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rocker arm noise


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Does it happen when it's cold or all the time? IF you have the '68/69 rockers there are metal pads in the rocker arms for the valves, and they do break, I've found a few split, but before I heard any noise. Almost all Buicks of this vintage with any amount of miles seem to make noise til the lifters build up pressure, then they run fine. <P>------------------<BR>Roberta<BR>BCA TREASURER 2000-2001<BR>BCA PRESIDENT 1998-2000<BR>BCA VICE PRESIDENT 1997-1998<BR>WEBMASTER<BR>1956 Special 2 door Sedan<BR>1966 Wildcats<BR>1968 GS-400 Convertible 4-speed<BR>1970 GSX Stage 1<BR>1970 Skylark Racecar - 11.26, 118 MPH, 7/22/00<BR>1986 GN, 4800 miles

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Noisy rocker arms in Buick 400-430-455 is often caused by front cam bearing failure, especially if the noise seems to be coming from the driver's side.<P>The driver's side lifter oil gallery is fed from a port in the front cam bearing. Oil is first fed to the passenger side gallery, then through a groove in the front cam bearing journal, and then to another port in the front cam bearing, which then feeds the driver's side gallery. As the front cam bearing wears, bearing material builds up in the port that feeds the driver's side gallery, causing the lifters to be somewhat starved for oil, resulting in noisy lifters and rockers.<P>If this is the case, you need to replace the front cam bearing. TA performance and others sell grooved cam bearings which can help to alleviate this problem.<P>BR

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Is there any other way to tell if you have front cam bearing wear without pulling the cam? I have what sounds like a noisy lifter on the drivers side that only gets noisy after the car warms up, my oil pressure is OK 35-40 psi warm.<P><P>------------------<BR>'68 GS400 Convert

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To 11M834:<P>I can only speak for the 400-430-455 series. I am pretty sure the 350's oil the same way, making them prone to the same failures, but I am really not 100% sure. I would double-check with TA Performance.<P>TA Performance's Phone # is: 480-922-6807, and they are located in Scottsdale Arizona.<P>To caGSxlr8:<P>Unfortunately I know of no quick way to positively detect front cam bearing failure without removing the cam. I guess you can try running the motor without the driver's side rocker cover and see if there's any oil getting up there. Another thing you can do is try to eliminate as many of the other "easier-to-check" possibilities as you can (described in the next paragraph).<P>But the type of failure I am describing will affect all of the lifters on the driver's side, not just one or two, as you described, and is most likely to occur in high mileage engines and/or engines with stiff valve springs, high lift cams and heavy duty oil pumps. Your problem sounds more like the conventional problem of either a sticky lifter or lifter with excessive leak-down (the most likely culprit). Other things to check for would be a worn or bent pushrod, a worn rocker arm or rocker shaft, a mushroomed valve stem or a sloppy valve guide, valve seat recession, a worn lifter bore, a worn cam lobe (this would be more difficult to accuralely check except for obvious visible defects), all of which can be checked without major disassembly of the motor (removal of rocker arm assembly, a couple of valve springs and the intake manifold is as far as you would need to go). If everything positively checks out OK then you have eliminated all of the possibilities and might want to consider removing the cam.<P>Happy Motoring<P>BR

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I had the same problem with my 72 455. I am on a tight budget and could not afford new/rebuilt rocker shafts, so I swapped the shafts from side to side...this cured the noise...valve stems evidently had worn the rocker arms and swapping sides caused the valve stems to contact the rockers in a slightly different area...thus eliminating the excess clearance!

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I have the same problem. I have a new engine inlcuding cam, lifters and adjustable pushrods and I still have what I consider a fair amount of rocker noise compared to other makes I have worked with such as Pontiac and Chevy. Of note, my rocker shafts are not new! I have a feeling that this is typical of Buicks. wm

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by wm:<BR><B>I have the same problem. I have a new engine inlcuding cam, lifters and adjustable pushrods and I still have what I consider a fair amount of rocker noise compared to other makes I have worked with such as Pontiac and Chevy. Of note, my rocker shafts are not new! I have a feeling that this is typical of Buicks. wm</B><HR></BLOCKQUOTE><P>New engine...old rocker shafts? <P>The valvetrain should not make any noise if the engine is rebuilt to factory specs. Don't know about reusing old rocker shafts on a "new" engine.<P>I assume you are running hydraulic lifters.<P>

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Thanks for the reply straycat. I should have been more specific. I rebuilt the motor so it is a new/used engine. I was told by several of the buick performance shops that you can reuse the stamped steel rockers which are better than the 1970 rocker shafts. However, I'm using 1973 rocker shafts on a 1970 motor. It is my understanding that this is OK. They are a lower ratio rocker but I compensated for that with the cam. Yes, I'm using hydraulic lifters and the eninge was rebuilt to apporximately factory specs. Little bigger cam and HEI are really the only mods. I doesn't have any loud valvetrain noise such as a lifter that is completely out of adjustment, it just seems that at 2000rpm I can hear more valve action than I'm used to hearing. I think the noise level is a matter of perception and having no prior experience with buicks I don't really know what is considered noisy! Any thoughts!

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by wm:<BR><B>...However, I'm using 1973 rocker shafts on a 1970 motor. It is my understanding that is OK...</B><HR></BLOCKQUOTE><P>It's very common to use the lower ratio 1973 and up stamped steel rocker "arms" in a rebuild. There should be no problem if installed right. There is a slight offset to all 400-455 rocker arms, thus there are "left" and "right" side rocker arms. These alternate down the shaft. Assuming that you got this right I'd check your oil pressure at 2000 RPM and up. It's possible to appear sufficient at idle, but not at higher RPM's.<BR> <BR>

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