Too Much Oil?

R

rookie

0
Jan 29, 2012
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So my oil car got smoked by my graphite cars by several car lengths. I followed the DVD exactly, except I used Jig. Everything was perfectly clean and blown out with air. Jig made the axles very slippery to hold after spraying. I stood them upright in a wooden block to dry and dusted them off lightly with a compressed air can before oiling. Wheels were prepped with legend and buffed clean and lint free under magnification.

I took the wheels off after and found that the wheels and axles were still quite wet with oil. I used 2 drops only and let it run off the axles before installing as shown in the DVD. Shook the DD4H oil well before applying.

Maybe it was still too much oil? That's the only thing I can think of why the oil car was so much slower than the graphite ones.
 
I am also thinking it may be the cars and/or prep. I have been through this many times with cars I thought were perfect, that performed badly.

Rear axle holes must be perfect. Even with Proxon drilled holes it is easy to meake a mistake, and occasionaly a predrilled block may sneak thru QC
Rear wheels must be PERFECTLY PARALLEL. Don't know if you had access to the Block, but one thing I do B4 Oi., Jig, etc, is mount the evenntual wheels very tight against the body, and using a micrometer, I measure the inner distance both front and back. Easy to do if body holes are with in 5 - 7 mm from car bottom.

Then check the Veer (drift) on an 8 foot board perfectly flat, and raised 2 inches so car rolls. If you don't have a test track then make it 12 - 13 inches

Two drops of oil was correct amount.

You have the DVD. Check both wheel bore and axles with a very strong magnifying glass. Possible one wheel or axle was flawed.
 
It was very light dust of the axles to make sure there was no lint or dust. That's why I used a can and not my compressor. No blowing off the oil at all. Assembled it just like DVD after 2 drops of oil.

Both cars are DD plug and play with tungsten cubes. Wheels are identical, Rage extremes, I think. In fact the cars are about as identical as they can be. I inspected the axles and wheel bores under 30X. I even used a selvyt cloth with alcohol to clean the axles.

I was really miffed and dumbfounded. I don't have a chance to do anymore test runs, so I broke the car down and re-prepped with graphite. This way, I will see how the cars do. If they are the same or close, I will know it was something in the prep. If the car is blown away again, I guess it's something in the car, wheels and axles. The problem is, it wasn't even close. The graphite cars, 2 of them finished within half a car of each other. My oil car was like 4 car lengths behind.....

I'll try again next year to build another oil car. Will the oil last until then?
 
There is a art to the oil process. My first 3 attempts my graphite cars were faster. I watch the video again and again and finally something clicked and my next attempt things were rolling.

You also need to make sure the cars that are beating you aren't running some 1g wheels. Apples to apples, oranges to oranges. That could be the difference.

One thing about pinewood derby and racing in general is there is always someone faster! There have been numerous times I thought I was going to set track records and blow everyone away to end up with a 5-10 finish. Part of the fun is figuring out whats holding you back and trying to correct it.
 
Just to clarify, all 3 cars I built, 2 graphite and 1 oil. I used the same process for all 3 except for graphite, I burnished the bores and for oil I used Jig and oil.

Some other details. After spraying Jig, I gave the axles 1 flick and set them up in a block to dry. The axles were covered with a zip lock bag to keep dust off, but the plastic never touched the axles. Axles were left to dry for a few hours as I was worried the jig would eat the plastic wheels.

I just expected my oil car to be faster than my graphite cars. Oh well, like I said, will try again next year.
 
I knew I should have payed more attention in school.
idea


rookie said:
So my oil car got smoked by MY graphite cars by several car lengths.QUOTE]
Click to expand...
 
One thing to check. Make sure the raised wheel isn't touching. I adjusted my drill press and I had one block I drilled that had the 4th wheel touching. That much distance is not prep. It is drag.
Click to expand...

All cars are 4 wheels touching. So I tore the car down and cleaned out the axles and wheels with alcohol and blew the clean with air. After that, I re-prepped with graphite and burnished graphite in the wheel bores.

Put it all together and ran the former oil car with the graphite cars. It was faster then on oil but still consistently slower slower than the graphite cars by a fair bit.

Cant' figure this one out. Maybe I just got a bad block. May try building multiple cars again next year
 
I found that the tuning table I use [ two cheap mirrors from Lowe's taped together], were wide enough to "race" two cars against each other. By careful placement so they do not collide, you can run a slow motion race that will mostly measure differences in rolling friction. This is enough to find and fix prep problems if you have no track. Because the wheels have the correct force on them you get a reasonable test where "spin test" is not so accurate with "oil". You can adjust the slope so the race lasts about 3 seconds. This removes the effect of aerodynamics and wheel reaction to the rail, but it is useful enough.
 
That's a good idea tx. I'll try that next time. Go figure though. The car I spend the most time and effort on trying to get perfect turns out to be the dud
wah
The most basic car I built was the fastest!

For a fleeting moment I even considered sending in my oil car to a proxy race just to how far behind it was, but it would have been a county behind you guys
dazed
 
I am wondering if Opa has this one ... did the formerly oil car pass a simple forward/reverse roll test to verify that the rears aren't touching the body with representative wheels/axles ? Multiple car lengths is a TON. Why wait till next year ??!!??? Find a friend nearby with a track, or build a practice one.
 
You can also send it to me to look at. If it is my plug n play I will gladly support it. One more thing to look at... check to see if the left front wheel is carrying more of the load and the car will rock a little to the front right.
Click to expand...

John, thanks for the offer. After all the back and forth shipping, it might be better for me just to try to build another one. I will send you some pics of the car before I break it down to recycle the weights and wheels for you to tell me what you think. The weight should be good. I moved a few cubes to the right side so the DFW would be weighted.
 
One thing I would try is take the prepped wheels and axles and put it on the car that is faster. Just to see what type of times you get.
 
RESO has a great idea. That's what I would do. Transfer your axles and wheells over to a known fast car. Easier to do than making a new car. This way you can see-if it's the build or the prepp job.......SPIRIT..........
 
That is a great idea. Unfortunately I don't have access to a track to test. I going to take pictures of all 3 cars and send them to John. The more I look at it, though, I don't think it's the car body. The wheels seem to all sit properly.

It's just one of these things.... very frustrating
surrender
 
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