More valves

grandpa Love · Mar 4, 2021

'47 8n. One busted valve guide. Pulled
all the valves out and cleaned everything
real good. Put all the exhaust valves
back in and checked them. .016 on three,
.025 on one. One keeper is loose,
thinking a weak spring, will try a
different spring. Got one intake valve
assembly coming, plan to pop it in there
and hope it fixes the problem. Assembly
came out of an old tractor, it's not new.
Any issues? Tractor may get rake duty or
finish mower. Not hard use. Enjoying
digging into a different project, my wife
is loving it too. Be rewarding to see it
run!

Dean · Mar 4, 2021

How do you plan to shoot the seats and grind the used valves?

Valve seals on intakes only.

Dean

John Deere D · Mar 4, 2021

I'm interested in how /what do you use to grind the valves and seats ???

Do you use Prussian bluing to check the contact area of the valves to the valve seats?

Thanks

Bob..Retired Power Engineer...

grandpa Love · Mar 4, 2021

Oh dear...." Shoot the seats"?

grandpa Love · Mar 4, 2021

More details about the blue stuff?

Dean · Mar 4, 2021

Shorthand for grinding the valve seats.

Unless the valve seats are in very good condition, you cannot get away with simply lapping in the valves.

It is customary to use a portable seat grinder (try finding one today) to "shoot the seats."

If the seats and valves are in good condition, you can lap the valves in but this will take time. Of course, the tappet clearance will close probably requiring that you grind the stems on an engine without adjustable tappets to achieve recommended clearance.

Dean

wore out · Mar 4, 2021

(quoted from post at 13:25:53 03/04/21) Shorthand for grinding the valve seats.

Unless the valve seats are in very good condition, you cannot get away with simply lapping in the valves.

It is customary to use a portable seat grinder (try finding one today) to "shoot the seats."

If the seats and valves are in good condition, you can lap the valves in but this will take time. Of course, the tappet clearance will close probably requiring that you grind the stems on an engine without adjustable tappets to achieve recommended clearance.

Dean

If the only problem was the broken valve guide AND that seat isn't too damaged/banged up AND they kept track of the valves and simply cleaned them up and put them back in the same location the engine MAY be just fine if they lap the new valve in a bit and get it's tappet gap to where it needs to be.

It isn't a high power, high speed, high compression engine, after all, things are a little more forgiving, and not much lost in the worst case scenario 'cept a head gasket and TIME.

IF they scrambled up the valves the likelihood of "keeping this simple and cheap" is greatly diminished, IMHO.

I asked in a previous post if the valves had been kept track of, if there was a reply to that question I didn't see it.

grandpa Love · Mar 4, 2021

Anytime we do anything to a tractor we
keep up with every nut, bolt and screw so
we can put it back where it came from.
So...of course we kept track of which
valve went where. So far, the only thing
we did was remove the valve assemblies
and used very fine grit wet sand paper
with oil on it to clean the bottom of the
valves and seats. Then we put the exhaust
valves back in and checked them for
clearance. What does "lapping" the valve
actually do? The broken guide didn't
appear to bang up anything too bad.
Nothing just jumped out at us.

John Deere D · Mar 4, 2021

Apply a Very, very thin even coat of Prussian Blue to the valve face. Press the vale to the seat, then rotate the valve 90 degrees CW ...then rotate the valve 90 degrees CCW ...

The BLUE colored grease is used to verify if the valve FACE is contacting the VALVE SEAT 100%.

SOME owners, take a lead pencil, scribe a mark across the face of the valve seat,at 12 o'clock....3 o'clock,....
6 o'clock,......9 o'clock
Inset Valve, rotate valve 90 deg cw (clock wise)..and then rotate valve 90 deg CCW (counter clock wise). Remove Vale and take note were all "PEMCIL MARKS" in contact with VALVE FACE.

IF the VALVES are not to be returned to the same location as they were removed.......they are NOT GOING to SEAT ...
When the engine coughs,pops,blows backwards into the CARB, or fires out the exhaust manifold...you then know the valves are not seated to the valve Seats.

There are those who will not agree with me, and that is fine..

Bob..

John Deere D · Mar 4, 2021

What is Valve lapping compound? Valve lapping compound is an abrasive. As you rotate the valve and apply pressure towards the seat, you are wearing both valve contact face and valve seat at the same time.

Lapping ensures that the VALVE FACE and the VALVE seat have the same matting profile.

There are those whom shall disagree with me and that ok...

Bob...src="https://www.yesterdaystractors.com/cvphotos/cvphoto80407.jpg">

R Geiger · Mar 4, 2021

(quoted from post at 15:20:17 03/04/21) Anytime we do anything to a tractor we
keep up with every nut, bolt and screw so
we can put it back where it came from.
So...of course we kept track of which
valve went where. So far, the only thing
we did was remove the valve assemblies
and used very fine grit wet sand paper
with oil on it to clean the bottom of the
valves and seats. Then we put the exhaust
valves back in and checked them for
clearance. What does "lapping" the valve
actually do? The broken guide didn't
appear to bang up anything too bad.
Nothing just jumped out at us.

The last one I overhauled, I had new seats installed and ground, used new valves and hand lapped with lapping compound purchased from NAPA. Lapping matches the valves to the seat to ensure total contact. you can look at the valves and seats to see if the pattern is even around all the valve and seats. I learned how to lap valves in the 50"s. would be best of course if old valves were ground tho, but the way we run these machines today, I feel lapping will work just fine. Of course you will need to check valve clearance in either case.

John Deere D · Mar 4, 2021

There is a lot to the theory of VALVES. Do it as to your $$$$$$$$'s. Consider taking the time to investigate what / why the MARGIN is important.
Consider as to how the HEAT is transferred from the VALVE to the Engine coolant..

Consider the ramifications if there is NO Margin on the Valve???

At the end of the day Sir it's your $$$$$'s and your project................

Bob..

Hobo,NC · Mar 4, 2021

I know you are just trying to get it going then evaluate its condition... (Right)? ... I don't think he has ran the engine...

Once you install the valves with them shut pour some gas on top of the valve it it leaks you will need to do something about that... If not then it should be OK to leave it be for the evaluation test...

One day you good luck is gonna run out...

Ken(Ark) · Mar 5, 2021

Use a magic marker and color the valve face and seat . Use a little lapping compound to see if it is seating . Test with gasoline to see if it really did seal . Disassemble and clean all of that gritty lapping compound . See if that gets you by for a year or two . Then if the tractor is worth it you can sink and easy $1k into a motor . Or you can spend $5K now and rebuild everything by the book because that is the correct way to do it < sarcasm off > You do need to know what the correct procedure is and the alternatives , then you can decide what you feel is best for your budget / needs .

TheOldHokie · Mar 5, 2021

(quoted from post at 17:20:17 03/04/21) Anytime we do anything to a tractor we
keep up with every nut, bolt and screw so
we can put it back where it came from.
So...of course we kept track of which
valve went where. So far, the only thing
we did was remove the valve assemblies
and used very fine grit wet sand paper
with oil on it to clean the bottom of the
valves and seats. Then we put the exhaust
valves back in and checked them for
clearance. What does "lapping" the valve
actually do? The broken guide didn't
appear to bang up anything too bad.
Nothing just jumped out at us.

Lapping a valve matches the out of round to out of round :roll:

I bought this a while back and its available as a very affordable rental for folks like you that want to do their own valve job. Simple easy tounderstand instructions and process.

You can take the valves to any shop and have them reground and cut fresh seats yourself. If you and the regrinder do it right you won't need any lapping compound. Prussian blue or Hobo's gasoline test will tell you if its right. If after cutting the seats and regrinding the valves its wrong lapping simply makes it wronger. :twisted:

TOH

Hobo,NC · Mar 5, 2021

This is the head off my golf cart, 4 new valves I did not mess with the seats they looked great. I did lap'em its in my blood... The valves are soft this is the second set a 1994 model. The valves last about as long as the rings 13 years the first rebuild was 2007. I have the valves covered with varsol no leaks good enoufh for me...

Why I lap when you think you are good to good to do the extra work it will bite you in the arse..

HarryVanderpool · Mar 5, 2021

I have the same kit as Hokie.
Here is what I did and my recommendation:
Remove your valves, guides, springs & clips and throw them all in the recycling bin.
Buy the complete set new.
Carefully, cut your seats back to specification (or better).
Check seating with prussian blue.
Take your time, don't get in a hurry and DO IT RIGHT!
OR:
"You can always afford to do it right the SECOND time around".
You won't believe how great you N will run and how much power it has!

ASEguy · Mar 7, 2021

Lapping the valves smooths out the valve face angle where it seals. It is usually done after you grind the seats and valves with a stone grinder. If you use the cutters as mentioned above you do not lap the valves. The cutter for the seat is 46* and the valve is 45* which gives you a 1* interference angle which will be beaten out after a few minutes of driving and also shows where the valve will seal on the seat.

9njoe41 · Mar 9, 2021

Whats the white floor material?

More valves

grandpa Love

Well-known Member

Dean

Well-known Member

John Deere D

Well-known Member

grandpa Love

Well-known Member

grandpa Love

Well-known Member

Dean

Well-known Member

wore out

Well-known Member

grandpa Love

Well-known Member

John Deere D

Well-known Member

John Deere D

Well-known Member

R Geiger

Well-known Member

John Deere D

Well-known Member

Hobo,NC

Well-known Member

Ken(Ark)

Well-known Member

TheOldHokie

Well-known Member

Hobo,NC

Well-known Member

HarryVanderpool

Member

ASEguy

Well-known Member

9njoe41

New User

Similar threads