Hi guys,

I am currently reassembling my Y block (272) after it came back from the machine shop. I have come across my first problem (guaranteed installer error).

Let me get this straight first... I'm no expert and I'm not pretending to be, I took on this tear down/rebuild to learn about engines and do it myself, so I had anticipated a few problems and the possibility of complete failure, but sometimes that's the best way to learn (unfortunately).

Anyway, had a friend turn down a cam bearing remove/install tool for me and it seemed to work pretty good. I installed a the bearings and put my old cam in to see if it fits and it did, until the last bearing. It spun fine by hand until the last bearing than I had to spin the cam using a rachet on the bolt. I even put the cam in the othe end of the block and it spun fine in the last two bearings (that was as far as the engine stand would let me). So I tried the new cam and it was the same.

So I figured it must be the last bearing that is not in square, so I checked and seemed to be equal measurements all round.

In conclusion, how much resistance is acceptable when spinning the cam? I saw a video of Tim McMaster installing cam bearings in like 2min and his cam spun easy.

Any help would be appreciated. Also I purchased my cam from John M so I'd imagine it would be in good condition.

Thanks.


Thanks, Dennis.

56 F100 - 272 Y Block
NSW, Australia.

Snug cam bearing fit is not  a new problem. A buddy of mine ran into it years ago. Apparently there can be more than one cause.. been told that some cam blanks are not dead straight. And some cam bores are not machined perfectly in line or have become distorted over time. And I think I read that its recommended to install the last bearing from the rear to help avoid cocking it. However, I'm not sure what is the best way to fix it. Old time mechanics used to "scrape" carefully the bearing to get some clearance, but there may be a better approach to use. I'll let someone qualified step in here now... Goodluck  


Paul

i have a unorthodox cure,take your old cam, grind a small grove on the rear cam bearing  surface no longer than1/8 in. after clean the surface of the the bearing surface with fine emery. then carefully install rotate the cam when it stops  then pull back and remove any cuttings then continue. if you are taking large amounts off best have a machine shop take over. i have used this on fes as well as 302s and ys. usually a minor cocking of the bearing or burr. good luck

Thanks for that info Paul.

1955meteor- I did try this method but to no avail. Didn't seem to be any shaving happening.

Do you think I might have to tap the last bearing to see if it finds its place?




Thanks, Dennis.

56 F100 - 272 Y Block
NSW, Australia.

put the old cam in place then get a piece  of hard wood and place i end on some lobes at the end that is tight giv it a good smack withe a big hamer  some times that will lighn things up. then try the new cam. failing that i would look to the machine shop for help. good luck

The camshaft should turn with no resistance.  First check that the camshaft itself is straight and true.  Run out should not exceed 0.003”.  If the camshaft is okay, then with the rear cam plug out, the camshaft can be installed from either end to determine exactly which cam bearing is the culprit.  I have a solid steel bar machined such that it will fit in all the cam bore holes before installing the bearings.  With this I can determine if the cam holes are too small and/or misaligned with each other.  Being too small is an easy enough fix but if there is an alignment problem, this can get touchy depending upon the amount of misalignment.  Severe misalignment requires the holes to be rebored to the 1954 239/256 size and a special cam bearing set installed to use the '55 and up camshafts.  Minor misalignment issues can be remedied by working on the bearings on an individual basis.

Lorena, Texas (South of Waco)

Thanks Ted,

I played around with it a bit with no success. I ordered new bearings and took it to the machine shop for them to install. Problem solved.


Thanks, Dennis.

56 F100 - 272 Y Block
NSW, Australia.

I recall at sometime in the distant past taking a piece of 600 wet/dry sandpaper and kerosend and very lightly polishing the offending cam bearing. Didn't take much and never had any problems. Not that I am necessarily recomending this fix today.