The FSM is very specific about the order of removal and install of the bearing caps. The lobes contact hydraulic lifters, which I replaced brand new with INA (OE) units. The bearing caps that the FSM indicated are the ones that I think press down the lobes in such a way to support the cam properly.Ouch, that sucks.
I take it that the cam rests with at least one lobe pressing against the valve spring? If that’s the case, it was likely the cause of the cam not sitting all the way in the bearings before you applied the final torque.
I’ve removed and installed cams a few times now on these engines without incident. Now the stupid tax.
I think when I hand threaded the two bolts per cap, I put those in unequally. That manifested itself at the final torquing.
I’m lucky in that MB puts numbers on each of the bearings.Years ago I lost the order of bearing caps while installing a crank. Granted i didn’t break it, but upon assembly, prior to dropping it back in the car, I put power to the starter and noted that the engine wouldn’t turn. After brainstorming a bit (I was 15 and this was my first rebuild that wasnt on a tecumseh) it occurred to me that I was uncertain at that step. So I separated it from the trans, put it back on the stand, flipped it over, and tried to resequence the bearings. Lesson learned - start testing to make sure it rotates and doesn’t bind while torquing down. Idk if this is a good idea from the pros or not, but it stuck with me.
Maybe it didn’t seat in the bearings, maybe the caps are out of proper sequence, perhaps a lifter was supposed to compress and didn’t, is this an interference engine?
By the way - I’m so sorry - you are doing wonderful work on an amazing classic, with less available information than say a gasser. Labor of love (or car disease, depending on perspective!)
My main curiosity is if I could have done something wrong with a lifter. After all, I’m replacing lifters and cam. I dunked each lifter in oil before inserting, but nothing else.
Removal:
Dunking:
Installed:
So if the oil in there could cause the lifter to not operate, that’s a concern. I have my doubts of that being an issue, as they weren’t filed underneath and I didn’t dump all kinds of oil in the bores that they sit.
I guess one lifter could somehow be stuck? Not in quite straight?
I think it was because of my hand tightening sequence. Occam’s Razor is likely true here. The simplest thing is that I lost count of the tightening in the bearing cap bolts, and so they didn’t all come down evenly and together.
But I don’t know how to validate that as the case.