Cam Shaft Welding for Racing Engine

If its cast steel and the guy doing the welding is good there should not be much of a problem. Cam shafts do not have all that much torque applied to them so it should work.

Possibly doing a good post heat after the weld is complete to let the welded area in the two cam halves settle back to the right alignment and help de stress itself wouldn't hurt anything either.

Camshafts do have a considerable load on them. Not only torque but bending.

With cutting and welding I think there is a good chance of failure. I would do a build-up weld then machine down.

I have to ask the obvious; why don't you get the cam specs and go to a good cam grinder and have the pair made made? My limited experience with trying to weld a SOHC cam back together was that it worked fine until it was put under the load of racing. Then it broke in roughly the same place and we had to replace the pistons, valves, rods and crank again! Getting one made to our spec was cheaper in the long run.

Have you checked to see if you can get a camshaft ground to the specs you need? I built small block Chevrolets with 180 degree cranks and had the camshafts needed to make the engine work ground from billets. If you could find cast billets, you may be able to get what you need.

Welding cams can certainly be done, but it's a real art form. I find few people can successfully weld castings and have them last.

Good luck with your project.

Why not just contact a competent cam manufacturer such as Comp cams, Crower cams. or Lunati. I would like to add crane cams but at this time I am unsure as to weather S&S cycles who purchased it in a liquidation auction in 09 is manufacturing cams. However all of the links above can supply you with very qualified advise and or custom grinds if you wish.

I agree that relative to the crank assembly the cam has little torque. However I have seen snapped cams that have never been cut and re welded. You also may end up with a cam that is not strait and have to send it out for regrinding anyway.

It can be done and it may work but wow that leaves big hole in your Murphy net

Don't expect too much of it. First lining these out and weld. Even they are cast steel, thermal deformation will occur. Cam shafts are machined in one piece, just for this reason. The best ones have been through a ciment process and are grinded all in line between two points for the buss bearing alignment and the cams on a programmed cam grinder. I expect the camshafts to wear out the bearing material and everything described before. Those cams have indeed a lot of force to work. (valve springs) Some motor builders had a lot a problems with wear and tear of them.

Are you talking about the camshaft or the crankshaft.

The crankshaft controls the piston location and determines the firing order.

The camshaft only controls the opening of the valves.

With your current crankshaft there is no point firing 1 and 4 together as one will be at bottom when the other is at top.

The OP is referring to a 180 degree firing engine, if I understand his request. This is often done to fire two cylinders (of four) at a time, but one can be fired as well.

In order to do either, the camshaft must be redesigned.

If I may suggest, scrap the engine now without investing any money, it will be cheaper in the long run!!

If the "cut & weld" fails, your engine will be wrecked as valves "meet" pistons......

You have received good advice, either get special cams made or live with what you have......

One question, what is the thinking behind this change? What will it do for you?

If its a Ford engine, they may have a camshaft(s) already for you as years ago they made both types for some engines......for industrial engine reasons I believe....

Hello dadsmuff969,

So your way of thinking is if you fire two (2) spark plugs at the same time during a combustion stroke this will double your horse power.

Food for discussion:

How many crankshaft mains bearings do you have in the block? I hope 5 mains.

You may have to change the counter balance weights on the crankshaft.

If you fire the two end cylinders 1-4 this will flex the crankshaft at each end. When you fire the 2 cylinder 2-3 this will flex the crankshaft down on center. I think the crankshaft will break.

If your changing the engine every race the crankshaft damage may not be a problem.

Camshaft Manufacturing:

To make the cam you use a hollow tube rail cut to length. Make centers on each end to facilitate grinding machine used for manufacturing process. Grind O.D. to similar diameter of original cam. Wall thickness should be no less than .25 to .30 ".

Cut 4 stationary grooves 90 degree around circumference or rail. Manufacture your main bearings on an centering arbor and machine O.D.to diameter size. I.D. will match hollow tube diameter. Slip fit no shake.

Machine all lobes to proper lift height, angle, and base circle diameter. Use the machine grooves in rail to reference angular location. Don't forget to put in the oil holes before details are hardened.

Harden all details including the hollow tube rail. All details will slip onto machined tube. locate each main and lobe to proper location before tack welding. Dimensions for location can be taken from original cam shafts. Final weld after all diameters are protected from welding sparks.

Allow main bearing diameter sizes to be larger then specifications. This will allow for shrinkage after hardening process. Specifications will vary depending on materials or steel stock used. Final grind mains bearing journals to specifications on centers. Don,t forget micro-finish specifications.

Done

WHEN RACING ON DIRT AS THE TRACK BEGINS TO TAKE ON RUBER AND DRIES OUT TRACTION BECOMES THE MOST IMPORTANT THING. WE PRODUCE ABOUT 200 HP AND THE CARS ARE ABOUT 800 LBS, THE TIRES ARE 80 INCHES IN CIRCUMFRENCE AND 13 INCHES WIDE ALL OF THIS BEING SAID IT IS STILL POSSIBLE TO EXIT A TURN AT 80 MPH AND SPIN THE TIRES ALL THE WAY DOWN THE STRAIGHTS.

IN A 4 CYL ENGINE THE POWER PULSES ARE 180 DEGREES APART AND VERY SMOOTH TAKING 720 DEGREES TO COME BACK TO #1 CYL. IF ONE MADE A GRAPH OF THE POWER PULSES OF THE TIRE APPLYING FOURCE TO THE GROUND IT WOULD BE A FLUID EVENT THAT DEFORMS THE TIRES AND CAUSES MORE SLIPPAGE.

IF WE GO TO A BIG BANG FIREING ORDER AFTER THREE AND FOUR CYLINDER FIRE THERE IS A 360 DEGREE PAUSE BETWEEN THE START OF THE NEXT POWER EVENT. THIS GIVES THE TIRE A CHANCE TO RECOVER AND GET MORE TRACTION. IT PRODUSES A CLAWING ACTION ON THE TRACK SURFACE.

MANY YEARS AGO HARLEY DAVIDSON WAS UN-BEATABLE ON THE DIRT TRACKS AND THEIR FIREING ORDER WAS GIVEN AS ONE BIG ADVANTAGE. OUR GEAR RATIO IS AROUND 10 TO 1 IF YOU TRACE THIS OUT ON A TIRE YOU WILL SEE WHAT I'M TALKING ABOUT.

Uh oh...

http://cr4.globalspec.com/thread/45911/CapsLock

Listen to the guys above about considering the cost of your engine verses the cost of a custom ground cam.

My advice would still be to check out the aftermarket manufacturers. Most of these guys have been involved in every conceivable form of racing. They store blanks for custom grinds just as you desire.

Dear sir

i would not tuch the cam - it will brake .....

i would increae the diameeter of the outlet valves letting the gasses to go out freely

put raditor - cooler befor the entrance of the air to the inlet system, including bernully pipe ,more air already in pressuer

in this way you will have reachest air with more oxigen

the fuel will explode with much more force !!

try and winn the race

their after just advise !

yours

j.w

w.j.technologies.ltd@gmail.com

Hey, as long as we are making individual lobes for the camshafts, do it the right way. Use a straight solid smooth shaft as a base. Put a compression type nut on each lobe. Then you just slide them over the smooth shaft, align each one where ever you need it, and clamp it tight. If it does not work out, you can return to original firing order. WTF, you can then advance or retard the lobes on any combination of cylinders to move the torque around where you need it.

There are cams that are being made that have pressed on lobes. If any of the aftermarket cam grinders have set up to do this, realigning the lobes to your specs should be easy.

Have you tried variable cam timing? A spring loaded timing chain tensioner would tend to stretch the spring as the chain momentum got higher. That stretching spring would retard the cam as RPM rises. Spring would control when, and amount of slack would control how much. Good luck. Send pics.

A new type of composite camshaft has been developed.

Precision PM lobes are fitted by the thermal shrink fit process to a prepared shaft and as a result no grinding of the lobes is necessary. To avoid lobe grinding, a manufacturing process for the lobes and camshafts was developed, which produces a sufficiently accurate lobe form within the process.

http://www.sae.org/technical/papers/970001

eeeek

scary

"Then it broke in roughly the same place..." The problem comes in the way of the heat affected zone or HAS next to the weld. This is remedied by a soulition heat treatment, which will soften the lobes of the cam. The cam lobes are heat treated by induction, sometimes carbarised. Grind a new one, in which the lobes will still have to be heat treated and ground...