Piston skirt oil hole dynamics to try.

Piston skirt oil hole dynamics to try. Jimmy Schimdt may be extra interested in this study on where and why to drill skirts to float on fluid.
http://www.federalmogul.com/en-US/Media ... cript2.pdf

hobot said:

Jim Schimdy may be extra interested in this study on where and why to drill skirts to float on fluid.
http://www.federalmogul.com/en-US/Media ... cript2.pdf

Click to expand...

See photos of drilled pistons in the "limitations" post.

that was heavy going. 304 piston design seems to be very effective and from the results, may not wear as fast as we might otherwise imagine. [ I liked the blonde as well though keep it up ] Now what was the question.

Hi Steve. the skirts were not drilled, they were relieved by only a few microns. [ I think that's what you were getting at ]. Are we going to live long enough to reap the benefits of this experimentation. According to an expert mechanic, 850"s will do 350,000 miles before reboring [ I guess that could be so if they were looked after correctly, and of course , I have known Toyota Hi Ace vans to travel up to 1,000,000 kms before needing reconditioning ]

Re: Piston skirt oil reliefs dynamics to try.

Hey Keri, I'd only glanced at article before putting a title on thread. What struck me of course was the oil reliefs of one design lowering friction with increasing rpm. Seems like hand filing could mimic this feature but as Ken pointed out the test engine's tighter bore clearances and lower rpm tested may mean its not applicable for real life Nortons. Fascinating area to search around on with studies on type and placement of oil ring holes besides lightening holes.

I WOULDN'T ADVISE DOING ANYTHING TO MODIFY THOSE PISTONS. They work ok as they are. Interesting article though. makes you think. I would think in th real situation, the high spot would wear off quickly leaving you with a normal piston, somewhat slightly smaller.
All the best. Dereck

Ugh Derack you should of warned Jim Schimdt too if ya'd not seen how risky lacy he drilled out the standard bean can size pistons when racing, so I really don't think much risk for such shallow oil pocket releifs. I'm equipped for this level machining by bench grinder, sand paper and buffer wheels. I'm not teasing on aiming at elite's track times in tightest type tracks but they still can zoom to 150-ish in the opens where wind drag piles up fast so I expect to have to strain fuel and friction heating to have a chance. Long strokes accelerate piston-bore friction speeds quickly especially over 7000 so this little piston trick might be another straw to grab before the huffing/puffing blow my house down tests start.

Fascinating! I dig on this kinda stuff. I like the final closing disclaimer; "Further verification studies on production feasibility, oil consumption, blow-by, durability and scuffing are required." I'll bet!

On page 1, there's the value "Crank ratio (L/r) 3.5". Does this equate "rod-to-stroke" ratio? If that's the case, then all bets are off, as the Norton (at least, the 850) has a R/S ratio of 1.68. Assuming that's the case in their studies, the rod angle would be drastically less than "real world" engines. I suppose the argument could be made that, if the results are that obvious on their test mule, it should be even better in the Norton. My fear, though, is that with the increased rod angles in the Norton and the associated elevated side-loads, is that the oil would be more inclined to be squished out with any sort of recesses in the piston that would decrease its bearing surface.

Steve, are you ready to sacrifice a set of pistons and bore to see? Maybe one stock piston, and one with the cutouts. I would, but she's running too good right now to think of taking her apart!
Nathan

What the study reveals is the #04 skirt reliefs allow the lower oiled bores to deposit enough oil to last the rest of the cycle. Seems to me that about regardless of B/S ratio angles and bore/piston clearances the same basic loaded areas will occur and benefit. Friction goes up non-linearly so maybe this would make 8 grand more worth while to seek to use. The only thing in Peel's engine that was not maxed out for rpm tolerance with current products is the Norton lifters but they been tested beyond anything I ever hope to rev to again thank you. Oh yeah I intend to use up a set of pistons about as fast as I can if that's what it takes to make the flashy elites seem mere colorful bait bugs to snap up. May dyno before and after if life allows, as we gotta find out somehow.

Hay Hobot, sorry Steve. Are you related to Bert Munroe. [ sorry yank version Burt ] ooops, your not a yankee are you. [ according to my history lessons ] I have a set of 71 750 pistons here that have done only 13,000 miles. [ warning though, I was told the tops come of those buggers ] You can have em if you want em. that was an interesting article. Its amazing what these backroom boys come up with. It the likes of me that end up fixing the f..k ups though. I suppose carefully drilling a few holes in the skirts in the right places might achieve a similar result. Let us know what your result is. If it blows up before you finish the test, that not good enough. if it blows up arfter the test, it too blooduy good. If it blows up as you cross the finish line, its perfect.
Al;l the best Steve. Look forward to hearing from you again.

Ugh Dereck [sp] I know what Burt felt like pressing luck riding then injured and recovering then ridding again knowing it'll happen again but doing it anyway. Atleast Burt was racing in recognized events for some sane incentives that don't apply to me. Trixie Combat ran great after starting up after a decade+ sitting in New Orleans shop but came apart coasting at 50 mph looking for a place to turn into a pasture of yellow flowers that matched her yellow. Turned out a taboo Al gasket was smooshed into the bores so piston rubbed it which piston could of stood but for the taboo comma shaped oil holes *in the oil ring groove* -not the lower skirt expansion compensating comma holes. Schimdt's lightening holes are not in hi stress area the rod jerks on so nil risk for the rpm mass advantage though might be placed differently with the oil film insights shown.

Really appreciate your recognition I'm not a United State's District of Columbia Federal troop 'yankee' citizen though those poor people got conquered right off the bat by US-DC illegal draft imposed. My Norton time is a comic relief from my fight with the *powers that be* [which I can ID by name and titles and time and treaty so not a nebulous term to me as it is to most others] > not to be charged as war criminal that requires a license to travel as a tourist through conquered US territory. In order for me to obtain a race 'license' like Burt to run the Salt flats and other crazy events on Peel I may have to take my case to the Hague I have won the biggies of passport as non-US citizen, bank outside the 9/11 Patriots Acts and IRS and my primary care physician license they tried to take away a few years ago but now we all receive them with our names written in Upper/lower case, ie: Steven Otis Shiver instead of STEVEN OTIS SHIVER. If ya don't here from me for a spell likely in jail again for a time.

Hi Steve, maybe you should look around for some good used head gaskets. RE use them like I do. Nothing like using the proved item [ joking of course but we have to have fun eh.]

Please be careful what you say on this forum, you know there is always a bad apple in every bunch and the prick might be looking at this site. I think a lot of us might be sorry to see you disappear. [ of course you were joking WEREN'T YOU ]
Must have that beer some time. [ come over to nz for our rally next year. Kerikeri-Kaikoura-Little Whanganui. only about 950 miles for me ]

Oh I've gotten all the good out of Trixie Combat copper one after glowing orangeish-yellow but after like 5x's its apparently been beaten down in its thickness consistency. Could be gas jet cuts in head but ain't had low mood enough to get that far in again. I'm about done with gaskets in both my Cdo's and just follow JSM wire, superglue and Hylomar. Jim said contact cement best he's tried but I shy-nay run away from anything with glue in the name on case covers or head. I just got a photo of JSM pistons with coatings done and don't seem like enough sidewall to apply oil recesses to matter. I got Hillary Clinton when Sec. of State documenting me as lawful American National w/o a legal presence in US so only place they can deport me is back where I want to be left alone in. We only got so many weekends left so focus on making good memories eh.