The Ford Barn

throwback · 10-23-2015, 12:40 PM

I had to replace the #4 exhaust valve seat. I have non adjustable valve (mushroom) style valves. I need to set the cam in the correct position to check the valve (stem) clearance to the lifter. So if I rotate the cam to where the number 3 intake valve and number 2 exhaust valve are open then I can use a feeler gauge to check the stem to lifter clearance on the number 4 exhaust valve. the motors manual gives a range of .0015-.0035. That seems like quite a range. Is there any recommendations on what is best to set it for?

Is there a different method of making sure the cam shaft is in the proper position for setting the number 4 exhaust valve clearance? such as removing the number 4 exhaust valve lifter and using a depth gauge??

I need to get it checked to see if lapping is the next step or if it needs to have the valve seat machined prior to lapping the valve seat.

I am not a mechanic and really would like to get this right. I looking for your experience and suggestions on how to do this.

Thank You!

bobH · 10-23-2015, 01:08 PM

Lots of ways ... one way is to rotate crank to bring valve full open, note crank position, then rotate crank one full (360) turn.
Recheck. That spec... .001-.003 doesn't sound right.

GOSFAST · 10-23-2015, 01:08 PM

Quote:

Originally Posted by throwback

I had to replace the #4 exhaust valve seat. I have non adjustable valve (mushroom) style valves. I need to set the cam in the correct position to check the valve (stem) clearance to the lifter. So if I rotate the cam to where the number 3 intake valve and number 2 exhaust valve are open then I can use a feeler gauge to check the stem to lifter clearance on the number 4 exhaust valve. the motors manual gives a range of .0015-.0035. That seems like quite a range. Is there any recommendations on what is best to set it for?

Is there a different method of making sure the cam shaft is in the proper position for setting the number 4 exhaust valve clearance? such as removing the number 4 exhaust valve lifter and using a depth gauge??

I need to get it checked to see if lapping is the next step or if it needs to have the valve seat machined prior to lapping the valve seat.

I am not a mechanic and really would like to get this right. I looking for your experience and suggestions on how to do this.

Thank You!

Just a "heads-up", those clearances you show above are for the "stem-to-guide" and not the valve lash!

Thanks, Gary in N.Y.

P.S. The lash on that unit would be .012" intake and .014" exhaust. Personally I would use .010" intake and .012" exhaust!

sprint29 · 10-23-2015, 01:11 PM

I always set mine to 12 1/2 thousand to 13 1/2 thousand. If you know when that lobe is at max. lift, then you can rotate the motor one full revolution and then you will be on the back side of the cam lobe

flatheadmurre · 10-23-2015, 01:12 PM

.0015-.0035 is the valvestem clearance in the guide.

Bored&Stroked · 10-23-2015, 03:11 PM

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Other guys covered the clearances, but I wanted to point out that if you replaced a hard seat with a new one, then the seat will need to be machined/ground to match your specific engine. You can't just drop a new seat and valve in. Also, usually quite a bit of material is taken away to position the edge of the valve seat where it belongs on the valve sealing face (almost to the edge) - this will result in the valve "sinking" down a lot (which is normal).

Hopefully you have somebody who knows how to machine/setup flathead valve trains and has the correct flathead guide-bore mandrels to work with.

throwback · 10-23-2015, 03:32 PM

Thanks for the correction of the clearance issue. I did list the stem clearance and it should have been the tappet clearance. I did notice that there is quite a bit of difference in the removed valve seat verses the replacement one material. Until I measure the tappet clearance I won't know how much will need to be removed. I was hoping that I could get it by lapping the valve and seat. But as you stated it may be a significant amount of material to get it close and require machining to get it correct. I will not try to do the machining on the seat if that is what it takes. I will have someone who is knowledgeable do this. Trying to do as much as I can and still not screw it up.

Thank You!

flatheadmurre · 10-23-2015, 04:00 PM

Depending on how worn your old seat was it can be a lot of grinding if youre gonna reuse the old valve.
Measure what kinda clearance you got after grinding the seat to correct shape.
If it still a real long way to go, a new valve might be an option instead of grinding away your new seat....

bobH · 10-24-2015, 04:39 AM

Quote:

Originally Posted by flatheadmurre

Depending on how worn your old seat was it can be a lot of grinding if youre gonna reuse the old valve.
Measure what kinda clearance you got after grinding the seat to correct shape.
If it still a real long way to go, a new valve might be an option instead of grinding away your new seat....

Yes and no.... there is a spec on approx where the top of the valve ought to be, after all is said and done. My last, and only recent experience with having a new seat installed, is that LOTS of material needs to be removed, to get the valve down where it needs to be. If this is the case, a longer valve could be a 'wrong' answer. Just opinion here, and each case might be a little different. If the valve is left ' too tall', might run into a problem of valve hitting head. Don't want to go there.
He posted he is not a mechanic, and presumably the seat was installed by someone who knows all this. A proper flathead machinist knows all this, and SHOULD have already machined the new seat down to put the valve close to where it should be.
This is already posted in #6...

flatheadmurre · 10-24-2015, 04:54 AM

Stock cam, stock lifter and a new std ford valve aint gonna hit anything.
If youre starting to add stuff ford never intended to be in there you can get into trouble.

Bored&Stroked · 10-24-2015, 10:03 AM

When installing hard seats - things to note.
1) Usually the height of the hard seat top is more than the stock one that was taken out. This is before any seat 'angle' is ground into it. The top of it will be sticking up higher than the original - due to the STD sizes you can purchase them in.
2) The first step is to cut the overall height of the hard seat to match the rest of the engine and get it down in the valve pocket to the correct depth.
3) Once this is done, then the actual valve seating areas are cut in. Methods -> it all depends on the valve equipment --> some guys use precision 3 to 5 way cutters to cut the seats to the initial setup, some use stones, some use combinations of things.

Note: Some shops have cutters that can do ALL the above steps in one go.

In the end, the seat depth and widths are setup by the final procedures - to match the valves and desired specifications (seat angle, width, depth, number of top cuts, number of bottom cuts, etc).

When I have this work done on my engines, most of the work is done in a big milling machine that has a block main-bore saddle fixture to hold/orient the block. A special guide bore pilot is used - it picks up the actual lifter bore and guide bores and centers the pilot for the machine work. This ensures that every installed hard seat has the same contour, depth, etc - for all 16 of them.

Final touch up is done with stones and lapping.

Also, when you put new seats in an engine, you'll usually be "raising the seat" as compared to the ones that you've removed - the seat will be higher and the valve will now be higher up in the combustion chamber. Due to this, the valve is now TOO SHORT as compared to it's past, so if you're using non-adjustable/stock lifters, then the valve guy will actually weld material to the bottoms of all the valves (to take up the gap) and re-establish the correct valve lash settings (valve by valve).

Now, when somebody then decides they want to drop in a performance cam - which will add even more gap to the situation, you can see why adjustable lifters became popular . . . they made it easy to swap stuff around and not have to redo the whole valve setup each time. With that said, you can't beat the original setup . . . it works, stays in adjustment and is extremely light . . . just some work to setup.

Ol' Ron · 10-24-2015, 11:16 AM

How do you measure 1/2 thousands, when checking valve lash??

HP Hunter · 10-24-2015, 11:26 AM

Quote:

Originally Posted by Ol' Ron

How do you measure 1/2 thousands, when checking valve lash??

If we need to check them that close we are all in trouble?

Harry

Bored&Stroked · 10-24-2015, 11:43 AM

Quote:

Originally Posted by Ol' Ron

How do you measure 1/2 thousands, when checking valve lash??

Veeeeeeeeeeeeery Carefuuuuuuuuuully!

10-23-2015, 12:40 PM	#1
throwback Senior Member Join Date: May 2010 Location: Lee's Summit, Missouri Posts: 225	1936 Ford Flathead valve clearance check to determine next step I had to replace the #4 exhaust valve seat. I have non adjustable valve (mushroom) style valves. I need to set the cam in the correct position to check the valve (stem) clearance to the lifter. So if I rotate the cam to where the number 3 intake valve and number 2 exhaust valve are open then I can use a feeler gauge to check the stem to lifter clearance on the number 4 exhaust valve. the motors manual gives a range of .0015-.0035. That seems like quite a range. Is there any recommendations on what is best to set it for? Is there a different method of making sure the cam shaft is in the proper position for setting the number 4 exhaust valve clearance? such as removing the number 4 exhaust valve lifter and using a depth gauge?? I need to get it checked to see if lapping is the next step or if it needs to have the valve seat machined prior to lapping the valve seat. I am not a mechanic and really would like to get this right. I looking for your experience and suggestions on how to do this. Thank You!

10-23-2015, 01:08 PM	#2
bobH Senior Member Join Date: May 2010 Location: so cal, placerville, vegas Posts: 1,396	Re: 1936 Ford Flathead valve clearance check to determine next step Lots of ways ... one way is to rotate crank to bring valve full open, note crank position, then rotate crank one full (360) turn. Recheck. That spec... .001-.003 doesn't sound right.

10-23-2015, 01:12 PM	#5
flatheadmurre Senior Member Join Date: Apr 2015 Location: Sweden Posts: 3,045	Re: 1936 Ford Flathead valve clearance check to determine next step .0015-.0035 is the valvestem clearance in the guide.

10-23-2015, 03:32 PM	#7
throwback Senior Member Join Date: May 2010 Location: Lee's Summit, Missouri Posts: 225	Re: 1936 Ford Flathead valve clearance check to determine next step Thanks for the correction of the clearance issue. I did list the stem clearance and it should have been the tappet clearance. I did notice that there is quite a bit of difference in the removed valve seat verses the replacement one material. Until I measure the tappet clearance I won't know how much will need to be removed. I was hoping that I could get it by lapping the valve and seat. But as you stated it may be a significant amount of material to get it close and require machining to get it correct. I will not try to do the machining on the seat if that is what it takes. I will have someone who is knowledgeable do this. Trying to do as much as I can and still not screw it up. Thank You!

10-23-2015, 04:00 PM	#8
flatheadmurre Senior Member Join Date: Apr 2015 Location: Sweden Posts: 3,045	Re: 1936 Ford Flathead valve clearance check to determine next step Depending on how worn your old seat was it can be a lot of grinding if youre gonna reuse the old valve. Measure what kinda clearance you got after grinding the seat to correct shape. If it still a real long way to go, a new valve might be an option instead of grinding away your new seat....

10-23-2015, 01:11 PM	#4
sprint29 Member Join Date: Oct 2015 Location: springfield,mo Posts: 75	Re: 1936 Ford Flathead valve clearance check to determine next step I always set mine to 12 1/2 thousand to 13 1/2 thousand. If you know when that lobe is at max. lift, then you can rotate the motor one full revolution and then you will be on the back side of the cam lobe

10-23-2015, 03:11 PM	#6
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,174	Re: 1936 Ford Flathead valve clearance check to determine next step Sponsored Links (Register now to hide all advertisements) Other guys covered the clearances, but I wanted to point out that if you replaced a hard seat with a new one, then the seat will need to be machined/ground to match your specific engine. You can't just drop a new seat and valve in. Also, usually quite a bit of material is taken away to position the edge of the valve seat where it belongs on the valve sealing face (almost to the edge) - this will result in the valve "sinking" down a lot (which is normal). Hopefully you have somebody who knows how to machine/setup flathead valve trains and has the correct flathead guide-bore mandrels to work with.

10-24-2015, 04:54 AM	#10
flatheadmurre Senior Member Join Date: Apr 2015 Location: Sweden Posts: 3,045	Re: 1936 Ford Flathead valve clearance check to determine next step Stock cam, stock lifter and a new std ford valve aint gonna hit anything. If youre starting to add stuff ford never intended to be in there you can get into trouble.

10-24-2015, 10:03 AM	#11
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,174	Re: 1936 Ford Flathead valve clearance check to determine next step When installing hard seats - things to note. 1) Usually the height of the hard seat top is more than the stock one that was taken out. This is before any seat 'angle' is ground into it. The top of it will be sticking up higher than the original - due to the STD sizes you can purchase them in. 2) The first step is to cut the overall height of the hard seat to match the rest of the engine and get it down in the valve pocket to the correct depth. 3) Once this is done, then the actual valve seating areas are cut in. Methods -> it all depends on the valve equipment --> some guys use precision 3 to 5 way cutters to cut the seats to the initial setup, some use stones, some use combinations of things. Note: Some shops have cutters that can do ALL the above steps in one go. In the end, the seat depth and widths are setup by the final procedures - to match the valves and desired specifications (seat angle, width, depth, number of top cuts, number of bottom cuts, etc). When I have this work done on my engines, most of the work is done in a big milling machine that has a block main-bore saddle fixture to hold/orient the block. A special guide bore pilot is used - it picks up the actual lifter bore and guide bores and centers the pilot for the machine work. This ensures that every installed hard seat has the same contour, depth, etc - for all 16 of them. Final touch up is done with stones and lapping. Also, when you put new seats in an engine, you'll usually be "raising the seat" as compared to the ones that you've removed - the seat will be higher and the valve will now be higher up in the combustion chamber. Due to this, the valve is now TOO SHORT as compared to it's past, so if you're using non-adjustable/stock lifters, then the valve guy will actually weld material to the bottoms of all the valves (to take up the gap) and re-establish the correct valve lash settings (valve by valve). Now, when somebody then decides they want to drop in a performance cam - which will add even more gap to the situation, you can see why adjustable lifters became popular . . . they made it easy to swap stuff around and not have to redo the whole valve setup each time. With that said, you can't beat the original setup . . . it works, stays in adjustment and is extremely light . . . just some work to setup. Last edited by Bored&Stroked; 10-24-2015 at 10:21 AM.

10-24-2015, 11:16 AM	#12
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,890	Re: 1936 Ford Flathead valve clearance check to determine next step How do you measure 1/2 thousands, when checking valve lash??