Stamped Rocker Clearance Issue?

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J

Jats

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Hey, having trouble with some rocker clearance. On a few (not all) the rockers are contacting the spring (not retainer). On the first picture, it shows how far down one rocker goes before interference. I can force it down, but something is definitely wrong here I think. The heads are 273 small port, small valve heads. The rockers and shaft are what came off the heads when I got them. They look stock. I was hoping to reuse them, they aren't in bad condition. I did notice that some rockers are larger than the others. (Last picture) idk if that's stock or someone before me mismatched them with other ones. Both some of the left hand ones and right hand ones are different sizes. They are comp springs and retainers that came on the heads. Not sure the part number. The diameter of the spring itself measured at 1.5 inch. Which is what I thought was okay with stock stamped rockers because when I took the heads apart, there was no visible wear on the rockers where they would be contacting now. The engine ran beforehand. Heads were rebuilt at machine shop, they reused the springs and retainers, just new valves. So in theory, they should be just like they were before. Maybe when they redid the valve seats, it changed the height of the valve tip? I'd like the just reuse the stock rocker setup because it sounds like the new replacement stamped rockers are junk and pushrods punch through them. I'm open to buying a good quality setup. Any opinions for sbm rockers and shafts for Hydraulic flat tappet .454 lift? I haven't ordered pushrods yet. Or can I clearence these rockers a little to clearance the springs? Is this common? Sorry about the long read, trying to learn. First mopar engine. Thanks everyone.
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sinking the valve seat or using a taller valve will make the valve TALLER changing clearances
 
If you look at 340 stamped lockers compared to 318 stamped rockers they are all clearanced it that area you have circled. My son has to clearance rockers of all types. We paid $1800 for a set of T&D rockers. Two were fitted to therngine without a clearance problem. After the tear down for refresh we found that several were hitting at the same place as yours. So it doesn't matter what you pay the fitment quality is all the same. Not very good at all. He made a fixture to clearance rockers now and many are very far off.

First pic is of the hit rocker

second pic is of the fixture on a rotary table for correct radius


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I just back grind them a little at a time till I can slip a piece of .030 welding wire bent in a half loop in-between...
 
Looks like someone has changed to 340 springs and you need the 340 HP rocker arms there cut back in that area.
 
None of the positions you picture the rockers in are anywhere NEAR in the operating range of the valve train. How about a picture with the rocker tip ON the valve stem?
 
RustyRatRod said:
None of the positions you picture the rockers in are anywhere NEAR in the operating range of the valve train. How about a picture with the rocker tip ON the valve stem?
Click to expand...


Good catch Rusty. OP, put the pad of the rocker on the valve tip. If you have clearance move on to something else.

The rocker will NEVER be in the positions you have pictured.
 
RustyRatRod said:
None of the positions you picture the rockers in are anywhere NEAR in the operating range of the valve train. How about a picture with the rocker tip ON the valve stem?
Click to expand...
Last picture ,Rocker on right you can see where it touched the spring, That little shiny spot on the underside, This is common with HP springs and 318 rockers that were not clearanced as stated above. All 340 rockers are clearanced. Many guys just bolt on 318 rockers and don't check this . The OP at least caught it . As I said , Looks to me like he has standard diameter HP springs and retainers and 318 360 rockers
 
I asked a while back and it sounded like you could run 318/360 rockers with 340/901 springs without any clearance problems. Sounds like there could be clearance problems with that spring/rocker combo afterall, but it shouldn't be anything a little light clearancing can't fix.

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Oldmanmopar said:
If you look at 340 stamped lockers compared to 318 stamped rockers they are all clearanced it that area you have circled. My son has to clearance rockers of all types. We paid $1800 for a set of T&D rockers. Two were fitted to therngine without a clearance problem. After the tear down for refresh we found that several were hitting at the same place as yours. So it doesn't matter what you pay the fitment quality is all the same. Not very good at all. He made a fixture to clearance rockers now and many are very far off.

First pic is of the hit rocker

second pic is of the fixture on a rotary table for correct radius


View attachment 1715883593

View attachment 1715883594
Click to expand...
No help to the OP, but Just spit balling, but could the spring be dancing around at higher rpm? Like it needs a bit more spring pressure? You watch these video’s of the springs on a spintron and it will keep you awake at night. Retainer a bit loose, bottom locator?
 
You can see why getting close to coil bind helps calm the spring a bit. Another thing, look at the roller, it is SPINNING! Under load!
 
I’d just grind some relief into the rockers, and/or put a chamfer on the OD of the top coil of the spring.

I show the diameter of the OE 273 springs as just under 1.400”.
 
There ya go....... 273 spring is under 1.4", OP says his springs are 1.5".
 
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