Michael Yount

iTrader: (1)

Thanks! Saw that one before...but the answer to the mystery question remains unanswered. How does a lobe peak that’s shorter than the journal raise the lifter higher than the journal?

G Atsma

OK- most cam blanks start with the "lobes" looking like bearing journals, at the same OD as the actual bearing journals. When grinding the cam, the base circle determines the lift. The peak of the lobe remains the same height as the bearing journal. This is why some cams need different length pushrods, as higher lift cams allow the lifter and pushrod to sink lower to account for the increased lift.

Michael Yount

iTrader: (1)

Got it - as I mentioned earlier, knew I was missing something. The fly in the ointment was my assumption that the lobe peak was smaller than the journal...you’re saying they’re essentially the same height which means if use the lobe to push the lifter to peak lift, the journal will clear it too. Provided, of course, that the retainer does it’s and doesn’t let it slip back down the lifter bore even a small amount. Thanks for the education. All the other older V8’s I’ve played with, you have to remove the lifters for a cam change. To remove lifters, at least the intake has to come off....and on some the heads too.

Michael Yount

iTrader: (1)

Also used to dealing with 5.0L motors where lots of different lifts are available with the same base circle - because lobe peak is shorter than journal....thought the LS motors were that way too.

fieroguru

iTrader: (1)

Ever jump a bicycle and go higher than the ramp?

If you spin the cam quickly, the lifters will effectively jump off the peak of the lobes and slide a little further in the retainers.

G Atsma

Now you know why cam changes in LS's are such a snap! Glad to help! It's what forums like this are all about.

Michael Yount

iTrader: (1)

LOL - yup, 2 broken arms and a broken collar bone later. Turns out, you just need to make a rotation or two at any speed, put the dowels in if you don’t trust the retainers and swap away. Although mine will stay stock....

77volvo245

Spun the center thrust bearing on the 4.8L. The plastic patch got sucked into the motor on the modified truck manifold on the 4.8L. Pulled the heads and saw plastic stuck to the valves. Bought a new 5.3 100k miles from LKQ (would never recommend them). Installed a brand new oil pump timing chain and a BTR stage III cam. Bought a true trac rear end, and I just need to install it. I'm will probably just leave this intake stock for now.


[/url]20170519_181029 (1)

20170519_150048

20170518_155604

20170517_224740

20170517_223840

received_10208862049378526

received_10208862050258548

received_10208862147220972r


[url=https://flic.kr/p/YNDQe7]20171006_164745

Michael Yount

iTrader: (1)

So she's back together and running with the new cam?

Brons2

It looked like on the 10/04 post that it was running and he had taken it to the dyno.

AAIIIC

iTrader: (19)

Not to derail the thread, but where are you dealing with LKQ, and what issue(s) did you have?

Brons2

It's already derailed, he sold the car!