valve seat

J

jbird56

Junior Member
Looking for some help anyone in South Jersey Area. I`m doing a valve job on my A and wanted to know if anyone with experience can teach me a thing or two. The seats need to be reground I believe. I have the valve kit from mac. I could use the help Thanks
 
Define what you mean when you say "the seats need to be reground". If they are badly pitted then the seat needs to be machined or ground. This involves grinding the valve seat relative to the valve stem guide using a special grinding wheel that is shaped to the valve seat face angle. A special motor driven setup is used to do this.
If the valve seat surfaces are in good condition then they can be lapped in to mate with one another. This is accomplished with the use of lapping compound (fine grit mixed with oil) applied to the bottom of the valve and inserting the valve in the head. A lapping tool which is a suction cup attached to the end of a wooden handle is then attached to the flat face of the valve. Placing the lapping tool handle between the palms of your hands and moving your hands back and forth causes an alternating rotation of the valve. The lapping compound removes a small amount of seat material but after repeated oscillations the valve face and valve seat surfaces should begin to match. Once the surfaces have a uniform grey look the valve is removed along with the lapping compound. This completes the lapping process.
 
one of the intakes is putted on one side. I was wondering if I could just use grinding stone to refresh it I still need pilot and do you need mutply stones for the angle or can on stone it.
 
post some pictures
how wide is the seat now
what valve guides are you using---original or "modern"
original tappets or adjustable
engine in the car or out

the width of the seat deteremines how many angles, or if the seat should be replaced--or larger valve ---it would be nicer if a little larger valve was made, this would "save" many seats from being replaced
as much as you would think a wider seat would seal better it is actually worse because of more surface area causes less pressure per sq inch, makes it harder to eliminate debris, promotes pitting from carbon chunks
 
jbird56 said:
one of the intakes is putted on one side. I was wondering if I could just use grinding stone to refresh it I still need pilot and do you need mutply stones for the angle or can on stone it.
Click to expand...

No, you need the right tools or the valve will never seal like it should.
 
they are modern valve guides one piece how ever they are not the stright ones they have the lip for the spring to push up against, the tappets are orginal, the engine is in the car but every thing is off( radiator, head, head bolts,) and the new valves I bought are ss modern but the same size as the orginal, will get some pics
 
You really need to get the seats done by some one that has the equipment to do it right.
If you changed the guides lapping will not work. Lapping is not the best way to do it any way.
They need to be ground with the right angle, right width, right location so they hit the valve in the right place. A three angle valve seat works better also. If you use a wide seat you have a better chance of burning a exhaust valve. There is a lot more to doing a valve job than lapping valves.
 
I agree with George. If the pitting is very bad sometimes even machining down to clean them before grinding them with the proper facets as described cannot be done. The best and more permanent solution is to have hardened valve seats installed and machined. This will also require installing new valves, valve guides, and adjustable tappets. If you plan on keeping the car and driving it I would go in this direction. This work can only be done by a competent engine machine shop.
 
jbird56 said:
Looking for some help anyone in South Jersey Area. I`m doing a valve job on my A and wanted to know if anyone with experience can teach me a thing or two. The seats need to be reground I believe. I have the valve kit from mac. I could use the help Thanks
Click to expand...

You don't say whether your A has a stock engine/original condition or what ?
Pictures of what you are seeing would help with more definitive answers for the situation shown in pics.
You have been given a good idea that there is more to this than a 'thing or two', eh.
I'm thinking that you are asking about an original engine.....with stock non-adjustable lifters. There is big skill/knowledge difference in fitting/use of one vs other method.
Simple 'lapping' a valve into a good seat is a lot of work overall (think disassembly/reassembly; maybe grinding /hardening stem to obtain correct lash; facing non adjustable lifter to make perfect again, ect)
Not simple to install hard seat and/or grind block 'seat' to restore correctly and to get proper/best seat angle for exhaust valve and best angle for intake.
Same seat angle for both.... is not 'one fits all' or best for both.
Most guys do not possess the machines/tools to do proper seats.
 
The lapping thing is for an engine where there is nothing really wrong, Just a freshen up while it's apart to repair something else. Also, most of the portable pieces for really doing repairs such as replacing valve seats that are too far gone to grind, haven't been made since the 1950's and are now worn out historic display items. So, the machine shops that have the more modern equipment that can assess the situation with experience, and the tools to do whatever is deemed necessary, will need the engine out of the car and brought into their shop.
 
For arthritic old buggers like me, it is permissible to mount the suction cup in an electric drill. Go very slow and check your progress often. Also vary between clockwise and counter clockwise.

Used to use this technique on hard seats in racing engines (motorcycles) back in the day.
 
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