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Old Feb 24, 2026 | 07:58 AM
  #46  
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Valve seal

Thanks for finding me on the other forum Leroy. I’m gonna go with your thinking on this one. I order some old stock off eBay and will reuse any that are still in okay condition. It’s strange that there isn’t really info on these little oil shield hats. As for the lack of seals on my exhaust valves I’m still a little unsure. I keep reading that using viton seals will dry them out and the umbrella type are no good. I know you’re an advocate for the umbrella, what’s the thinking with those?
 
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Old Feb 24, 2026 | 06:14 PM
  #47  
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To be completely honest, I'm not any kind of knowledgeable about valve seals,

I'm glad I could help by bumping your concern, but when I had my top end open, my valves looked good, so I didn't think anything about changing the seals.

I cant talk out of my rear end, like I would have a clue. I know lots of other stuff though, maybe I could help later on with things other than valve seals, wish I knew..

all I know, is that in general, you don't want seals that are too tight tight and starve the valve stems of oil, but you also dont want em blowing by smoke at idle,

Excepting stock rocker arms and mach fuel pumps that are junk and need updated/replaced on the 6.9's, all internal parts quality is good,

I wouldn't hesitate to use the same used or nos little plastic umbrella clips.
 
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Old Mar 3, 2026 | 03:05 PM
  #48  
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Heads are done for?

Just got a call from the mill shop. They said one side of the heads are already at minimum spec and the other side is close to 4.805 max. The middle is warped. Are these heads to far gone? What’s my move here?
here are the specs from the shop


I’m gonna run a Felpro head gasket which is supposedly 10thou thicker then stock when crushed. Would this potentially allow me to mill the heads to true flat (cutting out the bow) and still have enough valve clearance?
Im also gonna check the block I’ve read it’s unlikely that it’s also warped but if these are warped .006 out that would mean overheating at some point.
 

Last edited by TruckMonth; Mar 3, 2026 at 09:12 PM.
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Old Yesterday | 04:09 PM
  #49  
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Machine shop

Just heard from the machine shop after a month of silence. They keep breaking bits on the precups which they said they could do although I warned them about hardness. What’s my solution here. Could I punch out the cups and have them sent elsewhere where? Is the tolerance of +.0025 of stick out for precups possible to meet with the given amount I need to remove. Any one been at this point before?
 
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Old Yesterday | 07:51 PM
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It seems like they should be able to mill them flat, I don't know, because I didn't send my heads in, or even measure them, for that matter.

I'm a retired body shop man, and can see by eye and feel, even very minor defects, so I cut mine real good, but still, it was done by hand, and, I only aimed for 85% good enough.

Good torque on the head bolts or studs will take up a lot of slack and imperfection, on my stock 6.9 bolts, I went up into the low 90's. They'll crush and fill in small gaps.

I cut them flat with a knife stone by hand, as a hone. I haven't had any problems.

I wouldn't worry about the precups, but this is just anecdotal, just my experience, and perfectly flat is always best, if you really want it.

I just don't think they're all thaat sensitive, I just got it 85% and run it.

If they ain't buggared em' up, I'd just ask them to get em' pretty decent as they can with what they have on hand, and if in doubt, run head studs and crank em' tighter.

If you use your stock head bolts, I can attest that they'll take slightly above 90, I think I went about 93 lbs. If you use 7/16 studs you could probably go to 110.

Someone will probably have better detail with the specific answer on the specs, these r' just my musings.

 
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