Noisy valvetrain...

GrandeStang73

GrandeStang73

Member
Apr 16, 2005
93
0
6
VA
#1
Hey guys, back again.... Thanks for the guys who helped with my hydraulic clutch issues!!:hail: Now its driveable, but the motor is noisy as hell coming from the valve covers. Here is what I have done to the motor, on open chamber 4V heads.

- CompCams Magnum series .530 list cam
- Brand new lifters and double roller timing chain
-new pushrods and Crane Cams adjustable stud conversion kit
- new YBB stainless roller rockers
- Doube valve springs (spring pressure checked by machine shop, ok for set-up)

My buddy from the machine shop came over and we did the valve lash per-instructions. Fired it up and broke the cam in. It was still noisy so we gave it another 1/2 turn adjustment. It still sounds like there is not enough pre-load on the lifters. What would be my next step? I'm afraid to adjust them while the motor is running,:shrug: I dont want to wipe my cam out from putting excessive pre-load...:bang:
 

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#5
I would also check to make sure you don't have an exhaust leak at your headers. Will sound exactly like valve train noise. You should be able to verify valve cover by using feeling for vibration or using a dowel touching the valve cover and put up to your ear. Sounds strange, but works. Lastly, if it is valve cover interference then you should see scratch marks when you remove the cover. Good luck.
 
#6
HI,
How does t
GrandeStang73 said:
Hey guys, back again.... Thanks for the guys who helped with my hydraulic clutch issues!!:hail: Now its driveable, but the motor is noisy as hell coming from the valve covers. Here is what I have done to the motor, on open chamber 4V heads.

- CompCams Magnum series .530 list cam
- Brand new lifters and double roller timing chain
-new pushrods and Crane Cams adjustable stud conversion kit
- new YBB stainless roller rockers
- Doube valve springs (spring pressure checked by machine shop, ok for set-up)

My buddy from the machine shop came over and we did the valve lash per-instructions. Fired it up and broke the cam in. It was still noisy so we gave it another 1/2 turn adjustment. It still sounds like there is not enough pre-load on the lifters. What would be my next step? I'm afraid to adjust them while the motor is running,:shrug: I dont want to wipe my cam out from putting excessive pre-load...:bang:
Click to expand...


Hi
How do those adjustable studs help with P/R geometry? They don't!
It's quite possible you're contacting the baffles in the V/C. But, more importantly, did you check for the proper P/R length? Good Luck!
 
#7
Hey Guys,
I took my mechanics stehascope and listened around the valve covers, I didn't here anything hitting them. I took them off and ground down the areas where I thought they might hit. I also did the double valve cover gasket trick. I'm still getting the noise... :bang:
How would I check for proper push rod length with adjustable studs and 1.73 ratio roller rockers?? :shrug: I have stock 351C push rods, most likely I will be getting longer push rods?
 
#8
GrandeStang73 said:
Hey Guys,
I took my mechanics stehascope and listened around the valve covers, I didn't here anything hitting them. I took them off and ground down the areas where I thought they might hit. I also did the double valve cover gasket trick. I'm still getting the noise... :bang:
How would I check for proper push rod length with adjustable studs and 1.73 ratio roller rockers?? :shrug: I have stock 351C push rods, most likely I will be getting longer push rods?
Click to expand...

Hi,
OK, first thing is to get some engineer's blue for coating the valve stem tip ( I think the "blue-ing" leaves a much better foot print than the ever popular "sharpie"). Remove a rocker, ( I remove the plugs, as well) apply the "blue" to the tip. Replace and adjust the rocker. Rotate the engine through several cycles, then carefully, remove the rocker and note the shiny track left on the tip. If your P/R geo is correct, the track should be centered and about .070 wide. If the track is offset to the exhaust side, your PRs are too long, it goes without stating, in the opposite direction they are too short.
It is imperative you check PR geo when making the hardware changes you did. Also, check the rocker is not contacting the edge of your spring keepers.
Now, if they are offset, you should get a spring checking kit from Comp. It will come with a couple of "light" checking springs and adjustable PRs. There are a couple of different length ranges, so, you'll have to determine which fits best for you. Basically, you pick a cyl, remove the springs and replace with the checking springs. These springs are light enough to keep the valves closed but do not depress the lifter (hydraulic) plunger. Do the same check as before. The PRs are graduated, so, you screw out the tips and note the length as it's added to or subtracted. Order hardened PRs. Hopefully, I didn't forget anything here.
Good Luck!
 
#11
.530, is a lot of lift, for stock length pushrods...I lost a cam and lifters pretty quick using stock lifters on my Edelbrock performer RPM cam....I suggest confirming the wear pattern ASAFP, and getting new push rods as required, before you lose a lobe on the cam...
 
#12
I'm still wondering why push rod length is such an issue here? I thought that was eliminated when I converted it from the non-adjustable to adjustable rocker arms. The motor has great power, dosent miss or hesitate, or backfire. I guess it does sound like a sewing machine in a way, but i think its more of a tapping right now.
 
#13
GrandeStang73,
While your adjustable rockers allow you to achieve the correct valve lash and/or pre-load, an incorrect pushrod length will leave the rocker arm at the wrong angle/position at the valve tip/plane with the valve closed and throughout it's travel. Make yourself a few/several simple drawings of your pushrod, rocker arm, rocker arm pivot and valve tip and notice wahat happens as you change the pushrod length and rocker adjustment to compensate for the length with the rocker arm the same length and the valve tip in a constant position.
Just My $.02,
Gene
 
#14
GrandeStang73,
Here are a couple quick drawings to help your understanding:

[/IMG]


ValveLongPushrod.jpg


The second shows a completely straight across rocker angle (close to correct) and the first shows a drastic example of a too long pushrod. If you drag them to your desktop, so that you can zoom them, you will notice how the second has the rocker contact the center of the valve, while in the first the rocker is off center on the valve. Also, even though not noticeable in the drawing, in the first, the pushrod is no longer parallel to the stud/valve by a bit more than a degree.
HTH,
Gene

Even.jpg
 
#17
Looks like everything thing is good under the valve covers... :bang: The roller rocker is hitting the valve tip properly... valve lash is perfect... and the rockers are not hitting the valve covers... It just sounds like a "sewing machine" I guess :shrug: Should I record my motor running and try to upload it?
 
#20
Sure sounds like an exhaust leak to me. Are you using good quality header gaskets or the cheapos? Exhaust leaks sound like valve train noise, can be very deceiving. Not sure of the best way to check for location of leaks, but you could feel around the header flange when you first start the car before it gets hot.
 
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