Rings....BUT way off topic

[Fredvon4]

Decade or 2 back I decided to try and make my 1993 FXR  80 CI Harley Evo engine (46 HP) perform as powerful as a 93 CI S&S replacement V-twin engine (95HP).

(( I was in Germany where I bought this bike and needed to keep UP at AutoBahn speeds... but she ran out of umph around 96MPH/154Kph while most in that area were running 180~200Kph or 120ish Mph))

So I dramatically changed the final drive rations by the largest available drive gear and smallest available sprocket  (belt drive system)...but ran out of umph still 2 around 100Mph

I read and researched and brought to the table skills I learned Drag and Stock car racing at Spanaway, Tenino, Portland and Seattle, Sears Point, Laguna seca race tracks as a motor head/builder/tuner focused on small block Chev and Ford.

I decide on:
My own 1993 Fresh low mile 80 Ci Harley engine had a sound bottom end
New Harley jugs over bored +0.20
New Keith Black Hyper-Utetic pistons  +0.20
New lower cc heads from a Canadian source (Head Quarters)
New Cam (Head Quarters) specked for mid band torque
New roller big wheel lifters and roller rockers with adjustable push-rods
New electronic, infinatley adjustable ignition
New very high Kv coils 
New Mikuni carb and custom intake header
New Super Trapp (Tuned?) scavenging exhaust header/ muffler system

I contracted Jim's in Axte Tx to mate the pistons and jugs to a 0.025 clearance

I contracted Total Seal for new tech GAPLESS ring sets and sent them the machined and mated pistons and jugs (They had a fixture to pre load the jugs and get fit precise)

I contracted Hyper Tech Coatings and send assys to them for Ceramic top of piston coating as well as their Slippery Dry coating on the piston skirts

Calculated that my original 8.6:1 compression engine would now be in the 10.2:1 to 11:1 range, thus needing the slower burn higher octane fuel

Got 2 legit chassis Dyno runs on the stock engine= 48 HP at 6200 Rpm

Built engine and pre adjusted carbs and ignition to start and run relatively smooth--- bought more dyno time to fine tune carbs and ignition + 91 HP @ 5800Rpm ---torque went double also, but do not remember either value

I drove the FXR motor bike for six months until one day it would NOT start.... factory starter did not have enough to flip it over ... New better High zoot battery.. no soap
new High amp super starter...no soap....assumption; rings finally fully seated and compression way too high

NO room on an FXR for larger stuff (that did exist)

Push starts by friends for a few weeks

Pulled heads and sent to Jim's Harley Axtel Texas for a set of auto compression releases...now starts fine but pretty bad pre ignition when fed right wrist twist too fast...BUT now a 154 Mph top end motor bike ......grin....Texas State patrol not impressed....tho travel time to Tucson (1400 miles) from Killeen on 75 Mph I10 greatly reduced (( only road I was comfortable running 120 mph on) .....still can not out run Motorola...double grin

Add a second head gasket to lower compression a tad... worked to let me run Hi Test pump gas without additive octane booster

Point of all this... relative to the Frank Bowman ring thread... I am curious why some of the racing/ speed guys don't do some of the, NOW OLD school, high tech coatings and such

When I was deep into it, there were a few sources for Nitriding(sp?) parts, super slick coatings, ceramics, extruded flow polish and porting

Perhaps all the high tech stuff is being exploited and it is secret
Perhaps many do not know of the benefits
Perhaps none of this is relevant to modern 2 cycle alcohol fuel engines

[Steve Helmick]

I have some of that slick coating stuff, which I used on the rebore of my Honda XL-250 single (4-stroke). I also tried a Mikuni carb on it, one with the cable out the top that pulled the carb slide up. Best way to kill the engine was to twist the throttle to WFO and it died of fuel starvation almost instantly. Useless for riding trails. I ended up using the (left?) carb off a CB-450, which was a CV type carb (like an SU carb from a Volvo or Austin Healey). The throttle ran the butterfly, not the slide/needle. That solved the starvation problem, but made the throttle response too quick. I made up a really neat exhaust for it that weighed a lot less than the stock one, but of course, made a bit more noise. It would keep up with my buddy's Yamaha 360 Enduro. Pulled hard from idle to 10k, while the Yam nosed over by 7-8k. 

FWIW, I think the coating stuff would be ok in a ringed glow engine, but I have some doubts about it being useful for a lapped setup. I'd sure use it if I re-bore my 1980 Yam 175MX, which doesn't seem likely in my lifetime... mostly used it for chasing free flight models for the Aussie teams in '93 and 2001!  Steve   

[Fredvon4]

On a ringed engine I am not all that convinced that the slippery stuff on the skirts do much more than protect the piston in the long run

But I can attest that from all the car and MC engines I worked on they all had some measurable carbon on the tops. At 5800 miles on this build I mention I had to remove the heads to send off for compression releases... The Ceramic piston tops were just a very light charcoal grey and that smeared off on my finger revealing a still nice clean glassy piston top.  My understanding from the Hyper tech coatings guys was the ceramic provides a very durable thermal barrier, allowing a closer piston to bore fit cuz the aluminum piston does not grow as much.

That said, I did NOT pull a jug off to see if the piston had any scuffing

They also said and I forgot that the coating is several thou thick and reduces chamber volume... I did NOT take this fact into my predicted calculations....thus over compressed the engine a bit too much

Today I would not got all the trouble... one can just buy a Real Harley 110 CI engine that fits and has a warranty for about the same as I put into that build....

Just curious that I see all sorts of high zoot things done to combat and other model engines but never heard of any body exploiting some of these systems outside of supper close (or loose) ceramic bearing fitments

[RandySmith]

 " Just curious that I see all sorts of high zoot things done to combat and other model engines but never heard of any body exploiting some of these systems outside of supper close (or loose) ceramic bearing fitments "

And  ceramic bearing would add 30 to 70 dollars  to the cost of making an engine, sad but true  Price does still matter a bit in model airplane engines

Randy