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need help with rocker/lifted noise

5K views 24 replies 5 participants last post by  350chevyrob 
#1 ·
Ok recently iv been having a ticking noise.it sounded like a header leak so i put new gasket on and no change in the tick so i pulled off the valve cover and ran the engine with it off and the sound was definitely coming from somewhere in the valve train.turned off the engine and inspected to see if any rockets were lose or had any slop in the valve lash .everything seemed to be right.the engine has about 800/1000 miles on it and have not changed the oil yet.i think a lifter my be collapsed ... was thinking on re doing the valve lash a see if it go's a way...here's some specs on my engine

Sbc 389 stroker
650 DP holley
Camel hump heads 194s
XE 284 comp cam
1.5 self aligning roller rocker
comp cam harden push rods

Thanks Rob:thumbup:
 
#2 ·
I used to pretty quiet .but i have been racing it a lil ...it still builds great power but its only that one at as been ticking the other side of the engine sounds fine ..but you mite be right.i mite have a spec of crud in the lifter.i did notice when i have the valve cover off running the engine that one of the rockers didn't fill up oil as much as the others were ..so i thinking i should pull out that lifter and clean it or just change the oil with something thicker
 
#3 · (Edited by Moderator)
It used to be pretty quiet .but i have been racing it a lil ...it still builds great power but its only that one at as been ticking the other side of the engine sounds fine ..but you mite be right.i mite have a spec of crud in the lifter.i did notice when i have the valve cover off running the engine that one of the rockers didn't fill up oil as much as the others were ..so i thinking i should pull out that lifter and clean it or just change the oil with something thicker
.i did use a brake in additive and broke in the cam the proper way
 
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#15 ·
Well i took the intake off to inspect the lifters and found one of the cam lobe was roast .the lifter had some pitting and the cam lobe had flat spots ....soooo now im thinking what do the main/rod bearings look like.what is the chance that the bearings are ok
 
#16 ·
I will probably never buy another comp cam.this is the third one that has failed.and yes i did the proper break in for the cam.before i had the tick it ran great had good power but then it just took a ***** on me out the blue.im done with comp cam i rather run a summit special before i buy another comp cam
 
#20 ·
I do admit i did not have valve springs to match the cam.im thinking of building a new motor.this one was a slap it together and run it engine and i should have known better to do that and expect it to hold up to racing it.next one will be done right and take my time on.i really didn't have that much money in this one just a bunch of parts i had and threw it together
 
#21 ·
Actually this may well be the answer to the wiped lobe rather than a fault of Comp.

It is always best to go with a kit. The valve train is a place where lots of things can go wrong and often for reasons you don't suspect. When a failure happens it gets to a problem figuring out the old dilemma of which came first the chicken or the egg.

Some examples when mixing a high lift cam and insufficiently strong springs (there's other considerations with the springs but in the interest of keeping things simpler I'll stick to spring pressure) especially where it's a high lift rate the drop back on the closing side can result in the valve bouncing when it hits the seat. This will cause a tick if the lifter does not close the resulting lash and it drives the lifter being hit back into the lobe as the valve comes to seat after the closing ramp has passed the lifter. This condition will be worsened by a lifter that leaks down too quickly either because it's on the leaky end of the acceptable production limits or it's a fast leak down lifter by intent as these tend not to pursue lash in the valve train very quickly.

At the other end is stiff valve springs. These push back on the lifter's plunger with a lot of force. If the lifter is leaking down quickly, again either as a result of being at the fast end of the production tolerance or is designed/selected to be a fast leak down lifter, then in-so-far as the impact with the cam due to unexpected lash is concerned is the same as described above only the cause is different. In this case the valve isn't bouncing but the lifter is not closing the lash that develops fast enough as the lobe moves out from under the lifter on the closing side of a fast executing lobe.

In the old muscle car days the hydraulic cams used a lot of ramp at both the opening and closing ends which is one reason why these old style cams have a lot of duration and not a great deal of lift as it was a technique for keeping the valve train quiet by not letting the lifter get into the problems I describe.

There really isn't a cure for this and that includes adjusting the lifter plunger deeper into the body, it is rather the nature of the beast. If you're going to run cams like Comp's XE or Lunati's Voodoo then you're going have this problem to some extent. It will sound worse with a fast leak down (anti-pump up) lifter.

The solutions such as they are runs in two schools of thought:

1) Fully collapse a fast leak down lifter which of course requires a longer push rod to put the rocker and valve stem travel back into alignment. This wipes out any variable timing based on lifter leakdown rates from things such as the Rhoads lifter.

2) Using lifters with slow leakdown rates and running them with the plunger/pushrod cup nearly against the top end retainer so they can't pump up to a point that unseats the valve. This requires using a Circlip to retain the plunger if the lifter has a the wire retainer to insure enough retainer strength to keep the plunger/push-rod cup from popping out the top.


In the end you should always use the valve train components, especially valve springs, retainers, and lifters recommended or kitted by the camshaft manufacturer as you can be pretty assured that they have tested this combination across the operating range and know it's successful as a combination of parts.

Bogie
 
#22 ·
This may not work on Chevy but many years ago I had a ford with at 360 engine and one of the valves would click. When we quit using lead in the gas I started adding oil to the gas and magically the valve click went away. I would add a quart to a tank of gas (probably more than needed). I found that most of the oil ended up in the oil pan and the exhaust did not smoke.
 
#23 ·
lifter noise

I have had the same problem with 2 of my 350 motors. Solution: I changed the oil to Castrol 5-30 with the addition of 1/2 can of Seafoam and the filter. I ran them around for a while to let it work in. The noise doesn't go away in fact it gets a little worse but it loosened all the crud in the motors and the lifters. Then I changed the oil (but not the filters) to Castrol 10-30 high milage and after it got a chance to circulate through the lifters the noise went away. I really think Seafoam is a great product.
 
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