Hey guys, got one I wonder if anyone has run into during a flathead rebuild. I went to put a new Isky cam in and it won't go in. Mic'd the journals and they are .006 bigger then the journals on the old cam I took out. Has anyone heard of oversized cam bearings (the bearings look great so I left them in) and turned down cam journals or do I have a bad cam from Isky? Also does anyone know of a source for 30 over main bearings, my crank has already been turned that much before I got it. All my normal sources (local warehouses, Speedway, ect) only show 20 over max.
What should the dimension be? I have an Isky cam on the shelf to put in my blower motor when it gets back from the machinist real soon. I'll check mine. Thanks, Fourdy
I have a fair amount of nos Ford and some aftermarket brands of flathead bearings. What year motor? Crank journal sizes if year is unknown..... Mac VP
I don't know what the dimension should be, guess that's my delima. I don't know if I should replace bearings or cams. My machinest said he could turn down the Isky journals but I don't want to in case I have some odd off side bearings.
According to Ron Bishops book, Rebuilding the Famous Ford Flathead, cam journals should measure 1.796" to 1.797" on both early and late 24 stud motors, in other words all 59 and 8ba/8cm series blocks.
There are oversize cam bearings, but they're not common - I wouldn't expect to receive oversize journals on a cam from Isky unless I asked for them...seems odd. New cam bearings maybe? Old cam was already worn & turned down used with undersize bearings? I guess when you mic the Isky cam tomorrow (today) we'll find out!
Some flatmotor came with +. 010 cam bearings.Just change cam bearing to standard and everybody is happy.I have a- .010 cam if you want it.
Well, around here we have always called them .030 under bearings, probably a regeonal thing, but if we are talking about bearings for an undersize crank, if fortyfordguy can't come up with anything for you, Early Ford V8's in Balston Spa NY usually stocks them. WWW.EARLYFORD.COM 1-800-417-3347.
LOL 6 thou ain't nuthin a 5 lb sledge can't fix Hope you figure it out and please keep us posted on yer build.
i had the same problem with mine when i changed the cam. oversize bearings, had to get the cam ground
I thought of a big hammer Nailhead, just didn't think a cam should be a "press" fit! Thanks for the source Nobilleta, guess we always called them "over" bearings to fit an "under" crank. I mean mating two "unders" together, that just don't sound natural if ya know what I mean!
The I.D. of the bearing is under (smaller than) the standard size - therefore they're undersize bearings. Rings come in oversizes, bearings come in undersizes. I forgot, elephants come in quarts.
New cam bearings fit the isky, guess I got thru that. Now today the oil rings don't fit the pistons, they are wider then the old ones. Geez, I thought I'd be driving this thing by now, this old flatmotor just wants to fight me.
You had to change cam bearings; is it possible someone changed pistons too? Just for openers, does the piston have THREE rings ABOVE the wrist pin and ONE below? (four ring) Or only three above the wrist pin? It's possible the rings you have/bought are for the wrong pistons, or visa versa.
They're 4 ring pistons, but not originals for sure( .060 overs). Just like the cam, this things driving me nuts. Did they send the wrong rings or did someone put in the wrong pistons, I have no way of knowing. Does anyone here know if certain years had different size oil ring grooves?
have you cleaned out the grooves? if there is no ford stamp on them they are after market pistions and came with the rings. which can be whatever size the maker wanted.
Ummm, yeah, I cleaned the grooves. Does someone build motors without cleaning the parts? No Ford stamp, just a circle with a G inside (?) cast next to the pin. Interestingly the pistons are marked "front" on the tops in the Ford script, I had to look close to see it said front, not Ford.
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