Sunday, May 1, 2016

Flag is UP!

It's May! 

Only 29 days until the 100th running of the Greatest Spectacle in Racing.


And that means it's kart season.  WooHoo!!


Most of my time lately has been spent working on graphic design and letterpress projects.  ( Selfish plug: tagdesignstudios.com )

Christmas was a "KARTFEST!"  I received many kart related gifts including a new starter ( more of a Pam gift to herself since she will be using it), a GoPro camera, a new smoked helmet shield, two new chains, two new chain breakers, and several new sprockets.  All suggestions from my list.

Compared to last year I am way ahead as we approach Mid-Ohio in June.   Last year I did a full engine and brake rebuild, along with new axle bearings and adding the Digitron.  Not this year.  I will be testing for air leaks, pop-off, and check on timing.  Hopefully, that will be all before heading out.

I know it's silly... but one fun thing I put together over the winter was a new push stick. The one I created a couple years ago was steel tubing and bolted together... loosely. And with the tach/temp Digitron onto steering wheel now, the design was wrong and did not work as needed.  I found aluminum tubing at Home Depot then took it to a local tool/welding shop - Jerrett Welding - near Pam's workplace. The design came from the pushsticks engineered by the guys from Boston.
My new push stick 


The Boston guys' design




One of the problems I had last year was with the left brake.  It was always engaged and would not retract.  And brakes were spongy with only one caliper working effectively.  Over the winter I took an  Airheart brake caliper off the Hartman kart and got to know the mechanism much better.  Doing research on http://vintagekarts.com forums I found out even more from the kart veterans.  I also tracked down a vintage kart magazine article about the magic of Airheart brakes and the legendary "drag ring," which looks like a warped washer. Instead it is a highly engineered and machined means to keep the puck exactly the right clearance as it wears.
The Airheart retaining ring
One important thing was during rebuild to properly align the piston stem through the retaining ring as the piston is pressed back in.  Airheart sells a pilot, but of course I didn't want to spend the $24 for it.  I bought some brass tubing and had Jerrett Welding lathe it down to the proper dimension. Of course, I spent $30 on that.  Oh well!


Another important factor is not to "snag" or "catch" the piston stem as it is pushed through the drag ring. Many vintage guys suggested using a hydraulic press to install the piston (NEVER USE A HAMMER--woops! another rookie mistake), but after investigating and looking at videos on youtube.com I thought that was overkill. So I started thinking about how to make a small one.  Then BINGO! While at an antique store in northern Virginia I saw it... an antique bottle capper!  

It delivers nice, even pressure I can control and also feel if there is any "catching" in the process.  I purchased it for $12. The I made a tool from a PVC pipe fitting which gives a surface to press against during the "press out" process, flip it over, and use it for the "press in" process.  It works great. I am right proud of it!

Last week I took the offending caliper off the cart and worked through a couple things.  I replaced the bolts attaching the caliper to the frame from grade 5 to grade 8.  That's when I noticed washers between the two pieces of the caliper... which should not be there.
Where the extra washers were... 
Why are they there? Then I remembered that last year I had a hard time getting the piston all the way in, which would leave the brake puck sticking out about 1/16"...probably because I used a hammer and socket to "press in" the piston and the piston stem "caught" on the drag ring.  I must have "filled the gap" with the washers. With too much space the drag ring did its job too well and constantly caught the piston stem. NO Wonder the piston would not retract.

I took the caliper to the workbench and I pressed out the piston (the press worked great!), changed the o-ring seals, checked the retaining ring, and pressed it all back together in about 10 minutes. This time the piston pressed all the way in by hand. No need for extra washers.
Looking into the caliper at the drag ring with retaining ring removed
Looking into the caliper at the retaining ring, drag ring, and o-ring seal.
Piston and piston stem. Note the silver scratches on the stem made by the drag ring.

Bolt it back on, bleed it (thanks John Copeland), and all done in under an hour.
To bleed the brakes the master cylinder needs to be above the caliper, so I improvised and used a "get-along" to lift the front of the kart.

Tinkering and figuring out solutions are some of my favorite parts of karting.  OKAY... and racing!

Since I have two master cylinders, I use an adjustable linkage between the two.  Originally, it was designed to bias the front or rear brakes when this kart had four-wheel brakes. I am working on getting the two master cylinders to work exactly together.

With last years problems Van Gilder suggested biasing to the right brake and away from the left sticking one. I am going to ask Rick Chapman if he knows exactly how it works. It seems easy enough, but just making sure.

I have been dreaming of getting an automatic kart stand so I can work alone.  Then during a conversation with Rick he asked if I had a push stick. I said that I did but was dreaming of a kart lift. He has one and offered it to me for a great price.


It has a boat wench action so it will still be some work, but much better than lifting... and looking for help. :-)

One of the problems last year at Mid-Ohio was the chain. I dropped out of two races with a broken chain then a chain off the sprocket that clanged around and damaged the clutch sprocket. It actually cracked or broke off the tips of the hardened steel teeth on the clutch.

I asked Rick about it and he suggested I not use it. Fortunately, I have a second one from Dad's stash, but it did not have the bearing.  I identified it, looked all over for it, then Rick sent me three... for free. I found out how to press-in the bearing with a bolt and nut on youtube.

Due to the sprocket alignment problem last year, Rick suggested giving up on the Lemelo aluminum  oiler sprocket. It is a pain to align due to how it grips the axle.  Dad's stash had another light sprocket but it also had a tricky system.  I started looking for what Rich suggested - a sprocket with one sprocket head bolt for easy alignment. While looking for something else in the vintage stash bin, I saw something...


A never-opened GEM sprocket!  That's real NOS...NEW-OLD-STOCK!  Exactly what I needed.

Even before I got the kart running I had heard of setting-up the carb properly so it four-cycles at the end of the straight. At Mid-Ohio it does fine on the main straight but only lasts about 1/2 of the backstretch. So I sent a GoPro video of me at Mid-Ohio to Steve O'Hara, karting demigod, to ask for help. He was gracious and made two big suggestions:
  1. Since the engine was topping out at under 10,000 RPM, I should move up to a 64 tooth sprocket with the 14 tooth drive gear. This should allow higher revs. 
  2. The clutch was not engaging coming out of corners, so add weight to the clutch arms to get it to grab earlier.

To help with adjusting the carb, I have looked into using a remote carb adjuster.  I bought one over a year ago but had let it sit.  Recently, a vintage forum post asked about them and I joined in. SteveO posted some pictures of a set-up he used with great success using gears from remote control cars:
SteveO's set-up

SteveO's set-up

SteveO's set-up

I have finally found similar gears and am now in the middle making a bracket from aluminum. The larger gear ratio will allow me to get more torque to the High Speed needle for easy and precise adjustment.  We'll see how it goes.
future bracket being cut

19 tooth, 48 pitch, 5mm shaft R/C gear

57/36 tooth, 48 pitch, 5mm shaft R/C gear

57/36 tooth, 48 pitch, 5mm shaft R/C gear
Over the winter on a snow day I looked through Dad's old karting magazines looking for "how-to" articles. I found several that will help understand this old kart.  I also found several advertisements for the Red Devil karts back when they were "the kart" to have in the late 60s. As a graphic designer, they are very evocative of that era.






And... not everything is about karting:

video


video








Monday, July 13, 2015

Answer to Frustrations...

Hey Everyone,

The last post described my frustration trying to get on track at Mid-Ohio.   OI-Vey!!!

I gave the gas I had mixed with Blendzall to Rick Chapman to burn at his shop.  He called me last night to let me know that there was a problem.  He used the fuel at a sprint race last weekend and could not get the engines to run.  Lots of frustration until they changed out fuel.  BINGO!!  Another kart he prepared went to a race in Michigan with some of my gas and they also had problems until changing fuel. BINGO!!

Then it clicked.... My problems at Mid-Ohio, his problem this weekend, the problem in Michigan... all using my fuel.  Something must be wrong with it.  He opened it up and it did not smell like good fuel.  Then at the end of the day they poured it out on the brush pile to burn.... and it would not light!!  Nothing!!

I filled both 2 gallon tanks at Westerville, OH, with Regular Unleaded on way to Mid-Ohio.  Maybe the tank was near empty so I got bad gas.  It was raining on way to the track from the hotel, so maybe the rain worked into the tanks.

With this info I have learned another lesson: Check the fuel; buy fuel at the track; use only fresh gas.


Tuesday, June 23, 2015

Mid-Ohio 2015

video

This past weekend was Mid-Ohio hosted by Dart Kart Club.  Several family members came from Indiana to see us and experience a kart race.. some for the first time... some first time in 40 years.  Great to see Ann, Steve and Becky, Dad Glenn, and Scott.  Steve was a great help getting some things done on the kart. And he was the official starter... He did great, even after a 40 year hiatus.  It was a thrill to have him share in this.  Some brought hot dogs and burgers. Others brought chips and desserts.  Saturday was full of sharing about family and even meeting up with some old friends. John Copeland had lunch with us and told several stories about the old Indy Kart Club days.  Bill Willis had helped me some with the engine and called his wife, Linda, for Ann to talk to.  They had not talked in about 30 years.  Then as I was packing up on Sunday a classmate of mine from Brownsburg came in and introduced herself.  She had seen me on Friday and thought it was me but saw it was not a good time to interrupt.  She is married to a 2nd generation karter who runs 125 Laydowns.  Becky asked lots of good questions.


Enjoying the rain... well... family
















This photo is of our group watching the rain Saturday.  Racing in the wet started, but many decided not to attempt to run.  One race had one kart for the entire half-race.   We were cheering for him to at least make it to the checkered.  Dad Glenn had the comment of the weekend: "Weeeeeeeeeee" when describing the driver's excitement.

I had spent the last couple weeks trying to catch up on two years of not working on the kart: rebuilding breaks to make sure all fluid was consistent; building the engine; timing the engine; replacing 40 year old bearings.  I ran out of time and did not even start the engine.. but it had good spark on the first try!





We drove up on Thursday to unload into our garage. Friday practice day was cool and rainy, but I was not able to get out due to engine problems. Looking back it was my own fault.  I had a great spark at home but when I tested for it in the garage it was not there, so I tore the engine apart to re-time.  But I was in such a hurry and I confused myself to the point of not thinking right.

After getting help from a couple Mac guys the test start failed with John Copeland controlling the carb.  He said it sounded like there was an air leak.  Pressure tested and it was fine.  So we looked at the carb.

Rick Chapman spent about 2 hours trying to get it running with no success until 5:30pm Friday when he suggested the oil mixture was too much.  I drained the fuel and made up a batch with Zoomie's No Castor Mix.  Then he rebuilt the ignition and traded out the coil and condenser, set timing, stretched out the needle spring a bit... FINALLY, it started and ran great.

I bought a gallon of Zoomie's no castor magic oil blend. At 4oz per gallon of gas... that should work for a while. :-)  I had been using Blendzall at 16:1 or 8oz/Gal, which should be right.  The Guys from Boston said that would be great if it were in the 90s... but wet and cold makes the castor settle to the bottom and little gas makes it to the carb.

Saturday I was scheduled for the first race but it was raining.  When they did open the track many did not want to chance it on a wet track.  I skipped the race and spent time with the family expecting the rain to keep coming.  But it cleared up late and after some prompting I entered the Vintage piston port class. Yep, a illegal engine but should get some track time.  But my chain came off/broke after the Keyhole (turn 3).  GGRRRRRR.  On the tow line heading back in my brakes seemed really spongy.
Heading to the grid...with an illegal engine







Waiting for green flag for my class.  I'm at the far right. Steve is at the starter and Becky taking photos.


video

The guys from Boston in the next garage were very interested to help and had all kinds of good suggestions.  The best was bringing in Van Gilder. OH MY!!  What a personality and tremendous knowledge!  He found the left brake caliper was catching and not retracting.  He suggested several things: brake tethers should be loose; loosen the brake bolts; add washer to separate disc sides; change brake bias to the good brake and allow the second to add some more braking if needed; go back to the more sturdy chain oiler to help support the sprocket.  After getting dinner with family, I headed back to the garage to do those changes.  I finally headed out at about midnight.

On way back to the track


Sunday morning I was very down because when I left the night before I couldn't get all the air out of the brake system and anticipated not running practice.  BUT.. I say Van and asked his opinion.  He said it all looked good.  And all the air bubbles were gone!! I was flabbergasted! Van pointed out the vacuum pulled them to the master cylinder overnight.  I was psyched.  Then Rick helped resize one of my old chains but he ended up giving me one of his space chains.

Then I thrashed for a while to get all the stuff done to get to practice: change to oiler, add washers to axles to keep tires tight. I was just hurrying.  When was get to the grid for practice I did all the same things and signaled Pam hit the button on the starter.  I choked the engine and gas just poured out. The cranking engine would have pulled the gas in just fine.  JUST LET IT FIRE!!

Rick came to the rescue again and instantly knew the plug was wet.  We used his starter and a new plug and out I went and ran a couple sessions.













Race 1 & 3 were combined so I had to come in to get gridded.  We used an extra modern starter from Rick.  The old belt starter just does not have the umph to get the engine to fire right off. At the start it pulled right off the line and pulled great.  I was having fun going fast and sliding around some corners. Felt great!!  I was even staying in sight of Rick with his Piston Port engine. And the brakes worked well, but a bit spongy.  Then on the third lap the chain came off at the top of the downhill from turn 5 and ended up watching from behind the barriers of turn 6.  In my hurry to get in practice I had not lined up the sprockets. AND had not greased the sprocket, so it probably got hot, expanded and easily slipped off. CLANGCHHDHHHDCHALLANANG




Here are a couple things the Boston Guys have engineered:



I was running 60/14 and 61/14 sprockets but my RPM would not get above high 9,000s. Rick suggested using a 64 or even 66.

Not the type of race weekend I wanted, but there were good things.  I got to see family; some hopefully saw me in a new light; some might want to come back to another race!; Even in the frustration, I had fun and learned a tremendous amount of lessons.



Things l learned:

  • Carb gaskets (especially 40 year old ones) should not have cracks
  • Blendzall is not good for Macs in cool weather
  • 16:1 is way too much oil for Macs
  • cut triangles in the top holes of the outer manifold gasket
  • use Zoomie's oil at 4oz per gallon (32/1)
  • change to grade 8 bolts on brakes
  • check brake caliper
  • when done bleeding brakes, PUSH THE BRAKE WHEN CLOSING THE CAP!! this creates a vacuum which will suck up any remaining air in the system
  • add a bolt, washer, and spring to the caliper to make sure it retracts
  • DON'T CHOKE THE ENGINE!! unless the engine is freshly rebuilt or bone dry!!
  • get a modern starter
  • let Pam design the starter platform; she's the one using it!
  • When you test for spark, just briskly move magnets back and forth under coil.  No need to flip all the way around.
  • make an official pre-start check list for Pam to go through
  • use the feeler gauge under the right coil to flywheel at XXXX 
  • Push coil to the right then tighten
  • Have lots of condensers; learn to test them.
  • Maybe move to electronic timing
  • use feeler gauge for points break -- .018"
  • Grease the sprocket!!
  • properly align the sprockets!!
  • make a new push stick like the ones the Boston Guys have!!
  • it's OK to use modern spark plugs... the 40 year old Autolites are great but unreliable
I'll think of more as I go....