scottman20006

Hey guys I thought i would come here and post something ,autoworld is remaking the cox vega funny car and they have a company in china that is tooling this cox style motor for them and the guys at autoworld are having some issues with the motor and have sent them back a couple times for them to fix it.
I can give you all the info i have and if you guys need more ill try and get more info,if anyone on here can help with suggestions or causes it would be helpful and ill let them know all the info you guys give me.
Ok they are having problems with getting these motors to start,and they say it seems like it takes a long time to get one of them to fire and start.
here is all the info i know of right now.
Its a .049 cox style engine..Duh
they have check the glow heads and they say they are glowing bright Orange/using 2 D batteries.
They were trying to start them by spinning the back wheel and he said it wasnt close to starting,so they rigged up a drill to spin the motor and after a great deal of time it fired up.
He said they are using the needle setting of about 2 1/2 turns out like most cox engines do as a starting point.
They are using a 20% blend of fuel.
he said he finally got two of the engines running pretty well after some time and the other tow engines he couldnt get running or stay running.
Ok guys any other info you might need to make some suggestions let me know and ill email them
Thanks Scottman

DeviousDave

It sounds fuel related. Get a syringe and take the needle out to backflush the gummed up fuel out. Check the reed valve out too to see if it's sticking. 99% of the time when it will run on the prime and not stay running on a reed valve this is the culprit.

ETA: a motor needs spark, compression, and gas to run. You have the spark and compression if it has already run or will run after some difficulty. This only leaves the fuel delivery.

build light

This could be a tough one to fix.
First, there could be quality control issues. Have all these newly built engines from china been taken apart and checked for visual problems like sluff or just plain poor workmanship?
Secondly I wonder if this is a new design or is it a reverse engineered copy of the original Cox engine? The Cox engine worked so well because of the tiny tolerances in machine work. Also beware of shortcuts by the mfg. to keep costs down. Cox, Even with their high quality control and tolerances there can be problems like air leaks at the needle valve for example.

Using Straight castor oil for the lube in the fuel might be helpful. Would you consider letting a couple of the engine gurus here try a few each and let them try to figure out what the problem might be? Just a asuggestion.

Robert

Duane-RCU

My Feedback: (5)

They should have just bought a bunch of Sure Starts! I thought some Cox engines used more than 2 1/2 turns out. Maybe they could try 3 1/2? They could box one up and send it to me and I'll try it... I'm still trying to collect a few more parts for my original Vega, mainly cosmetic stuff now, but it runs and is CLEAN now.

jeffie8696

I'll test one, heck I'll test anything.

Toad

I think I would just like to see a pic of one.

scottman20006

Come on guys i need info,if you want to see what the engine looks like you can go to section of RC cars and off topic area,and go to cox cars making a come back and i think they are on page 8.

proptop

My Feedback: (8)

Most of the old Cox car engines with the product or plastic backplate and fine thread needle need to be open something like 5 turns or so...

Make sure the reed is operating properly...the reed should allow free intake of the fuel/air mixture and no back flow. The way I test is by mouth...draw in, it should take VERY LITTLE effort to suck through...and you shouldn't be able to blow back past the reed.

A good wet prime and fast snap/spin of the tire should at least get a pop or two out of it...if that doesn't do it try an upside down stingray bike rear tire as a starter wheel..

Have a look in the Reedie FAQ thread.
http://www.rcuniverse.com/forum/m_3747940/tm.htm

DeviousDave

Look Dude, we're doing our best with the limited info you have provided. Do we owe you something in life or miss a memo somewhere? Nobody helps a guy who won't give a little too.

Now be a good egg and go fetch us some pictures. Please.

scottman20006

iam not saying you guys owe me,i just need to ge this info to these guys asap,and so far you guys are doing great,iyou guys who are expert on this things to help me.By the way iam restore three of the sprite indy cars myself.
thanks guys all of this sounds like really good info keep it coming if you know anymore.
Also if you guys need more info ,tell me what you need to know,ill ask them on monday.

build light

Here is what we are dealing with.
I am guessing there was not enough R and D done on this engine before it was thrown together as a whole unit with the car. I have no idea if this engine is a proven design or what.

Robert

combatpigg

My Feedback: (3)

They haven't invented 1 thing on this Earth in 2000 years since the firecracker. I think trying to copy a Cox engine is expecting too much of them.

Lost Glider

If I understand this correctly, the engines won't even run off a prime. I think you're dealing with a compression problem. Stick the engine glow head and cylinder upside down into some fuel, do not submerged the exhaust ports, rotate the crankshaft to top dead center. If you see bubbles coming out where the head should be sealed, there's your problem. Other things to consider are, combustion chamber to large causing low compression ratio, or the piston cylinder fit is to loose. You may want to try posting this question at, http://groups.yahoo.com/group/049Collectors/

combatpigg

My Feedback: (3)

They'll just have to keep beating the forced labor in the piston shop until the fits get tighter......

Tim Wiltse-RCU

Well the fix is real easy...don't get stuff made in CHINA!!!! Several years back CS tried their hardest to make a clone of the Cox Black Widow based engine i.e. a 8cc tanked type engine and they just could not get the job done then either!!!! Maybe people don't care anymore but to me it's a real shot in the face of all americans to take a US made product and have some jackoffs run off with it to China where they don't have to deal with copyright and trademarks and have clones made...ell try to have clones made anyways. To think that LeRoy Cox was making these things back in the 50's without CN controled machines and even today in 2009 NO ONE...that's right NO ONE can come close to the quality that he made!!! To make matters worse or rather funny depending on which side of the fence you are on it sounds like no involved with this new funny car project knows a darn thing about Cox based engines to start with..whoever is funding this project ...whoever is making these clone engines or whoever is doing the testing....sad real sad.

LAter,
Tim

gcb

Scottman,

I posted this on your other thread, but here it is again:

First let me preface this by saying I'm not into cars so this is purely speculation...

From running an old Wen Mac boat long ago I found that there is a considerable difference between the needle setting under load and free running. If you set the needle to run free, it will immediately be too rich under load. If you adjust the needle for running under load, it immediately goes lean and dies with no load.

My solution was to place the boat's stern in the water once it fired and adjust the needle so it would peak while unloading in the water.

Bringing this situation to a car, you will probably need to adjust it to a much richer needle setting to keep it running under a no-load situation for break-in. Once break-in is complete, you may need to lean it a lot to get it to keep running under load. You will probably need several runs to find the peak setting. I'm sure the 2 1/2 turns may not apply until running under load.

I know this may or may not help your situation, but perhaps is worth a try.

George

KidEpoxy

Have you tried taking the engine out of the car,
strip off all that spur & bell junk from the shaft,
and see if you can start that cox clone with a 5x3 on the bench with a good tank location?

If you cant start it on the bench in a basic configuration,
dont bother putting in a model with extra stuff bolted on

proptop

My Feedback: (8)

Tim...now tell us how you REALLY feel...
I agree BTW... [:@]
But theoretically we're not supposed to get "political"...

Yuu

As a kid, my friend had one of those cars and we started the engine using a bicycle up-side down; spin the back wheel with the foot peddels, and touch the car tire to the bike tire, and ZOOM! Hey!! Is that a SIX FIN GLOW HEAD on that engine? Must need a lot of cooling. Sounds like a bad gasket, or sticky reed. The gasket might need to be replaced. [look to see if there is a gasket] Sticky reed... take engine apart and clean, or just diddle with it for 1/2 hour and it will clean out. I like the idea about tuning the boat with the prop in the water.... I can't remember what we did for the needle setting with the car. I ran the bike, and he started the car and tossed it across the barn attic wood floor, and it went round and round on a wire nailed to the center of the circle.

Big Al-RCU

Boy does that bring back memories!

As a teenager I took my McCoy 19 car out to my uncle’s farm. My cousin and I moved hay bales and swept out an open space in the barn’s hay loft. Set up the tether, fired it up and launched it.

Well that’s when the excitement started!

The wire snagged an exposed nail head at about its midpoint. The car made a couple of the fastest laps I’ve ever seen around that nail until the line snapped. It then ran free the length of the loft and smashed into the back wall. Naturally it missed the hay bales on all three other sides. Didn’t do too much damage, but scared the crap out of both of us.

scottman20006

Well I have copied almst of your guys suggestions and on another thread as well,and i hope all this info can help them get this motor problem solved,i really would like to this car make it out,and they did say if it does well then they will do other models,such as the dune buggy or the Baja Bug,and maybe others.that why i want to help them.

wjstek

Hey Scottman, I am not an Expert but I have been Extensively testing Cox 049 Engines for all most ten years now. I wonder about the Auto World 049?? Whats the compression like? Is it a sub induction Cylinder? is the backplate sealing well? In one of the photos it looks like the Engine has a Aluminum needle valve, I feel the Brass needle valves are Superior, Are they fine or Coarse threads on the Needle valve? I bet You Guys I could get ths Engine to Run. I have had some start at 3 and 1/2 turns open and others at 4 and 1/2 or More, MySilver Bullet Ski Doo 440 on You tube needs to be opened 5 turns to get running. One of the Guys mentioned about Having a Climate Controlled CNC Process and I will agree with that. The Cox company moved around a lot and I was told when they moved to Colorado they were not within the correct Atmosphere and not maintaining Climate Control. Oh Well,,,, Lets see whatChina can Do,,, I am ready to put one of My 049"S up against Their's. Bill

wjstek

Hey Tim, Real Men play with Cox Engines!!!!! No Girl Scouts Here!!!!!!!!!!!!!! Bill

wjstek

I hopeThat is not a aluminum needle valve, I have seen them snap in half after a couple of runs on other engines, perhaps maybe a better Design?

WINANS

I would bet that these guys don't know a da*m thing about what they are doing. They seem simple, but the Cox motors were made to exacting standards and they don't tend to come together in the sense of operating properly if you don't have all of your ducks in a row from a manfacturing tolerance and materials perspective.

I personally would not provide one iota of assistance to someone attempting to simply knock of these engines. Let them figure it out themselves, do their own homework, or go home.

Scott