I'm tearing down a 1979 258. When I pulled the cam out I noticed that some of the lobes have what looks like tiny fracture marks that run with the rotation direction on the ramps up and down from the lobe. There may even have been some flaking from the sides, but as the sides of the lobes aren't machined it is difficult to say for sure.
Is this normal wear, or caused by collapsed lifters slapping the cam, or or is this a failure?
I tried to answer your email but it bounced back...
Anyway, that cam sounds toasted.
There 'are' different cams for those engines according to what emissions package it has I believe. Something to do with the EGR flow I think.
I would recommend replacing it with new or rebuilt if such an animal exists. You will likely need the casting number off the old one to get the correct one.
I would also go for the high volume pump.
I have my old 258 sitting in my garage waiting for me to start building it up nice. The engine I have in now only has 60K on it, so should be good for a bit.
When I do mine, I am thinking on one step on the cam (maybe) with new lifters for more low rpm torque, a better carb or a TBI unit (maybe), a high volume pump, and headers.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT'sLee Ayrt>
Grrrr. Given the amount of spam my ISP allows in, you'd think.... Oh, nevermind. They're low-priced.
I thought so too, and was sure of it when I was able to pull flakes off the sides with a dental pick. Now I know what might have made those little grooves in the mains. A new cam will be here tomorrow, with lifters and pushrods (and bearings, seals, et cetera). To my surprise, the local discount retail chain matched my mail-order cost from a large, popular, Jeep-specialty outfit. More surprising, my favorite jobber quoted me prices half-again higher and didn't list the cam at all.
Perhaps AMC did that, but peeking over the counter at a data terminal it looked like the part number is now the same for a couple of years either way. For my curiousity, a cross-check showed it was no different for auto trans v. standards. Of course, with AMC it might have just been a case of whose shelf of parts was the low bid that month.
BTW, am I the last jeep owner in the US to find out that the connecting rods have a date stamped under the bearing? Now I know it is a late
1979-early 1980 engine. (Rods manufactured 9/79).Thanks for that advice. I did order the HV pump. To my amusement, all three sources I queried use the same Mell part number for their stock number. Much less amusing wass the fact that those three quoted me prices ranging from $88 to $160. Someone's packing in a little extra profit.
What do you like to use as an assembly lube? This engine will sit a few weeks/few months before getting to run.
Thanks again.
Be sure to run-in the new cam properly. Most cam failures are a result of improper run-in.
Careful with casting numbers, many times the same casting is used for different grinds.
replace timing chain too (common sense).
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