And you ran the sums, and they said cast piston go BOOM? And imagine what a pity it would have been if I listened to the formulas, and missed out on the most fun I've ever had in a car haha. There definitely does seem to be a sensible upper limit to mean piston speed though, even absolute screamers like the bike motors and Alfa DTM cars all seem to stay below 5K ft/min. Piston and rod weight will play some part, the fact that 1NZ rod and piston is so light is likely a big part of how it managed to go for so long without issues. So I might not be able to push the limit quite as much with the heavy stuff in the V6. A mate has a K24 that he's revving to 9k rpm - 99mm stroke so that's 5800 ft/min, bloody hell haha. Here's a pointless graph for you today @Stu 7 2 Quote
Popular Post ajg193 Posted November 24, 2023 Popular Post Posted November 24, 2023 The remaining pistons have proven to be high quality and free of defects, ideal for use in your next build 5 1 7 Quote
Roman Posted November 24, 2023 Author Posted November 24, 2023 While sharning about piston speeds. The StanceWorks K24A powered Ferrari blew its motor recently which is a pity. However it was running to 9500rpm with 99mm stroke. That's 6100 ft/min piston speed. Whether or not they were running on low boost, thats some crazy shit. That motor was not long for this world! 6 2 Quote
Raizer Posted November 24, 2023 Posted November 24, 2023 1 hour ago, ajg193 said: The remaining pistons have proven to be high quality and free of defects, ideal for use in your next build Needs to pop a second 1nz, then he'll hopefully have 6 proven pistons and rods for a custom V6 build. 3 3 Quote
GARDRB Posted December 1, 2023 Posted December 1, 2023 To be honest, when you start spending money on things like pistons and rods it takes away the charm of the 1NZ being a cheap cheerful motor built with ridiculously high compression (for an OEM) wrecker pistons and probably isn't always going to be the best option. I think your motor hit the sweet spot really. Other than if you had a bunch of motors and were able to put the parts that are most similar in weight together, you end up altering the smiles per dollar ratio too much and there are probably better solutions to be piling money into. (mostly thinking about the hillclimb car here) 8 Quote
oldrx7 Posted December 6, 2023 Posted December 6, 2023 A man of your clever-ness could easily build a 13B - bridgeport or PP will give you all the high RPM's you'll want 1 Quote
Alfashark Posted December 6, 2023 Posted December 6, 2023 1 hour ago, oldrx7 said: A man of your clever-ness could easily build a 13B - bridgeport or PP will give you all the high RPM's you'll want Not with today's price tag. This is more in keeping with the spirit of the late 90s - early 2000s critters flogging their Maketu drill-port 13Bs in the Bay Trader for $500... Except with more science and MS-Paint diagrams. Cheap(ish) and cheerful, and when it goes pop! Back to the wreckers/Pick A Part. 2 1 Quote
Roman Posted December 6, 2023 Author Posted December 6, 2023 Yeah I think it would be fun to build a rotary engine, I regret that I didnt earlier in life for a project. But that ship has well and truly sailed now, thanks to prices of things. A lot of the "classic" cheap and cheerful engines like 1JZGTE, 13B, 4AGE, 4G63, B18C... almost everything from that era you're paying an ever increasing amount for an ever increasingly pile of clapped out shit. It's easy to get stuck with the mindset that only that era of engines is good though. Or that K24 or LS1 are the only other options. But there are a few modern day gems I think. 1NZ was one of them I reckon. Hopefully the 4GR is too, but time will tell. 8 Quote
oldrx7 Posted December 6, 2023 Posted December 6, 2023 Yeh I get ya, was more that you’d be able to do the assembly and porting etc yourself, using 2nd hand bits to keep costs down. Aka Doug styles with his PP and that thing hums along real well. But yep, if it goes bang through R&D then there’s not the abundance of cheap n easy to find parts 1 Quote
Roman Posted December 6, 2023 Author Posted December 6, 2023 Yeah I love what Doug does. And I just cant believe how damn fast his wagon is. So good! Quote
yoeddynz Posted December 6, 2023 Posted December 6, 2023 12 hours ago, oldrx7 said: Yeh I get ya, was more that you’d be able to do the assembly and porting etc yourself, using 2nd hand bits to keep costs down. Aka Doug styles with his PP and that thing hums along real well. But yep, if it goes bang through R&D then there’s not the abundance of cheap n easy to find parts Don't forget the big savings to be had by not using genuine mazda housing seals but instead use appropriate sized electric cable. Not kidding. I've seen it done. 1 2 Quote
ajg193 Posted December 7, 2023 Posted December 7, 2023 Surely there is going to be an abundance of the new 830cc rotors in wreckers in a few years, they must have potential for fun Quote
fuzzy-hair-man Posted November 20, 2024 Posted November 20, 2024 On 23/11/2023 at 10:16, Roman said: The main point of trying to figure all of this out though. Is that if the piston failed first, then there's no point fitting aftermarket rods (which I already had) So in that respect it was disappointing to see that the piston seems to be what broke. As aftermarket pistons cost a lot. I'm not sure if there's too much more I can discern from these remaining pistons/rods as I dont have any decent measuring equipment etc. However it might be interesting to do a dye penetrant test on a piston and see if there's any hairline fractures etc. I'll buy a kit at some stage, and post up if there's anything interesting showing up. Thread revival I know but I had been wondering, this was running the pistons and rings from the Prius engine right? I'm guessing but the Prius could run tighter ring gaps to gain efficiency and reduce blow by assuming it would have less compression ratio, less revs and lighter duty because it has the electric motor to help, and well it's a Prius. I'm wondering if the ring gaps closed up jamming the piston in the bore, and the conrod pulling down ripped the bottom off the piston? Quote
RUNAMUCK Posted November 20, 2024 Posted November 20, 2024 That usually blows out the top of the piston. 2 Quote
anglia4 Posted November 20, 2024 Posted November 20, 2024 This thread still occupies so much space in my brain. I find myself constantly adding Echo's and Vitz'z to my trademe watchlist... 7 1 Quote
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