megavites
Well-Known Member
I have two diff. spec #'s. for 11/06/69 "675" head
one is 1.890-1.920
other is 1.907-1.937
one is 1.890-1.920
other is 1.907-1.937
Anyone have installed valve stem height spec?
- Thread starter megavites
- Start date
-
yellow rose
Overnight Sensation
If it's hydraulic lifters I'd split the difference and set them at 1.910. I don't have my book anymore. If it's a solid, or you have adjustable rockers, I'd stay under 1.937 and over 1.890 and make them all the same, within .010 or so. Plus or minus .005 either way.
pishta
I know I'm right....
There probably the same from 2 different sources. .030 is pretty small but the correction spacer is .0625.
megavites
Well-Known Member
Yea..I just want to verify the book # on this head for valvestem height.
Last night I found another ref. to 1.890-1.920.
I currently have a .032 spread, with the tallest .023 over the spec.
I could have head guy grind .020 off stem, but I dont think you want to go more than that.
Last night I found another ref. to 1.890-1.920.
I currently have a .032 spread, with the tallest .023 over the spec.
I could have head guy grind .020 off stem, but I dont think you want to go more than that.
nm9stheham
Well-Known Member
Is this all related to the variations in lash? If so, then using the spring seat as a reference plane just gets the top of the stem in the 'general vicinity' of where it needs to go. Is this one stem noticeably taller than the rest?
And how does this relate to that one valve with the large lash that you measured?
And how does this relate to that one valve with the large lash that you measured?
megavites
Well-Known Member
Yes, I know I have some stems up to .023 over spec. I'm confused when I go to measure using the Mopar chart, ie.
#1 TDC, check #2In, #8Ex...etc. ALL are ZERO lash and into the preload as I rotate around 90deg at a time...but...#2 Ex is
waaay loose up until #7 cyl is TDC, then its tight. I'm using the Hughes chart...
Column #1 Column #2 Column #3
Position this piston at TDC Adjust the INTAKE valve on this cylinder Adjust the EXHAUST valve on this cylinder 1 2 8
8 1 4
4 8 3
3 4 6
6 3 5
5 6 7
7 5 2
2 7 1
Even using this chart and rotating 90 deg at a time...I get #2 at TDC and 7In, #1Ex are compressing.
I had better luck bumping engine around and watching rockers. I know this Whiplash cam closes Ex quicker so maybe the chart is not the best guide.
FYI...I did realize I had rocker shafts 180deg out and it does seem to have changed original measurements...just trying to understand why, but still have loose rockers that I'll have to use pushrod checker to get proper length.
Holding out cause I know $600 would put Comp pro mag rollers on and solve the issue.
Last edited:
An absolute way to assure that you are on the cams base circle, is to do it 1 cylinder at a time. When #1 intake just starts to close, adjust #1 exhaust. When #1 exhaust just starts to open, adjust #1 intake. Then go to another cylinder.
I farted.
Shame or pain baby. Sometimes ya just gotta let it out or die.
Start with a level foundation. All this crap is why, when you do a head, you check the head surface to valve spring seat surface. Then you measure every valve length to see that they are the same overall and tip length. Measure all installed heights, then do the valve job to make all installed heights to the tallest measurement. Know what to do to blend the combustion chamber to the seat in the head. Replace the seats in the heads with hard seats if something is sunk beyond proper measurements or throw the head away and start with a good one. Or you could buy a lathe and cut 16 different push rod lengths to get uniform preload. Yeah, adjustable rocker arms are an option, but the head is still all screwed up if you don't start level. And you don't think knowledgeable engine shops are worth the money? I know, too damn expensive! Wanna race?
nm9stheham
Well-Known Member
Exactly..... that is why I doubt the effort to set valve stem heights to the existing spring seats is gonna fix anything.....and may make things worse. There is NO way to know if the seats are all anywhere near to being at an even height to start with. And determining valve height by looking at lash is looking at things the wrong way; the stack-up of parts tolerances in the valvetrain makes lash a 100% unreliable way to set valve stems heights.
Understood on the cost factor.... Changing the rockers around and having preloads change is no surprise; they are just stamped pieces of metal and only have so much accuracy in their dimensions.
OP, have you placed a good straight edge across all the valves and been able to observe that any valve is long or short? We don't know what you are fighting, and the valve stem heights over the seats may or may not be a useful measurement.
Is it possible that when you think you are at #7 TDC you are actually at #4 TDC? Remember, #7 TDC on the chart you are using means that the #4 valves are at overlap (both #4 valves slightly open).
I think the op's question should have been about valve adjustment, not stem height. He said he has a head guy, so I don't think he is setting heights or swapping valves or anything.
"But that's too much work and too much money. I'm not buildin a race car."
Sounds about right for around here.
The way I see it, somethin is either RIGHT or WRONG. Yet people argue to the end of time.
Sounds about right for around here.
The way I see it, somethin is either RIGHT or WRONG. Yet people argue to the end of time.
Yeah, lets not make sure the valve adjustment is right from the ground up. God knows, we wouldn't want him to luck up and get it right. <smh>
Haha, I love it! I knew when I saw you on my alert, it was going to be brutal! let's make sure the lash procedure is executed correctly before op goes tearing the heads off. If the lash is set correctly and it is still messed up. Then I'd pull the rockers and put a straight edge on it, to start with.
-
