I Rented a $35,000 X-RAY Machine to scan the metal used in Rotary Engines

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[@rickcupola6262]

First it was pixel-by-pixel analysis to measure the Hoonicorn's suspension, now it's an in-depth analysis of materials using an expensive X-ray scanner. Never change, Rob.

[@dadi2450]

ah yes, before the dark ages of the "where's the 4 rotor" comments, the happy days.

[@yasha1928]

Which video was that? It's been a while

[@omega1575]

Don’t forget spending thousands trying to drill a tight hole

[@kingrpriddick]

Next he'll be buying a hardness tester, then a heat treat oven. In a year he'll be a complete machine shop.

[@tonybates4308]

@@kingrpriddick when he gets to that point he'll be unstoppable

[@markhutchinson3367]

I used an XRF gun at a previous job. They do have a margin of error and the surfaces must be extremely clean for accuracy. Keep in mind that when you scanned the rotor and it had a lot of zinc, the rotors come from the factory with a zinc plating, which is why they are that gold color, to protect from corrosion. If you sand or grind off the plating, scan it again and I'm sure you'll find it is mostly iron. Great video!

[@RobDahm]

Yeah good catch! I scanned another rotor after filming this and the coating had worn off. No zinc to be found. I forgot to include it in this video.

[@Paul-IE-Repairs]

@@RobDahm you also may be reading some material transfer as well on machined surfaces from the tooling used to cut and finish it

[@Paul-IE-Repairs]

@@RobDahm i suppose you could test my theory by measuring raw, then deck it and measure it again, knowing how much material transfer occurs on the surface would be good to know as well

[@BrianBrunebjergNielsen]

It will be svanning the scattered radiation returned from the material... And some will come from in depth. I would belive that have different materials directly behind a scanned plate ( try laying a plate on different surfaces and se the reaction . ) If you are interested i can maybe send you some stuff.. A Dansih nerdy xray tech ( made project with Aluminium, copper, titanium as filtration material for nenatahl thorax xrayes ) ;) Does the system manual tell you something about misreading on thin layers of material as surface tratments.. Be aware of misreadings...

[@Mr05sti]

Pretty sure that is measuring oxidation as well.. right?

[@M.asa.]

Really cool you're investing this much time/money to learn about the engines and to improve your own.

[@spazzologist]

More like he’ll never have to rely on anyone to make something specific for his rotary. He makes it himself, and better😎👌🏼

[@neithertwosturrr3016]

Not only that but hes giving us a basic outline of how to learn ourselves and he's doing it for free. Never forget how much this dude has taught us about things we'd never know otherwise or learn about. Alot of people say he's gloating but they're just mad he has the resources to teach an audience about the future.

[@M.asa.]

@@neithertwosturrr3016 exactly. He's giving us free lessons and knowledge

[@xSupra]

@@spazzologist Yeah it sucks depending on others. Learned this pretty early on with group projects in school

[@EmazingGuitar]

@@neithertwosturrr3016 it’s not for free, we gave our data to KZbin 🥵

[@andrewable2634]

So fucking cool to see someone really trying to learn about this and apply it. Nothing more valuable than learning things about a subject your passionate about.

[@RX7FDfreak]

Dahm single handedly keeping rotaries alive with modern tech. Cant wait to buy parts and services from this guy one day. I need a tuner I can trust lol

[@ItsTheDon27]

Crazy I seen He use to be talked down on a lot but he’s actually my favorite rotary gear head. He’s come a long way and now he’s taking things into his own hands.👍

[@Bluebeast2005]

Absolutely! I want a sign up for his stuff! Totally down with getting some Dahm Racing parts! 🤙

[@mikescherrer4923]

“Mole-Eb-Din-Um” Molybdenum. Great video.

[@Armaniche]

Thank you, man. Bugged me so hard every time xD

[@RobDahm]

Hahah oh man. I am always learning. Shows I’m book smart but haven’t said the word out loud 😬😂

[@Armaniche]

@@RobDahm honestly, really thankful for what you do. You gain nothing by sharing this valuable info with the rest of us and yet you always do. Just a grand human being that the car community should be thankful to have

[@ell0hh]

@@Armaniche Idk about nothingg… Lol. Our views = $$$

[@thegforce522]

@@RobDahm in the same category, silicon (the element) and silicone (the rubbery plasticky stuff) are very different and are pronounced differently. Lots of stuff i recognised from my materials science classes, loved the vid.

[@OitsCody]

Being a certified XRF Operator its amazing that others like yourself Rob are open to learning new things like this. With Non-Destructive Testing, we use this almost everyday at the job site. Keep up the good work! Wont critique you on the mess-ups cause who cares! This is awesome!

[@Name-eg1uf]

Damn, that little xray thingy costs as much as the indycar engine.

[@disk0553]

Look at the cost of a full-size wavelength (rather than energy) dispersive instrument.

[@20somthingrealestate]

@@disk0553 waves are energy...

[@newtonfirefly3584]

@@20somthingrealestate You are clearly confused by the words and terms and lack basics in information and knowledge. Waves describe the means of movement, motion or the variation of the energy, force, flow, etc. perhaps if You will actually study physics, this will become clearer. Sincerely

[@20somthingrealestate]

@@newtonfirefly3584 poor guy. You lack the ability to speak competent English or use correct punctuation yet you're attempting to belittle me. You're beyond pathetic. "Wavelength" let that soak in then tell me that doesn't denote energy. "Waves denote variation in energy, force" So..uhh.. yeah energy. The best one "flow" god you're hideous 😂

[@pixill4ted593]

Duel

[@TheCorrupterX]

Now you need a hardness tester, you know the material, now you need to figure out the heat treatment and hardness. you should also do both micro hardness testing to test surface treatment hardness vs macro hardness to see the hardness under laying material. This can help you determine if the parts were case hardened or other types of hardening.

[@frizzlefry1921]

And a surface finish tool as well to meter the roughness may be required?

[@littlexanman]

Rob just cassualy dropping in: "I'll be using those for a 1000 ho 2 rotor." Like we aren't gonna question that

[@guerra3710]

I mean, are we?

[@mobilePCreviews]

it's rob, we have just accepted he's a madman at this point

[@nexgenhippy]

All you need now is a rotor balancer and an e-shaft balancer

[@Armgoth]

For said reasons you probably don't use the same guy as angel motorsport?

[@SupremeShuckle]

The chemical element symbol for Mercury, Hg comes from the Latin word “Hydrargyrum”. “Hydro-“ for water-y. And Argyrum which we know as Ag,, silver. Watery Silver. Hydrargyrum. Fun Fact for the day.

[@dimitridegrecia32]

That's actually a Greek word, Mercury is the Latin one (Mercurio). Υδράργυρος is the Greek word, comprising of "Ύδωρ", which literally means water even in modern Greek, and Άργυρος, which means silver. We actually use this word when we talk about mercury in everyday conversation, as well as the two separate words for water and silver respectively! And yes, you are right, it does mean watery silver!

[@iCorpius]

I've worked in a titanium foundry and its quite surprising to see what small amounts of other elements does to TI. As far as a good quality metal that'll stand up to tons of abuse almost all rotors in jet engine are made from TI-6-4 DQ, as well as TI-17. I cannot wait to see what you come up with next! Love the vids, extremely informative and fun to watch for me rob!

[@montyroussel559]

Bump this, I want rob to see that. Also if rob happens to see this, make a video on ceramic seals Iv been told they last an eternity

[@zephyr.r]

yes yes yes

[@grantconquest3313]

Ti is a cool material, but it SUCKS at evacuating heat. It withstands heat stress well and rocks for jet applications, but for a car motor... hell nah. There's a reason that ti internals aren't a thing

[@robrayne9144]

@@grantconquest3313 nsx have ti rods and so does ls7.

[@mfree80286]

@@robrayne9144 heat rejection isn't a problem for rods. Valves on the other hand... intakes are mostly OK, Ti exhaust valves have to be treated with kid gloves or they'll burn through, leaves them limited to special purpose applications (racing engines with low run times or cooler fuels).

[@jacquescrusan9500]

Some cool quick things I remember about aluminum alloys (haven't watched the video yet): when regarding pistons (and possibly rotors, haven't done research in that area yet): The main difference between heavy-duty, N/a and hypereutectic piston alloys mainly comes down to the percentage silicon content in the alloy itself. Interesting thing about adding silicon to an Aluminum alloy is that it reduces/limits the expansion ratio (percentage volume growth of a metal for a given change in temperature). -2618 alloy (regarded as the overall strongest alloy commercially available to the public with the highest compressive stress yield) is easily the lowest, and thus grows the greatest. It's one of the reasons why engines that utilize internals made of this alloy require significant (2-3 minutes) warm-up periods so that the more pure aluminum can expand and grow to properly seal off and come into contact with the oil boundary layer on the sides of the cylinder wall (or irons in a rotary). Until that point, the engine needs to be kept at a low RPM so that the piston skirts don't slap the cylinder walls so hard they fracture (again, not sure what the equivalent is in a rotary, but I wouldn't chance it either way...) -4032 alloy is arguably the goldilocks zone when it comes to forgings. Ranging from 8-11% (by mass) silicon content, they are arguably stronger than hypereutectic castings, and they have a considerably downsized expansion ratio (higher silicon content = less expansion when coming up to temperature). However, they're not the absolute best at dealing with extreme cylinder pressures or conditions, so these are primarily used on max-effort N/A builds (where their overall lighter weight is an additional advantage over straight 2618 forgings) -Hypereutectics castings are significantly stronger nowadays than what was being produced 20-30 years ago. With the highest Silicon content per mass, they have the lowest expansion ratio possible (which leads into why engines produced nowadays have ridiculously tight tolerances from stock), and are more than capable of dealing with hundreds of thousands of miles of regular use (not abuse). The two areas in which hyper-pistons struggle is in situations with high compression and tensile stresses (boosted applications for compressive stress and high-RPM applications for high tensile stress; the amount of force the connecting rod is pulling the piston down on the intake stroke at/above 6500 rpm oftentimes is too much for hyper-pistons to handle and either they break around the piston pin boss (tensile fracture) or at/near the ring lands (compressive fracture). Side note: in the casting process, if you're casting a piece from aluminum (or really anything for that matter) always feed the cast from the bottom, not the top. That allows for all the oxide formation and impurities to stay at the top of the in-flow, and can simply be skimmed off of the top, where they do no harm to the structural integrity of the component being cast. Second side note: most aluminum wear surfaces use a coating called Diamond-Like Coating (DLC). As stated in the video, this is usually plasma-sprayed onto a surface (think dirt bike cylinders with nikasil, or some late model ford V8's) Third side note: Chromium and Cobalt are sometimes used in alloys to increase the strength of steel-based metals. This leads to having thin-walled chromoly-steel tubular frames (both in motorcycles and race cars) that weigh significantly less than their regular steel counterparts.

[@madix124]

The billet iron might have been treated using diffusion in order to make the surface into an alloy. I was recently taught this process in a Meterial Science module for my Engineering degree

[@Ayane13b]

As a long time follower, and rotary lover.. Thank you for trying to do your best to save the high performance rotary engine scene. You're the best dad I've never had.

[@CrazyTony65]

I think Nikasil would be an excellent coating for housings and side plates. Edit: The RB is Nikasil coated, it's a nickel/chrome base metal with powdered silicon carbide.

[@duffbiker]

keeps with the 2smoke theme of rotary's as well lol.

[@SonicSpeedz]

i was thinking the same thing..

[@jonnyj.]

Nikasil would be my #1 choice for sure. If its good enough for almost every f1 team since the 70's and every 24h of le mans winner, its good enough for everyone :D

[@yutub561]

Armoloy

[@christianjforbes]

Having owned a few highly strung Italian 2 stroke scooters … nicasil def would hold up and was my first thought

[@UncleManuel]

I like the investigative approach of Rob. He doesn't believe hearsaying, he's testing stuff. Asking the right questions, drawing the right conclusions - this is how humanity progresses. 😎👍 Oh and yeah, that x-ray gun was pretty neat!😁

[@gdrumeller]

No actually the testing of the different variants would be a VERY interesting video Rob! We do want to see that!

[@yz5002]

I think its great that you are embarking on your very own "open source" rotary engine knowledge base. I also love the approach you are taking with the metallurgical analysis. While this provides an important aspect when attempting to "make a better mouse trap", it's only one aspect of the design that is critical to success. Don't overlook the impact that heat treatment has on metals, especially when dealing with steel and CI. Parts like apex and corner seals for example can go from success to failure simply by using the wrong heat treatment process or using an unsuitable temper. Good luck with your endeavor. Based on all of your progress to date, I suspect you will succeed where others have failed.

[@randomshitbekker]

Hey Rob. I'm an up and coming machinist down here in the dictatorship of Australia. I'm new to the game but I'm taking in everything I can like a sponge. I'm teaching myself cad/cam as we speak. If your rotary dreams of making housing ever gets big enough to were you want some locally machined in Australia, I'd love to have an excuse to work with Rotary's in a professional sense. It's a long shot but you never know until you put it out there. Keep killing it mate.

[@jaredcormier]

There's a lot more to metallurgy than just the composition... Quench hardened vs tempered vs annealed iron for example have vastly different hardness, tensile, yield, and toughness values....

[@joshuajones1319]

No doubt about that...When using this device it's all about "like" compositions, usually dealing with welding. We call it a PMI gun...

[@Hw3racing]

Always awesome when people share for the community. It shows good character. I hired a powder coated once to do a valve cover for me. He recommended a certain color that I agreed to and liked. He took the job knowing I do my own powder coating at home for all types of small brackets and other small parts for my build. When I received the cover I emailed him asking for the powder information so I could match it. He provided all the info but when I went to use the powder it wasn’t even close. So we spoke and he said he will never give away his process and if I wanted my turbo to match I could send it in. I was now held hostage when I thought there was a firm understanding between us what the goal was. Had I known he was using some proprietary process I would have never agreed to his recommended color. It sucks being stuck under someone’s thumb.

[@MrRotaryrockets]

Rob about 20 years ago we were plasma spraying Irons with Chromium Carbide.. the same mix they use on Jet engine blades to protect them.. it holds oil and wears very little .. the plates have to be lapped sprayed and re-lapped.., then finish surfaced with a softer metal to remove the swarf remaining on the plasma sprayed surface.. I still have a few Rotor housings we did as well..very similar to the Mazda 787 Engine coatings that were done in Germany...the biggest difference was the drop in Eng temp.. just recently, I put together my full needle bearing..12 A engine .for testing..

[@Sauerbrew777]

Rob: I'm not going to be held hostage! UPS: hold my beer!

[@JMB676]

Oops I was wrong class today Rob is goin to teach us how to make our own aluminum and titanium….. probably out of bubble gum, duct tape, zip ties, and a X-ray . Ok ok I’m ready. Start teaching. Love ur channel brother thanks for sharing as always.

[@AbbadonXII]

Been watching before 4 rotor. Never cared for the rotary engines, but that is not what keeps me engaged. It is the commitment and pursuit of never settling and always improving in builds that has earned a loyal subscriber.

[@theproceedings4050]

Hey look, x-ray flourescence, pretty cool technology, definately more fun than a temperature gun. Material selection is super important when building engines and machines on the edge like you do, glad to see you're taking the proper route.

[@suyogpatil2198]

You made my night 😂 "Everytime rob drops video it night for me "

[@catxx5480]

Normally I feel like that but this was great didn't have 2 stay awake. Kids did go 2 bed 10 mins earlier lol

[@chrisnopwaskey6914]

I love these videos because you often take things that I've learned in class and apply them to areas that I'm genuinely interested in. From calculus to chemistry professor dahm has taught me a lot.

[@nickchilds3104]

Thank you for making videos Rob. I've been watching every one for 2 years since I first saw the 4 rotor dyno video. I didn't know a single thing about rotary engines until this channel, and now I'm confident I could go buy an FC and somewhat understand it.

[@zacharyponds4582]

It's so refreshing watching someone like minded who just wants to learn how the world around them works without any BS. Keep doing what you're doing, let's learn together and build a better future!

[@Red6er]

Rob, remember when dealing metals you have to account for heat treatment process. Will change the grain structure and add or remove specific properties. Hardness vs malleability ect.

[@charlespletzke8311]

I would love nothing more than Rob unintentionally Discovering something that makes the rotary engine not only viable but better than a piston engine. Is that likely? No, not in the slightest, and I’m not holding out hope for it. But it would still be amazing nonetheless if it did happen

[@eellee95]

As a chemist seeing you geek out over the different elements in the various metals you use brings a very big smile to my face.

[@darbywing2]

For God's sake though, please help him pronounce molybdenum.

[@Jimboslicevr]

I love you so much for being so open to what you do. You are helping so many people by doing this.

[@Roosakomm]

Rob has made to the level of rotary mastermind and it's just great to see how far you have made 🤘 reminds me Smokey Nagata

[@jamesryan9493]

This came out as I'm taking my materials engineering class so this was super interesting to watch!

[@franklin732]

I like that you have a clear goal that you are pursuing as you also do the fun/video side for us viewers

[@georgesmith3876]

I can't think of anyone , literally anyone better than Rob for the car community. Dude is a hero!

[@theangrymarmot8336]

I never understood the "secrets" that people are hell bent in keeping with the automotive hobby. I have been building high end custom race / show / cars and hot-rods for over a couple decades and run into the bullshit all the time. People who think that not sharing some tidbit of knowledge about something somehow makes them "better" and will sit there and watch another person struggle or spend a ton of time/money figuring it out. To me, nothing screams "I am not a true enthusiast" and "I am not a true professional" than that kind of behavior - it is just counter productive and and a detriment to the lifestyle. I have spent countless hours taking photos and documenting how to do things on local forums so others can learn - and newsflash for all those dingleberries who won't share info - it has actually drastically increased the amount of business and reputation I have. After I started sharing my processes , techniques, and information I had people lined up at the door to have work done. Just further proof being "secretive" about stuff like this only hurts the community, lifestyle - and rightfully so - can negatively affect the person being a dick.

[@trd8749]

Louis rossmann is a good example of this. He literally shows how to repair laptops on KZbin, yet can't keep up with all the work he's gets.

[@rotorhead5826]

If you read the RX-7 book by Jack K. Yamaguchi, the inside of the aluminum rotor housing is a steel sheet metal insert that has a special chrome plating applied to it. It's called "SPC." Semi porous chrome. It is engineered to hold a teflon coating that emerges as the pores close under high heat.

[@knucklehead69deland]

Rob! You are a legend!!! You are what the car enthusiast community needs! The small percentage of us that actually care and love cars appreciate the depths you will go!...

[@RandomAuto12]

I love the info you give us out here. And to see you do things most people probably dream of doing is even better.

[@evil_me]

Rotor housings are hard chrome plated, I've heard that some people have been using nikasil as an alternative. Nikasil is a very common coating for aluminum bores in 2 stroke engines.

[@josephkemp4404]

I wish I had known you were going to do this, I have one at work I use for free all the time, future reference I guess then if you ever want anything analyzed shoot me an email or something.

[@lowcatalina6638]

Completely stumbled on this. Enjoyed every minute. Great job on being transparent and factual. Good luck

[@Luisszyramirez]

As someone who currently is in industrial heavy equipment ... all your videos help me understand so much more and get into so many cooler things. Thanks for all the effort you put it Rob

[@jeremycote3385]

Rob has consistently been 200 IQ lately

[@Zeesneakyninja]

Unless you’re getting a perfect connection around the tip you are for sure getting X-rays reflected out the side. I wouldn’t be hold anything that I’m scanning. I have done a lot of training on xrf because you need a license to use them in Canada. For short term use you’re most likely fine.

[@joshuajones1319]

The xray machine is too weak to cause any harm. You would be surprised at how much radiation we are allowed to receive in the US......5 REM per year....This device could be used everyday and you won't be anywhere close to that.

[@Humboldt710]

I've watched you for years and I am truly impressed with your videos as of late. You guys are doing so much more and teaching people so much now! It's great to see!! Keep it up and thanks for the excellent content!

[@christianc1562004]

Very interesting Rob. Great job going in-depth on all the different materials.

[@JMB676]

Let’s go!!! Ok class sit down rob goin to teach us how to make a rotary work with all the best mods using the cheapest tool they make.

[@JordanPayneLV]

Didn’t Porsche release a tungsten-Coated brake rotor recently to help with brake dust? Amazing that companies have figured all this stuff out. Can’t wait to see what you make rob

[@soycholon9219]

I'm not even a rotary guy but i'm starting to liking them and enjoying learning something new from every video, thanks for sharing all this stuff is so interesting!

[@troys.9188]

Great to show this off and help educate people! I love this stuff and learned alot of this when getting my degree in Materials Sciences. It's crazy what slight tweaks can do to material properties. Also, heat treatments/aging are just as important as composition but for how hot those parts will be they might not be able to hold it without annealing.

[@troys.9188]

Also, the engine oil might leave trace deposits. I would be curious is you see a composition difference on the same part from a place that saw oil vs. Dry.

[@NovaRedHead]

Rob has become a You-nicorn(sorry lol)... I know that quality is time and I'll still wait patiently but I love watching the details that Rob gets into.

[@Oplix]

It's mind boggling how this machine is able to tell you within a DECIMAL PERCENTAGE of what metals there are. That's insane.

[@spazz351]

I absolutely love hearing someone who clearly understands science talking about cars. So many car people use their gut instead of science and metallurgy.

[@thornsonmonday]

Daddy Dahm taking us to class today. This is the shit that keeps me clicking that notification everytime. I can't think of anyone else on KZbin that's putting out content like this.

[@dadi2450]

father dahm is becoming a real mad scientist

[@isocuda]

This is why I wish Formula 1 would just allow an arms race with rotaries, considering these engines have had an almost nonexistent amount of development compared to piston engines.

[@romchompa6858]

I love that youre turning this into a true science! Looking forward to things to come! awesome presentation.

[@CrazyCat229]

Wow. You've come so far with this. So cool that you are putting builders to the test and trying to figure out how to make the engine better. I can speak from experience have had my car sitting forever because of a bad tune blowing my engine. Said shop did it cuz they figured since I dropped the money for the ecu and tuning they could get a new engine out of me as well. Pisses me off cuz the dyno tuning is just about the only thing I can't do myself. So now I'm going back and forth with who to use to build me a fresh engine. Stresses me out cuz I want a good engine and a good tune. Don't have a clue who to go with.... or what ecu to get or turbo etc... it's super frustrating talking to different shops cuz none of them seems to agree on any tuning methods or intercooler setups nada. Sorry for rambling anyhow thanks for doing all this and recording it.

[@drivenbydemons6537]

I friggin love this guy. Must understand everything down to the molecule.

[@Oplix]

If I was ever trapped in outer space and I could have one KZbinr to save me, it would be Rob.

[@nikov.c.5644]

Just realized i started following this guy when he had just over a 100,000 subs now he's closing up on a million. Proud of this dude.

[@evandotzler529]

I'm loving all of your recent videos with real information, i catch myself coming to your channel just checking if you've uploaded. can't wait for cosworth content. anyway keep being inspiring man.

[@ceytoy13]

YES! I talked to the top rotary companies in the USA and was very surprised at their disgusting customer service. Only Canadian guys were able to give prices and timings for the work being done!

[@joshbrookes6439]

Contact a few of the better known workshops in Australia (Melbourne and Sydney) to compare mate, think you'll be pleasantly surprised and glad you did.

[@ceytoy13]

@@joshbrookes6439 Logistics, buddy, logistics ... I'm in Ukraine. (: BUT! Thank you for the attention.

[@Balomis]

I was always under the impression that Mazda's OEM rotary housings, because they were aluminum, used a Nikasil coating (like performance car engines and motorcycle engines have used on their cylinder bores for many many years), but I guess I was wrong. I wonder if Nikasil can be used on aluminum plates and housings, or if there was a reason besides cost why Mazda went a different route. I'm looking forward to your coating comparison! I hope Nikasil can be added to the list of Tungsten and Chromium-heavy coatings.

[@darbywing2]

I, too, am surprised that the housings/ surfaces are neither nikasil or even more useful alusil.

[@jerseydriftingsouth7400]

This is so awesome. Super excited for whats to come.

[@dieselmodz8967]

Idk why but most channels when they get all nerdy about information bores me. But for some reason your information and presentation has always kept my attention. I’ve never drove anything with a rotary but for some reason I want to know more. Keep it up man you’re on to something big.

[@Foxthrough]

I just wanna know what’s in that massive crate that says “CONFIDENTIAL” 😂 been watching you since the inspirational Diablo videos, and I love it all

[@martingray7439]

That was the billet 4 rotor crate

[@brandontorres6326]

Love your videos, this is exactly what I love to watch, very interesting!

[@LusiTron]

Hi Rob, my son just got a S5 GTU that we need to rebuild, and all the info you're sharing is just priceless. Of course the little guys working in his garage do not have the tools you have, so we're still relying on those rotary shops, but this info will definitely influence our decision at the time of buying parts. Since you've already invested in the machinery, and spent countless hours fine-tooning your processes, will you start taking in customer parts to machine? That would absolutely great, there's nothing more valuable than trusting your shop has your best interest in mind. Thanx Rob!!!

[@projectsprojectsprojects8922]

Really enjoyed this Vid, thanks for uncovering more and more rotary secrets, subscribed!

[@danielthompson3849]

Two stroke nicasil plating might be something to look at. Since it works at higher rpm With less support. At a higher Hp per cc. Than anything else. Out side f1 50hp per 125cc 54mm stroke 140000rpm

[@monkeybarmonkeyman]

Dat's the name I was trying to pull out of my 65 year old mind. Thanks! Yea nikasil!!

[@janeblogs324]

Doesn't work well under boost though.

[@danielthompson3849]

@@janeblogs324 why not ???

[@Sr1hawk]

“Have UPS lose it” if you felt that comment you’ve been here awhile.

[@fuzzwho20]

Hopefully Rob Dahm will be the whistle blower we needed in the past 9 years for the USA for rotary rebuild pricing. The current market has been nearly monopolized by the few shops price wise in California, Texas, New Jersey, Washington, and Michigan. Few shops like Rotary Resurrection in the USA and in Canada RX-7 Specialties are offering fair market quality assured rebuild pricing. The rotary market has always needed a price/quality standard, even more so since Mazda USA started to discontinue certain rotor housings and master rebuild kits. @Rob Dahm

[@loganreynolds263]

I love to see that you're putting your love of the community and growing the platform above being a salesman. More people need these type of values 👌👌

[@BecksArmory]

It's HVOF coating Rob. This is extremely common in aerospace cylinders. You didn't need to rent that machine. You could have just asked us. hahaha. HVOF has replaced chrome plating cylinders because the EPA get's all up in people's shit about it.

[@GulliJ]

That's a great way of learn! Soon you rent a 3d scanner by contact, and scanning all yours engines to duplicate them in the better way and in future you could buy in Mazda dealer a Rx9 Rob' edition 2025 What a Dahm idea no? Cheers from France 🇲🇫

[@MichaelHybrid]

Thanks Rob! Very fascinating episode. Keep up the good work.

[@The_Terridax]

It's really kind of you to put this type of stuff out there, man. Thank you.

[@One21P]

If Rob scanned himself, he would be 100% rotary affinity.

[@eddiepFW2345]

After hearing him mention spaceships I'm pretty sure we will be seeing a rotory powered rocket ship lol

[@KarelBeelaertsvanBlokland]

Well done! Hats off for your search into hard metals...

[@Hennessy754]

love to see some one goes that deep to find facts .. thank you for your great work ..

[@harzer99]

Rob your shop is becoming a lab! If I would live nearby I would apply for a job with my near physics degree.

[@urpalandrew7983]

When are we getting the Rob Dahm Rotary parts store? Gotta start making some ROI on that CNC machine eventually right?

[@alphadental2249]

I make dental prosthetics for a living in material sciences always been a fascination of mine. We had a scanning tunneling electron microscope to use to look at material that we had made and broken to see where it broke why it broke at a molecular level. Metallurgy is becoming more and more necessary because of biomedical engineering and source contamination. It's very important to know what's in what you are buying

[@piyiotisc]

Rob at it again! Thanks man. I don’t even own a rotary but this is what a community is about. 🙏

[@Nano606606]

Drinking game: Every time Rob mispronounces an element, take a shot. You would be smashed in the first 3-4 minutes.....

[@TheRealKarlis]

Or the word "bullshit" is a good option. Keep fighting the bullshit rotor community secrets!

[@geennaam1201]

Weird thought but could you make a rotary engine but replace one of the rotors with a electric motor? Rotor=magnet housing=spool Making it some wierd hybrid, and giving it a bunch of low end torgue Probably not, ignore me

[@geennaam1201]

@@greatestevar May be the better solution but for me that isn't always the most fun way I see electrification as the future, because electric motors now are just better But I see it as a soulless solution I would like to see electric motors complement an gas engine that has its power band in the higher revs, like a rotary or a bike engine or big turbo cars Give it a full thicc powerband with the great sound of for example a rotary Motor on the wheels can do that but it splits the heart of the car it two, and don't want electric only as an optiob BTW I know I'm rambling

[@The0Advent]

cool idea, but i feel like heat would be what kills it. magnets typically dont like heat.

[@capnthepeafarmer]

The SAE papers describe the housing materials in very good detail. The housing is cast (obviously) and it's cast with a sheet steel insert, those are the little fingers that you see on the edge. After the insert/casting process the sheet steel is honed then chrome plated (hence your high chromium content reading). Here's an excerpt from SAE 941030: "Since the engine maximum output power is made significantly higher, there becomes a concern that apex seal may wear due to the heat generated by sliding the rotor housing inner surface. In order to lower the heat, friction coefficient of rotor housing inner surface is reduced by carbon graphite coating. The coating is applied to the CrMo plated rotor housing inner surface" An older paper about the S4/5 engines SAE 860560: "The cast iron [rotor housing] shows greater durability in terms of strength, rigidity and thermal expansion at high temperature, but it is inferior in heat conductivity... In the case of the cast iron... the surface becomes too hot to retain a lubrication oil film..." The manufacturing process is also described in the older paper, "... the base metal of the rotor housing, a T-6 treated aluminum allow AC4D (Si 5.0%, Cu 1.2%, Mg 0.5%). The trochoid surface on which the apex seal slides is given hard chrome plating to provide good wear resistance. To prevent the chrome plating from fatiguing and peeling off under the apex seal vibrating load... a study was made to provide better adhesion... As a result a new process called SIP (Sheetmetal Insert Process) was developed. ...the aluminum rotor housing is die-cast under high pressure to the trochoid-shaped sheetmetal with one side jagged in the saw-tooth manner for better bonding with the aluminum alloy." I won't type up the entire paper here, but it's worth a read. The older paper goes into the testing of different coatings, including cermet spray. They ended up with hard chrome plating with micro-channel porous plating to retain oil as well as aid in oil wet out. But this is contrasted with the Mazda 787 racing team (SAE 920309) to choose cermet coating on the side housings which did provide slightly more wear resistance compared to the soft-nitrided cast iron, 19um wear versus 16um. I can only assume the choice wad down to it wasn't practical for a mass market car, but made sense in a racing environment.

[@capnthepeafarmer]

I know this is a way old follow up on this video and comment. I wanted to add that the high zinc reading you saw on the rotor was due to the zinc chromate coating (same coating you see on yellow zinc fasteners). Mazda added that primarily for corrosion resistance, much easier to see on brand new rotors. In later RX8 rotors you still have the zinc coating, and now the rotor flanks have a thermal barrier coating to improve overall engine thermal efficiency.

[@glenn9k]

Thank you for doing and sharing all this.

[@celiturbo]

Nothing even remotely special or hard to get done about the coating on that housing. The cylinders in the majority of 2 stroke engines since the 80's are a plated bore, its way cheaper than an iron sleeve, simple as that. Hex chrome blah blah blah, Its cad plating that is tough to get done and basically banned these days, any issues with getting a housing re plated would be entirely down to platers just lacking experience or not set up to handle the dimensions of the part. The plating on the billet iron was just common nikisil plating. You didnt even need to test it to pretty much know thats what it was, the straight chrome on the stock housing is the shocker here and shows just how penny pinched mazda was with these things. As far as the apex seals, I don't see why it would be any different than it is for piston rings, if you have a chrome mating surface you run a cast compression ring/seal. The cheaper part that can simply be replaced should be the wear item. Anyway, nothing new or special going on here for being a rotary engine, the material science has been long covered and known in 2 stroke use, just look there, its really standard stuff at this point, even some penny pinching oem's starting to chrome bore sleeveless 4 stroke car engines. If you think the secret sauce bs is a problem with the rotary people, just wait till ya start dealing with platers, simple chemistry and process but they will do anything to keep people from knowing.

[@MiguelGonzalez-gp2zz]

Awesome video! Thank you for sharing! I would scan everything in my garage if I had that thing.

[@Hyde232]

I absolutely love his heart in what he does. It is truly inspiring.

[@joekent6576]

XRF is X-Ray Florescence. Essentially it works by exciting electrons in each element to cause them to fluoresce emitting light. Each element emits light with a unique spectral signature, like a fingerprint. The various spectral signatures from the sample are detected, analyzed, and compared to a database preloaded on the unit. It's the same way we can know the composition of distant bodies in space. Such a cool tool. I can't wait until they are more affordable. I want to go pick one up at my local Harbor Freight.