Posted by: nwracing | December 7, 2015

Andromeda – 2015 round-up.

Apologies for the radio silence, but with little to report, resorting to regaling you with my moaning about not being able to get to the bottom of our issues, would not I fear make riveting reading.

However, I start this blog with sad news. Shakespeare County Raceway will close after the 2016 season. It appears that finally the opponents of the track and the change in planning laws have finally spelt the death knell of a place I have frequented off and on since 1980.

I will be sad to see the end of racing at Shakey as I have always found it to be a friendly place and my thanks go out to the organisers for their many years of dedication to British Drag Racing. In view of this news it has become even more important to get Andromeda ready for 2016.

Powerglide gearbox

The glide in pieces!

Firstly the gearbox…

… I decided that for the first time I would strip the powerglide. For no other reason than I had the time as I was not racing! Although the case was cracked at the rear the internal components are in perfect working order and the new case is being modified so that it can be rebuilt in the next month or so. This is great news but puzzling as the gearbox was reluctant to engage gear. However, in the absence of any damage I can only clean everything thoroughly and put it all back together.

 

The engine…

… a strip down revealed significant bearing damage, although the crank will clean up with a polish. The bores also suffered some surface damage which will clean up with a hone. My main concern was that I had made a mistake when clearancing the bearings using my new dial bore gauge.

Big Block Chevy

The remains of the engine

So after some discussion we shipped the whole reciprocating mass to She Devil Racing and consulted with Dave Milam who has been a staunch supporter of our efforts over the years. With the mass of experience Dave has he quickly identified that the cause of the damage was foreign matter that had worked its way round the engine. I was pleased that my bearing clearances were not at fault. In view of the fact that I have had both the engine block and crankshaft machined the fault for this must lay squarely at my door. I just hadn’t cleaned everything thoroughly enough.  So I have left it with Dave for him to clean everything in his huge wash tank!

 

But, we are still left with a mystery. We lost 25psi of oil pressure and nothing we have seen provides any indication of why this should be the case. So, after Xmas Dave will finish his work and then it is back to me for the rebuild and further investigation to determine the cause.

Finally I must also make an apology. My tow kart blog was widely read, and I thank you all for that. However, I failed to get the final pictures sorted as I have not been able to dig it out the back of the garage. I promise that I will post the pictures as soon as I can!

The great thing is that we are on target to be out in 2016 and I am really looking forward to being out there for the swansong of Shakespeare County Raceway.

Posted by: nwracing | July 1, 2015

Andromeda Tow Kart Part 7

The last real big hurdle before the fiddly bits like throttle and rear brake is the steering. Having worked on cars before I was well aware of the dreaded bump steer which can cause all manner of issues. Bump steer occurs when the suspension compresses and the steering arms are at such a strange angle that they cause the steering to move on its own. Now you would think that with a top speed of 12 mph this would not be a huge issue. However, the return roads at the tracks we go to can be bumpy so this was something I wanted to get right.

A rudimentary steering column was made fitted and the steering arms connected. It was clear that we were going to suffer big issues. This is not a problem on a normal go kart as there is no suspension. So I ended up machining a couple of standoffs to raise the height of the steering arms to keep them level.

Avoiding bump steer

Avoiding bump steer required these spacers

This is one area where I need to think differently in the future. I had focused too much attention on the chassis and created a number of issues that would have been avoided. Again, huge learning for me; and if I build a mark 2 will be incorporated from the outset.

As the tow kart has to fit in to the trailer when we go to the track the length and width was dictated by the available space. However, ergonomics also meant that things like the seat and handlebar height also had to be considered.

We found this out the first time we tried to load the tow kart in to the trailer only to find that it wouldn’t fit as the handlebars interfered nicely with the roof of the trailer. We managed to pull down on the suspension and clear the roof, but only just!

So I decide that we needed a steering column that could be split in half as I did not want to stress the suspension and it had to be movable with just one person. So as you can see in the picture I manufactured and welded two plates which enable me to shorten the steering easily.

kart steering

Complete steering column

004 (2) 005 (2)

This pretty much finalises the build-up. I could go on for hours about some of the little details that now appear obvious but at the time were very frustrating.

In the next and last blog on the tow kart, I will detail the learning I have taken from the build and if I can dig it out from the back of the garage will take some video so you can see the finished tow kart in all its glory actually moving!

Posted by: nwracing | June 24, 2015

Andromeda Tow Kart Part 6

A few weeks ago I had been talking with friends on the subject of photos taken with mobile phones and digital cameras and how few appeared to be printed. I was always worried that my pc would suffer a glitch and I would lose treasured memories. Sadly my comments now seem prophetic as I have lost a whole tranche of images including those for the tow kart. Worse still, my back up seems to lack these images as well! My intention for this blog was to detail how I fitted the engine. In view of this I have taken a different approach and have taken photos of the tow kart today and will use those to illustrate those areas where I don’t have any other images, so please bear with me. The engine chosen was a Chinese copy of a Honda motor that you see in almost everything from lawnmowers to generators. I chose this for two reasons, firstly I wanted to keep it simple and secondly crew member Julie who was going to use the kart had never ridden a motorcycle, so gears and clutch co-ordination was unnecessary complication. The engine came with a centrifugal clutch which made it a twist and go and very compact.

tow kart engine

Engine and clutch in tow kart

I made a plate welded it in and centered the engine on the plate. The clutch hub had a small sprocket built in so no messing machining hubs… …or so I thought! I worked out the gearing and realised that the rear sprocket would be bigger than the wheels and tyres! So after much messing about I machined and welded a hub to mount a different sprocket. So much for simple. I was so eager to try it out that I fitted the chain and started the motor. Steering was by feet against the front hubs!

Modified clutch hub

Hub modified to take bigger sprocket

DSC_2175With the throttle wide open it hardly moved and there was a horrible burning smell coming from the clutch! I went back to my gearing calculations. It was meant to provide a top speed of about 12mph and enough grunt to move the dragster. Err no, I had made an error and it was geared to do about 60mph! After much head scratching there was only one thing for it. I needed to make a jackshaft so that I could achieve the correct gearing without having ridiculously sized sprockets. I am lucky enough to have access to lathe and mill so this was knocked up in double quick time. One item that had to be scrapped was the clutch I had modified! So another one was purchased and fitted as supplied! It also meant that I had to cut the chassis and reinforce to clear the chain which took some time to achieve.

Go Kart jackshaft

Completed jack shaft

I have ended up doing far more engineering than anticipated but it is all good experience; and the cost is minimal. The disadvantage being time consuming reworking of the original design. Next time I tackle the steering system.

Posted by: nwracing | June 10, 2015

Andromeda Tow Kart part 5

Feeling a little more confident after finalising the rear suspension I moved on to the front suspension. Originally I had wanted to build a full a –arm suspension system much like those you see on quad bikes, however, reviewing what I needed to design from a chassis perspective and  based on the fact that the purpose of the tow kart was exactly that, I decided on a more simple swing arm front suspension.

Firstly I needed to fit the front mountings for the suspension arms and to be honest I used 6mm thick steel which is somewhat over the top but this is what I had. I used a steel bobbin which I turned down on the lathe so I could space the brackets and weld them in one go. Because they were so thick I was not too worried about distortion.

Kart front suspension brackets

Brackets all welded

The advantage of making a swing axle is that I could use a single piece of tube on each side. I turned a steel bush and threaded it to fit inside the tube it was then welded it in position. This was one end of the arm finished!

The other end was little more involved. Using some more 6 mm steel I created a ‘U’ shape using three pieces of steel and then welded this lot together which was quite a bit of work but cost pennies. I was quite pleased with the end result which fitted the go kart stub axles perfectly.

Stub axle

Axle bracket components.

 

All ready to weld

All ready to weld

 

 

 

 

 

 

 

All this lot was all well and good but one factor I had not considered was how much the shocks would compress, which in turn affected how much the tyres cambered in. As the shocks had come off my old Harley it was almost impossible to know how much they would compress so all I could do was tack weld the bracket, try it out and then move it until it was right. Then I had a brainwave…

… the heaviest member of the team would sit on it first and we would see how far the axles deflected then the lightest and measure again. I’m not saying who was heaviest!!! I pitched the brackets in between these two points and welded these on. Not particularly scientific but hey this is a tow kart!

shock mounts

Two positions for shock brackets before my brainwave!

 

Front axle

Mocked up axle

 

 

 

 

 

 

 

 

Tow Kart front suspension

Front suspension all fitted!

One of the great things about building something like this is that you can modify it as you go along and I have to say  it is great fun, but remember this was the whole purpose of the build, to gain as much experience as I could on something  that my life didn’t depend on.

Next time I fit the engine and contemplate steering angles!

Posted by: nwracing | June 6, 2015

Andromeda Tow Kart Part 4

My next part of the build was to finish tacking all the tubes together and make sure that everything was in line and fitted where it should. After my initial enthusiasm with the welder I had managed to distort the rear tube that the wishbone attached to. After a lot of heating with a blow torch I was able to tease this back in to position. This was a real pain and a proper gas welding torch would have made the process much quicker.  That said if I had done it right in the first place I would not have had this issue.

Rear Chassis Tube

tow kart chassis

The chassis tubes all in place.

As you can see from the picture the tow kart is really taking shape with all the tubes now tacked in place. My intention had been to weld everything using the TIG welding process which would give me some useful experience. However, I came up against an unexpected issue. No matter what I did the main tubing which has a 1.5mm wall thickness refused to weld. I was blowing holes and for all the world it looked like a pigeon had been depositing its droppings…  …not good!

However, no matter what I tired I could not get it to weld so I switched over to mig welding and this worked a little better but was still not great. After calling a few professional welders they thought I had contaminated the tube and recommended I clean everything with acetone. So I scrubbed everything and looked forward to having an easier time. Still no joy; it continued even with the mig welder. In desperation I took a couple of pieces of the tube to a welder I know and asked him if he could show me where I was going wrong. He had the same problem as me! On closer inspection of the tube the wall thickness altered around the circumference, and there appeared to be contaminants in the tube.

Lesson: Don’t buy cheap tubing. With the amount of time it took me to weld and clean and then re-weld those areas I was not happy with I would have been much better spending a little more and saving time and aggravation. Sometimes a bargain is not a bargain in the end!

The next job was to weld the shock mounts to the rear tube and test fit the rear wish bone. It  looked exactly as I had envisaged it would: result!

Tow Kart rear suspension

Rear Suspension fitted with shocks

Next time I build the front wish bones and then were are almost ready to put the engine in!!!

Posted by: nwracing | May 29, 2015

Andromeda Tow Kart Part 3

After my initial success with the rear wishbone fabrication and buoyed with enthusiasm I fabricated the remaining brackets for the front suspension and then fitted them in the jig with the box section which is the main structure at the front of the kart. The picture shows the completely welded brackets. They do overhang the box section underneath and will be strengthened with some 5mm plate. This should be plenty strong enough to take the loads of the front axles.

front suspension mounting brackets

At the front I have decided to use a simple swing axle as it is the easiest to fabricate. I did consider building a four link independent system which would look great however, with all the joints needed to make it all work would have broken my rule on using bits out of my spares bin. I did make a mistake on the front brackets as I added in an extra washer in error for welding only to find that the gap is slightly too wide for the superflex bush. A custom thin spacer will need to be made!

I then focused on the inner rails which go from front to back on the kart and will support the engine plate and tie in the suspension. To get the angles just right took some time and patience with the disc sander and I must have trial fitted each side about six or seven times until they were just right. I suspect that in the past this is where I would have made a mess of it as patience is an absolute requirement. As it turned out each side took about 20 minutes.

Front chassis tubes

My final job was to fishmouth the tubes for the side supports and rear axle.  No amount of DVD watching or talking to experts helps with this process as it does pay to leave them a little long and file them to fit. I think this gets easier with practice.

Rear Chassis Tube

At this point I thought it would be good to consider everything I had learned so far.

  1. Order more tube than you need. You will bend the wrong way or cut too short no matter how careful you are!
  2. Tack things together and leave the finish welding until the end. I did weld the front and rear suspension mounts fully but the rear did distort the tube they are fitted to which will need to be dealt with.
  3. Sequencing the build. My initial idea of how the chassis for the tow kart would come together was quickly thrown out of the window. I mocked up where the tubes were going to go and realised that a number of other things needed to be considered before I could attack the chassis with the welder.
  4. You can never have too many clamps! If there is one thing I wish I had more of it is G-clamps. You never seem to have enough hands to hold on to everything at once.

Next is some more quality time with the welder tacking everything together…

Posted by: nwracing | May 26, 2015

Andromeda Tow Kart Part 2

In the first part of the fabrication of the tow kart I was building the rear wishbone. When it was finished I couldn’t help myself and assembled the rear axle on to the wishbone just to see whether it looked like I had imagined it. A stick drawing (my blueprint) doesn’t really inspire! So here it is…

Tow Kart Rear Axle

The rear bearings carriers did take some setting up ready to weld and I was careful to tack both sides to make sure they remained in line. Even then there was still some distortion from the welding, Thankfully the bearings do allow some misalignment so this will not cause a problem.

Rear Bearing Carrier

Welding the eyes for the suspension bushes was quite difficult as it needed to be square in all planes. The bushes were superflex which I had bought years ago for a project that never got off the ground. Welding with them fitted would wreck the polyurethane so I made some spacers out of round bar and washers and used all-thread as a way of holding them square.

Rear Axle

I have to say I’m pleased with the result and it has inspired me to get a move on with the fabrication. I decided that I would complete the rear wishbone by making the mountings.

One of the things I have learned is that making brackets can take hours and one mistake can mean a scrap part and you have to start all over again. As one of the principles of the build was to use any metal I had lying around for brackets I used what I had so it is probably thicker than required at 5.00 millimeters. This made it just a little more difficult to cut and I wore out a couple of hole cutters and a number of sanding discs just to get the four brackets made.

Suspension Brackets

As I’m in bracket making mode I will make the front suspension brackets and have decided to build the front section  as a separate piece and then hopefully fit it all in the jig ready to put all the frame rails together.

Posted by: nwracing | May 22, 2015

Andromeda Tow Kart – Part 1

I don’t know why but I have always had a hankering to build my own dragster chassis or custom motorcycle frame, I think it must be the last piece of a vehicle that I have never built. Over the years I have met professional car and motorcycle chassis builders who have all been very helpful and shared their knowledge which has only made me more determined.

However, one of the key pieces of advice the pros all agree on is to start with something that is less critical than a race car chassis or motorcycle frame.

No-one in the race team crew has a hatchback vehicle so towing Andromeda has proved problematic. This gave me an idea for a project so the building a tow kart was hatched.

There are a number of design considerations:

  1. Cost must be low and use as many materials we already possess.
  2. It has to be light so as not to add significant weight to the trailer
  3. Must tow the dragster at 10-15mph
  4. Must have suspension to provide some comfort on the return road at the drag strip.

As I do not possess Solidworks or any other fantastic CAD program it will be designed on the back of a cereal packet as I took Art class not technical drawing in school! So sorry, there will be no fancy renderings to look at.

My hope is that building the tow kart will gain me some of the experience needed to get me that nearer to my goal.

So to begin…

After a couple of purchases off the internet I had some go kart wheels, front and rear axles with all associated bearings.

So the first part of the construction was the rear axle and wishbone. The picture below shows the first part of the construction.

Rear Suspension Arm

The jig you can see the tube clamped to is a motorcycle frame jig I built from free plans from Crime Scene Choppers a couple of years ago. I blame Ron Covell for this! After watching his DVD on how to build a Chopper Chassis I decided this would be my first attempt at fabrication.

Motor Cycle Frame Jig

As it was my first attempt at accurate fabrication it took me months  however, I was pleased with the results and as you can see it provides the perfect platform for building the tow kart. I even had a professional race car fabricator give it the thumbs up!

Posted by: nwracing | September 20, 2014

NSRA Hot Rod Drags 2014

Dragster being prepared

Preparing Andromeda for our first runs of 2014

After some significant issues with the dragster engine the team were all excited to be able to get out to race at Shakespeare County Raceway for the NSRA Hot Rod Drags.

If you’ve never been to this event before I strongly recommend you put this on your calendar for next year. It really is like stepping back to a time before the health and safety culture became all pervasive with great cars and motorcycles to suit almost every taste. The people also get in to the spirit of the age and you could be forgiven that you have stepped on to a set from American Graffiti!

So with this great backdrop we readied Andromeda for its maiden run of 2014. Initial running of the engine suggested that our oil pressure and ignition woes were behind us. The new fuel pump was providing a much more consistent fuel load and the resulting tears in our pit was more to do with how rich it appeared to be running rather than tears of joy! However, I have learned over many years that pit lane tuning can be dangerous so we got ready for our first run.

I would also like to mention that we were also testing the new tow kart I had built over the winter. I had wanted for some time to reduce our dependency on our Landrovers as they did not have a tailgate which made it quite difficult for towing back to the pits. Interestingly the kart appeared to attract more attention than the dragster!

After a short delay in the pit lanes, due to the huge number of cars taking to the track, we were ready to go.

The engine started easily and I moved in to the burnout box waiting for the starter to call me forward. We were not using the NOS system for the initial runs as I wanted to make sure the base motor was working effectively.  As I moved forward Chris indicated to me to start the burnout and the tires lit up with all the richness in the motor disappearing in an instant. As I pulled in to stage I settled in to business of getting down the track. The xmas tree lit up and I nailed the throttle and I was off! The car pulled like a train and went die straight. Although you couldn’t see me I was grinning like a Cheshire cat and as I passed the top end lights I was feeling very confident.

Unfortunately, my euphoria was short lived. As I backed out of the throttle the oil pressure warning light appeared large in my vision. I immediately cut the engine and coasted to a halt. After getting out of the car I had a quick look to see if anything obvious was causing the oil pressure drop. Sadly, there was nothing apparent.

Chris arrived with the tow kart and we towed the car back to the pits somewhat despondent. The timing ticket proved what we thought. The car had run well, with a 9.4ET and 138mph terminal speed. When we checked back through our data this was pretty close to our best normally aspirated run. After taking the spark plugs out to check them it was clear that we were running a little lean so we upped the jets in the carb.

I wanted to see if the oil issue was terminal so risking further damage we started the car again. The oil pressure light went out! But, the pressure had dropped by 15 psi so all was not well. More worryingly the gearbox didn’t want to change gear and turning it over by hand revealed some strange noises. So avoiding further damage we put the dragster to bed and enjoyed the rest of the weekend. We will be back in 2015 and look forward to welcoming you to the track.

Posted by: nwracing | June 5, 2014

Nearly there… Exhausting times!

One of my favourite things about rebuilding the Andromeda dragster is fitting the exhausts. The original exhausts were a four in to one design but our new ones we had built are drag pipe design. In theory we lose a bit of power but in practice this has not been noticeable.

So on they went and it is still the best feeling in the world sitting behind these beauties!

We are one step closer to firing her up, hopefully this weekend.

 

Drag racing exhausts

Exhausts all fitted

 

 

 

 

 

 

 

 

Dragster drivers eye view

Drivers eye view

 

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