390 valvetrain noiseJune 2 2011 at 6:27 PM
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|Mark (Login mr.galaxie)|
from IP address 220.127.116.11
I'm hoping someone out there can help me with a problem I'm having. I rebuilt a 390 for my galaxie and it has a valvetrain noise I can't figure out. It's a .040 390 with edelbrock heads, harland sharp roller rockers, edelbrock performer rpm cam, and intake. I fired it up, broke in the cam, and finished tuning it and heard a noise that I thought sounded like lifter noise so I readjusted them and it sounded the same. The adjusting screws on the rockers have one thread showing past the bottom of the rocker arm which is where they should be, it's got 30psi oil pressure hot and runs perfect. I wasn't fond of the edelbrock's retainer design for the lifter plunger and had one come apart on initial assembly so I changed to a set of comp lifters and it sounds the same. When cold it is barely noticeable when warm it's very noticeable at all rpm but loudest between 1500-2500. I had these heads on the previous engine in the car and was starting to get a noise similar to what I have now, but the cam was going away and figured that was my noise. I'm not saying that the heads are the source of the noise but I am not ruling anything out. The heads are the only thing from the old engine that are on the new one. I don't think it's in the cam or lifters but I can't figure out what it is. The contact pattern of the roller tip on the rocker to the valve tip wasn't quite where I thought it should be but since the shafts are mounted on the stands it's really not adjustable unless you shim the stands which actually looks like it would correct it some. Anyways I'm tired of typing and hope someone out there can bail me out.
One lame idea.. but mostly a simpathy postNo score for this post
|September 1 2012, 11:36 AM |
I can't say this is very likely (especially since you said the heads are the only thing that's the same on the new engine), but I had what I thought was valvtrain noise on a rebuilt 390 with new rocker arm assemblies and it turned out to be a broken conterweight pin in my distributor. This caused the counterweight to bang around inside the dist. housing and affect power at highway speeds.
Your subject title just really caught my eye and I remember going through alot of the same frustration as you're describing. Hope you've figured it out and have that thing running smooth. That upper end rattling used to drive me crazy.
valve train noise 390No score for this post
|October 30 2012, 6:19 PM |
I had the same experience 40 yrs.ago and it turned out to be a worn valve guide. Sounds just like a valve needing adjusted..