Different idea.... custom cam?..

[short4stuff]

Is it possible to weld on a cam and then remachine it ?... will that actually work?.... with just like a lathe? would the weld jsut break off ?... anyone have any idea's?

Probably a stupid idea don't shoot me. :eek:

[hrc85250r]

people do it, thats whatcompanys that require a core charge if you dont give them yours back do, the cams that you get when you buy from some comanies are remanufactured ones that have been "hard welded" with hard weld welding rod and remachined, i dont know if they do it on a lathe or if they do it with a milling machine, but the answer to your question is yes, they do weld and re-machine cams.... and weld doesnt just break off if it is done properly, especially with an arc or tig...

[short4stuff]

Hmm alright, so an arc is probably better.... I said lathe because i know how to use it ... at our school we have a milling machine too, but never used it... I'll see what i come up with.
anyone have the stock specs for a atc200 cam .. or atc200x ?..

[short4stuff]

Hmm alright, so an arc is probably better.... I said lathe because i know how to use it ... at our school we have a milling machine too, but never used it... I'll see what i come up with.
anyone have the stock specs for a atc200 cam .. or atc200x ?..
anyone have a cam for cheap?

[diggerzmound]

I did this exact thing the other day.

I welded on a camshaft with a wirefeed welder.. It was a 5HP briggs and Stratton camshaft.

When I was putting the Sage 1 Cam in my Raptor I noticed the differences in the cam from the stock cam. The lobes were taller naturally, but they were also slightly closer together...

So this is the pattern I used on my Briggs. I sprayed spatter shield on parts of the cam I didn't want welded, gear etc... Then I carefully welded the lobe taller, and on the inside closest to the other lobe.. Then I ground it down and filed the weld smooth.. There were a couple of pockets that i had to go back and re-weld . The end product looked pretty good, it wasn't the quality you would see from a company, and it wasn't perfectly true. At any rate it works!!! It really woke the little briggs and stratton Up. As a matter of fact, it run so well I was inspired to see how many more modifications I could do for free. I ended up welding voids in the aluminum head and then filing and sanding the head for more compression.. Then I used a dremel to make a timing advance key out of square key stock.. Then I sent the flywheel to the machinist and had it lightnened.. IN the end I was running 99% Alchohol in the engine, and it ran like mad, revved fast and to the moon. It floats the valves it revs so high.. The engine still runs fine but I am somewhat worried about the weak link (the rod). So i have come to a standstill on the project until I come up with a good idea to strengthen the rod....

So yes, I think you can weld up the cam yourself, just don't go overboard so much to cause springs to bind. And take your time to make the cam smooth.. It really doesn't have to be perfectly true, but smooth is important to keep timeing componints from wearing...

[thefox]

short4stuff- pm me your address, I have a 200x cam with worn down lobes you can have.

[diggerzmound]

If you want to send me the cam I will do it for ya, just send enough money for return postage.. I will also need a couple measurements of the lobe height of the original cam...

[thefox]

OK, here are some specs. from the Cylmer manuals

Lobe height (in inches).............200x...................xr200
intake............................1.2739-1.2802.......1.2470-1.2459
exhaust..........................1.2615-1.2678.......1.2315-1.2393


Also for the XR cam
intake opens at 15 degrees before top dead center (BTDC) @ 1mm lift and then closes at 45 degrees after bottom dead center (ABDC) @ 1mm lift.

exhaust opens at 45 degrees before bottom dead center (BBDC) @ 1mm lift and then closes at 15 degrees after top dead center (ATDC) @ 1mm lift.

The manual doesn't give the timing for the X cam :(


I guess this means the timing is different between the xr and x so that is why we see a difference, not the lobe height. Check web cam and megacycles to see what their cams do.

[thefox]

This is from megacycles...

[short4stuff]

Hmm thats neat (about the briggs engine)...
Looking at the Megacycle chart though I can see they changed the lobe placement.... like the valves are opening at different times during the stroke... Is adding lift to the lobe really gonna make that much of a difference?

[diggerzmound]

Actually adding lift, is as important as changing the duration.. Its not just adding lift hight but increasing the time that the valve is open, more air and fuel is able to sneak in. This is why high compression works well with higher lift and duration cams, the increased velocity caused by more pressure/suction capabilities of the higher compression piston has more of a chance to move air and fuel in..

[short4stuff]

alright thats cool.. BUT I was thinking that maybe they changed when it opened on the stroke because of such a large lift that if it opened at the stock time the valve would hit the piston?... Does that maybe make sence?.. I mean how do you really know how much room is between the valves and piston ?

[short4stuff]

I found 3 cams out in the backyard (in a bucket) that I didnt even realize I had! lol... so yeha I am gonna try and do something with one of them.. anyone else have any tips/tricks. Or has anyone else tried this?