Head milling

[duramax on fire]

Ok I’m getting conflicting info on resurfacing heads lbz. Machine shop said they took off .022 thousandths. But cut the valve seats and moved the valves with it. Running a grade C mahle gasket. Anyone have an issue with this?

 

[Chevy1925]

you sure you got the right info? if the heads have never seen a cut before and were withing the factory recess, taking .0022 off should not have required a valve recess. if it was .022, then yes.

your head gasket thickness depends on your piston protrusion and how much head to piston clearance you want to run. it has nothing to do with the amount of material removed from the head when the head is machines correctly

 

[duramax on fire]

Sorry .022 is 22 thousandths. Heads got hot and warped more than likely

 

[clrussell]

Hopefully they took the same Off the intake side also. It makes the y bridge way better fitment.

 

[duramax on fire]

Thanks Chevy 1925. What I found is. I’ve got one set of valves .008 recessed Into the head. The rest are about .015-.020 recessed.
Piston is .008 out of the whole. I’m trying to find valve to piston clearance minimum. I’ll keep digging. Thanks for all the help.

 

[Chevy1925]

sounds like you are well beyond what stock is, assuming you are giving the right numbers.

Valve Depth ?

Hello there, I'm Doing HGs on Friend's LLY, Using ARP studs and Grade C gaskets. I was doing my homework and checking the Intake and Exhaust valve depth on the head. Intake Valve depth : 0.5 mm Exhaust Valve depth : 0.8 mm I read somewhere that the factory valve intake/exhaust depression is 0.6...

www.duramaxdiesels.com

if they recessed them that much, you might have a decent amount of shrouding going on for the valves.

at those numbers, piston to valve is a non issues. even if they were factory numbers, the piston will hit the head before the valves will with too thin of a gasket in there. if all the pistons are . 008 out of the hole, id run an A gasket. make sure you measure over the wrist pin area on top of the piston and rock it back and forth looking for the highest number.

 

[duramax on fire]

Thanks James. I doubled check the measurements. My main concern is pistons touching the valves. From my figures I’ve got .0380valve clearance on the tightest hole. I double checked measurements.
.010 out of hole measuring over the wrist pin while rocking.
.008 recessed valve. That’s on the ends of the head. Looks like he didn’t cut the valve seats. Because the center valves are deeper. Shit I don’t know. Fixing to soft bolt them on with a .039 spacers and clay the piston to valve.

 

[bimmer95]

22 thousandth is a lot of material.I remember I had a set that was warped 17 and my machinist said that's too much head is junk.Im betting you will have trouble getting the y bridge in with that amount off.

Sent from my SM-G981U using Tapatalk

 

[Chevy1925]

Thanks James. I doubled check the measurements. My main concern is pistons touching the valves. From my figures I’ve got .0318 valve clearance on the tightest hole. I double checked measurements.
.010 out of hole measuring over the wrist pin while rocking.
.008 recessed valve. That’s on the ends of the head. Looks like he didn’t cut the valve seats. Because the center valves are deeper. Shit I don’t know. Fixing to soft bolt them on with a .039 spacers and clay the piston to valve.

the more you talk about these heads, the more you are not giving me that warm fuzzy feelin about them. you got me thinking that the rocker bridge might now also go into a bend and may or may not cause rocker arm misalignment or undo bind on them.

when they were pressure checked, was it under hot water (200+ degrees) and 90-100psi?

 

[duramax on fire]

Haha yeah I’ve almost talked myself out of these heads. Just got a bad feeling. Got two options. Get the fel pro .047 thick gasket and hope for the best giving me .0 valve piston clearance or get new heads.

James the top of the rocker mounting was .009 out of wack. Thats using a straight bar that’s .001 in spec

 

[juddski88]

I think you are also confused as to how to measure piston to valve clearance.

 

[duramax on fire]

I think you are also confused as to how to

more than welcome to school me please. If I’m .010 out of the hole. Running a .041 gasket. That leaves .031 to the gasket surface of the head to the top of piston. Valve is recessed .008 that comes up to .038. Please correct me if I’m wrong.

 

[juddski88]

Checking Piston-to-Valve Clearance, the Right Way!

Checking piston-to-valve clearance is an essential part of any engine build. In this tech installment, we show you how to do it.

www.google.com

 

[duramax on fire]

good article. Thanks for sending it. I’ll give it try and see what it comes up with. I’m still done with these heads though. New set coming Monday.

 

[juddski88]

good article. Thanks for sending it. I’ll give it try and see what it comes up with. I’m still done with these heads though. New set coming Monday.

Good move

 

[duramax on fire]

Just giving an update. And keep in mind this is an old work truck. I ended up talking with my head guy and I decided to let him cut all the valve seats down to bring them to .019 and .031 below deck. I’m always one to take a gamble. He said aluminum was good. He could tell by the way the surface cutting went. We slapped them on last weekend. Y bridge was a bitch. But it did fit. Also cross over pipe barely fit. Runs good. We’ll see how long it last. Not saying it is wrong or right. Do over again I would have checked them for straightness before taking them to him.