Piston skirt lubrication experiment
- Thread starter jseng1
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ugh guess which I get to ride the longest. Nortons can live a long time w/o Bore tech if operated sanely while my mowing is more like a WOT rodeo in obstacle course. Big let down on mower first rebore lasting less than a season and backed up by several small engine shops here that found once the factory surface gone - just new rings or even rebore/piston don't last a season before ovals bores. I think Ken Canaga looking around for Peel that settled on Bore Tech and forum awareness. Mower .040"+ new pistons chain filed. heads Singh Grooved and more CR w/o .050" head gasket. I know the difference between pure luxury items and something really useful.
Butt lofting backwards wheelie zero turn machine
Butt lofting backwards wheelie zero turn machine
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Rohan said:
It has been said that 'racing improves the breed'. Unfortunately competition extends into the market place for road going motorcycles. I don't think we will see another motorcycle engineer such as Phil Irving, spill his guts about Moto GP bikes. There is little altruism these days =- not much is done 'for the common good'. If you look at MotoGP Workshop on Youtube, there are distinct limits on the information supplied.
If Jeremy Burgess wrote his memoirs, he has worked/managed 3 different top factory racing platforms.
And Suzooks and Kwakas fell by the wayside at that level, so not much to contribute anyway,
although the reasons why (electronics management not taming the beast) would be informative.
A lot of info gets into the British (and Japanese) bike magazines, maybe we just need a wider reading horizon. (?).
BMW distribute and show a lot of info on their Superbike thingy too, seems a real weapon in the right hands.
Aprilia publicize whats in their V4 Superbike rocketship also, inc Mr Garners Norton Racebike is using its engine in their own chassis.
But we diverge, slightly-ish.
And Suzooks and Kwakas fell by the wayside at that level, so not much to contribute anyway,
although the reasons why (electronics management not taming the beast) would be informative.
A lot of info gets into the British (and Japanese) bike magazines, maybe we just need a wider reading horizon. (?).
BMW distribute and show a lot of info on their Superbike thingy too, seems a real weapon in the right hands.
Aprilia publicize whats in their V4 Superbike rocketship also, inc Mr Garners Norton Racebike is using its engine in their own chassis.
But we diverge, slightly-ish.
Rudge used to have an oil feed to the base of the cylinder, to prevent piston wear/breakage in the early miles of a TT. It was so successful that they included it on production motors.
Way back when, it wasn't uncommon to put shallow grooves in piston skirts exactly as OP, mine weren't as neat though! I had a pre unit T100 that was always scuffing the non thrust face, oil grooves fixed it.
cheers
wakeup
Way back when, it wasn't uncommon to put shallow grooves in piston skirts exactly as OP, mine weren't as neat though! I had a pre unit T100 that was always scuffing the non thrust face, oil grooves fixed it.
cheers
wakeup
I believe that the great W.O.Bentley introduced light alloy pistons to the automotive world, when he designed his 3 litre motor, in about 1919/1920. He had previously used LA pistons in the WW1 rotary engine he designed which was used in, amongst others the Sopwith Camel.
cheers
wakeup
cheers
wakeup
The story goes that WO got the idea from an alloy piston shaped paperweight on a visit to a French car
makers premises that he was importing into England. Rumour has it they already had alloy pistons in
their cars prewar (WW1), and so did WO, so who knows. A lot of folks tried to make it work, but finding
an alloy that stayed strong with heat was reportedly the key to it - and an al-copper alloy provided the answer.
Wasn't just Rudge that had an oil feed to the rear of the piston - that was common practice across many makes,
since that spot tended to be shielded from oil sling and consequently run dry. Nortons only gave up that feed to the
rear of the piston in the late 40s early 50s, when general road speeds (and crank speeds and consequently oil sling)
had risen so that underoiling was no longer a problem.
V-twins commonly had a feed between the cylinders for many a year, since the back of the FRONT piston tended
to run dry (and hot) for the same reason.
makers premises that he was importing into England. Rumour has it they already had alloy pistons in
their cars prewar (WW1), and so did WO, so who knows. A lot of folks tried to make it work, but finding
an alloy that stayed strong with heat was reportedly the key to it - and an al-copper alloy provided the answer.
Wasn't just Rudge that had an oil feed to the rear of the piston - that was common practice across many makes,
since that spot tended to be shielded from oil sling and consequently run dry. Nortons only gave up that feed to the
rear of the piston in the late 40s early 50s, when general road speeds (and crank speeds and consequently oil sling)
had risen so that underoiling was no longer a problem.
V-twins commonly had a feed between the cylinders for many a year, since the back of the FRONT piston tended
to run dry (and hot) for the same reason.
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'A lot of folks tried to make it work, but finding
an alloy that stayed strong with heat was reportedly the key to it - and an al-copper alloy provided the answer.'
I think the Hepolite pistons were made of Hiduminium RR55 alloy which was used in Merlin engines. That casting alloy was never made in Australia to my knowledge, and our local aftermarket pistons used to grow like crazy. After they had seized several times and the high spots had been filed down, they were sort of OK - just.
an alloy that stayed strong with heat was reportedly the key to it - and an al-copper alloy provided the answer.'
I think the Hepolite pistons were made of Hiduminium RR55 alloy which was used in Merlin engines. That casting alloy was never made in Australia to my knowledge, and our local aftermarket pistons used to grow like crazy. After they had seized several times and the high spots had been filed down, they were sort of OK - just.
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hobot said:
The Hines article (remember Vance&Hines Suzuki drag bikes?) above says that three 3/8" chamfered holes are drilled in the skirt. The holes both lighten the piston and provide extra lubrication to prevent seizures. It goes on to say that these modifications enable the bike to get through an entire season with out need of piston replacement.
See the photo below of the first lightweight Norton pistons I raced with back in the 1980s. By coincidence there are three 3/8" chamfered holes in each skirt (same as Hines). I'm still using the same technique in the photo at bottom and I have provided drilled pistons to some customers. Its more than just coincidence - its good engineering and it makes for a longer and smoother running motor.
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I was surprised on 1st seeing your holey pistons in Race Manual and now see more holes in the barrel fins so please fill me in on reason, though I hardly need a reason to feel like drilling something. I'm sorely tempted for fin thick dia seires of holes in Peel Swain coat fins.
jseng1 said:.............. I'm still using the same technique in the photo at bottom and I have provided drilled pistons to some customers. Its more than just coincidence - its good engineering and it makes for a longer and smoother running motor.
That piston looks like the way to go and the DLC wrist pin seems to have no wear at all, outstanding Jim , these are from the engine with 6 years and 20,000 miles, right?
You could give the piston skirts more clearance and fit Telfon buttons for engine pistons;
http://forums.pelicanparts.com/911-engi ... stons.html
http://forums.pelicanparts.com/911-engi ... stons.html
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cjandme said:jseng1 said:.............. I'm still using the same technique in the photo at bottom and I have provided drilled pistons to some customers. Its more than just coincidence - its good engineering and it makes for a longer and smoother running motor.
That piston looks like the way to go and the DLC wrist pin seems to have no wear at all, outstanding Jim , these are from the engine with 6 years and 20,000 miles, right?
CJ - Yes its from the same engine but its an earlier photo from when I reduced the crank balance factor to around 65% and lightened the pistons down to 170 grms with under crown milling, machining off the sides etc. And yes the DLC coated pins seem to keep looking like new.
Hobot- I'm going to do some more research on the Federal Mogul test and see if I can coat a section of the skirt to fit the Federal Mogul plan. I haven't decided which way t go yet. Also - there was a time when I reduced iron cylinder weight with fin drilling. But they have alloy cylinders now.
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My 1st engine re-build found pistons too loose in bores so had the used pistons knurled that may of helped Peel's hi rpm friction. After the over'rev event I found the knurls worn off load bearing areas but stil no slap on warm ups. Knurls usually done for cheap clearance take up but is also known as aid to bore lube too so another experiment to run someday. The hot rod shop I had the barrels honed had a fella with a hopped up chevy V8 he said that's what he did to his so we did Peels too and worked well in her too. If I ever tear next Peel down again I'll have many surfaces dry friction coated which also might of been a factor in Peel's nut case pilot being hunted down by out of state visitors and called out for pecking order games. In that era I was always on Peel so easy to find.
Jim, is that weight reduction of 170 down from a 750 piston that started out at 185 grams? I looked back over the thread but it wasn't mentioned, I mean another 15 grams, it's quite amazing to me, great work there, that's for sure.jseng1 said:cjandme said:jseng1 said:............its good engineering and it makes for a longer and smoother running motor.
CJ - Yes its from the same engine but its an earlier photo from when I reduced the crank balance factor to around 65% and lightened the pistons down to 170 grms with under crown milling, machining off the sides etc......
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cjandme said:
Jim, is that weight reduction of 170 down from a 750 piston that started out at 185 grams? I looked back over the thread but it wasn't mentioned, I mean another 15 grams, it's quite amazing to me, great work there, that's for sure.
The pistons in the photo are the first JE lightweight pistons for Nortons and started out at 190 grams. They had a little extra metal on the sides below the pin that you can see in the photo. After awhile I tore it down to check up on things. I milled off the sides and most importantly I undermilled the head and contoured around the valve pockets so the crown was a consistent thickness throughout and thats where I lost the most weight. I also taper-bored the pins and lost about 3-4 grams each there. The bike ran so incredibly smooth that I decided to market this stuff and the rest is history. There are hundreds of bikes on the street with these pistons now and I'm getting a lot of good feedback from them.
The pistons below are the very first lightweight Norton pistons - made from Wisco blanks from a GSXR suzuki over bore kit in the late 1980s. They went into an 850 and weighed less than 750 pistons.
Prior to going to the lightweight pistons I was breaking cranks and cases. All that stopped. I raced the monoshock Norton below against monoshock ducati's and did well - When I passed them in the turns they would re-pass me on the straights etc. I raced those pistons for a season, never tore it down and the bike always ran great.
Now I have a question for you CJ - do you have any personal experience with these pistons?
Man I sure wish I did Jim, so far all I've been able to afford is one of your flat slide carbs and manifold, but they are on my wish list for sure, along with the complete cam,valve & beehive spring set. Thanks for all the R&D and making this stuff available. Cjjseng1 said:
Fast Eddie
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hobot said:
I was told by Dave Degens that drilling holes in fins is a bad idea as it creates turbulence that disrupts correct air flow through the fins, thus reduces effective cooling.
Anyone ever tested air flow with drilled barrel fins ?
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