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Romans 2005 Toyota Echo


Roman

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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.

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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 :)

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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 ?

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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.

image.png.6913228c0ead5960afa5569d5fc1793c.png

Here's a pointless graph for you today @Stu

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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! 
 

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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)

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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.

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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.
 

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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 

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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. 

:thumbleft:

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