Valve Diagnosis

[Luke240z]

Are these good or bad???? Just cracked the head off my project and this is what I've got. Any thoughts appreciated.

The 6th Cyl. looks the same as the 4th Cyl.

THANKS

Luke

[halz]

Yep - looks like you've got a rare 5-cylinder version of the L24!

[Luke240z]

Thanks very much, I will try and find a 6th now. Thank you fountain of knowledge. :cheeky:

[26th-Z]

It's confusing to diagnose much from your pictures, but since you have the head off, do a valve job. Remember to keep your rockers and lash pads exactly the way they came apart - oriented exactly the same. I like the exhaust valve guides to be a little looser than the intakes. Replace the valve seals and have a good hard look at your cam wear. When you put it all back together, syncronize your carburetors.

[panchovisa]

I'm no expert, but looks like a fair amount of carbon build up. After the rebuild I'd suggest getting some NGK sparkplugs in a sligthly hotter heat range than what was previously used (unless engine was previosly driven by little old lady. Then just stick with recommended heat range). Good luck on your project.

[Ed]

Hard to be sure not knowing which picture is which cylinder and missing one. But notice the color of the exhaust valves. Two are nice and brown like they have been burned clean. The other three are black and covered with carbon like the intake valves. This means your running too lean on the brown valves and too rich on the black valves.

If you can take a picture of the entire head in one picture.

[Luke240z]

here is the full shot of the head.

And thanks again Guys for your help.

Luke

[Ed]

Well, I guess that my theory just went out the window :stupid: . But it does look like #1 is running hot, or lean. Take your head to a shop and have it hot tanked, 3 angle valve job, and have them do a pressure test. If it still has the old brass seats on the intakes have those replaced with some hardend steel. They will probably want to resurface the head to get it cleaned up.