cam bearings don,t fit?

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
starrcat2 said:
I'm rebuilding a 1978 chev. 350 2boltmain, that came out of a 1500 pickup. When I tried to install the cam bearings, the number 5 bearings are too small. I bought another new set, and the same thing. Its an 010 block . What could be my problem ?
http://www.jegs.com/i/JEGS-Performance-Products/555/25405/10002/-1
http://garage.grumpysperformance.com/index.php?threads/cam-bearing-install-tools-install-info.1479/
VERIFY,SOME DART AFTERMARKET BLOCKS DON.T USE OEM CAM BEARINGS
http://www.speedwaymotors.com/Dart-DT-1T-Cam-Bearings-for-Little-M-Chevy-Block-Set-5,24164.html

http://www.lislecorp.com/uploads/instru ... 726DB5.pdf

the tool Ive had and used for DECADES, it works reasonably well.
but check around for a used one in good condition, I bought mine at a chevy swap meet for $80


http://garage.grumpysperformance.com/index.php?threads/engine-block-cylinder-wall-thickness.976/

http://www.lislecorp.com/divisions/products/?product=58
http://www.lislecorp.com/uploads/instructions/18000_WebInstr_CC56DD9726DB5.pdf

http://www.kmjent.com/cart/product.php?productid=597 (good value)

http://www.dura-bondbearing.com/Portals ... lletin.pdf

http://www.pbw-india.com/theory.htm

cambearingaline.jpg

cambearpi.jpg


MAIN BEARINGS FEED FROM THE CAM BEARINGS SO LINING UP OIL FEED HOLES IS CRITICAL
cambearj1.jpg


most blocks only have the outer or end cam bearing journals grooved under the cam bearings making proper indexing of the oil feed holes on the 3 inner cam bearings critical, some blocks don,t even have those outer block cam bearing locations grooved
frontgroove.JPG

oil-gallery-groove.jpg

any time you go to install new cam bearings in an engine you first take detailed notes and a few pictures of the OLD cam bearing in the block under good lighting to note the location of the oil feed holes and and grooves, then as they are removed you number them each as its removed and measure them as on many engine they are NOT INTERCHANGEABLE between all main cap locations
chevy cam bearings are NOT all interchangeable, youll want to pay attention to the oil feed holes and the DIFFERENT diameters of the bearings, and ideally have the proper tools.
different BRANDS of bearings seem to have different tolerances, diam. and widths and some are tapered on one edge to make installation easier.
cam bearing tools also vary a great deal in how easily they can install and remove bearings, and the machining on blocks varies
cambearingaline.jpg

calipersaa.jpg


cam-bearing-guide.jpg

USE YOUR PLASTIGAUGE AND PRECISSION MEASSURING TOOLS , MEASSURE CLEARANCES AND BE SURE YOUR NOT BINDING< ANYPLACE
cambutclear.jpg

c60462.jpg

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this cam buttons correctly installed but the retainer plate tabs have not been bent up to lock the bolt heads from rotating
plastig1.JPG

plastig2.png

plastig3.jpg

plastig4.jpg

plastig5.jpg

plastig6.jpg

plastig7.jpg

plastig8.jpg

vincam.png

calipersaa.jpg
 
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OK now I am confused.. The cam bearings in my sbc were lined up with the oil holes in my block. I am reading now that the holes in the cam bearing are suppose to be in the 10:00 and 2:00 for the front bearing, and #2-5 bearings should be in the 2:00 position. This is suppose to create an oil wedge.
This information is in conflict with the information given above, where it states the cam bearings must line up with the oil holes.
Now I notice that there is no groove in the block or on the back of the bearing for #'s 2-4.

So how does the oil get into the bearing if it is installed in the 2:00 position?


oil-hole-location-min.jpg
 
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different blocks and bearing locations have slightly different configs,
obviously if theres no oil feed groove under the bearing the oil feed holes must align with the oil feed passages,
with the block in the upright position the cam bearings are fed,
from the upper central cam, or lifter gallery oil passage, look at the diagrams
most cam bearings come with instructions and diagrams.
and yeah it generally helps to look at the old cam bearings and oil feed hole locations, take notes and in most cases re-install the new bearings in a similar fashion.
chevy V8 cam bearings are NOT universally interchangeable between locations

oilpasse3.jpg

A-ENGINE-OIL-02-small-block-v8-lub-sys.gif

265_oil-2.jpg


sbcoilh1.jpg

sbcoilh2.jpg

cambearingaline.jpg

sbcoilh5a.jpg

oiltofilter.png

cambearpi.jpg


MAIN BEARINGS FEED FROM THE CAM BEARINGS SO LINING UP OIL FEED HOLES IS CRITICAL
cambearj1.jpg

frontgroove.JPG

carefully measure the old cam bearings and pay attention to oil feed hole locations
the bearings are not universally interchangeable and yes size varied

calipersaa.jpg


cam-bearing-guide.jpg
 
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I always read the installation instructions first and if none find the answer before installing. JMTCW
 
Now I notice that there is no groove in the block or on the back of the bearing for #'s 2-4.

Wow! Do I feel embarrassed now.
After getting my block cleaned, I now see that there are grooves behind the cam bearings.:oops:
Musta been filled with all the babbit that was missing from the rod and main bearings. :D
 
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