Checking Valves

[JackstandTSi]

I managed to pick up a head today completely free, guy at my job no longer needs it. He said its been sitting for awhile but wasn't sure if it had damaged/bent valves and gave it to me. I asked one of the Techs at work if there is away to check to see if valves are bent or leaking, He said you can put water in the ports if it leaks then no good, but he also said a better way is to go into a dark room with a light and shine them at the valves and if you see light threw the ports then no good also. Im not sure if he was just blowing smoke up my arse or not but wondering if anyone has heard of that or knows anyway to test them without spending alot of money or going to a machine shop. I know that it should be taken to a shop but ill be honest im very limited on money and before i spend any on a shop to tell me the valves are bad if there was a way i can test myself. BTW The valves show no sign of any damage to the eye. Just a bit dirty of build up. No noticeable dings or knicks in them.

Thanks for any info. I would like to get this up and rolling before my daughter is born.

 

[presterone]

Hes right about the water trick, I've never tried with light but that should work as well. You have to rotate the cams so the lobes on whichever cylinder you are checking are facing up and the valves are closed. Tip the head upside down get it level somehow and pour water (I used washer fluid because it was right in front of me) on the combustion chamber

 

[5OF2k]

Like he said, but ou could make it easier on yourself and remove the cams entirely from the head, allowing the valvesprings to hold all of the valves shut against the seats. Then, you'll be able to check them all at the same time.

The light trick works as well, for what its worth, but you dont necessarily need it to be in a dark room. You only need a brighter source of light than the ambient light around you.

The water trick is a bit better, just because its a physical element leaking from the chambers if theyre bent, but whichever you feel you wantto do will work!

Another good way to check them(if you have the means)is to actually pull them apart(after marking the valves origional location/orientaion), and take a look at the seats and valve heads where they contact the seat. The contact points withh be shinier than the rest of the valve, and inherently the wear/markings should be uniform around both the seats on the head and the valve itself.

Hope that helps!

-Jake

 

[rdomeck]

Taking the valves out and looking at the seat doesn't really tell you anything....If the valves are bent the engine was running when it happened and would show signs that the valves were seated even though they could be bent!

Water works ok, but it is a little to thick of liquid to really tell. Use something like Acetone. Or better yet do the old socket and hammer trick to get the keepers loose and pull things apart to look. Buy some valve lapping compound and see if you can seat the valves back to the valve seat. Would be a good to know what shape the valve guides are in.

If everything checks out you can install new valve seals and purchase a valve spring tool and do the work yourself and know it's done right.

 

[5OF2k]

uhmmm, yes it does. If a valve isnt seating properly, the wear on both the valve head and the seats will be offset, rather than evenly distributed throughout the face/seat. Next time you work on a car with bent valves, take a close look at the seats and valve heads, you'll see what I'm talking about.

-Jake

 

[rdomeck]

It doesn't run with bent valves is my point. If there is any difference in the seat it would be very hard to see to the unexperienced eye.........

 

[presterone]

The timing belt snapped on my car when I was on the highway. After pulling the head off you could barely tell that the valves were bent. The pistons had little ''kiss'' marks but I was suprised I expected total carnage. I have seen some serious carnage on other motors where the pistons and valves made sexy time. I just got lucky I guess.

 

[JackstandTSi]

The pistons in the block look badly chewed up thats what im worried about tho. I have a spare block but didnt wanna spend the money for a shop to pressure test it and what not when i could just bench test myself.

 

[rdomeck]

Wait.....I thought a guy gave you a head that he didn't need? You have seen the block that the head came off of and the pistons are chewed up? Valves are bent, no need to check them. Give us the whole story man and we can help you better!

 

[JackstandTSi]

The guy found the pistons that the head came from, the block was redone with new internals. Its only 1 piston that is beat up it looks like someone just started chopping at it with a knife. But the other three are fine and no damage at all and the valves have no damage to them. I will try and get pics up this weekend the head is at my mother's house.

 

[JackstandTSi]

Here are 2cylinder pics for some reason photobucket will not upload the other 2 but the valves look identical there is like a gold powder around them it's not any sort of metal it's very very fine and soft

 

[rdomeck]

That would be surface rust on the valve seat. Head has been sitting a while. The valve seats are pressed into the head and made from steel. Just surface rust......

It may just be the angle, but the valves look like they are open. Are the cams still in the head? If not I would say by looking at the pictures that the valves are bent. Even if the cams are in it, it appears that both sets of exhaust valves are open which would indicate to me that they are bent as the cams would never have more than two exhaust valves open at a time!

 

[fuel]

never mind the valves look at the damage to the combustion chamber on the first pic! That's almost certainly caused by detonation. That head requires skimming at the very least.

 

[JackstandTSi]

The cams are still in and what is the average price on skimming. Is this head even worth salvaging I'm not trying to dump a crap ton of money into it.