Hello recently acquired a set of 273 rockers ,I want to install them on a hydraulic cam 340 and plan on getting pushrod length checked for the right length pushrod...but my question is the set of rockers I acquired came with shims(cupped washers)...what is the reason for the shims?...is this an old trick to use on hydraulic cam?...just curious..I'm probably not even gonna keep the shafts because they don't have banana groves and I wanted hard chrome ones like rocket has...or do I need...should I modify mine with grooves?..thanks any advice is appreciated, Will
273 rockers on 340 with hydraulic cam
- Thread starter Mtrhead
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AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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I don't see any cupped washers, unless you mean the washers on the mounting bolts; In which case, those are sometimes used for geometry correction. But as you may have noticed, those rocker's need matching pushrods.
Going back to the cupped washers, if they are ordinary washers, with the same thickness in every direction, then they are some-one's bandaid and should Not be reused, because they cannot simultaneously fit both the saddles and the shafts and so they are somewhat unstable in the lateral direction. And very possibly the tiny bolts will fatigue and possibly come loose under the bending forces, that may come with much more than 318-type valve springs.
There are proper washers and Geometry kits to fix geometry errors, which in the Mopar camp, are common..
Going back to the cupped washers, if they are ordinary washers, with the same thickness in every direction, then they are some-one's bandaid and should Not be reused, because they cannot simultaneously fit both the saddles and the shafts and so they are somewhat unstable in the lateral direction. And very possibly the tiny bolts will fatigue and possibly come loose under the bending forces, that may come with much more than 318-type valve springs.
There are proper washers and Geometry kits to fix geometry errors, which in the Mopar camp, are common..
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Looking at the photo- I’ve never seen the top curved washer used on the bottom like that before. Maybe remove those as they are going to slow or stop oil flow to the shafts.
What AJ said..... Correct shaft shims cross section would have a banana shape, if you will.
You really don't need them
Crane used to make a specific pushrods for that application.
Probably for use with the 273 pushrods. They are actually too long to just throw in with the rockers on a hydro cam.
Sum-G6420 Is what you want. Somebody built that shim (washer) to run them on hydraulic cam but I think you would need twice that distance.
If everything is stock, yes. You really should measure but there they are, already made.
Not being smart, but maybe ask who you bought them from?
Don't know. You need to measure for correct pushrod length. What camshaft are you running?
PA Dodger
Well-Known Member
Mtrhead - your inbox is full. I just did this swap and have a pushrod length tool if needed.
mopowers
Well-Known Member
Toss those washers and measure for the correct length pushrods.
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