Why forged pistons when everybody says......

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john vanlandingham

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BillyElliot

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wildert

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john vanlandingham
"dude I know this dude whose cousin talked to a guy at the Seventy-leven whose buddy dynoed 480 with stock bottom end"

What those guys tend to forget, is that there is a shit load of a difference between a dyno queen doing a 20 sec pull or two, and the occasional drag race, and then doing a full out rally with several minutes at a time, at full speed.

Stock MAY be fine for dyno queens... proper motorsport is a different matter.

I don't see why a stock piston couldn't hold up to it or they even needed to go for all forged internals.

Don't worry, we understand.

Yeah, but you don't. My point is those guys were running a stock motor weren't they? Sure eventually everything will break, even forged stuff. Will forged internals last longer? Sure. But on a car where you can find a junkyard motor for probably less than a set of forged pistons, and competing at the clubman level, why should he spend that money? You're pretty much saying, if you race a car run forged internals or don't bother racing at all because your motor will end up in little pieces?

If they were running some 400hp turbo monster, I'd say yeah they should build a good bottom end for it. But there's really no reason an OEM piston should fail on an OEM motor like that.

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Ascona73
Imagine a drag engine taking full load and rpms up a hill for 7 minutes? And I see people cringe during a 15 second dyno pull.....

You want to cringe? There's a 2-hour long special (two 1-hour clips) on YouTube called something like "How F1 Engines Got Started". Might have even found the link from here.

It begins with a BDA-based engine (I think) on the dyno cell, just sitting there at 9000rpm and maybe 30 inches of boost, while the engineers calmly and slowly take notes. "Okay, take it to 9500." Jot jot, note note. Seconds pass. More seconds pass. "Okay, take it to 10,000". Jot jot, note note, seconds tick slo-o-o-owly by. "10,500." Jot jot, note no-**BAM**.

OTOH, if the engine can't handle running steady state high RPM/load like that, it sure as hell couldn't handle a race... (Also IIRC, the reason it blew was because the crank siezed in the block, which is why they abandoned the four and went with a clean-sheet V6)

Interestingly, in the owner's manual/service guide for an early 60's Mopar 426 Stage III which I had the good fortune to have to work on and tune, it said very explicitly to never use WOT for more than 15 seconds at a time. Sad thing is, the car really wasn't all that fast, compared to modern stuff. Last of the wedge 426s before they went Street Hemi - and yes, it still had the goofy box manifold with dual AFBs.

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.



Edited 1 time(s). Last edit at 05/07/2012 05:20PM by Pete.

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NoCoast
I was able to run more boost without overheating at Rally Colorado then I was at any of the 2-3 mile long hill climbs.

Same experience here but comparing a track day at PMI with 105 ambient temps (instead of a rally). Would've though the Evo if it survived lap after lap at those temps that a 5 mile qualifying run at Pikes with 45 degree ambient would've been fine...

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NoCoast
Which is why I'm not sure why Dave Kern isn't running the BMW this weekend at Temple Canyon.

Remember that part about sponsorship $ vs. getting a 2nd job? I picked up some program work at the Aurora mall. Plus, need to stay focused on the Evo if I'm going to get any testing days in before Pikes Peak.

Dave

Oh god. Why spend the money on forged internals? Let's do a thought experiment. This may not be typical for rally people; I may just be getting screwed by where I live. Whatever.

Let's say I had a 510 where that happened; let's say I was running it at the closest rally event to where I live, the Lake Superior Performance Rally. I would have spent $800 or so on entry fees, plus whatever on lodging... okay, I'll sleep in the car, whatever. Additionally I'll have trailered the car 700 miles total; call it $250 in gas. If I were going to the second closest stage rally, it would be almost 1100 miles of trailering, but whatever. So I'm already out $1050 wasted because some shitty stock part gave out. Then it's probably $500 to repair the thing. $1550, assuming my time is free, and the time of everyone else involved is free. Speaking of time, that's at bare minimum a whole weekend shot, probably at least a day taken off of work. I'm not going to bring up what a day of work is worth to me, but anyone who wouldn't put a value on avoiding wasting a whole lot of work is a nut.

A set of forged pistons for the KA is about $500, and a set of forged rods about $400 and it would then probably just last, whereas it would only have to fail once to have me out a lot more money.

Yeah, this is more explanation into this than it perhaps warrants, but I had a bad weekend. I've been roadracing with my dad for 10 years, and in that time I have no idea how many thousands of dollars and hundreds of hours of work we've lost to trying to save money on stuff that's 'good enough' or cutting corners on stuff because it would just work. We've probably lost 3 engines to carburetor issues that could have been solved by taking it to a chassis dyno or even having a goddamn wideband (which we finally have) have lost others to overheating, and I'm just going to stop. I'm willing to bet from the cost of all of this we could have bought a pretty nice formula car by now, and had a shop maintain it. It's not my money so it's not my say, but you can be damned sure it's influenced how I'm intending to go racing.

I'm not a gambler; not with that much money on the line.

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mekilljoydammit
Oh god. Why spend the money on forged internals? Let's do a thought experiment. This may not be typical for rally people; I may just be getting screwed by where I live. Whatever.

Let's say I had a 510 where that happened; let's say I was running it at the closest rally event to where I live, the Lake Superior Performance Rally. I would have spent $800 or so on entry fees, plus whatever on lodging... okay, I'll sleep in the car, whatever. Additionally I'll have trailered the car 700 miles total; call it $250 in gas. If I were going to the second closest stage rally, it would be almost 1100 miles of trailering, but whatever. So I'm already out $1050 wasted because some shitty stock part gave out. Then it's probably $500 to repair the thing. $1550, assuming my time is free, and the time of everyone else involved is free. Speaking of time, that's at bare minimum a whole weekend shot, probably at least a day taken off of work. I'm not going to bring up what a day of work is worth to me, but anyone who wouldn't put a value on avoiding wasting a whole lot of work is a nut.

A set of forged pistons for the KA is about $500, and a set of forged rods about $400 and it would then probably just last, whereas it would only have to fail once to have me out a lot more money.

Yeah, this is more explanation into this than it perhaps warrants, but I had a bad weekend. I've been roadracing with my dad for 10 years, and in that time I have no idea how many thousands of dollars and hundreds of hours of work we've lost to trying to save money on stuff that's 'good enough' or cutting corners on stuff because it would just work. We've probably lost 3 engines to carburetor issues that could have been solved by taking it to a chassis dyno or even having a goddamn wideband (which we finally have) have lost others to overheating, and I'm just going to stop. I'm willing to bet from the cost of all of this we could have bought a pretty nice formula car by now, and had a shop maintain it. It's not my money so it's not my say, but you can be damned sure it's influenced how I'm intending to go racing.

I'm not a gambler; not with that much money on the line.

If we had better emoticon smiley things I say "Plus Juan" and use the banging to beer mug together smiley..
We don't so "Plus Juan" and you get a free beer next time you're out here..

By the way, the OEM Nissan rods are good, maybe better bolts, maybe just new nuts... even the old L-16 Datsun rods were good, just use better bolts (9mm)

I try and convince people to build bottom ends you can't blow up, it IS cheaper in the long run....A dodgy head can't hurt a stout bottom end, you just don't get all the power-z.. But blowing up crap like that is just a crying shame...

oh and right on on the price for POPULAR off the shelf forged pistons...For less popular cars or customs its a couple of hun more.

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

This might warm some peoples' hearts.

Was reading an article on the new Viper. They were interviewing several engineers on the project.

They said, yeah, the cast pistons were fine, but people like to take these cars and put nitrous and turbos and superchargers on them, so we put forged pistons in the new engine to help protect aftermarket tuners from their mistakes.

The frame is also steel specifically because a large percentage of people take the things to track days and they tend to get banged up, and steel's more repairable.

I *like* these people. They know the kind of people who buy a Viper have serious Tim Allen issues, so they set about building a canvas instead of an end-product.

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.



Edited 1 time(s). Last edit at 05/07/2012 08:26PM by Pete.

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Pete
This might warm some peoples' hearts.

Was reading an article on the new Viper. They were interviewing several engineers on the project.

They said, yeah, the cast pistons were fine, but people like to take these and put nitrous and turbos and superchargers on them, so we put forged pistons in the new engine to help protect aftermarket tuners from their mistakes.

The frame is also steel specifically because a large percentage of people take the things to track days and they tend to get banged up, and steel's more repairable.

I *like* these people.

Yeah, but what do injur-nears know compared with genius-boys on turnerz forums on the Web?

Now a lot of stupid, simple minded and superficial people like to attck me and say "Your opinionated-ed" but often what they are screaming about is me posing questions. They are pointed questions sometimes but I think for most more or less adjusted people it's better to pose questions and on
this subjects I like to ask "Why do you suppose that Ford chose to stick forged pistons in all of their 2,3 turbo motors when they're only making a measly 175 bhp in the Xratty or 205 in the Thunderchicken, or 205 or 225 in the YB Cossie motor?"

With all the tuner-boiz speculating on all kinds of stuffs-n-stuff, they never ever address that rather pointed question. Ever.
Its always the "my buddy has __________ (fill in the blank with any number grabbed out of your ass) on a totally stock bottom end and he beats that thing hard, every shift at ___________ rpm (fill in the blank with any stupid number, again pulled out of the air)"

It's a real, genuine question...it's not like they don't know what cast or hyper-puke-eeeeech-tic pistons are, it was a choice. Why?

That little difference is ONE of the things I like about the Xratties. Its a crude ancient all iron POS but it has strong, very forgiving forged pistons stock which tolerate all kinds of stupidity---which is perfect for the typical reader/raller here. And they come FREE in every Xratty...

Give 'er some bewst and go.

And that's cheaper than building a good solid motor.

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Weird thing to me is how it turns out that Subaru moved to hypereutectic pistons in the STI motors for some reason. But whatever. I'm just sticking to them funny spinny dorito things... I've put in my time enough to know what makes them go wrong.

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mekilljoydammit
Weird thing to me is how it turns out that Subaru moved to hypereutectic pistons in the STI motors for some reason.

You can run 'em tighter, for less noise and better ring seal. I seem to recall Subaru engines getting awful slap-happy piston-wise when they get older. Check out knock sensor relocation on engines over ~75k - piston slap fakes the knock sensor and the computer pulls tons of timing, so you have to relocate it to the bellhousing to make it less sensitive.

They have to warranty the emissions systems basically forever (~150k miles is close enough to forever, percentage-wise) so they really need to keep oil consumption under control, since that kills the cats. It's okay if the ENGINE blows up out of warranty, as long as the catalyst is safe.

John, any time anybody says that they "beat on their car HARD" on the street, I tune 'em out. There is no way anybody can drive a car hard on public roads for more than a few seconds, period. Even the crap I do only lasts two-three minutes, tops, so I don't really consider it very abusive car-wise.

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.

I suppose I should say something since it's my car...

I'm not sure why the forged pistons thing came to be. Nowhere on my facebook page does it say anything about forged pistons, super high HP numbers or "my buddy told me this, that or the other thing". They were stock Nissan pistons on stock Nissan rods. For the first few months of 1989, the KA24E came with 9.1:1 compression pistons. That is what these are. Big numbers I know...

That motor made 131 HP. It was almost stock. Thats the way I wanted it. I could even run regular gas in it.

As to why it let go, I dont know. I think it spun a rod bearing, then proceeded to beat itself into nothing. It may have something to do with an injector that died as well. If I had stopped when it started knocking we may have figured it out, but I didn't. I beat the hell out of it for all of Passmore (17mi) and half of Far Point(5mi) before the rocking piston finally wore a hole in the bore into a water jacket.

Stock internal parts, at least in my application, are fine. 130 HP in a 2400lb car is more than enough for my skill level and my level of competition. I ran a junkyard KA24E with over 100k miles for 2 years rallying before this motor, and had no problems until there was just no compression left.

That being said, making a blanket statement like "stock parts are best" or "everyone needs forged internals to go rallying" are wrong and just dumb. All blanket statements are...

Interesting as to why my pic was used and no research was done to verify if anything in your caption was true...All this was on the Facebook page.

And #3 is labelled, written on the workbench

And we are from Green Bay, WI. Not Michigan.

Now everybody tell me i"m wrong

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Jim Scray
Driver-#510
Gravelspec Rallysport
Datsun 510
facebook.com/gravelspec

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jimmer84
I suppose I should say something since it's my car...

I'm not sure why the forged pistons thing came to be. Nowhere on my facebook page does it say anything about forged pistons, super high HP numbers or "my buddy told me this, that or the other thing". They were stock Nissan pistons on stock Nissan rods. For the first few months of 1989, the KA24E came with 9.1:1 compression pistons. That is what these are. Big numbers I know...

That motor made 131 HP. It was almost stock. Thats the way I wanted it. I could even run regular gas in it.

As to why it let go, I dont know. I think it spun a rod bearing, then proceeded to beat itself into nothing. It may have something to do with an injector that died as well. If I had stopped when it started knocking we may have figured it out, but I didn't. I beat the hell out of it for all of Passmore (17mi) and half of Far Point(5mi) before the rocking piston finally wore a hole in the bore into a water jacket.

Stock internal parts, at least in my application, are fine. 130 HP in a 2400lb car is more than enough for my skill level and my level of competition. I ran a junkyard KA24E with over 100k miles for 2 years rallying before this motor, and had no problems until there was just no compression left.

That being said, making a blanket statement like "stock parts are best" or "everyone needs forged internals to go rallying" are wrong and just dumb. All blanket statements are...

Interesting as to why my pic was used and no research was done to verify if anything in your caption was true...All this was on the Facebook page.

And #3 is labelled, written on the workbench

And we are from Green Bay, WI. Not Michigan.

Now everybody tell me i"m wrong

I bet if you had forged internals, you would have ended with the same fate. But I'm glad you came and gave an explanation to how it failed because I was curious if you knew what did it. Doesn't seem like your piston spontaneously exploded because it was a cast piston.

Lol. You're right there is a 3 in there. ;-)

Sucks to lose a motor. But you're saying it went 17 ish miles before grenading? That is enough to get you home most days

Jim, you don't have to say anything, its just a photo that was randomly grabbed off Google Images. I just borrowed the photo for illustrating what must be a heartbreaking and annoying type of failure.

And the various quotes are from various geniuses on the other forums (mostly---we have a couple of real smarties of the same sort here) I look in on..

Nobody made any references to you or the car one way or another.

The subject was as the title says..

The "meta-subject" is not the pistons cast or forged but the proliferation of the sort of so called wisdom that has flooded the world since the rise of the inter-net....3rd, 4th, 5th hand hearsay exaggerations, posturing....

Do you understand what I mean by meta-subject?

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

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aj_johnson
Lol. You're right there is a 3 in there. ;-)

Sucks to lose a motor. But you're saying it went 17 ish miles before grenading? That is enough to get you home most days

Last time I had a set of cast pistons in one of my motors it do the ka-blooey thing and we were maybe 16-17 miles from the highway and maybe 50 from home...It was a Friday night and all uphill from the highway and I managed, after a 20 point turn around---to coast to within 50-100 yards from the road, then shitty tied in knots toe strap behind my friends 510...the rest of the way home.

Broke the way cast always breaks: fractures from oil return grooves or drillings.. That piston it was a slot under the oil rings, one fragment has big enough to see the nasty cracks ...

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

I GOT FORGED PISTONS, IMA DO A WHEELIE!!!!!!!!!!!!!!!!!!!!!!!

Sorry I couldn't help it.

I had originally planned to build my motor using stock, cast, SOHC pistons for my DOHC motor. Sure I could have gotten forged pistons for 500ish, but that was 500 more then then free once I was pulling out of the old motor. That $500 could have, and did go to other parts of the build. Luckily I picked up a second hand set of forged pistons, so we will find out what kind of abuse they can take. Almost done with break in, time to re-tune, and bump the rev limit.

Without the boosties, I think the cast pistons would have been fine, but for the time, we will never know. With a goal of around 180 hp peak, I dont think a 2.4 will be working all that hard.

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I Seppanen, Car #240