Pushrod size question

[Brewzer67]

So, I am going to be finishing making my pair of pushrod length checking tools this weekend and coming up with the correct length I plan to order on Tuesday morning. My question is "what size ball/radius do I need to specify on the lifter end? I am using MRL's Pro plus solid roller lifter made by BAM lifters. The tools I am making will be made from some old Direct Connection 3/8" cut to fit pushrod stock. They have a ball end on them already but they seem a little bigger than 5/16" which I already know is the size of the adjuster on the rocker end (or a 5/32 radius per Smith bros.).

Is it the same on the lifter side? I plan on going with a 7/16 dual taper with .120 wall thickness for some extra stability. I know it may be a little overkill, but then I'm set if I need to go to a stiffer spring. The overall pushrod length is going to be a little over 10" so I can definitely see the potential for some guitar string-like harmonics so that is the other reason I am going overkill.

Can anyone tell me what the correct size end is?

 

[miller]

My question is "what size ball/radius do I need to specify on the lifter end? I am using MRL's Pro plus solid roller lifter made by BAM lifters.

BAM lifters? THEY should be able to tell you, if it's not documented anywhere.

 

[miller]

Going to depend on the design of the lifter cup. If it's an actual cup, instead of being a vee, you want the ball size, that seats in the cup.
Another note, is with the dual taper push rods, be sure you have clearance at the body of the rods, to the heads.

 

[Brewzer67]

BAM lifters? THEY should be able to tell you, if it's not documented anywhere.

Yeah, I thought of it too late and they were already closed for the day. I have next week Friday off to work on the car so really want the pushrods by then. Tuesday at work is already a full day of meetings so I won't get a chance to call until Wednesday afternoon which means I probably won't have them for Friday. I was really hoping someone on the board was already using them and could chime in.

 

[Brewzer67]

Going to depend on the design of the lifter cup. If it's an actual cup, instead of being a vee, you want the ball size, that seats in the cup.
Another note, is with the dual taper push rods, be sure you have clearance at the body of the rods, to the heads.

Yep, it is an actual cup. The one's I have for mockup fit but there is a small ridge right where the pressed in tip meets the rod so it is tough to get a good measurement. As far as clearance goes, I had the pushrod tunnels machined for clearance so I am good there. I am only going with the taper for extra clearance insurance on the rocker side. I am using Hughes 1.6 rockers but I have converted the adjusters to cup type instead for better geometry and will be using oil-thru pushrods.

 

[Brewzer67]

so I called BAM on a whim and didn't expect to reach anyone and I didn't. I did leave a message though and they were awesome and texted me back with the answer to my question, so I am set. For the record, their lifters are fine with either diameter 3/8" (.187 radius) or 5/16" (.156 radius).