proper installation of 48 M cam bearings?

d. coleman · Jun 20, 2008

getting ready to install new cam bearings in my 48"M" engime rebuild. JD shop manual calls out a 30 degree from horozontal + or - 1 degree for oil hole, and gives a illastration for fwd. bearing. im not fully understanding how oil gets to oil passage for cyl. head. does it leak or seep past rear bearing insert into space between cam and block plug, and enter oil passage that way? i read the caution about getting the plug positioned exactly right, but am still not sure about bearing oil hole positioning. thanks for all responses. d. coleman

Mike M · Jun 20, 2008

It's been a long time since I did our 440 engine I'll have to check that service manual and see if it gives any good info.

Johnnyputt · Jun 20, 2008

I just changed the rear cam bearing on a 40. I wasn"t getting any oil to the rocker arms. The rear bearing has a hole in it that must line up with the slot in the bottom on the bearing opening. (You"ll see it plain as day, once you pop that rear plug out.) If you get the bearing turned 180 out, it won"t line up. The top hole sends oil to the rocker arms. The top hole CAN be plugged if you place that rear plug to far forward. Once your bearing is in place, measure the distance between the rear of the bearing, and the rear of the block, then measure the depth of the plug you"ll put it, then measure the distance from the top hole to the rear of the block. Don"t drive the plug to deep or you"ll block that top hole. The oil is pumped from the bottom hole to the rear cam bearing, then through to the rear of the cam, up against that plug, then up to the rocker arms.

Johnnyputt

Mike M · Jun 20, 2008

My M MT I&T book and my JD 40 and 440 books all agree in that match up the hole with the slot in the block and the rear bearing hole and notch are to the rear of the block and when installing the rear plug cup side out to a depth of 13 7/32" from the frt.bearing thrust face on the block to the plug.

d. coleman · Jun 20, 2008

thanks for info. just wanted to make sure i was on the right track before attempting installation. local machinest says he should have tool ready monday. keep your fingers crossed!!! thanks again for taking time to assist. d. coleman

d. coleman · Jun 24, 2008

machinest finished cam bearing installstion tool, what a fantastic job he did! bearings went in without sligest problem. just want to thank all for assistance. oh, by the way i just purchased another "M" for parts, payed more for it than one im restoring!! oh well, i guess you cant get a great bargan every time. d. coleman

proper installation of 48 M cam bearings?

d. coleman

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Mike M

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Johnnyputt

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Mike M

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d. coleman

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d. coleman

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