Author Topic: Team Go Dog, Go! Modified Partial Streamliners  (Read 775950 times)

0 Members and 4 Guests are viewing this topic.

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 4940
  • Age: 65
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2535 on: September 09, 2016, 12:28:25 AM »
This book is available from the Society of Automotive Engineers.  It does not have an ISBN number.  It covers a lot of topics about cams and valve trains that will help a person be a more informed consumer.  It is an important reference for me.  I will be evaluating digitized cam profiles, lifter and cam material compatibility, cam follower motion like displacement, speed, acceleration, and jerk, etc.

Offline 4-barrel Mike

  • Hero Member
  • *****
  • Posts: 2968
  • Age: 71
  • Location: Portland, OR
  • Any fool can drive a V8
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2536 on: September 09, 2016, 12:32:59 AM »
http://books.sae.org/b-966/ $149 list (printed), currently on backorder.  None on eBay or Amazon.

Mike
Mike Kelly - PROUD owner of the V4F that powered the #1931 VGC to a 82.803 mph record in 2008!

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 4940
  • Age: 65
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2537 on: September 11, 2016, 01:17:03 PM »
Maybe I got the last copy?  It is mandatory reading for someone like me who is working on an odd engine and pushing it to near its limits, or my wallet's, whichever is lower.

The wear failure on my cam is at the point of maximum curvature where the flank makes the transition to the toe on the leading side.  Valve spring pressure is greatest here.  There can be numerous causes for a failure at this location.

The Dynomation program comes with a library of over 6,000 cam profiles.  Likely suspects that give good performance can be modeled and I can ask the grinders if they can put them on my cams.  I can ask for a cam profile analyses and Hertz stress printouts for the lobes.  Also, I can ask for descriptions of the cam facing and recommended lifter materials.  Using this, I can verify if the proposed system will give me the performance I need with durability I can afford.

The camshaft reference handbook gives all sorts of lifter/cam compatibility data and maximum allowable contact stress info for OEM cam materials.  My cams will likely be hard facing or similar that is welded onto the OEM cams that will be sent in as cores.  The handbook does not address this.  Does anyone have any info about it?   

 

Offline Old Scrambler

  • Sr. Member
  • ****
  • Posts: 689
  • Age: 72
  • Location: Wherever I park the RV
  • Going Fast - Slowly
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2538 on: September 12, 2016, 10:03:51 AM »
No help here..........other than welded-up cores are standard procedure at Mega-Cycle and my cam has no wear-marks. I am using standard rockers from a very low mileage motor. 
2011 AMA Record - 250cc M-PG TRIUMPH Tiger Cub - 82.5 mph
2013 AMA Record - 250cc MPS-PG TRIUMPH Tiger Cub - 88.7 mph
2018 AMA Record - 750cc M-CG HONDA CB750 sohc - 136.6 mph
2018 AMA Record - 750cc MPS-CG HONDA CB750 sohc - 143.005 mph
2018 AMA Record - 750cc M-CF HONDA CB750 sohc - 139.85 mph
2018 AMA Record - 750cc MPS-CF HONDA CB750 sohc - 144.2025 mph

Chassis Builder / Tuner: Dave Murre

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 4940
  • Age: 65
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2539 on: September 13, 2016, 12:03:25 AM »
This is a link to a number of papers by Gordon Blair and Associates.www.profblairandassociates.com/RET_Articles.html

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 4940
  • Age: 65
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2540 on: September 13, 2016, 12:18:49 AM »
Now, go down the list to "Making the Cam."  The type of valve train in the Triumph is bucket tappet as shown in Figures 1 and 3.  Note the cam profiles and especially Design D.  This aggressive profile is what I was using and need to use.  Note the oil film thickness.  It is less than with the other cams.  Any significant roughness on the cam or follower will break through the oil film and cause the radial scoring on the lifter and wear on the nose where the hertz stresses are the highest.  This is the distress I see.

Polishing the cam will be discussed with the grinder as well as the break in period with light springs.  One or both might be needed to wear and polish down the surface irregularities on the lobe and bucket top so they do not project through the oil film and cause metal-to-metal contact.  Also, using a 50-weight break in oil rather than 40 weight might help.  There is a special coating recommended by Kibblewhite for the bucket tops.  Slowly a plan is coming together.   

Offline fordboy628

  • Hero Member
  • *****
  • Posts: 2231
  • Age: 2
  • Location: Koozebane
  • GONE FISHIN' . . .
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2541 on: September 13, 2016, 06:57:55 AM »
DLC (diamond like coating), is being used on some Pro Level engines with VERY high part loads.

You might want to inquire whether DLC might be compatible with the cam lobe material/finish.

Gird your wallet, it is expensive.

 :cheers:
F/B
I used to be a people person.  But people changed that relationship.

"There is nothing permanent except change."    Heraclitus

"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."     Albert Einstein

Offline manta22

  • Hero Member
  • *****
  • Posts: 3383
  • Age: 80
  • Location: Tucson, AZ
  • What, me worry?
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2542 on: September 13, 2016, 11:07:04 AM »
F/B;

When I worked for Burr-Brown (later bought out by Texas Instruments) we used a diamond-like coating (DLC) on our integrated circuit wafers for surface passivation. I wondered then why it wasn't being adapted to cranks, cams, etc. It seemed like it would be even better than nitriding on journals. It sounds as if someone is using it now.

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 4940
  • Age: 65
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2543 on: September 17, 2016, 12:53:14 AM »
There is quite a bit of information on it on the I-net.  Layer thickness, method of application, and lubricating oil additive package all need to be considered for DLC.  It is an engineered system.  The topic "So close but so far away" in the Technical Discussion group has a link to a good paper on it.

Imagine falling out of bed and landing on the top of your head on something that deforms when you hit it.  The impact load is spread out and it maybe you will survive the fall.  Picture yourself doing the same thing on a hard surface that does not deform.  The impact is not spread out and your head feels the concentrated load, your skull cracks, and your brains splatter.

It may be to my advantage to stay with a conventional softer lifters, polish the cams and lifters, and do the break in with light springs.  Also, I need to be careful and to choose a cam grind that avoids high stresses on the valve train.

Offline Old Scrambler

  • Sr. Member
  • ****
  • Posts: 689
  • Age: 72
  • Location: Wherever I park the RV
  • Going Fast - Slowly
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2544 on: September 17, 2016, 10:44:54 AM »
Race Motor = High Stress

Not too much, but ENOUGH :-D :-D :-D :-D :-D
2011 AMA Record - 250cc M-PG TRIUMPH Tiger Cub - 82.5 mph
2013 AMA Record - 250cc MPS-PG TRIUMPH Tiger Cub - 88.7 mph
2018 AMA Record - 750cc M-CG HONDA CB750 sohc - 136.6 mph
2018 AMA Record - 750cc MPS-CG HONDA CB750 sohc - 143.005 mph
2018 AMA Record - 750cc M-CF HONDA CB750 sohc - 139.85 mph
2018 AMA Record - 750cc MPS-CF HONDA CB750 sohc - 144.2025 mph

Chassis Builder / Tuner: Dave Murre

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 4940
  • Age: 65
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2545 on: September 17, 2016, 01:34:44 PM »
The Hertzian stress values for the cam and the lifter, valve drop and lift speeds off of the seat, and lifter and valve acceleration and jerk will be available from the programs I am getting.  Typical values for drag racing, circle track, road racing, and street are in the user's manuals and literature.  The stresses will be set up for a hot street engine.  Never have I had the desire to build a true race motor. 

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 4940
  • Age: 65
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2546 on: September 18, 2016, 12:20:26 AM »
This starts the 2017 build.  It will use Dynomation 5 virtual modeling.  Folks not familiar with the engine will be watching this.  Various things in earlier posts will be repeated so they can get a full picture of what is happening.  The first step is to measure components to get input data for the program.

The valve stem diameter is greater for the upper section in the valve guide.  The smaller diameter of the section in the air flow is used as program input.  It is 0.186 diameter for the inlet valve.

The combustion chamber type is needed.  This is a pentroof head with a squish band.  Cosworth did some development work for this engine and it shows.   

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 4940
  • Age: 65
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2547 on: September 20, 2016, 12:09:42 AM »
The intake port shapes after the bifurcation are elliptical except at the valve seat.  The area of an elliptical port is as follows.  a = the smallest diameter and b = the largest diameter.  Area = [(a x b) / 4] x pi

The area at the entrance to the intake port just downstream from the bifurcation is 1.01 square inches.  The area just upstream from the hole for the valve guide is 0.980 square inches.  The area just downstream from the valve guide hole is 0.942 square inches.  The inside of the valve seat is 0.963 square inches.

The minimum port area is used to calculate wave dynamics properties.  The intake valve stem obstructs the smallest port area.  I was going to subtract the intake valve stem area from the smallest port area.  Tech support says the stem is not a significant obstruction from a wave dynamics standpoint and its area should not be subtracted.  The minimum port area is 0.942 inches per valve in the data input.

This is the valve assembly part of the valve train.  it is a stainless steel valve, a spacer shim, a spring seat, an inner spring, an outer spring, a titanium spring retainer, and two collets.  Everything is made by Kibblewhite.  The parts can be purchased and installed by the builder.  Kibblewhite installed these.  The reason is they adjust the valve stem length so it is midway in the range of valve shim thicknesses.  Otherwise, there could be problems with obtaining the needed shim under the follower bucket.  They also check spring pack length and other critical dimensions. 

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 4940
  • Age: 65
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2548 on: September 20, 2016, 09:56:45 PM »
These engines are run to over 10,000 rpm in Australia.  The standard valve train is used as a baseline and I will make a simple and semi-accurate analysis to see if I want to do the same.  The valve train stresses are proportional to the reciprocating mass.  Heavier parts make more stress.  The reciprocating valve train is considered to be the intake valve, 1/3 of the valve spring weight, the spring keeper, and the collets.  The stock Triumph setup weighs 97 grams.  The racing system, wit a 2mm larger intake valve, weighs 83 grams.  [(97 - 83) / 97] x 100 = 14% less weight

The valve train forces are proportional to spring stiffness.  Seating force with the Triumph spring is 45#.  The spring force with the race springs and no shim is 52#.  This is adequate for milder race cams.  The spring force with race springs and the shim is 60#.  The shim will be used, so this is a [(60 - 45) / 45] x 100 = 33% more spring force

The standard rev limit was 7,300 rpm.  The rev limit I am using now is 9,000 rpm.  The Aussies are using 10,000.  This is 3,650, 4,500, and 5,000 cam rpm.  The valve train stresses are proportional to the rpm squared.  Squared, in millions of rpm, this is 13.3, 20.3, and 25.0  Using 4,500 rpm, the increase is [(20.3 - 13.3) / 13.3] x 100 = 53% more stress.  With a 5,000 rpm rev limit, the increase is [(25.0 - 13.3) / 13.3] x 100 = 88% more stress.

Adding up the pluses and minuses for a 9,000 rpm rev limit, 33 - 14 + 53 = 72% more  Doing the same for a 10,000 rpm rev limit, 33 - 14 + 88 = 107 percent more.  This assumes the same cams for both situations.  It does not consider the greater stresses from a more aggressive cam or the thinner oil film in a more highly tuned and hotter engine.

I am not sure which way I will go.

   

   dli{(on the      engi

Offline Peter Jack

  • Hero Member
  • *****
  • Posts: 3627
  • Age: 75
  • Location: Calgary, Alberta
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2549 on: September 20, 2016, 10:36:04 PM »
"These engines are run to over 10,000 rpm in Australia."

Remember, down there the valves just fall back into place because the engines are upside down!  :-D :-D :-D  8-) 8-) 8-)

Pete
« Last Edit: September 20, 2016, 10:40:11 PM by Peter Jack »