Cut to suit pushrods

[mopar_mark]

Any one got any tips ,wheres Dave when you need him

Why do you want to use cut to length pushrods ?


I made simple pushrod checker using an old push rod, with threaded insert in the middle.

I could then adjust push rod to desired length, then measure & had them made to my exact requirements.

I found there was minimal difference in cost with Custom pushrods cut to required length compared to regular pushrods.

This option then gives you:-
Length you need
Choice of wall thickness choice/ Tapered wall, etc
Choice of end - Ball, Cup, etc.

If you want to go with cut to suit, then my advice would be:-

Measure twice, Cut once
Get decent vernier or micrometer for measuring
I would cut to rough length using hacksaw & finish to length using lathe.
Would use dab of grease before "pressing in" your choice of end.
I would probably start to press the end in using lathe & finsish using small fly press.
If you dont have access to lathe then mark pushrod using tape on circumferance & cut near to tape line with hacksaw & finish to length using a medium cut file.
Use small dab of grease before pressing end, depending on interference fit I would tap in using hide mallet & gripping pushrod in vice. Use soft jaws or piece of rag to stop vice jaws damaging the tube.

[Ivor]

Top response Mark, you could be an engineer!

[mopar_mark]

Thanks for the advice Mark ,i have got a fancy measure the lenght of your pushrods tool .I was advised by Mancinis boffins that cut to suit was the best root for my set up but Jim Chandler put me onto Smiths pushrods ,they do a million different sizes so i might measure and order from them , A big part of me wants to build this engine for the challenge of it but common sense says get an expert .A lot of money if i get it wrong but a big pile of satisfaction if i get it right

Smiths are good, I used to use Scott @ Straightline but he is no longer in this type of businesss, otherwise I would of recommended him to you.

Buying pushrods to the length is still part of building an engine & still part of the challenge, as you are doing the checks & specifying what you need

My advice would be buy then built to the length you need, from a reputable company like Smiths

Once you recieve then, make sure you check them for length, fit & forget. Nothing worse than that little guy in your head .......are they OK, what was that noise, did that end press in properly, did you hear that

[Anonymous]

What Ivor said.

[MrNorm]

Agreed, Smith Bros have a great rep, they are not even that expensive. the number of engines that have cocked off valvetrain geometry that could be fixed by proper pushrods is scary. They are about the only bit of my engine I haven't bought yet, waiting to assemble it then order the right length.

You could go the cut-to-fit, but I have heard some nasty stories where ends fall off etc, and for a component of this price I would just order the custom ones - smiths make it very easy.

[Dave-R]

Pushrods don't have to be an exact length. Give or take a couple of mm is close enough. But it is not hard to get them within 0.5mm of each other.

You just want to see a couple of adjuster threads showing on the underside of the rocker.

I personally wouldn't use cut to length pushrods with a 083" wall thickness on a 440 making huge power (more than 600hp). Some people say they are good up to 800hp?

But like Mark (and others) say you can get them custom made.

I decided to do my own the last time just for the hell of it. I am making less than 550hp. Plus if you get them done in the US you can't be sure they will do them right.

You still have to use an adjustable rod to find the right length.

I scribed mine at the correct cut point but cut them with an angle grinder slightly too long.
Then using a simple jig on the side of my bench grinder I take them down nice and square almost to the scribe mark.

Then they were finished with a hand file after putting a slight chamfer on the inside edge. Checking all the time that they are square.
If you get the rods warm on a very low oven (slow cook setting) and keep the cup ends in the freezer then they slide into place with a few gentle taps from a hammer.

[Dave-R]

No need to do any of that.

Set your rockers up. Check that are sat on the correct part of the valve tip.
Put the lifter on the lowest part of the cam lobe. Turn the rocker adjuster down to expose two threads on the underside of the rocker.
Increase the size of the pushrod until you have zero lash. That is the length you need.

Double check the rocker tip moves on the valve tip correctly and adjust the geometry to suit. Measure the pushrod length again.