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Audible noises coming from the valve covers?

 
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projekt70chevelle
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PostPosted: Sun Sep 03, 2006 3:24 pm    Post subject: Audible noises coming from the valve covers? Reply with quote

This is my first high performance motor and I just want to make sure there isnt anything wrong before I head out on the road. I'm reading good oil pressure about 30 psi at idle and about 60 above that. Its not a valve clicking noise just a constant purr if you will...

Is it anything I should be worried about?

I'm running manley valves with guide plates and double valve springs.
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jeep_406
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1972 Chevrolet Nova

PostPosted: Sun Sep 03, 2006 3:54 pm    Post subject: Reply with quote

Description of a constant purr kind of throws me.
Are your rockers kissing the valve covers?
Are the rocker arms coming into contact with the side of the valve springs?
How much cam lift are you running?
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10sec.et
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1969 Oldsmobile Cutlass

PostPosted: Sun Sep 03, 2006 6:38 pm    Post subject: Reply with quote

heard HV oil pumps make a "purring" sound. can you pinpoint the area with a stethescope?
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af2 wrote:
It seems we can look at our magical Balls and come up with a fix?

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projekt70chevelle
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PostPosted: Sun Sep 03, 2006 7:06 pm    Post subject: Reply with quote

Dont have a stethescope, but I may have to get one. I have stud gurdles and there is a good amount of clearance in between them and valve covers, nor is there any kissing on the rockers. I'm running a 679 lift.

This noise isnt anything really loud or sounding like something is wrong just something I'm not used to vs a stock 350. I couldnt hear any of this before since it was open headers but now with the mufflers on it I'm hearing noises I didnt hear before.
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artinla
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1971 Chevrolet Nova

PostPosted: Sun Sep 03, 2006 11:02 pm    Post subject: Reply with quote

Forged pistons make noise, roller rockers are noisy, if it has a gear drive they whine like hell. Performance engines such as that beast of yours will make some "New" sounds. I am not sure that I have ever heard one "Purr" but I think you may be hearing the pistons.

I doubt you have a real problem but I would be on alert for any big change in the noises.
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af2
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PostPosted: Mon Sep 04, 2006 1:22 am    Post subject: Reply with quote

As 10 said. I have heard the oil pump make that purrrrr sound. Tore my big block apart thinking it was not happy. Shocked A long screw driver is the next best thing to a scope.
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clay
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1972 Chevrolet Nova

PostPosted: Mon Sep 04, 2006 8:18 am    Post subject: Reply with quote

With that much lift, there will usually be some valvetrain noise even with a hydraulic. With you describing it as a "purr" I'm assuming this means a uniform light noise from the valvetrain and this is what I would call normal. If you have a problem with one valve, it will stand out and be louder than the rest. Do some more investigating under the covers looking where the pushrods come up through the heads, look around the guideplates for any wear, you have already checked the girdles so you should be o.k. if everything looks good. Look for fine metal around the bottom edge of the head and around the drainback holes. Is this a mechanical cam? If so there is definately going to be noise, but like I said, I have heard some noise from hydraulics at the lift you are talking about. I don't think you have a problem, but do some more poking around and look under the covers another time or two when you get some more miles on it. Clay
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Big Dave
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PostPosted: Mon Sep 04, 2006 8:25 am    Post subject: Reply with quote

And like Jeep406 said, a lot of extruded aluminum roller rocker bodies contact the spring coil because there isn't enough clearance at the trunnion of the rocker. To get the strength required to resist grossly deflecting under the open spring pressure they have to be thick. The rubbing as the rocker rotates about the trunnion causes the springs to vibrate like a bow drawn across a stringed instrument. (it also puts undue wear on the valve guides).


Big Dave
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10sec.et
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PostPosted: Mon Sep 04, 2006 10:42 am    Post subject: Reply with quote

af2 wrote:
As 10 said. I have heard the oil pump make that purrrrr sound. Tore my big block apart thinking it was not happy. Shocked A long screw driver is the next best thing to a scope.


forgot about the screwdriver trick thumbsup . just put the tip if the screwdriver on the motor and your ear on the handle. works great. hurts like hell if you get it in the fan though retard

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af2 wrote:
It seems we can look at our magical Balls and come up with a fix?

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af2
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1933 Willys Coupe

PostPosted: Tue Sep 05, 2006 12:13 am    Post subject: Reply with quote

10sec.et wrote:
af2 wrote:
As 10 said. I have heard the oil pump make that purrrrr sound. Tore my big block apart thinking it was not happy. Shocked A long screw driver is the next best thing to a scope.


forgot about the screwdriver trick thumbsup . just put the tip if the screwdriver on the motor and your ear on the handle. works great. hurts like hell if you get it in the fan though retard


You did that too Shocked You wake up quick! And deaf. Cheers
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