Adjustable rocker clearance specs?

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4spdragtop

4spdragtop

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Hi all, wondering what the side to side "play" specs are on factory adjustable rockers? NOT the shaft to rocker spec.
I measured .074" on one pair. Nothing in FSM.
Thanks
Steve
 
I can’t see how you’d ever need more than .015-020” per pair.

.074” may not ever bother anything, but I’d probably shim that down some.
 
IIRC its not a controlled spec: I think they find their own running position, just dont jam them up with shims so when they heat up they bind.
 
.015 is what we always used... however as I'm sure you already know looking at the factory layout, it's just not the most critical clearance measurement in the engine. Less than. 015 may be asking for some trouble tho.
 
I also run.015 clearance with Isky style with the jam nuts. I also went to B3 for geometry correction.
 
Steve, have you measured the width of each rocker & checked to see how they center on the valve stem? I went though about 3 full sets before I got mine set up to my satisfaction. (Opinions may vary) LMAO
 
Yeah Im kinda suprised the FSM has no specs, the rocker tip stays on the valve, but seems a little loose.
I have only measured the one pair, but to go from .074 to .020 is .054, call that 4 @0.015 approx, so 16 per shaft?? So I would need a few sets from Summit(10 per kit).
I saw Hughes has them also, I wonder if new spacers is the way to go??
 
Thanks Bill to be honest, I havent, the heads are stripped down as I was doing a DIY port on them, also looking for new springs, locks, retainers to go with my new cam. So I didnt want to install the old springs to check, would rather wait until I get new springs etc and then do some more checks.
I could still measure the rockers as they are all loose.
Demonracer said:
Steve, have you measured the width of each rocker & checked to see how they center on the valve stem? I went though about 3 full sets before I got mine set up to my satisfaction. (Opinions may vary) LMAO
Click to expand...
 
0.015 to 0.008 is fine,
Buy some shim sets and CENTER over valve stem is very desirable
and worth the effort. You can grind the spacers if needed
 
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I found thicker shims from Harland Sharp that are 0.062" thick. #SP062K. That leaves approx 0.012" clearance.(gap is 0.074") My thoughts are these would be better than stacking a buttload of thinner spacers.
Thoughts?
Thanks
Steve
My concern are these are made from aluminium and wonder about the durability?
Also, HS offers a wide variety of spacers. I wonder if I should replace the oem ones with larger HS ones?
Again, thoughts?
Components
 
Oops, yer right, thanks!
I've been checking a few mfg out and sure I saw alum ones somewhere.
What's your thoughts on replacing ALL oem spacers and going with larger ones?
PRH said:
HS shims/spacers are steel, not aluminum.

Look on their site or give them a call.
Click to expand...
 
I think I misinterpreted what you were looking to do.
I saw you mentioned “shims” and thought you were saying those were aluminum from HS.

Looks like you’re talking about changing the hold down clamps as a possible solution.

My suggestion is to bolt the complete rocker set up onto the heads before ordering anything.
 
4spdragtop said:
I found thicker shims from Harland Sharp that are 0.062" thick. #SP062K. That leaves approx 0.012" clearance.(gap is 0.074") My thoughts are these would be better than stacking a buttload of thinner spacers.
Thoughts?
Thanks
Steve
My concern are these are made from aluminium and wonder about the durability?
Also, HS offers a wide variety of spacers. I wonder if I should replace the oem ones with larger HS ones?
Again, thoughts?
Components
Click to expand...
Went through the same deal, Summit shows aluminum. Turns out they are very trick magnetic aluminum! Yes. Steel
 
I was mentioning HS as alum. (Summit description).
I'm not looking to replace the hold downs, BUT looking to replace oem spacers with larger ones?(hope that makes sense)
PRH said:
I think I misinterpreted what you were looking to do.
I saw you mentioned “shims” and thought you were saying those were aluminum from HS.

Looks like you’re talking about changing the hold down clamps as a possible solution.

My suggestion is to bolt the complete rocker set up onto the heads before ordering anything.
Click to expand...
 
Last edited:
Got it.

Mock everything up as is....... figure out what you’d need to end up with the side clearance you want...... then order what you need.
You may want a mix of thin and thick ones to help better locate the rockers on the valves.
The HS shims/spacers come as 4-paks.
 
4spdragtop said:
I'm not looking to replace the hold downs.....
Click to expand...
And if you were.........
upload_2022-4-17_7-59-35.png
 
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