Should I grind the steel rockers?

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Ant

Ant

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Howdy everyone!
As a mechanic/former mechanic I find that there is always something new to learn. This time it's rocker arm to valve spring clearance with my new valve springs from hughes part# h1110 on some old 675 castings. The springs are a bit wider in diameter than the old ones and with the spring shifted towards the rocker they do touch against each other. It seems fine when the spring is center in the retainer, so I figure it should be fine because the spring can be pushed and move back more than enough.

I mostly deal with stock stuff, so I never gave it much thought. I could see if something similar happens on a stock configuration, it's just me learning this mopar performance stuff. But hey! If I can hotrod a Ferd, maybe I can do better on a Mopar.
 
You certainly can. The factory clearanced the 340 rocker arms. That said, you should also check the rocker shaft location, as most of the time, when you run into that, the rocker shafts need relocating.
 
Which rocker arms do you have, the HP or stock run of the mill rockers? They made 340 stamped steel rockers to clear the valve springs.
 
Do what they did at the manufacture. They ground the 318 rockers for the 340's. Give them enough clearance so you cannot make them touch. If they touch it will destroy the valve guides.

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Demonracer said:
Which rocker arms do you have, the HP or stock run of the mill rockers? They made 340 stamped steel rockers to clear the valve springs.
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Stock stamped steel rockers that came on the 318 I believe.

If all I need tp do is grind a bit where it's rubbing with my rotary tool, then that will save me some ca$h.
 
I slip piece of welding wire through and if it could slip back and forth through there there's thirty five thousands...
 
RustyRatRod said:
You certainly can. The factory clearanced the 340 rocker arms. That said, you should also check the rocker shaft location, as most of the time, when you run into that, the rocker shafts need relocating.
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Do you mean like to be shimmed up?
 
B3 engineering is the guy you need to talk to, he is a wizard at correcting the geometry of rocker arms.
 
RustyRatRod said:
Up and over, yes. They are usually too close to the valves. Mike at @B3RE (B3 Racing Engines) can help with it.
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I already started ginding a few rockers, but I don't like how close it's getting the groove for the oil. I have more stock rockers, so it is not that big of a deal. Shimming the rocker shaft may help, i think that valves are sitting a bit higher because I had the seats cut.
 
Ok, I found one rocker that is fitting a little tighter than the others. I guess I need to grind some more than others. It's cold out now and I need to find my other burrs. So I will resume work on this another day.
 
The SBM rockers are quite short. Interference with the springs, especially springs with a bigger OD is possible. That would have nothing to do with the geometry, although there may need to be a geometry adjustment for other reasons.

Has anybody compared the 'clearanced' rockers side by side with unmodified rockers? Maybe they were a new stamping?
 
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Correcting geometry with the paddle rocker system is a waste of money. not needed
I'd just shim them for clearance, shouldn't need to grind
 
Ant said:
I love getting contradicting information!
Some say grind and some say don't grind.

I'm so confused.

Also, yes I read the articles about rocker geometry.
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The factory clearanced the 340 rocker arms to clear the 340 springs, so I think it's ok.
 
RustyRatRod said:
The factory clearanced the 340 rocker arms to clear the 340 springs, so I think it's ok.
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Thank you,
I will grind them just enough to make them work fine. Even my mopar engines book says to clearance the rockers for larger springs. I just needed some advice as my springs are not that much larger in diameter than the stock ones, maybe like .046 difference.
 
Ant said:
Thank you,
I will grind them just enough to make them work fine. Even my mopar engines book says to clearance the rockers for larger springs. I just needed some advice as my springs are not that much larger in diameter than the stock ones, maybe like .046 difference.
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This is just one of many threads documenting this.
www.forabodiesonly.com

Rockers and rocker shafts 340

So getting ready to do the heads. Hopefully just a general cleanup and painting. First thing I noticed was how loose the rockers are on the shaft. The bored in the rockers are a lot larger than the shafts... by like 1/8”. Is that normal? No spacers or shims between them. I’ll take them apart...
www.forabodiesonly.com www.forabodiesonly.com
 
Update!

I might be a goof. I was looking at my valve springs wndering if I should buy different spring retainers to take more space and center the springs.
IDK, probably means nothing, but I might ask the engine builder that did the machine work for me. I still need to grind the rockers even with the springs center, so I'll get to doing that.

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Did more grinding till the cardboard feeler guage fits.

I got 8 more to go and I'm doing this very slow, but just want to be careful.

Also, the dimple on one of the rockers is from when I used a ball shaped burr, it is fine.

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Remember, sometimes the spring can move around under the retainer. So you will have to allow for the total movement of the spring.
 
Bewy said:
Remember, sometimes the spring can move around under the retainer. So you will have to allow for the total movement of the spring.
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Yep, I shifted the spring towards the rocker to figure out the clearance.
 
Finished grinding the rockers, some definitely did not need as much as the rest. I had some surface rust accumulate on the heads over the winter, so I thought it would be a good idea to clean one of the heads with white vinegar. Well... I was left with a bit of a yucky mess, so now I cleaned it and soaked the head in WD40. Eh, it'll be fine, it's wiping off.

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