Cam Bearings

Has anyone here had issues with cam bearing dimesions? went to install mine today and there was as much as .020 difference in .O.D, SO I WENT AND BOUGHT ANOTHER SET AND THE SAME PROBLEM .I checked the block dimensions on each cam journel and they were within .002. is this a common problem or have i been lucky enough to have gottin ahold of 2 bad sets. one set was duro-bond and the other set seal-pro, the latter i bought just to check measurments. i am going after clevites in the morning but will i have the same problem? should you have to check each one to get the right amount of crush and maintain cam to bearing clearance for oiling? Thanks Dan

 

that is nuts but anything is possible sometimes different types may have the same manufacture and had a bad batch if the block is ok then the bearings must be the prob post what you find out so we do not need to go trough the same problem thanks Craig moss

 

Bearings

well i tell ya ,my engine builder is beside himself and so am i, this aint my first rodeo and it darn sure isnt his, we meassured the cam journels,the cam journels in the block,the .o.d&i.d. of the old bearings the .o.d &.i.d of the new bearings and the only thing we found was the inconsistant was the .o.d as much as .022 on the new bearings, but they had the same .i.d measurement within .002.we will hopefully know more tomorrow and i will keep you posted. Now i think ill have me a COLD BUDWIESER AND CHILL OUT!! LOL!!

 

this might be way out there...but if you have an issue of the bearing being tight on the cam call me I have the answer on the fix, this same thing happened to me, when I got all the bearings in all different brg. id,,,,well then the cam became an issue..let me know. Dave 1-620-249-5909

 

Check the #'s on the bearings are they the same on all the ones you took out.In the new set are all the #'s the same? Most aftermarket blocks do not take standard sets , they usually take individual bearing of the same size.

 

Sounds like wrong bearings. What kind of block? bearing numbers?

 

There is the whole different OD thing when talking about BB Chevy's, CNC blocks vs not CNC'd. They are 2 different part numbers.

 

5 all the same

No answer as to what he is working on?

If it's a BBC, the Dart and some GM Bow Tie blocks take all 5 of the same outside diameter.

Dart & GM Bow Tie w/ 2.120" housing bore = set # GMP-12 Dura-Bond (or 5 # CHP-12-3 Dura Bond)

John Gates
Santee, Ca

 

Bearings

That is exactly what we figured out ,after market alum blocks take the all the same bearing, and factory cast iron motors takes 3 different .o.d bearings i believe,that was the one thing that was consistant about the bearings we took out they were all stamped 12-3 and then my builder remembered that when we bought the block they sent the cam bearings with it. which explains why i was getting 2 bearings out of each of the sets i bought that would work because in a stock set of cam bearings you buy over the shelf 2 of them are 12-3s. anyway we have the right bearings on the way. i sure appreciate all the input that i got from everyone here. if i kept better records this would not have been an issue lesson learned

 

The reason for this is that the OEMs bore the cam bearing from each end, at the same time, the stepped size allows the tools to be removed easier, them many of them, Ford in particular, install the cam bearings and then take a light cut straight through. This explains why that many times you install a set of cam bearings in a stock block and the cam is tight. The bores aren't perfect, but were corrected by boring the actual bearings. Most aftermarket blocks are bored straight through initially and therefore use bearings with the same O.D.

 

481 read what you said makes no sense.

 

Dura-Bond

BBC w/ stepped housing bores;

Web = Housing Bore & Max Wall
1 = 2.1400" & .0941" #CH-12-1
2 = 2.1300" & .0891" #CH-12-2
3 = 2.1200" & .0841" #CH-12-3
4 = 2.1200" & .0841" #CH-12-3
5 = 2.1300" & .0891" #CH-12-2