how to check if valves in head are good

Atuca · 09-21-2009, 01:14 PM

Hey guys, kinda off topic from my build thread/blog so I thought I ask in a new thread.

I got a used 1g head off a blown motor 1g. I don't remeber the exact cause of death of the 1g car, but I do know he ran 18 psi of boost on a stock ecu, stock fuel injectors, with no tuning software. I guess we can safely assume he ran really lean alot of the time.

With that said, how do I know the head is any good? is it something I can visual check and if I don't see any bend valves, I am good to drop it on my new engine? I rather not spend money on new valves, valve stems, ect because I want to use stock bore size on the head (im building for low end torque) anyways. I plan on running evo springs and retainers since that is just an easy swap while the head is off, and 3g lifters.

Is there any other things I should look for or buy to have this head read for my car?

and can anyone tell me the benefits of lighter evo springs, and 3g lifters. As far as I know, 3g lifters don't "tick"; any other benefits?

thanks, and here is my build thread for any of you who wish to give my guidance with reference to my road racing goals.

http://www.dsmtuners.com/forums/hang...ld-thread.html

page 1 twards the bottom is the only good pictures I have it atm. and that doesn't even show you the bottom and valves.. I just see golden dirty and want to clean it.

Defiant · 09-21-2009, 02:19 PM

Turn it upside down, rotate the cams so the valves are closed in a given combustion chamber, and pour it full of kerosene. After thirty minutes, make sure none has leaked.

Or better, disassemble the head and examine the valves and seats. Hand-lap them at least.

notverygood · 09-21-2009, 11:05 PM

You can get a lapping set at most auto parts store. It consists of a wooden suction cupped tool, and some fine abrasive compound. Id definately dissasemble, clean, de-carbon, lap, and make sure to replace the valve seals-how often do you want to take a head off t do it? great opportunity! If the valves are bent youll be able to tell when youre spinning them to lap them. If you cant feel the bent look for areas that arent shiny after lapping. thatll show you which sections arent sealing! good luck!

95gst16g · 09-21-2009, 11:35 PM

Quote:

Originally Posted by notverygood

You can get a lapping set at most auto parts store. It consists of a wooden suction cupped tool, and some fine abrasive compound. Id definately dissasemble, clean, de-carbon, lap, and make sure to replace the valve seals-how often do you want to take a head off t do it? great opportunity! If the valves are bent youll be able to tell when youre spinning them to lap them. If you cant feel the bent look for areas that arent shiny after lapping. thatll show you which sections arent sealing! good luck!

When you lap the valves it will leave a dull ring all the way around if they are sealing.If it's shiny in spots the shiny spot is the part that isnt sealing.

notverygood · 09-21-2009, 11:39 PM

when I said that I was referring to the carbon on the valve seat still being there (dull area), and the shiny area being the finished section that was lapped. I guess I could have been a bit clearer with the description.

95gst16g · 09-21-2009, 11:43 PM

Quote:

Originally Posted by notverygood

when I said that I was referring to the carbon on the valve seat still being there (dull area), and the shiny area being the finished section that was lapped. I guess I could have been a bit clearer with the description.

Yeah I just didnt want him getting confused...

notverygood · 09-21-2009, 11:47 PM

Kewl. Good looking out man. Ive lapped more valves than I care to think about-tedious by hand to say the least.

Atuca · 09-22-2009, 09:04 AM

oh trust me, if there is something that could confuse me at this point in time it would be the head. i understand the basics of how it works, but im far from understanding the fundamentals of each individual parts of the head.

now you guys mention lapping. that is something i've never heard of. a quich search yielded its some type of cleaning procedure? if im understanding you guys right, you are wanting me to clean either the valve or the valve seat (valve seat being the lip on the actual head right?) and seeing if they seal properly by checking if there is a transfer of caron from one part to the other.

am i understanding you correctly, and can a little n00b in no rush take the time to do this correctly with a normal tool set?

any ideas how to clean the head of burned oilalong the inside of the head? or does that not affect anything at all.

thanks for the help guys!

rlacasse1 · 09-22-2009, 09:30 AM

one way to do it that is cheap is to use carburetor cleaner. make sure that any given valve is fully closed. if you take out the cams they will be closed. spray the carb cleaner into the each exhaust or intake port one at a time and look for leaking around the valves. according to a guy who built engines a tiny bit of leak is not a huge problem but if it dumps out its bad. this is how i checked mine and my car runs fine.

#40Fan · 09-22-2009, 10:09 AM

Pull the cams so all of the valves are closed. Turn it combustion chamber up and fill all four chambers with water. Let it sit for a good 30 minutes. Then take a light and look up the exhaust and intake ports and see if any water has dripped in them.

When you remove the valve springs to change them out, go ahead and take a good look at the valves. Especially the exhaust. Make sure you keep the valves in order. I like to get a box and poke holes in the bottom and put the valves down the holes. Mark the box which way is towards the front of the head placing the valves in order when looking at the head from the bottom side.

Carb cleaner and an old tooth brush will clean stuff up good!

Defiant · 09-22-2009, 02:46 PM

Do not use water. Use something that won't cause rust. Oh, like kerosene.

As for lapping:
YouTube - Valve Lapping

#40Fan · 09-22-2009, 04:41 PM

What's in there that is going to rust?

notverygood · 09-23-2009, 03:21 AM

whats in there thats going to rust? valves, valve seats, springs, spring cups, followers, lash adjusters, retainers, etc, etc. NO SIR! use a solvent-petroleum based-some sea foam (lol) will eat the carbon away, so will pb blaster. as for lapping, it requires the springs be taken out. basically it uses a lightly abrasive compound to seat the valves in the seats again and remove light pitting/scoring and carbon.

nice video of the process

97ebaygst · 12-14-2010, 04:38 PM

Will lapping help if its leaking? I used some old gas to do my test.

BogusSVO · 12-15-2010, 07:54 AM

any liquid will work for the fluid test of the valves/seats

if the head is warped bad the warpage can also cause the valves to crack off the seat.

some info for you...
How to lap a valve

How to check a head for warp

if the head is warped and you have it surfaced....
How to Surface a 4G63T Cylinder head for a MLS head gasket

and read this....
Why NOT to let your head be Belt Surfaced

also you will want to do this...
4G63T Head oil port mod

also info on springs.....
4G63T Valve spring Info

97ebaygst · 12-15-2010, 10:45 AM

I know its probably ill advised but I can't afford to do a head job on it. I'm just trying to get it back on the road after a broken timing belt. I plan doing it right after I can get a stable job but for right now I just need it to run.
I'm trying to do anything that I can do to make sure it runs and doesn't break down on me. I haven't pulled the head yet but I bought another one to slap on. ill post pics of it later and the test I did

donniekak · 12-15-2010, 11:16 AM

If you run it with leaking valves, you increase the chances of melting one of them. At least lap them into the seats.