Lifter Angle Question

[727]

This has been on my mind for a while. Why did Ma Mopar install the lifters out of plane with the push rods? My guess is if they changed the angle of the lifter to be in line with the push rods then the rods would most likely have to penetrate through the intake manifold. If they lowered the cam to make them straight, it may have interfered with with larger stroke cranks and required longer push rods. Thoughts, Ideas, Insight?

 

[toolmanmike]

Yep!

 

[kramer]

I thought it was mainly due to the old early poly 318 and hemi heads that basically used the same block needed that lifter angle and then when the LA style head came out first with the 273 for whatever reason they neglected to change the lifter angle to better match the different valvetrain layout on the LA style head, i'm sure money and redesigning it played a factor and they obviously didn't feel it was warranted.

 

[Darter6]

I had a chevy guy tell me all the things wrong with the Mopar small block and why they are no good. But for some reason he always gets his *** spanked by them at the track. Hummm?

 

[RJRENTON]

This has been on my mind for a while. Why did Ma Mopar install the lifters out of plane with the push rods? My guess is if they changed the angle of the lifter to be in line with the push rods then the rods would most likely have to penetrate through the intake manifold. If they lowered the cam to make them straight, it may have interfered with with larger stroke cranks and required longer push rods. Thoughts, Ideas, Insight?View attachment 850810

IMHO...
I believe what you say is true...however if you do a hypothetical force vector analysis of the difference of the lifter angle to pushrod angle, from parallel to the angle presented, you would see the difference in opening force of the push rod is slight. This can be overcome by lobe lift and degree of when the lifter starts to move from the base circle thru max lift. Yes...there is a slight increase in friction, but I would think that the design has proved itself in being able to be adapted to a multitude of vehicles and outstanding horsepower to weight ratio of the existing configuration. Just my opinion of course.
BOB RENTON

 

[dvw]

Left over from the old Poly blue prints. If it was that big a deal it would be been changed. When you get up in the .700" lift+ and 8000 rpm range the race blocks have the angle changed 59-48. Though many have been raced successfully with the original angle. On 99 % of the stuff makes no difference. Tell the Chevy guy the reason his is junk is it has stud rockers.
Doug

 

[Hemirunner]

I thought it was mainly due to the old early poly 318 and hemi heads that basically used the same block needed that lifter angle and then when the LA style head came out first with the 273 for whatever reason they neglected to change the lifter angle to better match the different valvetrain layout on the LA style head, i'm sure money and redesigning it played a factor and they obviously didn't feel it was warranted.

That’s my understanding as well. They’re much more in line on the early hemis.

 

[33 IMP]

Agree with others, leftovers from poly days.

 

[Dipstick]

When the old Pro Stock factoring system favored the Mopar, Bob Glidden overcame the LA's bad lifter angle by milling the entire valley out of the block and welding in new structure with a better lifter angle. His Arrow was a winner until it was factored out. The factory followed suit years later with the 48 degree blocks.

 

[Crackedback]

Yes a holdover from the earlier engine.

If you think you are getting .450 lift from your cam lift .300 x rocker ratio 1.5 at the valve with these angle, you got another thing coming. The 59* angle is detrimental to actual valve lift.

 

[dvw]

Some people just worry about what doesn't really matter. This isn't Pro Stock. Build it. Run it. Don't worry about it.
Doug

 

[RJRENTON]

Some people just worry about what doesn't really matter. This isn't Pro Stock. Build it. Run it. Don't worry about it.
Doug

BUT.....Sometimes, some people worry about or ponder the little things that other people think are insignificant....sometimes to their chagrin or dismay. Often, it's the little things that make the difference between winning and losing....words of wisdom???....maybe.
BOB RENTON

 

[727]

Not looking to win or loose. I was just curious as to why it was done this way. If I were the engineer in charge of this particular item, I would have come up with a different way of doing it. Better or worse, not sure. But I wouldn't sleep at night knowing it was something I would put my name on.

 

[Dipstick]

Some people just worry about what doesn't really matter. This isn't Pro Stock. Build it. Run it. Don't worry about it.
Doug

A friend who has built lots and lots of small blocks says that the lifter angle makes it more likely to have hydraulic lifter problems than with the big block using essentially the same lifter.

 

[66chargerpat]

 

[RJRENTON]

A friend who has built lots and lots of small blocks says that the lifter angle makes it more likely to have hydraulic lifter problems than with the big block using essentially the same lifter.

Please define the quantity "lots and lots"....is it 2 or 10 or 15 or 1000? What was the definitive reason for the more likelihood of having "problems" (and what were those problems) that occurred? And the reason for the small block vs big block (presumably both Chrysler designs not GM) using the same lifter? Without a definitively stated problem or occurrence its difficult to understand or come up with a solution to resolve the issue. It's almost like saying "how high is up" or "why is there air" (for blowing up basket balls...according to Bill Cosby). Curious minds want to know....
BOB RENTON

 

[727]

 

[Hemirunner]

Not looking to win or loose. I was just curious as to why it was done this way. If I were the engineer in charge of this particular item, I would have come up with a different way of doing it. Better or worse, not sure. But I wouldn't sleep at night knowing it was something I would put my name on.

It probably came down to ROI on the redesign and they probably decided it wasn’t worth it.

 

[Dipstick]

Please define the quantity "lots and lots"....is it 2 or 10 or 15 or 1000?

More than me.

What was the definitive reason for the more likelihood of having "problems" (and what were those problems) that occurred?

The pushrod angle upsets the valving in the lifter causing them to tick. His theory, not mine.

 

[RJRENTON]

More than me.



The pushrod angle upsets the valving in the lifter causing them to tick. His theory, not mine.

First question....how many have you done?
Second question...wrong...the lifter end of the push rod is spherical which is designed to allow for angular operation. The lifter rotates (spins) as it travels up/down due to the cam's slight tapered face across the lobe and the slight spherical radius on the lifter face; done to promote even wear of cam and lifter. Does your friend understand the significance of the cam/lifter interface? BTW...the lifter's internal check valve is usually a flat disc held closed by the lifters internal spring. If the lifter is clicking (not filling with oil after opening/closing, its usually due to high leak down rate and the internal disc valve stuck open or closed. Just thought you might like to know.
BOB RENTON