roller cams in AMC 401 engines

[jimjamm65]

I need some good info regarding installing a mech. roller cam in an amc 401. my question is weather the lifter bores require bushings or not. there seems to be some info that there is an issue with the lifters unloading the oil pressure either out the top of the bore or below it. I know this can happen on other brands of engines under certain circumstances, but these are fairly well known. some guys have said that ALL amc v8's MUST be bushed, others say a custom lifter is needed. however, none of these sources are professional engine builders so the info is speculative. calling the cam companies doesn't get much of a confident result either. does anyone on this great forum have any real world experience in doing this? your help would be greatly appreciated.

[Ken_Parkman]

The problem is the wheel cut out can uncover the oil galley at high lift depending on the lifter design. Some companies do a shrouded lifter and there is no problem, and hydraulic rollers are shrouded so no problem with them. On the "old" Crane lifters the wheel cutout was sufficiently small the lifters did not uncover and those were OK with no bushings. But anything more modern I've seen has a large wheel cutout and they uncover the galley. So using those with an aggressive solid means you should bush the lifters. There is a Johnson fully shrouded solid, but it has a smaller wheel and I would not get too aggressive with those.

One other thing to note is the AMC lifter diameter spec is a touch larger than the Mopar, and as you typically get mopar lifters the running clearance is loose and causes more oil loss. Another reason to bush. I've had Johnson make correct AMC spec hydraulics rollers, not sure what is standard now.

[Jeff Lee]

Ken is right. To ad to that, and only if installing the bushed lifter bores is out of your budget, I have found that the AMC lifter bores are pretty much spot on with the angles and spacing so you could go cheap and not rent or buy the BJ Lifter-Tru fixture.
FYI - T&D makes a shaft rocker system.

[Walter R. Malik]

I need some good info regarding installing a mech. roller cam in an amc 401. my question is weather the lifter bores require bushings or not. there seems to be some info that there is an issue with the lifters unloading the oil pressure either out the top of the bore or below it. I know this can happen on other brands of engines under certain circumstances, but these are fairly well known. some guys have said that ALL amc v8's MUST be bushed, others say a custom lifter is needed. however, none of these sources are professional engine builders so the info is speculative. calling the cam companies doesn't get much of a confident result either. does anyone on this great forum have any real world experience in doing this? your help would be greatly appreciated.

I have had bushings made by "Trend" for that lifter bore size to bush the lifter bore to a smaller .842" lifter diameter.

No block machining and uses Comp Cams "Endure-X" Chevrolet lifters with #839-L tie bars.

I have been told that Morel will install any tie-bar on any lifter pair, if you ask.

[jimjamm65]

thank you all for your time and information. looks like bushings are in order for the job to be done correctly, and that is what we all want. walter, one of the good things about these amc's is the .904" lifter diameter. if I went with the .842" lifter would I have to have a specially ground cam, or will they run ok on the .904" lobes?