Moparts

Shortening pushrods....looking for advice 1st timer

Posted By: HemiRick

Shortening pushrods....looking for advice 1st timer - 09/14/17 07:08 AM

I've got a set of pushrods that are too long....they are good Manton ones w removable ends, and they can be safely shortened upto .015....I've recently ordered a 12 inch dial caliper and gotten a ball bearing....to accurately measure them. I understand if I heat up the end of a pushrod tube, the end should pull out reasonably easily, then I was thinking I could chuck them in my drill press and push down against a grinding stone to shorten them. Does this sound like a workable plan? Any suggested ways to do it better? Does it matter which end I do this to?

Thanks for any and all help
Posted By: Cab_Burge

Re: Shortening pushrods....looking for advice 1st timer - 09/14/17 08:24 AM

I think I was told by Manton employees that they could shorten most of there race pushrods up to .150, no more work
Call them for advice first twocents
Don't heat the ends up until you know your safe doing that tsk twocents
Posted By: 62SAVOY

Re: Shortening pushrods....looking for advice 1st timer - 09/14/17 09:02 AM

Also depends on how hard the pushrod tubes are. The CompCams ones I am making to length are hard. Also because of them being a thick wall tube size. I have to drill them out in the lathe for the cup to press in once shortened.
Posted By: rumblefish72

Re: Shortening pushrods....looking for advice 1st timer - 09/14/17 01:19 PM

There was a thread on this topic some time ago ... take a look at: https://board.moparts.org/ubbthreads/ubbthreads.php/topics/2248608/1.html for some sage advice.
Posted By: jwb123

Re: Shortening pushrods....looking for advice 1st timer - 09/14/17 05:45 PM

I used to buy pushrod kits from mancinni and build all my own push rods, but the quality of the kits went south so I stopped buying them. The main issue is the inside diameter of the push rod and getting the proper press fit. Most of the tubes have to be reamed to get the proper fit. Use a lathe or be very careful with a die grinder and cut the outside until you can pull the tip out. Its pretty hard to square the ends up without a lathe once you get the cut to length. I have chucked them in a valve grinder and used a file to square them. I built a fixture to press them together, its a thick wall piece of tubing welded to a flat plate, the inside diameter is about .060 bigger than the pushrod tube. The tube holds the tube square to the press and helps from bending the tube while pressing, put the tips in the freezer for a while, and I warm the tubes with a heat gun, put the ends in and a couple pumps on the press and its done. Make sure you look at the radius on the tip where it goes into the tube, you usually have to take a bigger drill bit and put a champfer on the inside diameter to get the tip to seat fully on the tube. I have been giving Manton a basic length and they send me the push rods with only one end pressed in, so I can finish them myself.
Posted By: HemiRick

Re: Shortening pushrods....looking for advice 1st timer - 09/14/17 05:55 PM

Yes I called and asked its .150 they can be shortened not .015 my mistake.....So if I can get an end off/out this plans seems good. Any advice on getting an end out? As this seems to be the hard part....And yes to have shortened by Manton is only few dollars less than a new set.

(I was just thinking that it shouldn't be too hard to make a tool to carefully push the cup ends off the tubes if they are that tough)
Posted By: crlush

Re: Shortening pushrods....looking for advice 1st timer - 09/14/17 07:39 PM

Do you know anyone with a lathe, cut one to the length you want then add a stop and cut the rest.
Posted By: dthemi

Re: Shortening pushrods....looking for advice 1st timer - 09/14/17 08:09 PM

I've shortened many sets of manton rods. You won't get the end out. The way shorten them is put them in the lathe. Grind a cut off tools thickness to the amount you want to shorten them. Run the cut off into the rod just under the insert. The insert is hard so when you hit it, no big deal. Usually harder than the tool you'll use. So you wind up with the thickness of your cutter removed from the length of the rod, and the insert bare in that spot. Then heat a little and press the insert deeper into the rod.

manton reams that press fit, and you'll keep your rod straight this way.
Posted By: CompWedgeEngines

Re: Shortening pushrods....looking for advice 1st timer - 09/14/17 08:42 PM

Originally Posted By dthemi
I've shortened many sets of manton rods. You won't get the end out. The way shorten them is put them in the lathe. Grind a cut off tools thickness to the amount you want to shorten them. Run the cut off into the rod just under the insert. The insert is hard so when you hit it, no big deal. Usually harder than the tool you'll use. So you wind up with the thickness of your cutter removed from the length of the rod, and the insert bare in that spot. Then heat a little and press the insert deeper into the rod.

manton reams that press fit, and you'll keep your rod straight this way.


Thats a good way to do it. A clean square end and counterbore are key to the pushrod, and obviously not bending them trying to get an end out.
Posted By: merpar

Re: Shortening pushrods....looking for advice 1st timer - 09/14/17 09:56 PM

If you make a cutter and part the .150 off you may be able to get the end out, maybe. But if you cut the .150 out don't press the end on in. The end has a slight radius where the shoulder is and the push rod tube will have a sharp edge. Therefore the end will not press flush to the end of the push rod. Also the bore may not be deep enough. I've been there and done that, but only on one push rod. Bought a new set. Maybe I'm too picky, just me.
Posted By: HemiRick

Re: Shortening pushrods....looking for advice 1st timer - 09/15/17 01:52 AM

Thank you DT Hemi, guess I'm calling my old friend w a lathe in his garage....this way does sound easy, consistent, and reasonably fool proof.

Is there a preferred end to do this to? Or does it not matter?
Posted By: RUNCHARGER

Re: Shortening pushrods....looking for advice 1st timer - 09/15/17 04:34 AM

I had a guy shorten my Manton's. He never took the end off, just lathed it carefully and then shoved the tip in the rest of the way.
© 2024 Moparts Forums