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99 STS VIN 9
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Discussion Starter #1
For the most part LS heads are very good quality, you find that most (even higher mileage units) do not require a valve job. If you are swapping on a used set, and want to save some $$$ at the machine shop, here is an alternative for you. I hope this gives you an understanding of valve sealing, and saves you some money.

These heads were taken to a machine shop. They were cleaned and milled lightly but no other work was performed. The bill was around $80.



Here's an intake valve. Notice the silver streak around the lower edge. That's where it seals to the valve seat in the head. We are gonna freshen that surface and hopefully widen it some for a better seal.



Take your compound, and spread it like so. Doesn't have to be perfect.



Stick it into its hole and clamp your drill onto the stem so you can use the drill to spin the valve in the head.



Use the slow speed setting on your drill, and move it in and out (on and off the seat). Wow what a difference 20 seconds makes.



Comparison.



The sealing surface in the head.



Exhaust valve comparison. A little pitting on them is normal and nothing to worry about. Once i mate a valve to a hole, it stays there. I dont move it around once its been ground in. Also make sure you wipe as much of the compound off the head and valve as you can when youre done and hit the valve stem with some wd40 to help it slide in the valve guide easier.



Thats it, repeat the procedure for all 16 valves, makes sure you have a nice even band around each valve and you're good. If one looks off or not even all the way around check the valve and see if its bent slightly. Any questions just ask.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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66,922 Posts
Good pictures. I like the old handheld suction cup tool, rotated back & forth between the hands - tedious but gives a better feel. Several other mechanical methods, too.

Valve grinding compound - those heads and valves need to be surgically clean. ANY traces of compound will eat rings and cylinder bores in a hurry.

https://www.amazon.com/Performance-Tool-W86552-2-Piece-Lapper/dp/B004GBJAOG

Here's a set of new lappers - Mine are over 50 years old. You can still buy separate suction cups for them.
 

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Discussion Starter #3
I originally learned to do them by hand. Found the drill was way quicker. Haven't done it by hand since.
 

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2006 STS V8 AWD, '95 Ford Ranger
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I use marker pen on the valve and then insert the valve and turn it some some to see where the seating surface hits the valve face. The seating area should be about 0.090" wide and the valve should always overhang the seat on both sides. I use Sioux equipment to grind both valves and seats. I have an egg beater like device for the lapping to produce the reciprocating motion. Around and around with a drill is for amateurs. Full seating and the width and location of the seating surface are the keys to a valve job that lasts.
 

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Discussion Starter #5
Nobody said this is the perfect way to do it. It is a way to clean already acceptable surfaces. It works, Ive done it a bunch of times and made a ton more hp with one engine then your STS and Ranger do combined. Dont make this a pissing contest.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Your pictures and advice are refreshing, given the tendency of many "builders" to let the shop do the head work. Brings back many memories.

Nobody's starting a pissing contest. Just three other people that build engines - some since 1954 - pointing out that there are several perfectly acceptable ways to true up and refresh valve seats and valve sealing surfaces..... and we all build Briggs&Stratton, John Deere, and a dozen other engines, too ........

hell, man - I still have several (obsolete) hardened metal cutters for doing the time-honored "3 angle valve job".

Your retort about building power. We have ALL built power - gobs of it. It's not exclusive to one engine or one builder. For sheer balls I like the Olds 455s and GM 454 derivatives.

Olds 455 bored to 461, some tricks ..... I build them for boats.
 

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Registered
99 STS VIN 9
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293 Posts
Discussion Starter #7
As crude as this is, it does work. And for some who may have an acceptable set of heads and want to try it, i offer the info. I started doing it years ago and have had wonderful success with it. It is not a replacement for a valvejob, it wont fix a jacked up seat or valve. This isnt about proper machining techniques, if anything it might serve as educational for someone who has never disassembled heads.
 

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Premium Member
2006 STS V8 AWD, '95 Ford Ranger
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I apologize if I offended anybody. My experience is with aircraft engines where lives are on the line and a lick and a promise don't provide the required margins of safety.

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Back in the day, the final exam for automotive valve work was grinding the valves and setting the clearances on a flat head Ford without the benefit of Johnson adjustable lifters. Been there, done that.
 
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