Shorten assembled Manton P/R

[slalombuggy]

I'm recamming my big buggy engine so I'll have to cut new P/Rs for it, but the ones that are in there are about .150 longer than what I measured for the motor in my 57.

Has anyone ever pulled on end off of the assembled P/Rs and recut them. If so, what tools and technics do you use? Warm the tube up with a torch a bit?

As always THANKS

brad

[Dan Ruddock]

I have taken my dremel and cut an angled slot with a cut off wheel which relieves the press fit and am able to pull out the end. The problem with this is it only works if you need to shorten the pr a lot. Dan

[75smith]

if you have a band or scroll saw, you can carefully cut away the extreme end of the pushrod, then pound in the end peice

^^that was described in How to Hot Rod VW Engines, and I've got to say works decent if you only need to shorten a little bit- I used a hack saw, with pushrod in vise, took a little bit but works
_________________
My 1975 Beetle Build Updated 8-21-12

My engine build

[Dougy Dee]

Hold the pushrod in a sturdy vise. Heat the end with a propane torch. (Experiment with the time required.)
Grab the tip with Vice Grips and twist. The Vice Grip should help shrink the tip. I often smack the Vice Grips with a hammer, like an improvised slide hammer, to help slide the tip out.

[slalombuggy]

[nsracing]

Looks like hack-jobs that nobody has tried above.

You gotta have a clean way to pull the ball tip out. I made a small slide hammer and a collet to fit under the neck of the tip. Slide the hammer back and the tip comes out.

As for trimming the mantons square since they are tapered is the tricky part. You have to have a way to accomodate the taper..this case I made a sliding type collet smaller hole on end and larger hole the other end. Slide the whole collet over the tube the large portion first and then slide the small end till it stops. Then lock that whole shaft in the collet and grind the end square on the valve grinder ( the tip dressing side of the valve grinder).

If you are not taking much off the pushrod then you should have enough reamed area from before for the tip to go into. If not, then you need to ream the ID some to make room for the tip or it will bubble and not stay.

[mark tucker]

I dont think I would be torching the end.could cut it on a lathe so it is thin the length of the pushrod end them get it out, or the wacke mathod if you dont effup the end or rod, or both. or stick that set on the shelf&spend $58-70. and get a new set. I only shorten the aluminum ones for very mild motors, but I did try to get the end out of a cr 1 time it aint easy unless there the empi or cb that had some of the tips too small.(they come right out with fingers)but that was years ago.

[nsracing]

Mantons are tapered. The stickout is going to be about 4-6 inches from where the taper is vs. the straight side of the pushrod.

The tip can be cut safely if you have a center rest to steady the cut. Chuck the straight part of the pushrod and use the center rest to hold close to the ballend.

If you just chuck the pushrod and try to cut way it will likey bend the cutter bit f*ck the ball all to hell.

[SRP1]

What you do is you take a small ball-peen hammer, and carefully tap the end of the push rod tube right up beside the tip, the area that is the press fit. Tap, roll, tap, roll, tap, roll, until you have gone all the way around.
This will free the press fit and relax the tube, the tip will just slip right out.

Once the tip is out, you will then cut away the portion you tapped on anyway to achieve your new length, and the tip will press back in just like new. I cut push rods on a lathe, but to each there own, whatever works.

[neil68]

Brad,

I've shortened a set of Manton chromoly pushrods when I adjusted CR in my 2332 cc engine. I just used a hacksaw to create an angled cut in the pushrod just below the end-cap...which allowed the pushrod to expand, so I could remove the end-cap.

The very end of the cap (inside the pushrod) is usually narrower, so you don't need to go all the way...just cut near the end of the pushrod "tube" until it loosens up the cap tension.
_________________
Neil.

Der Kleiner Rennwagens
68 Beetle 2332 cc, 204 WHP
12.5 seconds @ 107 mph
Dynojet Test: https://www.youtube.com/watch?v=M9B_H3eklAo

[stealth67vw]

[stealth67vw]

I shortened my Berg .035" wall pushrods when I went from 5.5 rods to 5.352 rods. I chucked them up in my lathe and used a .063" wide groove tool and grooved them until I had about .005" wall left. I then use used the drill chuck in the tail stock like a slide hammer and yanked the tips out. It worked perfect. The pushrods have seen7,800 since I reassembled them.
_________________
John Bates
JB Machining Services
1967 street Bug 2276 w/ 48 IDAs, 2020lbs with driver
7.76 @ 89.55mph 1/8 mile
12.34 and 108.10 mph 1/4 mile

[Slow 1200]

[modok]

[slalombuggy]

As always Thanks to everyone. I should have stated that they are not tapered, I don't have a lathe and I usually cut them with a small tubing cutter and finish with a file and deburring tool. I'll try tapping around the end to relax the tube and if not then try cutting a slot. I've got to remove about .150

Thanks again, brad

[slalombuggy]

Well I got all the ends out. I tapped around the tube to relax the metal and then clamped the pushrods in a vise (with a rag so it didn't scratch them) then I used a chizel I made from a brass drift and tapped the ends out. Worked great. Thanks to all for your suggestions and help.

brad

[flyboat]