Just starter up my 56 235 pass. engine after some minor work over the last few months. After a few minutes running up at temperature all the hydraulic lifter noise stopped except for one click or rap. I cannot locate it with a hose or stethoscope. I have done my best to adjust any valve lash several weeks ago. Is there any way to check for a bad lifter prior to taking them out? Does this sound like a bad lifter or something else? The po had the engine rebuilt a few years ago. The noise does go away some after driving but does not totally stop. The pushrods are not bent. Thanks
cassie: Noise can be from several things. To isolate it can be a bit of a challenge. If you think it is a lifter, you can try the following. Set idle as low as you can. Remove valve cover and with a bit of practice you can adjust each valve with the engine running. A 5/8 short box end wrench will loosen the lock nut and a stubby screw driver will make the adjustments. You need to develop a "limp" wrist to do this but it is not too hard to do. Start at the rear, #6, and loosen the nut and tighten the adjuster 1/2 turn. If the motor slows down or stumbles back it off until it is smooth. Repeat for each valve in sequence until you find the noisy one or they are all done. If this does not stop the noise you most likely have a bad rocker arm, push-rod, or lifter. Possible bad arm on the fuel pump. This works for solid lifters as well. But it is hot and messy so only advise it for troubles like yours. Keep the idle as slow as the engine will run. After the nut is loose let the wrench "float" so it will not clatter and won't push down on the rocker arm. Do this when the engine is warmed all the way up. Also a good time to look at the oil flow at each rocker arm. I think you will find the noisy lifter and I think it will adjust to quiet. On the one that is noisy you might need to turn the adjuster a bit farther But stop if the engine slows or stumbles. That would mean that the valve is not seating. The trick is to let the valve set on the seat and take out the mechanical clearance from the lifter, push-rod, rocker arm, valve stem, and cam. You will be able to do this and hear if and when it makes a difference. When you are done set the idle back to 450-500 RPM put the valve cover back on and see if it stays quiet. You might have a bolt from the coil mount rubbing on a push-rod. To tell if it that, you will have to back off the bolts 1 at a time while it is running. If that makes the noise go away use a shorter bolt or add a washer or 2 to the bolt that is rubbing. I would start with the bolts to the coil. Should have put that first.
Just been there and done all of that with my 56 pass 235 too. I had some worn valve guides and that was the majority of my upper end noise but there was hydraulic lifter tap I had. I removed it by cutting a small groove in the ball of the pushrod ball. Lifter gets some air trapped in it and it can't get out. Talk to pre68dave on this forum, he may have a pic, but basically cut a small groove from the center of the ball on the pushrod to the outside of the ball, just a few thousands deep. Cures the tick. Here is a vid of my idling 235
1953 Chevrolet 3100 261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done In the DITY Gallery Video of the 261 running
1964 GMC 1000 305 Big Block V6, sm420, the next cab off restoration
Do this to find the lifter take a .002 or .003 feeler gauge and starting from the front rocker (engine running) slide it inbetween the valve and rocker when you get to the noisy one you'll hear the differance and than you can readjust that one.
Some lash caps have tiny holes in the end for that very issue. I guess the same principle would apply to the lifter/pushrod contact point. Having a little groove in the end of pushrod would let a little oil in.
Dave. I read your info about a noisy new lifter. After how many miles will a new, tight hydraulic lifter break-in. I have one that is noisy until the engine reaches operating temperature, then everything is fine. I have noticed that 1,500 miles after complete rebuilt, the tight lifter is not at noisy as it was at 0 thru 1,000 miles after rebuild. Can I expect the noise to go away completely, or would you recommend replacing the lifter?
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
Doubt that lifters break in, if it is noisy it has air in it and needs to be relieved by grooving the pusher as per Dave's depiction. Hydraulic lifters seldom cause any problem and usually never need replacing unless they have been damaged by improper preload.
1953 Chevrolet 3100 261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done In the DITY Gallery Video of the 261 running
1964 GMC 1000 305 Big Block V6, sm420, the next cab off restoration
Dave. I read your info about a noisy new lifter. After how many miles will a new, tight hydraulic lifter break-in. I have one that is noisy until the engine reaches operating temperature, then everything is fine. I have noticed that 1,500 miles after complete rebuilt, the tight lifter is not at noisy as it was at 0 thru 1,000 miles after rebuild. Can I expect the noise to go away completely, or would you recommend replacing the lifter?
It is hard to say how long it will take. If it is improving I would keep running it.I am assuming you grooved the bottom of your push rods?
I guess I should start by removing the lifters and cleaning them. They seem to all tick until the engine has been hot for 15-20 minutes,and the one never quiets down. It may be gunked up. I don't know at this point if the seat has a hole in it or not. I had the fuel pump off months ago and it seemed ok. What causes it to make noise? Broken spring? Thanks to all for your input.
Since it is an easy job pulling push rods, I may pull the one on the sticky one and groove it to see if the cold engine lifter noise goes away. I'm not too lazy to groove all of the push rods, I'm approaching it as a research project. I will report back under a new post.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission