camshaft question

[jrisingmoon]

Is there anyway of telling if a camshaft needs to be replaced? How often does this need to happen anyway? Just curious since if I'm going to pull the heads off minimum, I may as well be thorough, even though I think the camshaft is pulled from the front of the engine, not the top of the block.

 

[icanfixall]

It pulls out from the front of the motor. They are expensive at around $500.00 to $800.00 depending on who you buy it from. Northern tools has one for about $500.00 in the latest catalog. They really don't go bad unless a roller lifter breaks on you.

 

[bikepilot]

Yep, you can measure the lobe height and look for scoring on the part the that rides on the bearings.

 

[sle2115]

It pulls out from the front of the motor. They are expensive at around $500.00 to $800.00 depending on who you buy it from. Northern tools has one for about $500.00 in the latest catalog. They really don't go bad unless a roller lifter breaks on you.

Northern tools has camshafts?

 

[jrisingmoon]

When I pulled the lift pump the end that rides on the eccentric cam was really worn, with a grove sheared into the arm.

How will you know if a roller lifter breaks? Can you look at the valves and tell?

 

[gunnie]

if that is the only problem with the cam, you could install a electric fuel pump

 

[The Warden]

When I pulled the lift pump the end that rides on the eccentric cam was really worn, with a grove sheared into the arm.

This is very common. IIRC the lift pump eccentric can be replaced by itself if you want, or just put in an electric pump.

If you're pulling the heads off, you'll be at a point where pulling the lifters will be easy (since the pushrods have to come out anyways, you're right there already). If all of the rollers roll freely and don't have any flat spots, I'll just about bet $$ that the cam lobes are happy. But, if you really want to pull it to make sure (not that I blame you; in fact, I did the same thing), pull the timing gear cover, then unbolt the two bolts on the thrust washer holding the cam in place, and pull the cam out. If you don't need to, I would suggest not pulling the cam timing gear off the camshaft...short of replacing the gear or the cam, you probably won't need to, and I found out the hard way that you need to press the timing gear back onto the cam

 

[jrisingmoon]

I replaced the lift pump but I was thinking about an electric pump at some point.

So if the rollers roll freely then the cam should be happy? I guess the rollers are on the heads then?

 

[Freight_Train]

Nope,I take it you don't have much time around engines. The rollers are on the bottom of the lifters down in the valley riding on the cam.We have a Hydrolic roller engine.The Lifters have a Hydrolic top with a roller bottom.But when you go to pull the heads,you gotta remove the valve covers,take off the rocker arms(all 16 of them)(Keep them in order on a numbered board),Pull the Push rods out(also keep them in order so everything goes back in the same hole).Now pull the Injection pump(small window on front of gear tower,Remove the 3 small bolts from gear,3 nuts on back side holding IP on,Losen all IP lines and supply lines,Slide the pump back and lift it out-gonna be tight with the lines on),unbolt the intake manifold and pry it out,remove the bolt holding the sheetmetal valley pan on(dont' forget the big drain thingy in the back),Now you can remove the head.1/8th turn working reverse torque order until everything is loose.Also,once you pull the valley pan you can see the cam and the lifters if you pull the 3 bolts holding the hold down plate in place in the valley.

 

[jrisingmoon]

Freight--
Nope, not a lot of engine time. I'm not sure if the rollers and the camshaft lobes are the same thing. Will I be able to tell the condition of the rollers once the valley pan, the rockers or the pushrods are removed or will I simply need to remove the camshaft to tell? If so, I'm not sure if it's worth the extra work...

 

[LUCKY_LARUE60]

Rollers and cam lobes are 2 different things. The rollers are part of the lifters and ride on the cam lobes as the cam turns. The push rods sit on the lifters and go up and down aginst the rockers to open the valves............. Jim

 

[jrisingmoon]

Rollers and cam lobes are 2 different things. The rollers are part of the lifters and ride on the cam lobes as the cam turns. The push rods sit on the lifters and go up and down aginst the rockers to open the valves............. Jim

Thanks, that helps. Guess I'll be able to tell the condition of the rollers quite easily once the rockers, pushrods and lifters are removed then. Learn something new everyday....

 

[obinella]

if you are concerned about the cam and want to check it, set up a dial indicator to measure the movement of the tappet in combination with a degree wheel turn the engine over slowly in the direction of operation and you can measure the total lift, duration and lobe centers in degrees. all lobes should be the same within manufacturing tolerances. by turning engine over slowly and observing the indicator you will be able to see any flat spots, however small. clear as mud?

 

[jrisingmoon]

if you are concerned about the cam and want to check it, set up a dial indicator to measure the movement of the tappet in combination with a degree wheel turn the engine over slowly in the direction of operation and you can measure the total lift, duration and lobe centers in degrees. all lobes should be the same within manufacturing tolerances. by turning engine over slowly and observing the indicator you will be able to see any flat spots, however small. clear as mud?

No, I think that makes sense. Don't know if I could explain it but I think it makes sense. I guess this could be done with the cam still in place??? Would the dial indicator just go into the pushrod holes????

 

[obinella]

set it up in the valley to read the tappet body movement. you don't want to read off the push rod ,valve or rocker assy. as the hydraulics in the tappet will through off the measurement