Hi all, Its me again with an oldsmobile 455 question. In a previous post I stated that I had bent a pushrod in the motor due to over tightening a roller rocker. Well I replaced all the pushrods and adjusted this time with the motor off following the firing order and spinning motor 90 degrees at a time. Well I finally got the motor running but its still not running right so I need some advice. When I tightened the rolloer rockers I spun the pushrods with my fingers and tightened the rocker arm till there was resistance on the pushrod. Then I went a quarter turn more. Maybe I should have gone more than a quarter because I still have a lot of lifter clacking. Also it was hard to maintain a steady idle without stalling till I closed down the air bleed screws on the idle circuit. This made the idle go up a bunch and helped to smooth motor out. However it is still running real rich. Is there any correlation between the rocker arm adjustment and the motor running too rich, it was popping a bit too when I revved the engine. Also I must add that I broke a bolt while tightening the intake manifold down but I dont believe this would have caused a vacuum leak since it was a center bolt and it happened on the final torque sequence. I have not tested for a vacuum leak but even if there was one wouldnt the motor be running to lean as opposed to to rich. Please help as I cant start my bucik 455 rebuild till I get this olds on the road. Allen allioop108@aol.com
You might have the adjustment too tight. I would go through the adjustment procedure again. This time loosen the adjustment until you feel there is clearance moving the pushrod up and down. Then slowly eliminate the clearance, and go 1/4 turn more. Too tight can prevent the valves from seating making the motor run rough especially at idle.
I was kind of thinking the opposite since someone gave me directions saying to snug then turn adjustment 1/2 to one full turn where as I only went a quarter turn thinking it would be better to start off conservative (definate lifter clackity clack). Also I know carb is good since I pulled it off my buick and it was running mint on there. Now you have lots of fumes, unburned gas, and closing the bleed screws smooths out and increases idle so I know it is pulling to much gas on the olds motor but didnt do this on the buick motor. Any other opinions???? Allen allioop108@aol.com
I agree with Larry - when the up-n-down movement of the pushrod is gone, then tighten 1/4 to 1/2 turn. Also make sure the valves are closed when you adjust - physically watch the intake valve close, rotate the engine a couple of degrees more and adjust both valves on that cylinder.
The main difference between what you did and what was supposed to be done was spinning 'em vs. checking for up&down play. Just wanted to chime in to give you some confidence. If you readjust until the up& down play is gone, then go another 1/4 to 1/2 as suggested, you should be good to go. I think what happens is the valves are kept off the seat when the lifter pre-load is so high and that causes incomplete combustion and a loss-of-vacuum sensation. Another symptom is that it will start right up, then when oil pressure builds (like in a couple seconds) it dies right away. When the oil pressure is built-up in the lifters, it makes cold starting a little more difficult.
ok, but what about the car running way to rich? how can I fix this? Stock holley 3310-4 (750) carb. Allen
It may appear to be running rich, if you are getting incomplete combustion. Adjust the valvetrain first, then see how it burns
I know it sux, but adjust each rocker by itself. Get the lifter on the base circle, then adjust it. I know the 90* thing is supposed to work, but why chance it after all this frustration?
Ok, I took things back to square one. When I pulled the valve covers to re-adjust the valves there was coolent on the rocker arms. Same with the dipstick. I'm assuming this was from when I pulled manifold last month and coolant spilled into the motor although I didn't think it was that much and no in my haste I didnt change the oil. I had it running yesterday and it never overheated so I'll rule out head gasket problem. Today I decided to pull the head so that I could remove that broken intake bolt. After removing intake there was just a tiny piece of the bolt sticking out from the head. By some miracle I was able to grab it with the vice grips and spin it out of the head. Good thing I didnt start by disconnecting the headers. Afterwards I tapped each bolt hole and oiled them. The gasket didnt seem to indicate any type of leak, vacuum or coolant. One observation, when I removed the intake bolts they did not seem all that tight. When I had tightened them I torqued them to 40 foot pounds in the sequence of 10, 20, 30 and then 40. While I'm waiting for my new gaskets and bolts to come in mail I'll change oil, pull plugs and do a compression reading to make sure there are no other hidden surprises. If that goes well then I'll bolt everything up and hope for the best. Allen allioop108@aol.com
