[Son of Magni]

So I want to replace the valve seals, but I don't have an air compressor. And I really don't want to take the head off. Anyone know of another way to keep from dropping the valves into the cylinder???
SoM

 

[Zuber]

remove spark plug
rotate piston to tdc
stuff rope (nylon) into spark plug hole until full
do those two valves

x6

 

[Son of Magni]

...and you've gotten through all 6 without dropping a valve using this method?

 

[DylanZ]

I may need to do the valve seals as well, but am not sure. How does a person check the seals? My 83 burns about a litre of oil to every three tanks of gas, and likes to give a little puff of smoke on cold startup. It's no smog machine, but it does use a bit. I have the head off right now, and the cylinders are like mirrors, with a lip at the top that is barely noticable to the touch. don't have anything measured, but it looks great. However, the oil pressure sits at 1/4 at idle, but climbs to half, which is where it's supposed to be, above 2000. What do ya think?

Dylan

 

[Zuber]

Yes, several times. Do one piston's worth at a time. If you stuff the hole, the valve cannot fall down. I prefer this to an air compressor. There is less that can possible go wrong. With the piston at top dead center, the valve can only drop so far, even without rope. The rope just keeps it from dropping at all.

Whatever. Don't trust me. You asked for an alternate method, and I've told you what it is. Next time do a search on the subject you want information about. After you read the 300th consecutive consistent answer, you can believe it.

 

[Son of Magni]

Zuber...

Did you forget your Prozak today? Sheesh. All I asked was whether this worked reliably for you. I'll probably use your suggestion, I wasn't looking forward to listening to an air pump all afternoon...
SoM

 

[Son of Magni]

I haven't actually seen mine yet but I'm burning oil and I know it won't hurt to change them. You need to take off the valve cover to see them. Then if they're cracked or hardened or just look like they leak then replace them. If for $50 you can cut oil consumption in half, it's sure worth it...
SoM

rings are next...

 

[RobH]

www.zcar.com/forums/read.php?f=1&i=148076&t=148054

You may want to read this previous post it is long and a little hard to follow but it explains the procedure down to the last detail, and I think the choice of tubing in the cylinder is much better.

Good luck

 

[yurmohill]

if someone is doing valve stem seals on z's for $50. i have plenty i want to sublet.

 

[Son of Magni]

LOL, I mean $50 for parts and do it your self silly ;-)

 

[Al 260Z]

Rope or hose will work...

Just don't crank engine with loose vlaves or you'll lose it! Remove battery neg terminal just to be sure.


The Nissan tool for compressing valve springs is handy, but many say a big screwdriver levered against the camshaft works too. (Don't pry against a lobe tho!)

------------- Al