Board index

My Home Page

PilotOdyssey.com By hoser...


PilotOdyssey.com Chat Room

PilotOdyssey.com Photo Album

* Login   * Register * FAQ
http://www.pilotodyssey.com/PO/adm/images/imagemenu/smiley_cool.png PilotOdyssey.com Chat    http://www.pilotodyssey.com/PO/adm/images/imagemenu/find.png PilotOdyssey.com Google Search    http://www.pilotodyssey.com/PO/adm/images/imagemenu/emoticon_tongue.png FL400 Parts    http://www.pilotodyssey.com/PO/adm/images/imagemenu/emoticon_grin.png FL350 Parts    http://www.pilotodyssey.com/PO/adm/images/imagemenu/emoticon_evilgrin.png FL250 Parts    http://www.pilotodyssey.com/PO/adm/images/imagemenu/emoticon_unhappy.png Admin Email    http://www.pilotodyssey.com/PO/adm/images/imagemenu/emoticon_grin.png PilotOdyssey.com V2.0   
It is currently Wed Aug 16, 2017 9:37 pm

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 7 posts ] 
Author Message
 Post subject: New DCP to end #3
PostPosted: Sun Dec 27, 2015 3:35 pm 
Online

Joined: Fri Jan 12, 2007 2:17 pm
Posts: 2838
Location: Wichita ks
Good morning all board members.
Well since some have and some have not I have been off board for a while, busy as all get out. I thought I would provide some after holiday reading regarding my Mudd piston experiments. Doing so I have accumulated a lot of Engine data to which I can share some of the cool stuff with you. As most know I have four pistons to play with in a variety of combinations. My latest prior to cold weather setting in was MUDD #3. This piston received a coating that allowed to piston to fit the bore during running operation. The factors involved was how and when to set the wear pattern on the piston in relation to the bore. Sounds easy does it not, however lets regress a touch. What is one of the issues related to the Wiseco and its relationship to the bore in our machines? Ok I know there’s more than one. For this topic I will choose a cold environment in a static fitment to a running Engine in a dynamic one.
If one has been reading and keeping tract you will know I posted a super crazy thought about coating and negative fitment in regards to piston to cylinder clearance. I bet most thought Adnoh has lost it and finally went off the deep end in Engine theory. Glad to report I have a clean bill of health with a test under my belt to prove otherwise or otherwise so far so good. I used once again the DCP pilot Engine for this test so I have data on past data to relate it to. This will or could help if an issue would to arise by limiting some variables. Piston #3 received a full skirt coating of a hush-hush type for now due pending results. So I fitted the piston with proper ring end gap and zero to negative piston to wall clearance in way of coating. To achieve this one would set up the Engine with piston clearances based on performance or output levels. For my set up I set the pre coat clearance and ring end gap to my likings than have the piston coated to achieve a negative clearance. Once I received the piston back I altered the coating to a desired fitment for the cylinder. The reason for fitment would be remove some excessive material that will be worn away anyhow.
For those not so versed in piston geometry. The piston is not round and has camp and barrel ground into it from the factory for a given shape at a given load. This is where most of us muck it up. We either fit it poorly or fail to control the shape via load. Granted there are a lot of configurations that will yield a load that the piston design does not like. After all it’s a forged one piston design does it all type of thing. Back to the pistons camp and barrel. The coating does away with this as the piston now has full skirt area in contact with the cylinder wall. This area is the area below the rings and ring land area. Why does the book tell us to measure the piston where we do? Because, this is the fattest part of the piston due to its taper and out of round configuration. Now instead of a portion of the piston making contact with the cylinder we have a much greater area touching the cylinder. When we look at friction in % and area would we now after coating have the friction force spread across a greater area reducing the %. This would achieve less scuffing based on less load at a given point or area%. Time for am experiment, take your two index fingers and run them together back and forth. Now take the palm of your hands and rub them together. Here’s what should happen, you friction area has increased and the palm of your hands should slide easier with more heat transfer. By the way did you notice your finger tips rock back and forth? What happens to the shape of the piston with less heat transfer as it retains more and more heat? Does it not grow in size and change shape. Also ask yourself this with a hot piston and a cold cylinder does the cold steel sleeve resist shape change and the aluminum forged piston have the opposite effect. See how the seize co came about. Appling the hand rub theory do we not take heat away from the piston and apply it to the cylinder to which that heat can be extracted to the atmosphere via coolant/radiator or fins of an air cooled jug. Also keep in mind the how we lubricate the cylinder. Would we want more surface area for an increase in boundary layer protection? Holy cow bat man, we can now run a hotter Engine and by that I mean extract more power without failure. Another area to touch on would be piston rock. Would this also improve ring life and seal based solely on, the greater the piston thrust surface area and with less piston will rock. The less we rock the piston the less the rings will twist in there grooves. Now we combustion twisting the rings with less piston rock that will put an edge on the rings (shaper edge) leaving us with a larger ring surface area in contact with the cylinder. Now we have greater heat transfer and better ring seal. Pay attention to ring surface area and shape when you disassemble and Engine. A barrel face is a good one a sharp edged one is a bad one. That alone can tell you a story. A high performance Engine with bad ring seal will go away quickly from poor heat transfer. When the rings fail to transfer heat the piston retains more heat. We already discussed what happens when a piston retains heat. Yes, its size increases and the boundary layer according to friction area% will lead to scuffing and failure.
There are a few things to consider when taking this approach. I had to guess on where and when I wanted my set up to run in or at what load at what temperature I wanted my final coating wear to be on the piston. This is where Engine parameters come into play. I have acquired data for my Engine design and base decisions upon them. In my case my operating Engine coolant temperature is around 175 under load conditions. I have ran as low as 160 and as high of 245 without failure. Each is its own animal believe me. I would rule out 245 if I was you. Depending on your dynamic CR you will not last long in a stock set up pilot. In this test I ran 174 degrees at 7950 rpm and speeds around the yard of up to 45 mph. I also cold ran this Engine, by that I mean I put it together started it for a heat cycle to be sure coolant and other item were in check that ran it. I do not recommend this to anyone as I am experimenting. My goal was to do the first wear at cold run condition to reduce cold seizure and than do a final wearing to load conditions. The goal being the coated piston is now fitting the cylinder in a dynamic condition for maximum surface piston to cylinder area.
There is another kind of cool thing to add here. Let’s say you have a slight Engine issue. Take you old Wiseco piston clean it up and have it coated and fit in a new set of rings. Holy cow $85.00 compared to $185.00 if the piston is even available, I know what I would choose. There is another option out there as well and yes I have had one done being tested right now by another board member. I took his 80.25 mistake which need to go to 80.5 and turned it into a plated 80 mm with new coated piston. Yes I made the mistake and felt responsible to fix it without further over bore. Time will tell if I did him justice however I gave him a 300 hr guarantee on that piston and cylinder. That Engine should run 100 hrs before re-ring. Than new hone and rings three times before bore back to 80 and new coated piston. I can even opt to have the piston recoated for the next ring cycle if need be. Time will tell if I’m all wet.

Video of test around yard: https://youtu.be/8rb33bPEyuo


Attachments:
Coated pisdton and cylinder .jpg
Coated pisdton and cylinder .jpg [ 40.41 KiB | Viewed 358 times ]
Coated piston in cylinder fitment.jpg
Coated piston in cylinder fitment.jpg [ 36.46 KiB | Viewed 358 times ]
Top
 Profile  
 
 Post subject: Re: New DCP to end #3
PostPosted: Mon Dec 28, 2015 12:46 am 
Offline

Joined: Tue Jan 17, 2012 3:19 am
Posts: 3852
Location: Hope, B.C Canada
adnoh wrote:
Also ask yourself this with a hot piston and a cold cylinder does the cold steel sleeve resist shape change and the aluminum forged piston have the opposite effect. See how the seize co came about.


Your not making fun of me are you ?? :-)


Top
 Profile E-mail  
 
 Post subject: Re: New DCP to end #3
PostPosted: Mon Dec 28, 2015 12:47 am 
Offline

Joined: Tue Jan 17, 2012 3:19 am
Posts: 3852
Location: Hope, B.C Canada
Man your on some heavy stuff bud :-)
But glad you are on our team.

Here is something for you to shoot at me about -- my Engine has .007 clearance and my brothers has .005 clearance ( I had them bored that way as I got tired of doing rebuilds on engines I knew nothing about). We run 100LL avgas at 50/1 Castrol mix. They now run great and we don't warm them up -- just fn start n go. Now that I know very little instead of fn nothing about these engines the next time they need rebuild I will go .004 clearance. In my opinion all they needed was liquid cooling and Avgas. The temp never goes over about 145' F.
PS: I like reading your ramblings on these engines.


Top
 Profile E-mail  
 
 Post subject: Re: New DCP to end #3
PostPosted: Thu Dec 31, 2015 8:01 pm 
Online

Joined: Fri Jan 12, 2007 2:17 pm
Posts: 2838
Location: Wichita ks
no not poking fun at you. I.would stick with works for you. I would give some thought to CHT and go from there.


Top
 Profile  
 
 Post subject: Re: New DCP to end #3
PostPosted: Tue Jan 05, 2016 10:30 am 
Offline

Joined: Tue Jan 10, 2012 10:21 am
Posts: 2646
Location: NW Ohio / SE Michigan
Fun stuff. Slack-time well spent reading this in a training class, lol.

Mystery coating, eh? Hmmm...
E-coat?
PTFE?
Moly?
DLC?
Cera?
PC9?


Top
 Profile E-mail  
 
 Post subject: Re: New DCP to end #3
PostPosted: Tue Feb 02, 2016 8:29 pm 
Offline

Joined: Thu Jan 28, 2016 4:32 pm
Posts: 8
DMoneyAllstar wrote:
Fun stuff. Slack-time well spent reading this in a training class, lol.

Mystery coating, eh? Hmmm...
E-coat?
PTFE?
Moly?
DLC?
Cera?
PC9?


Top
 Profile E-mail  
 
 Post subject: Re: New DCP to end #3
PostPosted: Tue Feb 02, 2016 11:23 pm 
Offline

Joined: Tue Dec 23, 2003 10:31 pm
Posts: 5508
Location: New Jersey
Amazing work indeed, I love reading these testings. I am also glad to know the pistons worked out in the long run and the testing here will provide myself and others with valuable information in options for these types of pistons and current bores, clearances in multiple environments. Great stuff !!


Top
 Profile E-mail  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 

All times are UTC - 5 hours [ DST ]


Who is online

Registered users: adnoh, badbob66, Baidu [Spider], Bing [Bot], Brittabrat, bullnerd, DarkAngel, ez71pilot, fuesselfc, Google [Bot], hoser, jknarfal, Jordant, MPDano, New To Odesseys, Q, rmesser, RoboRex2005, Threerivers, xlint89, Yahoo [Bot]


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group