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Topic Review (Newest First)
09-12-2012 06:27 PM
350chevyrob
Quote:
Originally Posted by oldbogie View Post
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
I do admit your right!! I chinched out by not getting the right springs and i do have a lot to learn about on how to build a engine and "make it last".i am pretty much learning the hard way lol.i rush in to getting the engine built just so i can pit it in and blow the motor.i and learning that hast makes waste.do it right the first time or don't do it at all...on another note the engine i have now has already been bunched on .60 over i have honed the motor twice.now if i disassemble the engine can i hone it out one more time or should i just build a fresh .30 383 block with all new rotating assembly
09-12-2012 05:03 PM
6426yy What springs did you use for breakin? I have a XE comp cam in my 454 it's noisey but not terrible. You may of had stud pull out and that would cause situations like bogie is talking about also.
09-12-2012 01:45 PM
mellowfellow
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.
09-12-2012 08:01 AM
Williams2 [COLOR=#000000]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.
[/COLOR]
09-10-2012 06:37 PM
oldbogie
Quote:
Originally Posted by 350chevyrob View Post
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
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
09-08-2012 09:26 PM
350chevyrob 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
09-08-2012 09:08 PM
350chevyrob Yea i probably got a defected cam ..i broke in the cam and used the comp cam zinc break in additive .the motor had about 800 to 1000 miles on it before the cam went south
09-08-2012 09:00 PM
F-BIRD'88 The Comp XE284H-10 cam I have in my 406 was custom made for me "in house"
and seems to be holding up.

Well with any .500" lift cam like that in a SBC you would want to at least drill and roll pin the rocker studs or
use screw in studs. The pressed in rocker studs will pull out with hi perf cams and springs. The valve guide-seal to retainer clearance must be checked.
Correct springs must be used with all these cams too.

The Isky Z-27 mechanical cam #201027 with .507" gross lift has .491" net lift w lash. (1.5:1 rockers .016" hot lash)

It's a sweet street/strip cam. Use Isky 235-D springs or the Isky dual springs or something equal.

You'll probabily really like this one and have the valve covers off and on a lot less often all said and done.

I have a little trick I do when breaking in a cam like this in a SBC. I use old stock SBC valve sprngs set up at max installed height. ( about 60-70LBS seat pressure under 200 open)
No shims etc 1.75"++ max installed spring height to reduce spring pressure for cam break in.
Then I install the correct high perf springs at the required installed height. (110 to 130 seat 300-340 open)
The reduced spring pressure on the cam lobes (and the Moly slip) really helps the cam and lifters get friendly during initial run in.
09-08-2012 08:59 PM
350chevyrob If i do put another cam in the highest lift that i would be comfortable is .510 because the 291 heads are stock and have pressed in rocker studs
09-08-2012 08:53 PM
F-BIRD'88 The only way you will know for sure is to pull it apart and look.

Here are a few isky part numbers to consider for replacement.

Isky solids "Z-27" 201027 "534-A" 201534 (degree this one in on a 102 intake C/L)

its easier to set the valve lash cold. Set the cold valve lash .002" to .004" tighter than the "hot lash" cam card lash spec.

Isky Hyd 286 Mega Cam 201286/6

292H Mega cam 201292
09-08-2012 08:44 PM
350chevyrob You think the main and rod bearing didn't get fried .im pulling the motor next weekend to inspect the motor
09-08-2012 08:37 PM
F-BIRD'88 I use and recommend Isky flat tappet cams
Solid and hyd for all flat tappet performance cam applications.

High quality, in house manufacturing . Use Isky or GM lifters too.

I use Moly slip E oil supplement in the oil to aid in successful cam lifter breakin and long life.

ISKY Racing Cams - Do It Right. Race with the Legend. Camshafts, Connecting Rods, Valve Springs, Lifters
Molyslip Canada Inc. :: Molybdenum Lubricants, Performance Lubricants, Copaslip Anti-Seize, EP2 Grease, Wear Reducing Lubricants, Oil Additive

You need to now tear it down and clean out all that metal.
and check your lifter bores.
09-06-2012 06:30 PM
350chevyrob 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
09-06-2012 06:13 PM
350chevyrob 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
09-05-2012 07:54 PM
350chevyrob Ok i re-adjusted the valve lash and still a tick .but when i was adjusting them i noticed one of the rockers slowly raising back up when i stoped bumping the motor over .same side it is ticking from .could that be the bad lifter
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