Topic: High Performance Coatings!!!

[Dresda500]

I haven't seen much mention of coatings in the various engine build threads, but I'm sure many of you are using them or would like to know more. I first got interested in coatings in a big way about 20 years about when myself and some friends starting racing out at Bonneville, albeit with a little 260ci Chevy V8 in a '23 roadster on gasoline. That little Chevy made over 600hp naturally aspirated on gasoline and we shifted at 9800 rpm...custom 2.5" stroke and over 4" bore. That got us our first red hat and into the 200mph Club...anyway in the coming years we went from the little E class motor all the way  up to the AA unlimited class and took every record in every class, many still standing today. Running 5 miles at WOT REALLY make you think about how to make an engine last...I think of a LSR motor much like a road race motor....you want gobs of HP, but not so much that it's unreliable. In the end basically every single moving part has some sort of special coating on it. Sorry about the ramble....so anyway...what are you guys using on your race motors? Any lessons learned?
I've been applying Techline coatings in my shop for a good 15 years. Some things I've learned along the way are that you really need to look at each specific motor, how it's designed-air cooled-liquid cooled-, how it will be used...what type of fuel...
Ceramic heat barrier type coatings are amazing and I love them, but you need to be careful before coating everything and the kitchen sink. Many race motors will get a ceramic on the piston crown ( and Dry Film Lubricant -DFL-on the skirts) as well as the combustion chamber and faces of the valves in an attempt to keep ALL the heat in the chamber...because heat is HP and if it's in the chamber, it's making power right? As well there is another type ceramic that I put in some exh port runners to both keep the head from overheating and as well to keep the exh as hot as possible, which turbo motors really love and NA can be good in some cases and motor design...but one also needs to consider things like...if you are keeping all the heat away from the piston (which heats the oil quite a lot on many motors) and away from the head, which also gets the motor and oil up to temp, especiailly on a water cooled motor....so then you end up with a motor that can't get it's oil to temp until the last lap...but you made 0.02% more HP due to combustion efficiency, but lost 0.5% HP due to cold oil. those are just hypothetical numbers for the lesson.
Fuel quality....pump gas, race gas, E85, methanol....when you keep all the heat in you chamber, you better have good fuel and also be able to keep an eye on detonation and control it. You can't make HP if you have detonation...or not for very long... ..E85 and alcohol/methanol are great, they keep everything cool and doesn't really matter if you are a bit rich or lean, your aren't going to hurt the motor. Nitro..that's another thread. I have a customer here in Norway that has a giant turbo on his old Volvo rally car. The 98 we get at the pump isn't really as good as you might think so we ceramic coat his pistons to protect them, but not the chambers so they can extract some of the heat from the process and he can run a bit more timing without detonating. His motor lives and he wins races.
On our air cooled inline 4 motors, they are all quite similiar from the smaller variations to the big bore liter plus bikes. Basically all sliding friction surfaces could likely benefit from a DFL coating on just about everything I'd think. The majority of all wear on  plain bearing(insert bearings) comes from the time you start the motor until the bearing gets oil pressure and its riding on a film of oil. The DFL helps hold oil on the bearing surface so you don't get that wear and as well can decrease the frictional losses as well. Same principal on your piston skirts...they are just a sliding bearing and while crank centerline to bore centerline does have an effect on the side thrust, all the wear and business end of a skirt is the sides perpendicular to the pin, which is why you can cut down the skirt on the pin ends with no loss of function and decrease your frictional losses. You can even coat your tranny gear teeth faces and thrust faces after you spent all that time lapping them together...And rod bearings!!! Oil control is via your clearance of the bearing to crank...it is not and should not be controlled by tight clearances on your rod side clearance to the crank...run those suckers loose...the Dyno will thank you.
You can also coat your rotating assemblies with oil shedding coatings so you aren't carrying extra ounces of oil on you parts turning 10-12000rpm....when you just got done balancing the assembly not taking this into account...

I'm rambling and my wife is yelling that I'm being rude that dinner is on the table....please post you experiences and thoughts!!

[Tracksnblades1]

^^^^^^^^^

🤔
Sounds like reading the Modern high Tech version of “Smokey Secrets”.

Especially since everyone moved on to ceramics. Remember Ole Smokey
recommending baking an aluminum cylinder head with its water jackets filled with irontite*
on a rotisserie in an oven. Trying to reduce the thermal conductivity to that of a
Cast iron head. So he  could gain back his lost horsepower and still enjoy the aluminum heads
weight savings…

How long can your coatings last?
What clearance change is realized on the plain bearings?

Ramble on, I find it informative 😁

[Old Scrambler]

Coating the internal chains for our motors may be helpful..........or just the sprockets?

[grcamna2]

subscribed

[PeWe]

I searched on piston coatings when I had a setup with too much piston-bore clearance.
If it can reduce the total ca: 0.04/0.05mm. This means a coating thickness of half those numbers. Possible to hone bores a little.

Coating to tighten it for better clearance. But shops doing this too far away made it too  pricey.

[Dresda500]

^^^^^^^^^

🤔
Sounds like reading the Modern high Tech version of “Smokey Secrets”.

Especially since everyone moved on to ceramics. Remember Ole Smokey
recommending baking an aluminum cylinder head with its water jackets filled with irontite*
on a rotisserie in an oven. Trying to reduce the thermal conductivity to that of a
Cast iron head. So he  could gain back his lost horsepower and still enjoy the aluminum heads
weight savings…

How long can your coatings last?
What clearance change is realized on the plain bearings?

Ramble on, I find it informative 😁

Smokey was an innovator to no end. I still remember getting a copy of Smokey Yuniks Speed Secrets book when it came out in the 80s, I must have been 14 or so. That book and another "How to build a racing engine" that was a small print version were my bibles when building my first motor ground up in high school. I ported my first set of heads using my dads Black and decker drill and those black steel burrs you could get at the local hardware store. They likely flowed worse than stock, but it was fun (and my '68 Camaro was the fastest car in town..

But back to the bikes and coatings!  On plain bearings the thickness is usually not even measurable, so if you have a crank in spec with a certain bearing, you can coat them without worry. That's not to say another manufacturer or applicator might build a bit more thickness, but I checked this a LOT when i first started doing bearings and it made no real difference.

Lifetime really depends on where the coating is applied and as well the individual motor. In general the higher performance the motor the thinner, as in width,  the bearing surface is, so the force per area is higher., and as well we have higher PSI in the chamber and more rpm..therefore whatever bearing surface/frictional surface wears out faster than a street bike. Cam bearings are a good example. If one is still using a plain bearing on the cams as we do, the higher the spring pressure, the more wear you will see on your bearings so you need to keep a log of both your cam journal diameter and you head bearing surface if you are trying to go super duper proper...this way you can catch a trend of wear before you suddenly realize that you are out of spec two days before a race. That's the nice part of replaceable cam bearings on the head side which gets all the wear. As mentioned earlier most of your wear will come from startup before you have oil pressure. Another car example from Bonneville...our team consisted of a group of gearheads and half of us engineers but while I had been building motors at a somewhat high level before, this was new to me. We noticed in our first years of racing that after coming back from Speedweek that our cam bearings were thrashed after one week of racing...still going fine but very worn, even with coatings. this was due to the crazy high seat pressure on the monster roller cams. If we make 10 passes, that's 50 miles of WOT...or 200  passes at the 1/4 mile drag strip, but with no cooling off between rounds...we went to 50mm roller bearings on the cam and never looked back.
But for a more simple answer to your question, on most race motors, you will see some wear on the bearing surfaces, some worn through to the original bearing material in a race season in both road race and drag race type motors. Street motors usually see a lot more miles before teardown and you don't always get feedback from your customer if it's not one that you deal with on a constant basis...and hopefully you aren't tearing down your street motor every winter..   Pistons vary quite a bit depending on the varying amount of skirt side loading. I will say that the pistons that come from the factory with coated skirts tend to be more robust than the aftermarket coatings just due to the fact of the thickness. The factory type are usually much thicker from experience so they look like they wear as much, but I don't have much real data on actual piston wear from the same motor with different coating types...on another side note..I've experimented with a special coating from Techline (TLMB) that is meant to build up a surface if its slightly out of spec. I've used this on piston skirts before applying a DFL with good results...this might sound hokey but it seems to work and it's been on the market for quite a few years now. It can really extend the life of a set of custom one off pistons that are perfect other than some skirt wear. I do lots of vintage HD motors as well , mainly from the 30s to 60s and typically those guys run #$%*ty filters or no filter as most of us do on our race bikes. MAny times the piston clearance might be borderline what one would want from a fresh build and have a bit of damage on the skirts from dust/grit/grime...so one can spray with the TLMB to fill in some unwanted scratches, prep it, then coat with a DFL s usual.   I actually use a piece of tool steel that I have run in the surface grinder so is very flat, as a sanding block and some 800 grit paper to hand surface the skirts after the TLMB....yes, I block sand my skirts haha,  then coat the DFL and burnish that with a soft scotchbrite pad and they are good to go. You can double or triple the life of a piston this way.
As a last bit of fyi, the skirt coatings are very good at showing you the pattern of contact on your cylinder wall, so you will will know immediately upon motor teardown if you have a bent rod or small end bushing that is not 100% parallel to the crank bearing.

[Dresda500]

I searched on piston coatings when I had a setup with too much piston-bore clearance.
If it can reduce the total ca: 0.04/0.05mm. This means a coating thickness of half those numbers. Possible to hone bores a little.

Coating to tighten it for better clearance. But shops doing this too far away made it too  pricey.

Haha, looks like you posted while i was typing, I just talked a bit about this exact thing! Yeah, I understand. I'm in Norway now and  it's not near as easy to find people to do specialty work and shipping has gotten outrageous

[Dresda500]

Coating the internal chains for our motors may be helpful..........or just the sprockets?

Sprockets can be done no problem. I've never done chains due to the inherent problem of you need to sandblast the surface lightly to get a surface that the coating will adhere to.  And don't worry it's light blasting with a careful hand, so even shell bearings are not hurt.