monotherm steel pistons for CR from a stock renault application

Renault 1.6 dCi 130 R9M
supposedly comes with steel pistons, like there are supposedly being made for the BMW motor and are certainly well proven in cummins motors
80mm bore so you do need to sleeve a 2.0 CR block down but the smaller bore is better for cylinder wall rigidity anyways.

Only hitch is that I can not find them for sale anywhere. Mahle supposedly made a million of them back in 2015, but even on their site there are only ring sets for them.

Here's a picture I found on facebook:


Looks like the piston pin is wholly oversized, but you can bush them down easily enough

ETA: still no luck finding them for sale anywhere, and one further supposedly federal mogul has a "new" line of 'light duty' steel pistons too, but there is absolutely no information available regarding dimensions. I'm drowning in marketing garbage, but nobody even has a catalog on the internet.

nice find! whitbread is also working on some steel pistons, he's just getting some M57 ones powered out now.

Sweet. Looks like the set in the photo has seen better days.

Havent seen many fail on CR so far. I would not bother.
I have different solutions in mind anyway.
This would be also too expensive, 1k for custom rods, machining the block ..to do what? 300hp?

Stock pistons on the 335d bmw take 650-700hp so far and none have failed in 3 cars.

Mercedes OM654 has steel pistons, nanoslide skirts and stepped-lip twin-vortex combustion chamber bowl geometry at 82mm.

https://www.osti.gov/servlets/purl/1375296

http://lmgtfy.com/?q=OM654 "stepped lip" "steel pistons" &s=g

Soon you won't have to go outside of the VAG Group to get steel pistons. They're coming to the TDI!

Why, I'm not ragging on this at all, infact I'm mostly curious.
Why is the cons of increasing weight by a huge factor and having to do this much work worth the pros of steel pistons. Aluminum and its cousin of alloys have never been an issue at 700hp (as stated above). What is the major benefit? I would think the weight, thermal capacity and expansion, complexity, ability to replace, harder parts against the cylinder walls, and some other minor cons outweight the pros, if there are any really!
Aluminum has set world records. Is this steel softer than the cylinder walls? Is there a coating to prevent the harder pistons from more aggressive wear?
I'd rather make 20hp less and have a faster revving engine! Please school us less educated in this mystical world of over engendering!

The only reason I thought some Cummins had steel pistons was to help with the moment of kinetic energy vs having a massively oversized flywheel to help with upwards compression. Cummins dont like to run anything past 1400f but our TDIs run well into the 1500s, I know it's all about the turbo temps but , again , why?

Steel pistons are not heavier, in fact they are similar weight or can be even lighter than aluminum because the wall thicknesses around the skirt, between the crown/wrist pin and areas directly supporting the gas pressure can be much less.

Most of the drive toward steel pistons as far as OEMs are concerned are for goals of improving fuel efficiency and emissions. Because the pistons run quite a bit hotter than the surrounding bores they run in, they will want to expand more. In addition to that,, aluminum has a higher coefficient of thermal expansion than steel, so to counteract this need have larger radial clearance especially when cold (causing more piston slap and blowby), and also more clearance to prevent seizing at high temp. Less blowby leakage increases efficiency, less oil consumption and less oil sump contamination.

Steel pistons maintain their strength to higher temperature than aluminum can, and therefore can be run hotter (less heat loss for better fuel efficiency and less CO/HC emissions, especially in the crevice volume area), shorter ignition delay, less fuel wetting on the piston crown/bowl surfaces again for emissions.

Interesting tidbit about piston/bore clearances. It has been said one of the reasons why it's not so simple to drop-in a Formula 1 engine into a road car is that the tolerances are so fine that you can't just start the engine whenever you want to. You need to run engine oil at operating temperature for quite a while before you go through a painstaking process to start the engine.

https://www.roadandtrack.com/new-cars/car-technology/a28366185/why-f1-engines-arent-in-road-cars/
https://www.motor1.com/news/359685/f1-engine-road-car-fyi/
https://www.youtube.com/watch?v=pZZfbcQ7Ilw

well, when you put it that way, i would love a set of them, i hate diesel blow by so much, its such a PITA to deal with when you dont want it!
So i was right about most of it but i missed the point why, now i know!, Thanks. Well why not make them out of titanium!, heck why not the block too!

TDIMeister said:

Interesting tidbit about piston/bore clearances. It has been said one of the reasons why it's not so simple to drop-in a Formula 1 engine into a road car is that the tolerances are so fine that you can't just start the engine whenever you want to. You need to run engine oil at operating temperature for quite a while before you go through a painstaking process to start the engine.

Click to expand...

Not just that, all your fluids and tires are heated up to proper temps (actually higher) and some engines even have block warmer blankets on them.

Fun bit on the extreme of the other side, 2,000+ HP drag engines are just as fine as a tolerance build but designed to use the fuel as a coolant and run a waterless solid block. Pusing over 77 gallons every minute really sucks up a lot of heat. then again its garbage after the 1st set of hard pulls if not just the first.
https://www.youtube.com/watch?v=xGTbQuhhluY

Mongler98 said:

Well why not make them out of titanium!, heck why not the block too!

Click to expand...

First, you own a 20 - maybe 30 thousand dollar car when new, not 20-30 million. Even F1 engines don't use titanium pistons/blocks (although they have been tried in certain, extremely limited applications. Second, titanium is a material very prone to galling. Titanium fasteners are mostly a joke for this reason, unless special coatings are used to avoid galling and seizing.

great, mongler's here.

I will admit however, my reason for wanting them is kind of stupid
cut the bowl out, and weld in a different bowl
IDI style injectors spraying into a very small bowl, like the ancient hercules multifuel motors ran
really high compression and hopefully better burning of engine oil with the high surface temperatures possible with the steel

But there's the obvious other benefits of the steel slugs for everyone else too.

486, calm your self please and stop being such a guy! every time man, you all cant even take a JOKE
anyways yea that was a joke
but back to the topic, i was just talking with one of my guys, Ed, mentioned this to him and he said back in his day they would grout (fill with concrete) the water passages of engine blocks and put steal pistons in them to drag race because it could take the heat all day long of 1/4 mile 600HP pulls on a sbc, granted this was back in 1960's he did this. i had no idea, always though that aluminum was a winner! never considered otherwise. Now i know.

Grout? every water jacket I filled got high temp, low expansion on cure epoxy. Never getting that stuff out.

As far as the rebuild every quarter mile goes, HP numbers are at 1000 hp per jug.

For the Hercules, I've always first thought of the Bristol 2-bank, 14 cyl, sleeve valve radial. And its bigger brother the Centaurus...which are OK, but certainly no Napier Sabre...

I'd love to see having to deal with Coffman starting in cars...and the calls that would result: I am out of starters, and it is raining/snowing/dark and you'd best bring me a few so I can get underway...LOL
cheers,
Douglas

and Turbo/Direct injection debuted on the R3350 some 70 years before Ford hauled it out and re-labeled it as ecoboost.