#21 - Life Saving Failure

As many know, I was on the way home from a nice ride down the coast and snapped my cam chain.

While this would normally be a horrible thing, in this case, I got lucky and no major damage from the chain break occured.   On the other hand, I did find a shim had eaten nearly completely through one of the Ti Retainers and was ready to be spat out.  I also found the intake valve clearances had shrunk considerably from .008" down to .001" on the worst valve.  It appears the cam chain snapped just before other things started to cause carnage!

As a result I am changing Cams, Springs, Retainers, tensioner, cam chain, and tensioner blades to different parts, not just replacing them with parts that will fail again.

This gets to the design philosophy of the original Carpenter 265 kit.  While it makes good power and it runs pretty well, in my opinion it has some fundamental flaws, all of these changes should fix those issues.

Springs will be a good bit lower rate than the 100lb seat pressure and 220lb open pressure springs that were installed.  No need for such strong springs when the valve+tappet+shim+retainer+collets only weight 70 grams combined.

The cams going in are both higher lift and longer duration, yet have more gentle ramp rates and won't be as violent with the valve train, allowing for lighter springs to have better valve control.  They're also not regrinds, they're billet, so should flex less at high RPM as well as have the OEM base circle, making for shorter shim use, all good things.

Here's a visual comparison new cam at top:

While researching the cam chain I found there was a change in 2010 from a full strength chain with 4 then 5 plates per link alternating to a waisted chain using 4 full them 3 full and 2 shortened plates per link.  I'll be using the older, stronger design coupled with the better blade design from the Roadster to hopefully achieve the best system possible, strongest chain paired with most gentle blade curvature.





Finally, the graph below is the prediction from enginesim on what the torque curve will look like with all this done, numbers are flywheel:

Hopefully this shows up and is realized once assembly is complete.  This chart doesn't account for significantly lighter valve springs, and it's set using 92 octane pump gas, so there should be around 7% more than this available with the right fuel.  To normalize the above to wheel values use 0.875 multiplication factor.

#20 - Refining My Modeling Software

  Thanks in no small part to the man in the tin shed, I've been able to improve the accuracy of my Rocket 2294 engine model in my software.  It's now quite accurate in predicting flywheel power of various engine configurations, from mild to wild.

As a result, I've now been able to finally settle on the intake configuration I'll be designing for, years after I started this project!  Long has the problem of runner length been problematic for packaging on the Rocket III.  I think I've finally come up with a solution to the problem.

Since I'm not a math genius and not an engineer I am using the Chrysler Ram Induction model so the formula for length is this:

(y / 60) 360 = x 

z / x = t

t*1125 = d

d/2 = L

L / f = m

x = crank degrees per second

y = RPM for desired torque boost

z = 720 - cam duration

t = time between intake valve closing and opening at target RPM

d = distance traveled by wave during t

L = length of runner required because sound must travel up, then back down

f = number of times the sound wave will travel up and down the tube

m = the actual runner length to be used

Since I've not yet disclosed the cam size I'll be using, I will not provide the formula with all my variables plugged in. Suffice it to say that 20" long runners from the TB to atmosphere add a considerable amount of torque below peak without destroying top end. 

Here is the estimated plot of using the 4" velocity stacks in Yellow/Pink vs 20" runners in Green/Blue vs the 4" runners on the smaller intake cam. 

It provides not only a big boost in bottom end torque, the area between 6000 and 7000 sees a little bump in power, and peak is up by 8whp.  The 6000-7000 range is critical in this effort as it's the area the record will be set.

#19 - 2020 Prospects Looking Better

  Made a trip to the flats today, what an amazing place.  It's worth so much to put your bare hand on the salt and understand what the surface is, how it feels, that's it's hard like cement but still slightly gives under pressure.  Most of the area was a shallow lake still, it's early in the season, but there were dry spots where one could get a feel for the salt.

  2019 is unfortunately out, a series of family and personal health issues combined with other factors, have made it impossible to attempt a land speed event this August.

  I can't describe the feeling while there, but, I feel the pull, the draw of the place.  It's a strange kind of tension, the possibilities, the potential of the place that I find powerful.

#18 - Time to Make a Decision

I've recently switched positions in the military, and, I now have confirmation that the final week in August is "white space" on the calendar.  Up until now, I've been patiently waiting to find this last piece out before moving forward with the plan.

This was the final piece totally out of my control.

The list that remains of prep is actually pretty small.  In the next week or so I'll either commit to a 2019 attempt or 2020, I'm going, which year will be mostly determined by finances and what assistance I end up getting from other competitors in the area.

#17 - Prospects looking good

Thanks to a fellow R3owners member, I now have a lead on getting my rear rim modified to 17x6.  So now speed rating for tires will be solved.

Grip, I recently learned the record set by Jason Desilva at 174.xx was done on a custom Dunlop with a seriously slick custom tire.  I'll almost certainly have better grip, being 60lb heavier than Jason, and running a Michelin Power RS tire.

Next piece is all my concern over power.  As it would turn out, both of the record setting Carpenter bikes were 240 kit bikes not 265!!  So I'm already well ahead on that front.

My larger cam is in the mail, so whether I need it or not, I should pick up 10-15 hp above 6500.  Paired with other small changes recently, I expect 270-275 on pump gas.

Fairly close to getting to a point where I'm comfortable making an attempt with confidence that I can not just set a record, but a new benchmark well beyond the current speed.

Now having final timing for the new intake cam from the man in the shed, I was able to model the change it will make to the power curve.  The new cam should arrive sometime in November and I'm trying to get it on the dyno in early December for tuning and testing. Very curious to see how this matches the actual dyno plot once I have it retuned and tested.  There are three things this doesn't account for, crankcase being under vacuum now, any ramair effect, and race fuel, all of which should add between 5 and 8 percent more.

This is estimated flywheel not wheel power:

#16 - Crank Case Evacuation.... Working!!

My original intent was to use a Toyota 2JZ check valve, they're positive closing and quite robust.  The idea is as each pulse passes by the Venturi in the exhaust it creates a small vacuum which the check valve allows to pass a vacuum signal into the crank case.

As the pressure swings from vacuum to positive it must shut quickly, to prevent exhaust gasses from flowing into the crank case.

The Supra valve is a great piece, but doesn't react quickly enough for this application.  Enter the replacement.

This is a piece with very low opening pressure and a light weight piston.   As a result it can react quickly enough to actually generate a solid vacuum signal in the crank case.  Vacuum is generated even at idle and gets quite strong as RPMs rise.  With the bike actually moving instead on the side stand I expect a very strong signal, at least 5 or 6 inches of mercury.  All told it was $20 for the welding, $6 for steel 3/8 brake line to make the Venturi, and $12 for the UPR check valve.

The UPR part uses delrin for the piston, aluminum housing, and steel for the spring.  Should not have any issues with chemical reactions living in this application.

Even if it only gives me 2 whp, it's a very cheap way to prevent oil leaks, keep the engine oil cleaner, and sneak in a touch more power!  All wins.

#15 - Starting To Come Together

Took the bike out for a shakedown today.  New narrow bars are so much fun! I should have do e this ages ago.  Those I am very happy with, just need to pick up some longer bolts for the risers, in the name of safety.

New increased fuel pressure worked out great, I've had to trim fuel out everywhere, the full throttle ratios have fallen into the 11 or 12 AFR, right what I'd hoped for, now I have headroom.

Steering Damper, great function, almost transparent but removed my higher speed wobbles and the jarring effect crossing bumps and joints leaned over, overall just smoothed the steering response out.

New TPS fixed the erratic activity at 1-2 percent throttle, now it's a consistent response to minor inputs.

Throttle body balance improved the feel a bit, they're "exactly" right now.  All even vacuum across the three.  I removed the vacuum reservoir I was trying, no appreciable effect with or without.

Going to 9 range plugs instead of 8s, and coil on plug conversion yielded a much sharper throttle response than before, it's snappy as all hell, a little sharper than I want actually.  I'll be pulling some timing out of the 1200-2200 RPM range, it's hard to ride smoothly at the moment.

The ride couldn't be all roses though, brake line banjo leaked, front brakes went away.

Crank case evac setup needs a different check valve, the Supra PCV allows too much back and forth flow with the pulses of the exhaust, at least at low RPM.

Mix is quite lean at 1-2 percent throttle from 1800-2400, where I was having issues with the TPS, but, since it's consistent now, I can tune that out finally.

Starting to look and feel like a land speed bike, when it gets cold, I'll drill and wire all the requesit bolts and nuts, and Fab up the number panels / mounts for them.

Mufasa is an absolute bonkers bike, rowdy, angry, and a hell of a lot of fun!  Really looking forward to bigger came that'll bleed off some of the extreme compression ratio!

OH and then there's this, which I am going to tear down over the colder months and do some prototype work on :P

#14 - New Cams, New Software, New Priorities

With the discovery that there are bigger grinds out there, I’ve started playing with Engine Analyzer Plus and Pipemax to better understand the relationship between cam specs and output.  The cam setup  I’ll be swapping up to trades about 5 lbs-ft below 5500RPM for big gains over 6000RPM.  Carrying the post peak torque power much better.  If I’ve gotten the numbers in the software right, I should see peak HP gains in the 20-30whp range, and peak torque arriving right at 6500, which is right at the current land speed record.

As a result, my intake project has moved up in the priority list, I want that extra torque, even though it chokes the top end off a little bit.  This simulator cannot account for any sort of ramair effect, so the potential 3% gain seen at 150mph and up is not reflected, which, will put it even stronger on top than the plot with no plenum but with big cams.

Pic. Blue/Green - Current Build + new cams + Plenum || Teal/Red - Current build + new cams || Purple/Yellow - Current build

Pipemax showed numbers dead on to what Les Laidlaw built for me, optimal primary length between 20.6 and 23 inches, actual headers are 21.5” primaries.  Diameters all match up as well, so, props to Les, whether you used the software or not you nailed your design right out the gate.

Where the rocket motor seems to be most limited using the software is, honestly, stroke.  By increasing the stroke 6mm, the simulator  anticipates a gain of 30 pound feet from 3500 to 5000 and it carries between 10 and 5 pound be more from 5000 until 8000. Those of the kind of gains that make a motor more fun to ride because the mid range torque makes it feel a lot bigger than it is.

#13 - Some Secret Sauce Sprinkled In

I won't divulge who or any details, but I've been approached by someone with an offer to provide more camshaft :)  Who could say no to that?

The new intake cam will be both more lift and longer duration, advertised duration will pass 300 degrees on the intake cam, and nearly 300 on the exhaust.

Suddenly my goal of 275whp or better just got that much easier, and, if I'm right I'll end up closer to 300 whp than 275whp in race trim using Bonneville gas class fuel.

I can't wait!

#12 - Things are starting to take shape: Race Bar Mockup

I got my tiny bars in today.  Mocked them up and they work without hitting anything, but just.  I need to reroute the cabling and brake line to remove strain on them, but I think they're going to work well. I can "just" get my head in behind the gauges and be all stretched out on the bike, in a good tuck.

Please disregard the mess in the shed.  Oh, and I got my (enormous) steering damper mounted, that'll be replaced with a smaller one before race day.