Valve Seal Replacement

[Ben's Z]

How hard is it going to be to replace my valve seals with the cam still on? I searched google for this and did not come up with much. Doesn't someone make a tool to help you do this procedure?

[Zed Head]

I've seen it described around the internet, and pretty sure I saw it at Hybridz along with some non-Nissan options for seals. Search 240Z, 260Z or 280Z and valve seal and you'll probably find some write-ups.

It involves some rope or hose or air pressure to keep the valves up and a couple of tricks to get the seals on without cutting the edges.

[Diseazd]

http://www.classiczcars.com/forums/showthread.php?39492-valve-spring-compressor&highlight= This is the tool.....doing it in the car is a job I wouldn't want to attempt.

[Jeff G 78]

I've replaced valve springs with the head on and it's very possible, but not fun. Doing the seals is essentially the same job as replacing the springs. It does save time compared to pulling the engine or even the head, but not a lot. The cam will need to come out which then requires a lot of other stuff to be removed. I'm very comfortable around Z's and Z engines and the job still takes me a full day. I used vacuum hose in the cylinders and it works great, but it does compress a bit more than rope. With stock valve springs, this isn't a huge issue, but performance springs are hard to get on with any give in the valves.

Pulling the cam requires the engine to tip rearward until it can slide out the front and clear the radiator. The hood has to come off as does the trans mount, exhaust, radiator shroud, timing gear, and fuel rail.

The only savings IMHO by not pulling the head is that the head gasket is saved and the cooling system stays filled. If you have a header, leaving the head on saves time as well since the head cannot easily be pulled with the intake and exhaust in place. The header gets in the way. With a stock manifold, you can leave the intake and exhaust and lift the assembly out.

On a carbed car, I can pull an engine/trans and yank the head quicker than I can pull the valve springs with the engine in the car and the head on.

[Diseazd]

Quote (On a carbed car, I can pull an engine/trans and yank the head quicker than I can pull the valve springs with the engine in the car and the head on). Ditto that.....I would much rather pull the head and do it on the bench.....better still.....take it to a machine shop and let them do it. It ain't that expensive!

Edited June 8, 2011 by Diseazd

[Zforce]

It's a 3 maybe 4 hour job with the proper tools (kd tools 3087) valve spring compressor,magnetic screwdriver and about 10 feet of nylon rope, I used clothesline rope from the supermarket. You DO NOT need to remove the Cam, the hardest part of this project is finding the proper valve spring compressor. I found one on ebay for about 40.00 dollars.

What you have to be carefull of is making sure you get the valve retainer collets out without losing them down the engine especially on cylinders 1 and 6, stuff a rag down the timing chain before you begin. Start with cylinder 1 and continue in the firing order and before you attempt to compress the valvespring smack the retainer with a socket and a hammer to losen the collets.

As you replace the valve seals use the litttle valve stem condoms that come with the new seals and place it over the valve stem,lightly oil the seal and push in on, you should feel a click when it bottoms out around the valve stem. Also as you go DO NOT mix up the rockers or the lash pads very important otherwise you will be pulling the cam in short order.

As a preemptive measure take a coupe of ibuprofen tablets or the painkiller of your choice because your back is going to kill you.

[darom]

Here is a nice write-up on this procedure:

http://www.geocities.com/inlinestroker/seals.html