We got into a lively discussion over on the .org site about hydraulic lifters. Here's what I wrote and also found out. I thought I would share here, since it's useful information.
Alrighty! I already had one spare new Lunati Micro Trol big block hydraulic lifter. I ordered a sealed power 2089 slant six hydraulic lifter. As I suspected, there is one small difference, but not in operation. The slant six lifter has the disc check valve eliminated under the pushrod cup, to allow oil to bleed back out of the lifter and back up the pushrod, since it does not have the hole in the side body. Other than that, the two types of lifters are 100% completely interchangeable. The big block lifter is the same dimensions and has the bleed off hole in the side, which would certainly work in the slant six. In fact, there ARE some part numbers for the slant six hydraulic lifters that DO have the bleed holes on the side, just the same as the rest. Just look at the Comp 820 hydraulic lifter for the Slant Six. They have the side bleed hole and although I've not torn one down, I can guarantee they also have the disc check valve as well. That's the only reason the Sealed Power does not have it, is because they choose to leave the disc out and allow the in hole to be used for the out. On the slant six lifter here, oil comes in the pushrod cup hole, fills the lifter on the base circle and then expels a very small amount, like all other lifters, just AFTER full lift. Rinse and repeat. The only difference is, the lifters without the side bleed holes, use the same hole going out as they do coming in. The lifter is pressurized just the same in one hole as it is the other. Here are pictures. I did not get a good shot of the disc in the Lunati lifter on the left, but it is under the pushrod cup. The disc does not stop oil from going into the pushrod on the AMC engines, it simply controls "when". Again, these two lifters are totally interchangeable in the slant six, just as I said before and have done and seen done for a long time. Luntai lifter on the left, Sealed Power slant six lifter on the right. Argue away.
Alrighty! I already had one spare new Lunati Micro Trol big block hydraulic lifter. I ordered a sealed power 2089 slant six hydraulic lifter. As I suspected, there is one small difference, but not in operation. The slant six lifter has the disc check valve eliminated under the pushrod cup, to allow oil to bleed back out of the lifter and back up the pushrod, since it does not have the hole in the side body. Other than that, the two types of lifters are 100% completely interchangeable. The big block lifter is the same dimensions and has the bleed off hole in the side, which would certainly work in the slant six. In fact, there ARE some part numbers for the slant six hydraulic lifters that DO have the bleed holes on the side, just the same as the rest. Just look at the Comp 820 hydraulic lifter for the Slant Six. They have the side bleed hole and although I've not torn one down, I can guarantee they also have the disc check valve as well. That's the only reason the Sealed Power does not have it, is because they choose to leave the disc out and allow the in hole to be used for the out. On the slant six lifter here, oil comes in the pushrod cup hole, fills the lifter on the base circle and then expels a very small amount, like all other lifters, just AFTER full lift. Rinse and repeat. The only difference is, the lifters without the side bleed holes, use the same hole going out as they do coming in. The lifter is pressurized just the same in one hole as it is the other. Here are pictures. I did not get a good shot of the disc in the Lunati lifter on the left, but it is under the pushrod cup. The disc does not stop oil from going into the pushrod on the AMC engines, it simply controls "when". Again, these two lifters are totally interchangeable in the slant six, just as I said before and have done and seen done for a long time. Luntai lifter on the left, Sealed Power slant six lifter on the right. Argue away.
