Help, I have a few questions concerning valve train adjustment (olds 455 motor). I tried adjusting as per the advise I was given: Start with number one cylinder at TDC loosen up rocker arms. Then tighening till all pushrod up and down movement was gone then tightening an additional 1/2 to one turn. Then spinning motor 90 degrees the going to next cylinder in firing order. Now the problem was that once I started the motor I have a lot of valve train noise. So next I tried adjusting by loosening up the rocker arms and then tightening till the valve spring started to compress. Then I backed off till valve should be on the seat. After starting the motor there was a lot less valve train noise but still some tapping. Upon further investigation I noticed that not all the rocker arms take the same amount of adjustment: some are at the top of the rocker arm studs before the valve spring starts to move while others are close to the bottom of the rocker arm studs. Two of the rocker arms were right at the bottom so I couldn't even get the valve spring to start compressing. I suspect this is where my tap tap tap is coming from. I dont know if this is typical but my guess is a longer pushrod on these two rockers would fix things. So my question is has anyone mixed and matched pushrod sizes to get a perfect adjustment or should I get a whole new set of longer pushrods and re-adjust everything using the second method, that is waiting for valve spring to start compressing since that gave me the best results as far as quieting the valve train tapping. Allen allioop108@aol.com
olds if this is an oldsmobile you just torque the bolts down to 25 or 35 ft lbs if you still tap you can sand the bottom of the rocker pedestal till you get about 030 lifter preload or adjust with push rod length good luck ps pull the olds and install a buick!!! :Smarty:
Let me clarify some more on this. This is an olds 455 engine in a 70 cutlass. The reason why I an posting here is cause the people on the olds forum are not so helpfull or knowledgeable. Also the engine has harland sharp roller rockers, not the stock rocker arms mounted on the screw in rocker arm studs. With that in mind can anyone offer some advise on my previous post. Allen allioop108@aol.com
I can tell you how I do it, maybe it will help. When you adjust a hydraulic cam, spin the pushrod between your fingers while tightening the nut. Once it stops spinning (you'll feel resistence), tighten the nut 3/4 to 1 turn. As far as order. Go to #1 cylinder. Turn the motor over until the exhaust valve starts to open. Adjust the intake rocker. Go to #8 cylinder, bump it until the exhaust valve starts to open. Adjust the intake valve. Follow the firing order on around and adjust all the intake valves. (18436572) Now go back to #1. When the intake valve reaches full open and then starts to close - adjust the exhaust valve. Follow the same sequence (firing order) as above. I use this same sequence on my solid lifter race motors also. It's a little tricky on a new hydraulic cam because of the spring in the lifter. You should go through the sequence twice to make sure everything is set right. Hope this helps. Have fun.
FIRST: When converting to adjustable rockers, DID YOU VERIFY PROPER ROCKER GEOMETRY? This is measured at the valve stem tip, but adjusted with different length pushrods. This was engineered into your old pedistal mount rocker system, but adjustable rockers are very picky about this. Go no farther until that is taken care of. DO NOT just slam longer pushrods into the engine and expect problems to go away. SECOND: Hydraulic cam??? It is much, much easier to go to a junkyard (or wherever), and buy an extra valve cover. Cut the top open to allow access to the rocker adjuster fasteners. Run the engine til it's fully warm. Put the modified valve cover on the engine and start the engine again. Back off the each rocker nut until you can hear THAT ROCKER make noise, then tighten until the noise JUST goes away. Do all the rockers on that bank the same way. Shut off the engine, tighten each one another 1/2 turn, install the "real" valve cover, move the cut out cover to the other side, and do those the same way. Reinstall the original cover, and you're done.
What ratio rockers are they? New lifters? It sounds like you had it right the first time. If you did not put the lifters in oil and "pump" them up getting all the air out before you put them in the motor they will be noisey for a minute or two until they pump up with oil. Go back reset it like you did the first time and keep the rpms down until they pump up. I don't know my Olds that well but the spring retainers can hit the rockers making noise and on high ratio rockers the pushrod can get hung up on the pushrod hole in the head keeping it from seating in the rocker cup. This is because they move the pushrod cup in the rocker toward the pivot point to get the ratio up thus sometimes the pushrod hole needs slotted.
Everything was set up by the machine shop years ago and the motor has been run for a while, just no street driven miles so lack of oil is not the issue. I just noticed when I go to adjust that I can get some pushrods to start tightening when spun by hand while rocker arm is near top of stud and others while its at bottom. The ones at top are no problem since I could tighten till valve spring started to compress then backed off till spring was fully open. The two rockers that were near the bottom didnt even have room left to start compressing spring. Thats why i was wondering if anyone has used different length pushrods in a motor. I'm guessing that with adjustable pushrods they are not all coming out to the same lenght after being adjusted. Now I know this is not the proper way to adjust rocker arms but it got the motor the quietest. Anyway I started it 2 days later and after about 3 seconds of lifter clatter, like on a buick motor, it got quiet, much quieter then when i first posted. Started it today and still running quiet, no tap tap tap so I'm going to leave the adjustment as is. Would still like an answer to different pushrod length or do adjustable pushrods end up at same length after they are adjusted? Allen allioop108@aol.com
lifters is your intake on? if you can see lifters this is the easiest way take all slack just out of push rod dont spin it as you may get a false "feel", go up and down with it, after all slack is out tighten nut 3/4 to one turn if they are rhodes or crane variables this is what the directions say but it works well with any hydraulic lifter I've literally done thousands. just make sure lifter is at bottom of cam lobe when you do this you should not use the spring compressing to do this as the lifter will probably be too tight. also you may have a bad set of lifters if they bleed down when valve is in open position this may be the case it happens and will give you fits! as to your pushrod length question if you didnt have adjustable rockers the different lengths may come into play the valve stem heigth is what dictates this. it is common on fords to play with pushrod length as they are non adjustable also mopars, and olds hope this helps walt :Comp:
