Anyone with a Comp cam please respond to this....

[Tony91Sport]

I am having nothing but problems with my cam. Will someone tell me what they changed in relation to the valvetrain. Ive tried different pushrods. I have the worst clattering noise.

I AM ABOUT READY TO ROLL MY EXPLORER OFF A CLIFF.

Dead Link Removed My face is really this color, and looks exactly like this.

Tony 91 Sport

 

[JAY]

I have ran both of the Comp cams in my engine and haven't had any problems. I assume that you have the smaller one of the two. How much longer did you go on the pushrods? The average is .050 longer according to Comp but I had to go to .060 longer on mine when I had the smaller cam. Did you replace your valve springs? The stock valve springs are not near strong enough for the cam. You will need to get new springs that meet the tension requirements at the recomended installed height. If you had a shop install the cam for you than they should have made you aware of these problems. If you installed the cam yourself than it isn't your fault, Comp doesn't tell you this up front, but will if you call them complaining. Either of these will cause a noisy valvetrain, and rob power also. I hope this helps.

 

[SteveVB]

Tony,

Sorry to here about your trials. I am in the process of getting my engine back together now - should be done in the next couple of weeks( Ive had some delays due to work, my wife lost her job, and a BA tax payment), you asked on another thread, but I thought Id post it here

There should be some pre-load on the lifter when the cam is on the base circle. If you are using adjustable pushrods you should adjust them when the valves are closed so that they have 30 thou of preload on the lifter I think.

On the 4.0 engine the rocker arms are on a shaft and not adjustable( you can shim or mill the pedestals for very small changes as long as the rocker still is making acceptable contact with the valve stem)
A lot can change when the engine is machined, if the block was decked or the heads milled, and with the cams-a smaller base circle will throw off the pushrod length.

The question would be; when the adjustable pushrods were installed were they adjusted when the cam had the valves closed? If not you will need to go through and check and change the pushrod length on each cylinder with the valves closed for that cylinder.

You also should check, as Jay pointed out, your valve springs. If you old ones had more than 60k on them then new ones should have been installed. I dont know the specs -they are not on the cam card, still looking for a solution on this for my engine.
JAY what did you use, part # or specs. Cam card has no info.
I called C C and they recommended something with 110 on the seat - pretty vague about it. The info from CC has not been the best.

Tony I am replacing everything in the valve train, cam,pushrods, rockershafts&arms, timing chain,gears,tensioner.

------------------
Steve VB
91 Navajo
2 1/2" Rancho,
31" Goodyear AT/S

 

[Tony91Sport]

Where did you get the correct valve springs and pushrods? I bought some adjustable pushrods from Smith Brothers and they don't seem to be doing the job. And by the way I had an engine shop install the cam while rebuilding my engine. I am looking to pursue legal action against them because they did not notify me of any of these problems and gave me my truck back without saying anything.

Tony 91 Sport

 

[JAY]

Your right, the cam card for these aren't very helpful. I can't remember the exact specs on the lifters, I can look in the shop for the box they came in. They are sitting at 125lbs at the recomended installed height, but I can't remember what it is off hand. You need to be careful with the spring tension, too much or too little will cause problems. Steve is right about the preload on the lifters also, I can't remember what that is either but I think it was around the .030 range. The lifters on the 4.0 are sreing loaded, even though they are hydraulic, so they are always at there max height. If your pushrods are the correct length the lifter will be preloaded about half the distance they can travel (this is actually where the valve preload comes from). It is very likley that when the shop installed your pushrods they just snugged them up thinking that when the oil pressure comes up the lifters would tighten things up.
Hope this helps. JAY