OK the machinist said the seats looked ok to him and he suggested unless I just want to go for a valve job... I use lapping compound on the heads and let him know if any leak afterwards...


so having never done this a few hits on advice would be great..TIA

he wants 8.00 seat / 2.50 valve to do the heads.. and there are no hard seats.. 168.00 to do the heads ?? doesn't sound crazy..thoughts ?

 

I prefer letting a machine shop do the heads. I have done the lapping compound on the heads trick many times though when i was younger, lived on the farm, and money was tight. Actually if the valves and seats are in good condition you can do a very good job with lapping compound. I used to buy the 2 stage compound...coarse and fine. Pull the springs off the valves and start with the coarse compound...put a dab of coarse compound on a valve and then spin the valve using a drill...you can do it from the top with a suction cup attachment...I used to just chuck the valve up in the drill...use tape to protect the stem...then as you're spinning the valve pressure it into the seat...spin a bit....let off so the compound can get back in there...and then pressure it into the seat...repeat several times. Clean off and see if you've got a nice even ground seat and valve area....if so then do the same with the fine compound. This is a great way to mate the valve to the seat but they have to be in decent shape to start with for this to work. The best machine shops will touch the valve with the fine compound after a valve job to be sure they are seated good. After you are done clean the heads and valves thoroughly, put new valve stem seals on and reassemble. If you're going to do this you really should mic the valve stems and guides to be sure they are within specs....FE heads are very sensitive to stem and guide wear causing smoking and oil consumption issues. If your engine was running decent before the rebuild and the heads, valves and seats look to be in good condition then you'll probably be just as good to grind them yourself as paying the machine shop to do it.

Good Luck!

Tracy

 

I hand lapped valves for years with a tool that had a suction cup on it that goes onto the valve head and then you rotated it inthe palm of your hands like you would if using a stick to start a fire...that was along time ago...gave it up...I just let the machine shop touch up the seats if usuable and the intakes valves, one thing I don't do anymore is reuse old exhaust valves on old high milage engines..I just replace them..my 02cents

 

might not be bad 50.00 spent.. I'll keep it in mind...

 

If you've got the time and the palms, and your valve/seats look decent then go for it! Other wise let the machinist handle it...and mic up your guides like the other guys say!! Thats how i found that my valves had sunk into the heads which leads me to also tell you to get hardened seats put it regardless if you do go to the machinist!!!

 

About the only reason for lapping compound these days is to check the seat width

It acts like sandpaper and leaves a flat-grey finish where the valve touches the seat.

I did it to brand-new valves and seats that I personally put in my 390 heads (using machinist friend's shop equipment) and everything checked out. Better than not knowing.

If you're going to the trouble of removing the heads, and the valve springs, imagine if you put it back together and something's still not right?

 

considering my decisions so far I'm guessing another 3-4 weeks and 200.00 is just par for the coarse right ??? LMAO I was thinking toss it back together then my brother gave me that lifted eyebrow look... and that usually means if option b is taken I'll regret it.. so here we are.. hell it has given me time to get to the Glasspar -- got the primer done today on the deckside items..just paint to go now and the puzzle is ready to put together LMAO

 

Boy is that true!

 

I think it was on this board, about 4 years ago, I mentioned lapping compound and got FLAMED from every direction as being an "antique".

Most of the problem was that no one read past a certain point, and didn't realize I was just trying to explain how to check the seat width. You need a lot of high-spot blue to check all the seat widths