I am rebuilding a 1941 GMC 228. I am having a bear of a time finding push rods and lifters. the lifters that came out of it are more like cam followers, they are just hollow and ride on the cam, rod sits down in the bottom of it. They look like simple metal shot glasses. Lifters are 12 7/8 inches long. Has anyone out there ever experimented successfully with a different lifter push rod combination?
Bill, been following along your journey on YouTube. I've been piddling with my 39 GMC for a couple of years.
Do you still have your original lifters out of the engine? I just sent my 228 lifters and cam off to Oregon camshaft on Tuesday to be refinished. I have the same style lifters. I spoke with Ken on the phone and he's got about 50 years of experience. He knew exactly what I had when I told him I was working on a 228. You might give him a call and pick his brain.
I use the Sealed Power/Federal Mogul AT 887 lifters with the later model shorter push rods. I still have the attachment on my old Sioux valve grinder to regrind the crown on lifters, but I haven't used it in years. Back when I started working on GMC engines almost 70 years ago it was common practice to get rid of the old style lifters and replace them with what we called the milk jug lifter. I'm not sure if the AT 887 lifters are still being produced, but there are probably NOS ones on eBay. Push rods are around. Chev used the same as GMC.
Aren't lifters supposed to have a slight radius on the bottom, not completely flat? I'm in the process of building a jig for my lathe to use a die grinder and a small sanding disc to put either a 60" or 72" radius on lifters, depending on how the jig is set up. Jerry
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Lifters need a slight crown to rotate. I used to chuck them up in my old Sioux valve machine. Many years ago I wrote this on my manual for my old Sioux valve machine. The edge of an approximately 7/8 lifter needs to be 0.0021-inch lower than the centered reading. I'm not a machinist and I would have difficulty setting up a dial indicator to run across the face of the lifter to be able to measure 0.0021 from the center of the lifter. I usually just chucked them up and refaced them from the center to the edge. The crown can be felt by putting a straight edge across the face and I could feel that the center was higher than the edge. But they have to be crowned in order to spin. I always made sure I put the lifter in the hole from which it came. If I used a used lifter I gave it a little crown and watched it when it was running. Lifters aren't that hard to pull out and put back in on a GMC. With Y-Blocks it is a different story. They need to be right the first time. I'm not sure what the tolerance is on an old 645 Sioux valve grinder but I just kinda guessed at things like the crown. Y-Block lifters chucked up just like a valve. GMC lifters were too big so I did those on the back side where I ground the tips of the stems. It has a V-Block cradle against a flat cupped stone. I laid the lifters in the V-Block and the stone and then spun them with the middle of the lifter at the edge of the stone. Nothing scientific, but I never had a cam go flat. But I'm an old fashioned country fixer. I thought I was really uptown by having a glycerine filled made in Germany vacuum gauge. The vacuum at the fuel pump on a Cummins N14 or ISM like we run needs be about 6". Otherwise there is a restriction somewhere. I recently saw a guy that had a $600 adapter for his Fluke digital meter. He discovered something like 12.325 Inches of vacuum. That might impress him, but If I read over 7" I start looking for restrictions.
