ok well i just disassembled my buddy's d16y8. the motor was pulled because he threw a rod through the front of the block. my question is, what is the underside (piston side) of the valves supposed to look like? are they all supposed to be closed? he has two intake valves slightly open on cyl #2 and 2 exhaust valves slightly open on cyl #3. mind you, he threw the rod on cyl #4. let me know whats up with this. and also, is there any way i can repair floated valves?? cause otherwise, the head is good, and i picked up a good block for the car, so i need to know if the head is ok before i re-assemble the motor.

thanks for the help.


Brett

 

this would be normal - if the camshaft is still there, they can't all be closed - the intakes on #2 are almost closed when the exhausts on #3 are just starting to open - turn the camshaft and make sure they all open and close - if any stay open all the time, they are probably bent

 

Whenever you remove the head, there should be one cylinder with the intake valves open, and one with the exhaust valves open.

 

remove the cam, exhaust mani, intake mani. lay or stand the head on or up the intake ports . so the exhaust ports are facing up. pour water in all of the ports if water leaks out of the valve area the valves are bent with possible valve seat damage. repeat the water trick with the intake facing up to check the intake valves.

 

hmm..doesnt water cause machined surfaces to rust?

 

uh aluminum heads, rust? last time i checked no.

 

I still wouldn't use water. Maybe oil, gas or some carb/choke cleaner. What are the valves made out of?

 

If you manually turn the camshaft and watch the bottom (piston side) of the valves as you rotate the cam, you will get a pretty good idea if a valve is bent or not by whether or not it closes against the valve seat. However, "floating" a valve happens only while the engine is running, and the valve spring does not produce enough force to close the valve fast enough for the RPM that the engine is running at, and the valve "floats until the next time the cam lobe activates it.

 

the valves are made of steel, so it might corrode them, but they are almost always being oiled once the motor gets running again, so that check would be ok.

i know the head is in good running order, it came off a good running motor (till it threw the rod). thanks so much for all the help guys, you made this whole ordeal much easier on my friend. its his only car, and knowing that the head is ok just let him breathe a sigh of relief.

another question, its got a pretty new (10k mile) d16y8 OEM Honda metal head gasket. ive heard these are designed to be re-usable. the gasket looks perfect, and because its three layer, i think im gonna pull out the middle layer to up his compression a little bit (its a Y8 he needs all the help he can get) is this a good idea? i see no reason to buy a new gasket if i can re-use this one and up the compression with it.


Brett

 

the best way to check for bent valves has done bee implimented.POURING WATER IN THE PORTS.rust will not set up right away.and only if you leave it in a place were there is alot of humidity,besides take a dam rag and wipe the rest out.

 

If you want a better way then water, use alcohol, the molecules are smaller and will go where water wont.

Also try doing it right. Head upside down with no cam, alcohol in the combustion chamber, compressed air into each port. If you see bubbles its leaking.

 

Water is fine, just spray in some light oil when you're done and try and dry it out as best you can. You guys do know water vapour is a standard product of combusion. Don't worry about it.