Valve lash technical advice needed

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Model T Ford Forum: Forum 2012: Valve lash technical advice needed
Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Tuesday, November 20, 2012 - 03:14 pm:

I'm doing some valve work with the engine in the car. All the exhaust valves & seats were badly pitted. Purchased new valves, reground seats and adjusted valve lash to .014 (I know its a little much but being sure of good closing was important to me).

The intake valves and seats were like new, Didn't even grind the seats because the finish they had was better than the seat grinder could produce.

Valve Measurements

Exhaust
(Replaced) Length Clearance
1 - 4.988 0.014
4 - 5.024 0.014
5 - 5.030 0.014
8 - 4.994 0.014

Intake
(Reinstalled) Length Clearance
2 - 5.038 0.023
3 - 5.017 0.019
6 - 5.025 0.024
7 - 5.028 0.013

The old original intake valves have too much clearance. I would prefer about .012 .

Question is: Should I buy 4 more intake valves and adjust to .012 or will the excessive clearances I have REALLY make a noticable differance?

I don't really care about a little tappet noise nor do I care if I lose a fraction of a horsepower. A loss of anywhere near 1 HP or greater I would consider undiserable though.

So you techies out there, oil up the slide rules and give me some advice please. ;o)

Thanks in advance
schuh


Top of pagePrevious messageNext messageBottom of page Link to this message  By Adam Doleshal on Tuesday, November 20, 2012 - 03:28 pm:

I have been told by a very reliable source that from a design standpoint, the stock T cam develops slightly better power at the "stock" 1/32" gap (around .031").

However, it is a bit quieter at a closer gap (maybe around .010").

From a technical standpoint, if your cam is worn and you don't have about the same lift on all valves, then it really doesn't matter too much unless you time all your valves by piston position, in which case you will have to start with all your valves gaped to your "biggest" clearance (.024" in your case).


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem on Tuesday, November 20, 2012 - 04:35 pm:

Bud,

I would have the valves ground. This will have the effect of making the stems longer. Then trim to suit the lash you want.

Just be sure when you have them ground to tell the shop not to trim the stems as well. Sometimes they'll do that so you can maintain same clearance, which you don't want in this case.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Tuesday, November 20, 2012 - 05:12 pm:

.030 thousandths clearance was used, because of the old steel valve stem, and the Cast Iron valve head.

With .030 clearance, the valve stem, and the solid lifter, just beat them selves to death.

You had to regrind the T valves every 3 months, if the car was used regularly, as they can burn very easy. And so a bigger gap, to make sure they closed.


Top of pagePrevious messageNext messageBottom of page Link to this message  By steve miller- mississauga,ontario on Tuesday, November 20, 2012 - 05:26 pm:

If you mean original TWO PIECE valves, replace them.
They are a problem waiting for a place to happen.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Tuesday, November 20, 2012 - 07:44 pm:

Sorry Steve, guess I should have mentioned, they are all one piece replacement valves.

schuh


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roar Sand on Tuesday, November 20, 2012 - 08:26 pm:

Bud,

Not to nitpick, but the term "tappet noise" is a misnomer. The noise you hear is the valve hitting the seat at a higher than designed velocity. This happens when the clearance is too high, causing the valve to close off the closing ramp on the cam lobe.
When grinding seat and/or valve to achieve the desired lash, make sure the OD of the valve head ends up overlapping the OD of the seat.
FWIW,
Roar


Top of pagePrevious messageNext messageBottom of page Link to this message  By Erich Bruckner, Vancouver, WA on Tuesday, November 20, 2012 - 08:38 pm:

Hope you used new valve springs while you have it apart. The old ones may be all different lengths/strengths like mine were. New set is cheap.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Aaron Griffey, Hayward Ca. on Tuesday, November 20, 2012 - 11:01 pm:

When I have too much valve clearance I have the ends of the valves welded up.
It is a shame to grind away valve seat material.
If you get new stainless steel valves and they are too short just have a good welder add an eighth of an inch to the valve stem and you can grind them square and start over.
I have never tried welding up regular steel valves.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Tuesday, November 20, 2012 - 11:13 pm:

Thanks all for your comments.

Jerry: I think it will be cheaper and better to just buy 4 new valves and set to the right clearance. Good idea though.

Roar: Are you saying that what most people call tappet noise is really the valve seating?

Erich: New valve springs ready to go. Old ones tested at 16 to 17 lbs.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roar Sand on Wednesday, November 21, 2012 - 08:22 am:

Yes, Bud.
When the lash is too high, the valve will seat before the tappet gets on the closing ramp of the cam lobe. The velocity of the valve is then much higher than when the tappet is on the closing ramp, and you hear the valve hitting the seat.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Wednesday, November 21, 2012 - 09:03 am:

Roar

I learn something new here every day! Thanks for that.

schuh


Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Gould on Wednesday, November 21, 2012 - 09:13 am:

Check the tension on the new springs. Some are too stiff.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem on Wednesday, November 21, 2012 - 01:15 pm:

Roar,

By that same thinking, the tappet will also have a higher velocity when it finally contacts the valve stem. Result: tappet noise.

You're saying, the noise of the valve closing is more pronounced. I'm saying, the noise of the tappet contact on opening is also more pronounced. Which one your hear more is probably up for debate, as all things Model T seem to be ;>)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman - Sumner,WA on Wednesday, November 21, 2012 - 01:52 pm:

Roar - I guess I have a problem with that. I believe the co-ordinated mechanical action of the tappet and the valve is the same due to valve spring pressure, no matter how much or how little valve lash exists. In other words, the valve stem maintains constant contact with the tappet and has the exact same motion (velocity during opening & closing) from the time the cam begins to lift the valve off of its seat until the valve closes and again bears on the valve seat. The only difference in the velocity of the valve train motion would occur as the rising tappet closes the excessive gap (valve lash) and begins to lift the valve off of its seat, which I don't believe would cause any noise from the head of the valve lifting off of its seat. The noise comes from the tappet closing the gap and striking the bottom end of the valve stem, and the more the gap, the more velocity is present when the tappet eventually strikes the valve stem. More gap, more velocity when contact is made and hence,....more noise.

I obviously can't "say it" very well, but that's the way I see it,......harold


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman - Sumner,WA on Wednesday, November 21, 2012 - 01:54 pm:

Jerry - Just re-read this and I said the same thing you said but I used a lot more words,.....you said it better,.......harold


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem on Wednesday, November 21, 2012 - 04:57 pm:

Harold,

Thanks. I had a great english teacher that always taught me to use as few words as possible to make my point.

The more I think about it, I think she just didn't want to hear my voice!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Aaron Griffey, Hayward Ca. on Wednesday, November 21, 2012 - 09:48 pm:

If the closing ramp keeps the valve from making noise because it slows the valve closing speed down and the valves are quiet at 500 RPM why are the not noisy at 2000 RPM?
I always read that a T cam does not have a closing and opening ramp.
So the noise only is heard on the closing of the valve.
That makes sense, otherwise we would hear a double click.
Maybe the noise is only heard when the lifter, cam and valve stem take up slack because do you really think we could hear the valve hitting the seat with all that metal around it?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Wednesday, November 21, 2012 - 10:43 pm:

Yes, Bud.
When the lash is too high, the valve will seat before the tappet gets on the closing ramp of the cam lobe. The velocity of the valve is then much higher than when the tappet is on the closing ramp, and you hear the valve hitting the seat.

I hope you are not serious!!!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Wednesday, November 21, 2012 - 10:56 pm:

Tappet noise is always made on the opening of the valve, as the lifter is slammed into the valve stem!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roar Sand on Friday, November 23, 2012 - 11:19 am:

Take a look at the size and mass of the valve and compare that to the tappet. Then tell me which you think is making the most noise, - top end of tappet hitting bottom of valve stem, or valve head hitting the seat in the block.
Roar (still burping turkey)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Friday, November 23, 2012 - 11:26 am:

You are not very mechanical are you Roar!

Valves make no sound.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Gould on Friday, November 23, 2012 - 11:45 am:

I guess I am not very mechanical either. But I do have a curious mind that has served me well over the years. So I am trying to understand why the valve head makes no noise when returning to the seat. Any scenario I can imagine doesn't explain the absence of noise. So can someone explain it to me so that someone without mechanical knowledge can understand it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Friday, November 23, 2012 - 11:58 am:

With engine running, the noise in the compression chamber/inside block is pretty well masked by explosions of the combustion. Any noise the valve makes when it hits the seat is unheard. Like a tree falling in the woods and no one in ear-range.

Now the tappets are running against the stems in the echoing open valve chamber, even the cover and gasket over the chamber can't mask the sweet sounds of clicking ticking tappets....I like that in my T. :-)

So does everyone when the hood is up...


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roar Sand on Friday, November 23, 2012 - 12:11 pm:

Mr. Kohnke,
Thank you for revealing to the world my lack of mechanical ability!
In spite of that, I made it as a design, test and development engineer for over 36 years at one of the (now not so) "Big Three" car companies, and for all of those years I worked on valve train systems.
If I were still at work (retired for a log time now), I could lay my hands of many studies with microphones, vibration pick ups, high speed videography and more, backing up my statement.
I have often admired your knowledge and dedication, and I admit my own limited knowledge of everything "T", but I think it is time you get off your high horse of know-it-all and get used to the possibility that there are people around that may have more experience than you in some areas.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Friday, November 23, 2012 - 12:14 pm:

On closing the spring keeps tension between the valve stem end and the top of the tappet till the valve is lowered to the fully seated position then the cam continues it's rotation till it's peak turns past the seat of the tappet allowing the tappet to follow the cam to what ever gap it is set at. Tappet nose comes from the rotation of the cam pushing the tappet up to close the gap between it and the valve stem on opening. The bigger the gap the louder the tick.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Friday, November 23, 2012 - 12:43 pm:

Any body that has set lifters on engines such as Chevy 6 cylinders while they were running, could tell where the noise was coming from, and all you would have to do is watch, not knowing anything about engines at all.

A lifter with .030 thousandths clearance will make noise. Set it at 12 to 15 which is the limit in most cases, it will not.

As some have pointed out on here, the valve in under spring pressure. No matter if the valve has .010, to .100 thousandths clearance, when the lifter lets the valve down, on its seat, it is the same, it is the lifter that keeps going, the valve still works the same, it just didn't have as long of travel with the larger gap! It is on the return trip of the lifter, as it hits the valve stem, that a sound is made!

With the .015 thousandths extra clearance, on the lifter, that means the valve dropping .015 would have to make a clicking sound from a .015 thousandths drop, and a valve head with a 45 degree grind is going to make any kind of sound, I don't think so, and I know not.

If that was where the noise was coming from, a Original Ford two piece valve would blow heads all the time.

Boys, this isn't a big thought process, or some obscure, secret!

When a Hydraulic lifter collapses, the same sound is heard, you don't replace the Valve, you put in a new lifter, so it doesn't slam the valve stem, and make noise, and pound the valve stem.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Friday, November 23, 2012 - 12:50 pm:

Thank you for revealing to the world my lack of mechanical ability! "END QUOTE"

MR. ROAR, you done that your self!


Top of pagePrevious messageNext messageBottom of page Link to this message  By William Rowles on Friday, November 23, 2012 - 03:34 pm:

Boys, boys.....play nice and don't fight! The guy doesn't care where the noise comes from, or even if there is a noise.....he asked if the excess valve lash on the intake valves will cause a noticeable loss of power. I don't know the answer, but I sure would like to hear it if someone does! Bickering is a waste of time and nobody learns anything as a result.
How about some dyno performance data on the subject question....anybody know where we can find some?


Top of pagePrevious messageNext messageBottom of page Link to this message  By joe bell on Friday, November 23, 2012 - 07:21 pm:

The more clearance in a valve train, the less the valve will open, result are less gases entering the combustion chamber, less Hp, unless you are force feeding it with a turbo or my favorite the 6-71 super charger! Been there done that!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Aaron Griffey, Hayward Ca. on Friday, November 23, 2012 - 09:43 pm:

I ran a B16 Volvo for a year or so with two push rods removed because that piston had a hole in it and the car would smoke real bad AND run on three cylinders anyway. With the push rods removed the valves stayed shut and no oil from that cylinder could get into the exhaust system.
My point is that since there were no push rods being pushed down by the valve springs the lifters would float. When one would drop down on the cam I could hear the all-to familiar tappet noise. Just like setting a valve too loose.
If we can hear the valve hitting the seat why can't we hear the fuel charge exploding in the combustion chamber?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roar Sand on Sunday, December 02, 2012 - 10:58 pm:

I have been away from my computer for a few days, and am now trying to catch up.
I admit I don't know what the idle speed is for a Model T, but for discussion's sake let us assume it is 200 RPM. I think that translates to eight valves opening or closing 100 times every 60 seconds, or, if you will, 13.3 valve cycles every second. You are a remarkable man, Mr. Kohnke, if you have the eye to ear coordination to be able to distinguish exactly where in each lift cycle the "click" occurs. I never thought, in my wildest dreams, I was that good, so I chose to use instrumentation.
Since you seem to know all things mechanical, I am sure I don't have to educate you on how a hydraulic tappet works, but could you please tell me how a hydraulic tappet makes "tappet noise"? We will not count tappets with stuck plungers.
A hydraulic tappet, also known as an "automatic zero lash adjuster", when functioning as designed, doe exactly that. It keeps the lash at zero. "Tappet noise" most often occurs when air enters the high pressure chamber in the tappet, but because of the internal spring and oil pressure, it will not allow lash in the system, so there is no components of the valve train that clash together during the opening part of the lift event. What happens, however, is that a spongy tappet, due to air, will compress a small amount and not reach full lift. During the closing the valve will therefore hit the seat before the tappet has reached the closing ramp of the cam, and so the seating velocity will be much higher than when controlled by the closing ramp. So, when there are no parts hitting other parts on opening, it seems pretty obvious to me that the "tappet noise" comes from hard valve closing.
I am sure Mr. Kohnke will come up with some kakameni reason why I am totally confused, or he will, as seems to be his usual m. o. when someone dares to have opinions that differ with his, revert to personal attacks.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob McDonald-Federal Way, Wa. on Monday, December 03, 2012 - 12:00 am:

I'm hard of hearing, I don't hear any stiken tapping noise. If it bothers you don't start the engine.

Bob


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Monday, December 03, 2012 - 12:34 am:

Well Mr. Sand, I do know how a Hydraulic lifters work, but the guts of a Hydraulic lifter does not concern me, only the Noise one would make, not what happens inside a lifter, as it would be junk.

I would no more be concerned about that as I would a Big Stinking, Loud Fart! My only concern is if you get the noise to go away, you have fixed the Problem!

Mr. Sand, and I don't think you are confused, I just think you have told us more then you know.

You clearly have not had any hands on, working knowledge, as shown by that paragraph explaining the workings of a Hydraulic lifter that you plagiarized!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roar Sand on Monday, December 03, 2012 - 12:46 pm:

It is nothing but sad to see that a mature person, mature at least in years, has such a hard time accepting that someone else knows more about a subject than they do and resort to accusations of plagiarizing. It says a lot about that person's psyche!
I can assure you, Mr. Kohnke, that after more than 36 years of professionally working with hydraulic lash adjusters and all other valve train components, both in test, development and design capacity, I have no need to plagiarize in order to explain simple concepts on your knowledge level. You may very well exceed my knowledge level on most things related to the Model T engine, but not on this specific subject.
I expect you will continue ranting on here, like you usually do, so you can have the last word. If that makes you feel good and in your own mind make you think that you won, go ahead.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Monday, December 03, 2012 - 02:31 pm:

It says a lot about that person's psyche!"END QUOTE"

My Psyche is fine Mr. Sand, they are even starting to trust me with my own fork at meal time!

All my Med's I get at a large discount from what my neighbour makes in his basement!

Model T motors are less then 10 percent of the motors we do, lots of which, you have never heard of.

Just like a liberal, hollering racism when they don't have a good argument, for, or against a subject hoping every body else shuts up.

You are trying to make every one believe valve train clicking comes from valve seat, valve head, and for Guys on here that want to know the truth, you can't learn by your, misinformation!

I would suggest Mr. Sand, that you read again, the posts from Jerry, Harold, Aaron, Dan, Mark, and Joe. They all have a handle on it.

So please excuse me, Mr. Sand, I have Ranting to do else where!


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