Valve Guide Clearance

[JKrebs]

Hi All,

Looking to see if anyone has a procedure for checking valve guide clearance by measuring the end play at the top of the valve. I have a set of X heads that are on the bench. The valves hold a good vacuum and i will be disassembling them for a clean up, some new springs and seals. Just don't know if i need to have the guides done. I feel slight movement when i move the valves from side to side, I can put a gauge on the valves but i have no idea on what is in tolerance. Thanks

 

[yellow rose]

.0025 on the intake .0035 exhaust for .375 stem valves a bit less for .342 stems

 

[yellow rose]

.0025 on the intake .0035 exhaust for .375 stem valves a bit less for .342 stems

Edit: that is max on cast iron guides. They can be a bit looser with bronze guides. And good seals.

 

[JKrebs]

Edit: that is max on cast iron guides. They can be a bit looser with bronze guides. And good seals.

Just what i was looking for. Thank you for your Help!!

 

[MOPAROFFICIAL]

They'll be different opinions on this.
Both loose .0025-.0035 and spec .001-.002 will work, with one being more detrimental to seat life than the other.
One thing you do not want...is too tight.

 

[IQ52]

.0025 on the intake .0035 exhaust for .375 stem valves a bit less for .342 stems

At what valve lift?

 

[MOPAROFFICIAL]

And there it is.haha

 

[JKrebs]

And there it is.haha

Thanks for your input. As it turns out my guides are defiantly in need of replacement. I'm looking at end pay with the valve closed at any where between .004 and .008. Guides are steel not bronze. Valves look good with not much scuffing or any ridges. .

 

[yellow rose]

At what valve lift?

If the guide is straight and round, what difference does lift make?

I measure guides with a bore gauge.

 

[toolmanmike]

If the guide is straight and round, what difference does lift make?

I measure guides with a bore gauge.

Have you ever used the spiral guides?

 

[AJ/FormS]

Ahhh, the wiggle test
I got a better test; stand the head on end, and push all the stems down flush with the top of the guides. Next stick your tongue onto the top of the guide to cover it. Now yank the valve out the other side. Repeat two more times and average out the numbers.Record you results. Move to the next one.
If the vacuum so produced tries to suck your tongue into that teensy hole, that is a 3 on a scale of 1 to 5. If your tongue bleeds, it is a 5. If the suction is barely perceptible, that is a 1, and if you're not sure if you felt anything, that would be a Zero. The goal is to have as bloody a tongue as possible after the test and you have to wait 7 days to test the other side. No blood at all, means either you didn't do the test right, or the head is toast; start over.
Of course I'm kidding. Was it funnier in my head? Well at least I had fun.

 

[toolmanmike]

Ahhh, the wiggle test
I got a better test; stand the head on end, and push all the stems down flush with the top of the guides. Next stick your tongue onto the top of the guide to cover it. Now yank the valve out the other side. Repeat two more times and average out the numbers.Record you results. Move to the next one.
If the vacuum so produced tries to suck your tongue into that teensy hole, that is a 3 on a scale of 1 to 5. If your tongue bleeds, it is a 5. If the suction is barely perceptible, that is a 1, and if you're not sure if you felt anything, that would be a Zero. The goal is to have as bloody a tongue as possible after the test and you have to wait 7 days to test the other side. No blood at all, means either you didn't do the test right, or the head is toast; start over.
Of course I'm kidding. Was it funnier in my head? Well at least I had fun.

You can do the same with your finger. A healthy "pop" and you have a healthy giude. Very unscientific and inaccurite. Lol

 

[yellow rose]

Ahhh, the wiggle test
I got a better test; stand the head on end, and push all the stems down flush with the top of the guides. Next stick your tongue onto the top of the guide to cover it. Now yank the valve out the other side. Repeat two more times and average out the numbers.Record you results. Move to the next one.
If the vacuum so produced tries to suck your tongue into that teensy hole, that is a 3 on a scale of 1 to 5. If your tongue bleeds, it is a 5. If the suction is barely perceptible, that is a 1, and if you're not sure if you felt anything, that would be a Zero. The goal is to have as bloody a tongue as possible after the test and you have to wait 7 days to test the other side. No blood at all, means either you didn't do the test right, or the head is toast; start over.
Of course I'm kidding. Was it funnier in my head? Well at least I had fun.

This is what happens when you live where it's cold for months on end.^^^^^^^^^^^^^^^^^

 

[yellow rose]

Have you ever used the spiral guides?

Yes, the hardened cast iron ones.

 

[IQ52]

If the guide is straight and round, what difference does lift make?

I measure guides with a bore gauge.

I do too. The OP is obviously using the wiggle/wobble test.

 

[IQ52]

Ahhh, the wiggle test
I got a better test; stand the head on end, and push all the stems down flush with the top of the guides. Next stick your tongue onto the top of the guide to cover it. Now yank the valve out the other side. Repeat two more times and average out the numbers.Record you results. Move to the next one.
If the vacuum so produced tries to suck your tongue into that teensy hole, that is a 3 on a scale of 1 to 5. If your tongue bleeds, it is a 5. If the suction is barely perceptible, that is a 1, and if you're not sure if you felt anything, that would be a Zero. The goal is to have as bloody a tongue as possible after the test and you have to wait 7 days to test the other side. No blood at all, means either you didn't do the test right, or the head is toast; start over.
Of course I'm kidding. Was it funnier in my head? Well at least I had fun.

Real funny.
Less bloody by plugging the guide with your finger and using the POP volume test. The louder it 'pops' when you pull the valve, the better the guide.

 

[RAMM]

Real funny.
Less bloody by plugging the guide with your finger and using the POP volume test. The louder it 'pops' when you pull the valve, the better the guide.[/QUOTEquews

To answer the w

Real funny.
Less bloody by plugging the guide with your finger and using the POP volume test. The louder it 'pops' when you pull the valve, the better the guide.

Guides are perfect @ .0015" intake .002" exhaust. I use gauge pins to check guides--best way there is.Rob

 

[yellow rose]

Guides are perfect @ .0015" intake .002" exhaust. I use gauge pins to check guides--best way there is.Rob

You run 3/8 stems that tight?

 

[RAMM]

You run 3/8 stems that tight?

Often tighter. Like all things with engines--Depends. J.Rob

 

[AJ/FormS]

You can do the same with your finger. A healthy "pop" and you have a healthy giude. Very unscientific and inaccurite. Lol

Yeah but then you don't have a funny story to tell.
Wobble tests mighta worked in the "old days", And I'm sure a guy who builds heads all day can make use of the information so gathered, but for guys like me, I take heads to the head experts, and let them do what they do best, while I do what I do best, which is starting to be very little.
Well, except that YR finds me entertaining, and occasionally someone else gets a kick out of one of my posts.

 

[famous bob]

Guides are perfect @ .0015" intake .002" exhaust. I use gauge pins to check guides--best way there is.Rob

---------------------------this is more like it !

 

[RAMM]

If the guide is straight and round, what difference does lift make?

I measure guides with a bore gauge.

I got stung by a bore gauge once. They don't show you if the guide is actually straight--picture a mandrel bent tube here. The I.D. of a bent tube will measure the same diameter all along its length but a straight shaft longer than the guide will have zero clearance at each end. Gauge pins rock at finding bell mouthed or reverse hour glass shaped guides.

In this example the valve measures .3408" and the gauge pin is a .342- and measures .3418" and just slides in for a clearance of exactly .001" which is just fine. J.Rob

 

[IQ52]

I don't have gauge pins so I have to use the valve as such. I start with a guide smaller than the valve, hone until the valve just slides in, then measuring with the dial bore gauge, keep things as uniform as possible to the desired clearance. There may be better ways but I have to use the equipment I have. I try to keep the intakes at .0012 and the exhaust at .0017. I believe the difference in valve stem diameter expansion between 11/32 and 3/8 will be less than 0.0001" so I use the same clearances for both.

 

[MOPAROFFICIAL]

They'll be different opinions on this.
Both loose .0025-.0035 and spec .001-.002 will work, with one being more detrimental to seat life than the other.
One thing you do not want...is too tight.

Trying to be funny, a lot of things will work or run...just some not for very long.
.001-.002 is where I like them

At what valve lift?

.900

And there it is.haha

Ah someone caught that...lol

Guides are perfect @ .0015" intake .002" exhaust. I use gauge pins to check guides--best way there is.Rob

Whew, thought I was the only one!

I don't have gauge pins so I have to use the valve as such. I start with a guide smaller than the valve, hone until the valve just slides in, then measuring with the dial bore gauge, keep things as uniform as possible to the desired clearance. There may be better ways but I have to use the equipment I have. I try to keep the intakes at .0012 and the exhaust at .0017. I believe the difference in valve stem diameter expansion between 11/32 and 3/8 will be less than 0.0001" so I use the same clearances for both.

That works, those are the limits of longevity.
Less expansion in that tree trunk stem.