carl48

i am confused the pdr cam has the fuel pump lobe and i did not change lifters i think i will call tomorrow and check on this

ratsun

Ummmm.... I don't think I understand what your saying, hows the foot change anything other than give a larger umbrella to catch and hold oil?
I used the CR lifters when I put the H2 in my motor since that's the ones Don recommended and while they are close the fit just fine. I believe he said they were a little harder than the stock 12v ones also.

ratsun

If your stock lifters look ok than you don't need to change them, thing is in order to look at them you need to have them out and for the cost of new liffters I wasn't going thru the work to put the old ones back in. Pulling lifters in these things takes some effort so.....?

GLHS

Now you got me thinking.
If this is true; the cam maker has given me some misinformation.
I will do some more calling tomorrow.

dzlfarmboy

How do you figure?

The wider tappet foot helps with tappet rotation. The tappets do not ride directly over the cam lobes, their offset to the side to give them the spining affect.

Captain

Is there an advantage to running diffrent lifters when installing a new cam in a 12v?

GLHS

Yes.......

GLHS

They do not need to be directly over the lobes to have this affect.
For exaggeration purposes; think of a 1" lifter or a 10" lifter. Which would ride on top of the lobe longer? The arc (for lack of a better term) is not as sharp on the 10".

carl48

i still do not see it i have a oem cam i was going to send to pdr for a third cam. i am goig to use a 1" disc and a 1.5" disc on the cam with it chucked in a indexing head in the lathe i do not think the lobe is as high as you think it is

Captain

but shouldnt the new cam allready be setup for the lifters in the truck if that cam is made for that motor? And is there any disadvantage to changing the lifters to something longer?

ratsun

The new tappets are not longer, they just have a bigger diam foot.
Changing out the tappets to the new ones will change nothing as to the profile of the cam or its specs. Any tappet will contact the lobe on the same axis. All it will accomplish is give you a new harder surface for wear and a little larger umbrella for oil.

WICKEDDIESELS

The maximum that the lobe can take advantage of is 1.250"-1.300"

Going to a CR 1.50" diameter lifter will give you about an additional 4 degrees of seat to seat timing. We have checked this in a fixture, using a degree wheel and a dial indicator. The rate of lift, can not maximize the foot diameter of the bigger lifters. Standard lifters will work fine, and do not subject the block to as much side loading of the lifter stem.

GLHS

That's what I was going to do to verify this!

WICKEDDIESELS; I have called a few times and left one or two messages inquiring about your cams with no response yet.
Watcha got for cams?

carl48

thanks wickeddiesels. saved me a lot of work,