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Valve Grind, Top end Rebuild


D81938
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Hi everyone, I'm new to the forum. I have a 1938 Dodge D8 touring sedan. 217.8. Flat Head I'm keeping the car all original while doing a light Refurbishing. I'm going to do a top end Rebuild, if anyone can give me tips on a good grind kit to purchase. And any tips on successful top end rebuilds, would be appreciated. The car has 48,961 original miles. But it had some stuck valves. It Sat for a long time in a barn. I never had a Flatty before! Thanks !!

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Welcome to the forum. I'll share my experience to try and help you out.

 

I pulled the head and the manifolds. I hand cut the seats. Made somewhat of a cut, I think, of the stellite inserts. I installed all new valves and lapped them in. I did not replace any valve guides at that time. I had thought about it but was under pressure to get the job finished. Since that valve job, I have punched out valve guides in a different engine. They are stubborn! An air hammer got them out. However, I learned it is not the right tool for installation. I bought all new gaskets, new valves and springs from Any Bernbaum. New head bolts too.  I got a valve seat cutter tool and scissor type valve spring compressor tool from e-bay. I stuffed new clean shop rags into the cylinders and used a brass wire wheel on my grinder to de-carbon and clean everything up. Followed up by lots of diligent vacuuming with a strong shop vac. You need to be sure no wire wheel pieces get down and lodged into piston ring grooves. This is also why I used brass. It's soft and malleable.

 

The valve grind took time effort and patience. I used a speed wrench to clean up the seats. Lots of time leaning over the big fenders and hand grinding.  I used some lapping compound and prussion blue dye.  I achieved good results. I'm glad I did it. I learned a ton and had fun. A very rewarding and worth while job.

 

Seen are a few pics through the job. - K

 

 

IMG_0019.JPG

 

 

IMG_0109.JPG

Edited by keithb7
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Here's the cutter I used.  I know there are more professional ways to do this. For a hobbyist at home, it worked fine. No shortage of grunt effort though.

 

 

FullSizeRender (11) (1).jpg

Edited by keithb7
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At the auto parts store machine shop I worked at as a kid. The machinist did very similar to what you did @keithb7. The only thing he used grinding stones with center guide post and a big 1/2" chuck right angled drill. He would "kiss" the stone to the seat and then check the width of the land created with a gauge. The gauge was basically a piece of heavy paper with lines .120" or .090" apart or whatever size he was looking for compared to the land on the valve. To do a fancy 3-angle valve job he would just use 3 stones of a different angles and do the same thing. Starting the 60°, 45°, and the 30°. Then lap them in the valve and seat, nothing fancy there. Compound and the suction cup tool.

 

image.png.d75dcdec04c37ed59de1ea1c5d0ef2a5.png

Edited by ccudahy
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4 hours ago, ccudahy said:

At the auto parts store machine shop I worked at as a kid. The machinist did very similar to what you did

 

I am wondering if he ever just chucked up a 1/2" drill and lapped the valves that way?  Like we saw in a recent video, lol. 

 

Anyway, cutters are for the rough in, stones for the finer work and lapping compound for the finish work, all three play a part.  Sort of like sanding, you don't just sand with 80 grit and paint over that, you work you way up to finer grits. 

 

One reason to consider replacing guides, you can check the wear specs, is that all the valve seat work is centered on the guide, if the guide is sloppy the seat will be too.

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No, I never saw the machinist use the drill for lapping...LOL!

 

I thought we were discussing just reconditioning an existing valve seat. Not a  new replacement seats with only roughed in geometry, then it was cut with carbide cutters on the head machine. Then finished with 3 grades of stones (rough, semi-finish, and finish) and then lapped. 

 

Kids and guys on budgets, use to come in and ask for a quick valve job. While in the middle of doing a head gasket or valve guide replacements, often enough. That all that was done with a quick touch up with the stones. They even use to knurl the I.D. of the valve guides to "puff them up" to help with oil consumption and save money. Not everyone came in for a full house NHRA build or could afford too. It's an experience I will always look back fondly at.

Edited by ccudahy
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The hardened seats used in the flat sixes do not cut well at all with cutter type tools. They tend to dig in with enough pressure and skip leaving edges.

 

I bought a used motor that a friend said the seats were cut with a cutter and never lapped in. A waste of effort on his part as it came out quite bad.

 

The fact that others did get it done that way is surprising to me, but what do I know? Just that one experience.

Wonder if unhardened seats have been  sometimes used as replacements by unknowing or uncaring shops?

 

I currently have a valve grinder for the valves and the setup complete for grinding seats also. Only one problem with them is new stones are needed  for some sizes, cannot complain as it was all given to me by a past employer and is going to someone else soon my friend you now has it in his shop hopes.  (This Not a for sale ad) Just worth saying as I have no plans to build another motor.

 

DJ

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Well, I just spent an interesting hour or so at Neway' site reading about seat cutting.

 

To do it myself with their stuff wouldn't be cost effective, but it would be satisfying.  Sometimes that is worth the cost.

 

 

 

 

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I have an old air powered Sioux grinder for seats along with a fair assortment of stones, holders and pilots.  I also have a few seat cutters.  The cutters will cut nice seats with not further grinding needed, just a little lap mostly to prove seating.

 

That said, I prefer the grinder.  Especially the air version, much lighter than electric grinders.

 

Valves themselves are refaced on an ancient grinder.  So old it has no coolant.  Takes a delicate touch to not overheat them.

 

When I swap engines in my truck, I'll probably check the guides, replace if needed and  grind the seats.   Just to have a spare block ready to go if I ever need it.  Then it will probably never get used until sold at that last auction.

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On 2/5/2021 at 11:42 PM, keithb7 said:

 

 

Welcome to the forum. I'll share my experience to try and help you out.

 

I pulled the head and the manifolds. I hand cut the seats. Made somewhat of a cut, I think, of the stellite inserts. I installed all new valves and lapped them in. I did not replace any valve guides at that time. I had thought about it but was under pressure to get the job finished. Since that valve job, I have punched out valve guides in a different engine. They are stubborn! An air hammer got them out. However, I learned it is not the right tool for installation. I bought all new gaskets, new valves and springs from Any Bernbaum. New head bolts too.  I got a valve seat cutter tool and scissor type valve spring compressor tool from e-bay. I stuffed new clean shop rags into the cylinders and used a brass wire wheel on my grinder to de-carbon and clean everything up. Followed up by lots of diligent vacuuming with a strong shop vac. You need to be sure no wire wheel pieces get down and lodged into piston ring grooves. This is also why I used brass. It's soft and malleable.

 

The valve grind took time effort and patience. I used a speed wrench to clean up the seats. Lots of time leaning over the big fenders and hand grinding.  I used some lapping compound and prussion blue dye.  I achieved good results. I'm glad I did it. I learned a ton and had fun. A very rewarding and worth while job.

 

Seen are a few pics through the job. - K

 

 

IMG_0019.JPG

 

 

IMG_0109.JPG

 

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T.Y. I appreciate all help and responses

 I was a truck mechanic for 30 yrs, but I was frame down mechanic. Suspensions, drive line, alignments n rears only.  I do have general knowledge of engines as my dad had a scrap yard when I was young n we had refurbished vehicles.  Thanks again!#👍

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