273 rockers on e-heads

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Uncle Bob

Uncle Bob

Shiny paint causes stress.
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I've got a set of e-heads set up for hydraulic flat tappets and 273 rockers that are giving me fits. I started grinding on the rockers to get .clearance between them and the valve but have some that just won't give me the clearance I need. So I swapped that rocker for another one that clearanced fine, but I still don't have clearance on that problem valve and the rocker that had insufficient clearance to start with has plenty of clearance when installed on a different valve. So it seems like it's valve/retainer related.

This is those two valves - the one on the left has insufficient clearance, the other one is fine.
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I think I've ground them about as far as I'm going to, so I wondered what the chances are that valve will center up under the retainer with use, like the other one is?
 
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Yeah I called Mike already. A little known thing is that you have to do the relocation before bolting the heads on because you need to clearance for the pushrods. He seemed confident that grinding the rockers would do it, but I didn't have that photo of the valve above to show him either. FWIW he recommended about .035 clearance, which is handy because you can use welding wire for a go/no go gauge.

I noticed in the photo after posting it that it looks like the spring cup isn't in the center of the spot face - but I don't think that can move around.

I'm hoping that working the spring, maybe with a spring compressor, will get the spring where it should be.
 
After looking at the pictures again, it looks like the exhaust valve spring is a larger diameter than the intake spring. Are you sure the springs are a matched set? Just a thought.
 
Demonracer said:
After looking at the pictures again, it looks like the exhaust valve spring is a larger diameter than the intake spring. Are you sure the springs are a matched set? Just a thought.
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Those are what came on the assembled 60779 heads. All of the valves were taken out. I noticed a piece of aluminum caught in one exhaust valve so all the springs came off.
 
I still have a solid lifter cam in my 273 but I changed the valve springs. Of course I had clearance issues. Those 273 rockers and shafts are cheap and strong but they just weren't designed to be used with large diameter valve springs. ALthough I have never tried them, I like the looks of the Comp style rockers but damn are they expensive. (because they require shafts which drives the price up) but don't feel bad, The LS shaft rocker kits are about the same price. Chevys ain't always cheap!

Anyone tried thee Speedmaster version?

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I noticed in the photo after posting it that it looks like the spring cup isn't in the center of the spot face - but I don't think that can move around.
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Looks to me like it’s either missing the cup altogether, or it’s a different(smaller) diameter cup.

How close are the tip heights to each other?

Just so you’re aware, the Comp rockers use ball/ball pushrods.
 
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Demonracer said:
After looking at the pictures again, it looks like the exhaust valve spring is a larger diameter than the intake spring. Are you sure the springs are a matched set? Just a thought.
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Left spring sure does look bigger and so does the retainer. Matter of fact, both retainers do not look centered, maybe the angle of the picture.

Did you buy these heads from edelbrock or private party?
I believe its time to get out the dial calipers and start checking diameters of springs and retainers.

If you bought these heads from a private party and springs and retainers turn out not to be a matched set, I would buy a new set of beehive springs and retainers. Much better springs and you will have all the rocker arm clearance you need.
 
I just checked, with my harbor freight caliper/micrometer they measure about 1.47, while Edelbrock specs them as 1.46, so that's within the tolerance of my capabilities to measure.

The offset spring cup is an optical illusion. They're both fine.

The heads came from edelbrock, new in sealed boxes from the machinist's wholesaler.
 
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years ago, ran a 1.5 dia springs on my 340, had to clearance 273 rockers to clear them. i found a comp spring , was 1.44 dia, had no clearance problems, 926 is spring number, has a high rate and enough pressure . just food for thought, put beehive springs on it. btw, ran engine to 7500 in traps
 
Anecdotal side track……..

I had some of those heads sent to me for a look over a few years ago.
They were built from bare castings.
Found a few things that weren’t great…..

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As soon as I took this head out of the box I noticed the one spring was bigger than the others.
Also, in addition to the ex valves not really being the correct length, they also had a longer groove-to-tip length. Which combined with the shorter overall length resulted in an even shorter installed height for the exhaust valves.
So, the bigger longer spring, installed at the shorter exhaust installed height ended up as a combo of parts that was coil bound at a bit over .500” lift.

Of course, none of that was any fault of the heads.
 
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Uncle Bob said:
FWIW Edelbrock lists the spring diameter as 1.46". The Comp Cams rockers list a max spring of 1.54"
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ANd if the spring is shifted in the pocket slightly, there won't be enough clearance. :BangHead:
 
Did those heads come with spring cups to center the spring? You have way to much clearance between the OD of the spring and seat.
 
mderoy340 said:
Did those heads come with spring cups to center the spring? You have way to much clearance between the OD of the spring and seat.
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Yes there are cups with brass shims under them. The cup seemed to fit the spring correctly when I removed the springs. I think the angle of the photo is causing optical illusions.
 
when those heads first came out they didn’t use spring cups.
The spring pocket was cut to something like 1.480, and then there were just shims under the springs.
The machined pocket is what located the springs.
Fundamentally that’s not a problem, but Ede didn’t use heat treated shims, so the spring dampers would chew up the shims over time.

The first set I had here where they had cut the spring pockets to a larger OD and used actual spring cups was within the last 18 months or so.
I don’t get too many of those heads thru here, so I don’t have a good handle on the timeline when that change was implemented.
 
I taped the jaws on a set of channel locks and turned the spring CW a little bit. Now I've got clearance. Seems like it could be the springs aren't seated in the center?
 
I keep staring at it but nothing changes.

I checked that the shaft is straight and the tips of the valves are level. No problem.

I taped up a pair of channel locks and tried working the spring around a little bit but nothing seemed to change. Then I grabbed the top of the spring and gave it a little turn CW and now I've got clearance. I'm not sure what that tells me, if anything.
 
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