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PostPosted: Mon Mar 25, 2013 6:29 pm 
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So 49cc speedchaser dome would be ok for this setup?


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PostPosted: Mon Mar 25, 2013 7:28 pm 
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Hello "H", Do not know as of yet the prelimb numbers are 7.68 for the 42 cc head and 6.3 to 6.6 for the speed head. I assume all your degree numbers are ATDC in the rotational direction of the Engine running? Still working on the math. I also assumed you deck is close to zero now? If you could, measure down from deck in inch or mm to port opening on the exhaust and transfer. Thanks.

AT 81.5mm bore the stock head gasket will be border line for a zero deck. Make sure it it centered or it could come in contact with the piston. Compare gasket ID to the bore. A cometic 82mm gasket may be better and if used in conjunction with the speed head may be a better combo depending upon thickness of the gasket. I can figure it in if I had a number for the compressed thickness of the cometic. It will however reduce squish clearance over the stock. I 'll keep crunching.


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PostPosted: Tue Mar 26, 2013 10:59 am 
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adnoh wrote:
Hello "H", Do not know as of yet the prelimb numbers are 7.68 for the 42 cc head and 6.3 to 6.6 for the speed head. I assume all your degree numbers are ATDC in the rotational direction of the Engine running? Still working on the math. I also assumed you deck is close to zero now? If you could, measure down from deck in inch or mm to port opening on the exhaust and transfer. Thanks.

AT 81.5mm bore the stock head gasket will be border line for a zero deck. Make sure it it centered or it could come in contact with the piston. Compare gasket ID to the bore. A cometic 82mm gasket may be better and if used in conjunction with the speed head may be a better combo depending upon thickness of the gasket. I can figure it in if I had a number for the compressed thickness of the cometic. It will however reduce squish clearance over the stock. I 'll keep crunching.


The piston is now below deck but because of the radius of the piston its almost impossible to tell how much by measuring my guess is .010 to .015 below deck I have no way to accurately measure it.

Number on top of the piston is 77550

From the deck to to the top of the exhaust port is 1.541"

You should see the exhaust port they made the opening bigger but only for about 1/4" past the face of the cylinder wall, then the exhaust port tunnel sharply tapers back to the stock port tunnel I.D., its like soon as they got past the cast steel and met the aluminum they tapered it back to stock not sure what the point of making the port opening bigger if you have a sharp taper shortly after all this does is disturb the flow, they made a nice funnel, not even sure how they were able to get a tool in the cylinder to cut it like they did.

Thanks

EDIT: I tried to get a picture of the exhaust port showing the way they enlarged just the opening basically just made a huge bevel... Makes no sense at all goes against everything I have ever been taught about porting and flow.


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DSCN0520.jpg
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PostPosted: Tue Mar 26, 2013 5:26 pm 
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Pretty cool though. I was working with the numbers a a red flag cropped up, the blow down seam to at 36 degree. I am gona have to work on T for the two piston positions( spaced and un spaced) to see if that is why. Gota admit this one is a fun one.

Thanks for the numbers and pics.

I have 81.13 mm (3.194 in) OD and .71 mm (.028 in) thickness for the stock head gasket. 3.67 cc,s

I did some deck testing a while back I will pull out of file and see where were at.


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PostPosted: Tue Mar 26, 2013 7:59 pm 
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With all these numbers would it be possible to just run a thicker base plate? I know it doesn't change the porting but....I don't know much. Just askin :)


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PostPosted: Wed Mar 27, 2013 10:25 pm 
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Every one look this over and see if it looks ok before I go on. These will be the base line numbers I work with as I get into the port timing.

I have a 2 cc issue sow i will go back and review my multiplier for piston dome volume for wiseco 81.5.

Adnoh


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rppjr base line number.pdf [156.43 KiB]
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PostPosted: Thu Mar 28, 2013 9:57 am 
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adnoh wrote:
Every one look this over and see if it looks ok before I go on. These will be the base line numbers I work with as I get into the port timing.

I have a 2 cc issue sow i will go back and review my multiplier for piston dome volume for wiseco 81.5.

Adnoh


So I would need to use a 43cc dome?


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PostPosted: Thu Mar 28, 2013 1:21 pm 
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hoser wrote:
adnoh wrote:
Every one look this over and see if it looks ok before I go on. These will be the base line numbers I work with as I get into the port timing.

I have a 2 cc issue sow i will go back and review my multiplier for piston dome volume for wiseco 81.5.

Adnoh


So I would need to use a 43cc dome?


I think he talking the cc of the dome with minus piston volume

speed


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PostPosted: Sun Apr 07, 2013 9:52 pm 
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Ok finally got my head somewhat wrapped around this thing. Yes I gave myself a headache time to share some of my pain.

This Engine has a few things that set it apart for most of our fl400's."H" has already listed them with numbers and even degreed the Engine which I did confirm with him to be sure I was on the right track. I will post up a pic and pdf of the degree wheel relationship to the EXO/EXC/TRO and TRC.

The common dominator is simply the piston. The piston cannot (pretty sure anyway) be a stock or wiesco fl400 piston. First let’s look at the cylinder and why it was milled down so far and compare the thickness of the plate and gaskets. This is to accommodate the removal of material from the piston skirt or the difference of the piston skirt compared to the stock piston. The piston skirt in the Engine has to have or be shorter to accommodate the Gudeon pin offset (wristpin offset), there’s around 2 to 3mm reduction to account for. Also when you do this the cylinder has to be raised in order to keep the exhaust port closed off at TDC (Top Dead Center). The piston also may have a higher or lower pin center than stock which may account for some of the change.
Now for the fun stuff, with the wrist pin offset the crank angle tells the story the degree wheel does not. This puts the crank angle at BDC around 176 to degrees ATDC. Normally when looking at a degree wheel BDC is 180 degrees. When you move the piston pin center one way or the other (toward intake or towards exhaust) the crank pin is either before or after BDC depending on the rod angle in relation to the crank centers. When you do this it also will pull the skirt lower in the bore than if there was not any offset. Basically more offset less skirt, if not the skirt will hit the crank at BDC depending upon the rod ratio. Another thing to consider when you do this, the piston will not travel up the bore the same distance as the stroke from BDC. Again the crank angle will not allow the piston to travel the 79 mm in this case and this will affect the swept volume for the CCR (corrected Compression Ratio). This will also change the distance from BDC to EXC and have an effect on CCR as well. The pin offset will also change the speed the piston travels per degree of crank rotation and be different from ATDC to BDC corrected first cycle and from BDC to TDC (Top Dead Center) on the second cycle (2-cycle Engine). This also explains the large blow down time in degrees to help scavenging. This also increases Dwell time at TDC (Top Dead Center) and at BDC and could account for high rpm pumping loss if the transfer ports are not raised enough with an increase in angle. The down side to this much offset is the piston thrust and the force on the skirt. This should be visible on the cylinder and the piston in terms of wear.

When looking at the degree wheel ( pic/pdf) remember the port roof in the cylinder from deck is fixed and the degree numbers are different. So it has to be a crank angle calculation to account for the difference. I Also “H” you can check the deck by using a filler gauge and laying it on the piston crown. It is not exact but will get you close.
Now with the exhaust duration at 180 which seems to be low and with transfers at 128 it appears to be a high rpm Engine design. The 180 seems low however with a high short LT rpm pipe the return wave would be fast and the angle area likes the value on the lower side of the scale for the larger bore. If it had to long of duration it would require a richer mixture or longer LT. The higher transfer number looks good for the pumping loss it may have at high rpm. I would check the exit angles of the transfer and the intake boost port roof angle if you change heads. The more you center the combustion chamber the greater the boost port angle (speed head note). In the above LT for a torque (lower rpm) pipe you would want a longer EX duration or you stuffing charge may be weak and your over rev would suffer if pushed past 7600. So rev delete and torque pipe longer duration or high side of the angle on angle area.

This is just an assumption as I do not have the Engine to check and see. It is just what I came up with based on the numbers. Heck I could be way off.


Attachments:
File comment: Not exact but close
Rppjr port degrees.JPG
Rppjr port degrees.JPG [ 69.85 KiB | Viewed 1312 times ]
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PostPosted: Tue Apr 09, 2013 8:16 pm 
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[quote="adnoh"]Rppjr, Thanks for the information, more the better as it all important. In order to be as accurate as one can there's a lot to account for. Please keep in mind I'm no professional in any way just a shade tree back yard hacker.

I have logged all the info I could from this post and started going through it. The first thing that smacked in the back of my head was the spacer/deck cut numbers and the picture of the piston above deck. I would say this is the very first thing I would need to get straight. My reading and comprehension skills are a little lacking to say the least so I will need "H" and other to review what I come up with and correct me.

When we talk about piton and deck height or piston deck height, what were looking at is the position of the piston at TDC (Top Dead Center) ( TOP Dead Center) or the piston at the top of the cylinder. In the case of the oddy and pilot the piston is crowned (not flat) the piston edge at the crown is what I'm looking at. In case of the ody and pilot stock this edge is below the cylinder deck (flat part of the cylinder at the top). From that edge to the heads flat or recessed edge is the squish clearance. The when you place the head gasket between the cylinder and head it will increase squish clearance. When the Piston Deck Height is above the cylinder or Positive it decreases the clearance. This bring us to the first question and the numbers in the PDF.



^^^^^^^^^^ SHADE TREE BACK YARD HACKER MY ARS!!!!!!!!! ^^^^^^^^^^^^^^


At this point I'm thinkin you build top fuel dragsters for John Force!!!! You might have some of these other guys fooled, but not me buddy! hahahaa


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PostPosted: Wed Apr 10, 2013 12:33 pm 
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Location: Wichita ks
Easy Pro-Pilot-Popper, I have meet Mr. Force however I doubt he would remember me. As far as a job that would be way cool. Heck I would love to work for any Engine builder and learn. I have no issue with using a broom. They may find it strange as I sort the trash and go through it.

A little story about our meeting. I watched the news one day and they were talking to the track officials and driver/car owners at Topeka K,S. They were talking about the attempt to break a record and how conditions were right for breaking this record. I went UMMMM, so I went off to Topeka to find out why. Came home with a better understanding of Altitude,air quality and conditions as they relate to Engine performance. I also learned a touch about traction. Who better then Force to discuss Force. No did have a discussion however did have a few chance to listen to him talk to his crew chief. I did walk away with more questions than answers but that is how we learn. The funny thing is that weekend is when I found out I had dyslexia. Adnoh= Honda. I then found myself on the right path to understanding the way things worked or at making since of what I read. Read = Red to me, Yes a Honda color and Black = dark. Welcome to my world.

Any way I thought I better post up a coupe of pics and a PDF of the pics for review as how I arrived at my post above.

I worked off the premise that the cylinder hole (port) is fixed. The only issue would be the distance from piston crown edge to wrist pin center. Another item to keep in mind that the BDC # is effected from wrist pin offset.

I posted the pics as the Engine would rotate and the degree wheel would read. "H" use total degrees and I use ATDC and BTDC. Both are accurate just have to change my way of looking at it and the way my charts are set up. I use ATDC/BTDC because of the cycles involved as they relate to combustion and cylinder charge. Then timing can be brought into it, easier for me. It also help me understand pre ignition and detonation ect.


Attachments:
82 ATDC.JPG
82 ATDC.JPG [ 19.34 KiB | Viewed 1278 times ]
262 ATDC.JPG
262 ATDC.JPG [ 19.55 KiB | Viewed 1278 times ]
rppjr crank angle post.pdf [113.31 KiB]
Downloaded 73 times
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PostPosted: Wed Apr 10, 2013 10:04 pm 
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Now that I have an idea, I hope of what I’m dealing with I have to make some changes in my math to get some corrected numbers.
First of all I corrected the piston dome volume to reflect the 43 cc reading “H” got when he used the stock head with the bases gasket thickness and spacers.
Next I corrected the port duration based on the degree taken by “H” and the new BDC number. This put the exhaust port duration at 180 degrees. This is important because the Angle Area Mean Line is used in the angle area calculation. What this will do is increase area without altering the port. In the base formula I had port duration at 195 degrees. See the importance. This changes the AAML to 47 BBDC from 48.99 degrees BBDC. This allows for more mm squared for the port to use in time or rpm. Remember why I use BBDC in place of total degrees because I’m dealing with the combustion cycle or how much the port can flow at a given rpm. I arrive at this numbers based on true BDC then subtract EXO from new BDC then divide by 2: 176-82=94 then 94/2= 47 degrees Before Bottom Dead Center(129 degrees).
I will take this and transfer to graph paper and plot the opening. I do this using the posted pdf showing the degree wheel and rod length with the cylinder measurements “H” posted. I can assume a few things from the pictures and ask a question; with the piston at BDC in the cylinder is the crown edge at the bottom of the port as in a normal fl400 cylinder.
Here’s a quick check tip for those reading take your 400 cylinder and place it on a flat surface then slid in the piston. You will notice that the piston crown edge is the bottom of the exhaust and transfer ports or should, If not ask yourself why and start looking. If you look at the piston in the cylinder with it on the case this should be the same unless you altered the base gasket thickness, the piston is different or some has altered the port. Again if different start looking. If the bottom of the exhaust port is below the piston crown static on the bench then you may have a short cycle in that port at TDC (Top Dead Center) unless you space the cylinder of have a enlarged wrist pin offset. So check your exhaust port at TDC (Top Dead Center) upon assembly. At high rpm some short cycle is ok however not desired unless designed in.
Back to port plot. I used the number “H” had taken to establish the port height in the pictures and now with the assumed crank angle I can graph the AAML. I will also include some numbers for bore increase without retaining the port area. This will affect the calculation of port time area. I have set the exhaust port cord width at 70% in the pictures and the bore at 81.5mm.
I also included a pdf of the angle area for the numbers I come up with. This should give one an idea about the exhaust port rpm. The angle area I comes up with is, 5.574757.


Attachments:
rppjr AAML.pdf [81.29 KiB]
Downloaded 112 times
AAML rppjr.JPG
AAML rppjr.JPG [ 19.19 KiB | Viewed 1268 times ]
rppjr (T) and angle area.pdf [218.75 KiB]
Downloaded 123 times
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PostPosted: Fri Apr 12, 2013 6:17 pm 
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I went ahead and did a comparison between what I came up with and then uncut deck and no base spacer. Here is a pdf of the comparison for review and discussion. It clearly shows a rpm diff for the exhaust port. I will be busy for the next few weeks so I will not be able to work on the transfers until then. I do have a few idea on them though.


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PostPosted: Fri Apr 12, 2013 6:42 pm 
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That's some pretty amazing stuff there. I never figured they were that complicated. I appreciate all the information you are gathering and taking the time to calculate. Do you think a cool head will work or would it be better just to take a stock head and mill it down like the old one. I know it cuts into reliability but just looking for options.
Thanks
Bob


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PostPosted: Sat Apr 13, 2013 11:30 am 
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Good question. It really depends on if #1 if my numbers are correct. A cool head would be a nice addition. It may or may not require a special dome. For discussion sake, lets say the piston is different from stock or stock replacement. "H" has the volume at TDC (Top Dead Center) with stock cut head. Then we would need some additional numbers. We need to look at the piston crown angles verses the head squish angles, area, Engine timing and rpm. Bore and port closure also is factored in. You can see where the port timing play into this. No need to set your head design around the wrong rpm. Why run it higher in rpm than the port can support. If you do it will make noise but run slower. It will also make you head design ineffective.

I have adjusted the piston dome volume to match what "H" measured and it did lower the CCR ( corrected compression ratio) If you install the larger cc cool head it will lower it further (CCR). It would also slow down the msv. Here is where it gets touchy as far as what to do. There is trade off's to be considered and it really depends on your ridding style and components.

Please do not take this wrong as its only for discussion. If you build a race motor (( Internal Combustion Engine ? )) and operate it like a play motor (( Internal Combustion Engine ? )) it will only go south on you. Basically there less forgiving. With a high performance Engine you have to be on top of it all the time, you get lazy and rut ru. Usually the builder set the design around a discussion with the owner. Couple of reason for this as the builder does not want the owner coming back on them and they also want the owner to get what they pay for. If the owner say I can operate it at the higher level then so it will be built with less safeguards. If the owner uses the wrong fuel or old fuel etc and blow it up it hard to blame the builder. Then one will de-tune it to operate with the limits of the owner. This happens more than one thinks. I personally know shops that will change the gasket thickness as they over bore with telling the owner. I have seen them look at the damage and make an assessment on how the owner runs the machine and make adjustment without saying a word just so it does not come back.

Time for a short story, I built a small block a few years ago and the owner which was a friend of a friend drove away happy. However not for long as it came back. Yep smoked it and blamed me. I fixed it however this time changed a few things. What I found out he did was after running it a few times he had a buddy that said if you advance the timing it will pull harder off the bottom. Need I say more, for some reason the owner failed to mention that. It did pull harder for a couple of runs then the pre igniton and detonation tore it up in short order. These was no knock sensor on that Engine. You can see how a lot of time no one will give you a solid answer. Live and learn type thing.

Back to your head. "H" would make the final call and I do mind throwing out numbers as long as one considers that there only a guess. I also base the numbers off of what I do and what is supplied even then it still a guess.

Based on the area numbers for rpm and the CCR I would look at a lower squish area ratio with an increase in angle. This will reduce peak torgue a touch however run stronger on top. Th MJ will be under square when compared to the MS and change the degrres BTDC. The degrees at which max MSV is at related to the Engine timming at full retard is important.
You can simply make a 1 to 2 degree change and make all the difference. One need to look at the pistons position when spark ignition occurs and the lag time of the flame front (flame speed). See how fuel works over gas. If your msv in degrees is to advanced the retard in flame front via the flame kernel/fuel can help correct. You can also see where (T) plays into this. As the Engine speed up in (T) it will effect combustion and related combustion events.

I suggest one goes to any online calculator and run the compression numbers based on what "H" provided. Then make adjustments to get the CCR where you would want it to run at a given rpm then enter in this data to a head program.

He has given bore, EXC, and total volume at TDC (Top Dead Center). The rod is 144 mm. When you do this make sure to note the base and head gasket information. When looking at squish clearance consider the head gasket squished thickness and the yet to be a documented deck. Since we do know hat number yet use zero as "H" noted with the proper base gasket/spacer in place the piston is now below deck. The EXC and deck to port opening number was taken with the piston below deck so your margin of error is less.

Also remember this is with out the new piston in it (I do believe), final numbers are based off of the final assembly. Change the piston type,etc change the numbers.

Kinda sounds likes I 'm passing the buck, don't it. I'm not just trying to help others have an understanding of the numbers. Just because it worked on one Engine does not mean it will work on yours. I got some piston to show that.

What I come up with as far as CCR is 7.0524, Based on what I see so far I would looking at 1mm squish clearance,45% squish,4 Degrees with a CCR @ 6.8 for starters. I based this off I have read and calculated for a dune Engine (non drag race).

Parts. Rev pipe, large Carb, Low primary CR, Multiple angle, large tip area ratio, low reed lift valve, Light clutch/rotating assembly and heavy rear tire load.

Keep in mind its just a guess from a Back Yard Hacker.


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PostPosted: Sat Apr 13, 2013 1:23 pm 
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I was just throwing those ideas out there. I will go with whatever you and Hoser recommend. It will be used primarily as a dune motor (( Internal Combustion Engine ? )) with a little bit of desert and track thrown in just for fun. I don't race anymore, I just like to go have fun. First,second whatever doesn't matter to me anymore. My daughter is getting into riding more and more and I want her to see the fun side of it. I am mostly looking for something that will be reliable in the end. I don't mind wrenching on stuff but I don't go out of my way to tear it apart just because..
Thanks
Bob


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PostPosted: Wed Jul 17, 2013 7:29 pm 
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Hello Hoser, wondering how the work was coming along. I have the funds for the motor (( Internal Combustion Engine ? )) and shipping. Let me know if there was anything else needed. Can't remember if it was myself or PPP that contacted you and discussed what we were going
To do with the Head.
Bob


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