We took the '73 240Z out for a brief run yesterday. Hubby (whose Z it is) is already challenging me and my '74 260Z to some friendly competition.

The first few times I tried starting it, it blew huge clouds of white smoke from the tailpipe. However, after running for awhile it gets better and the water vapor get less noticeable. Cylinder 4, which has very low compression, has a sparkling clean sparkplug, a sign (I hear) of water leaking into the combustion chamber.

I haven't yet tried retorquing the head bolts, suggested in an earlier post. However, I am preparing for the eventuality of pulling the head. I checked the gallery to see if I might find a photo of where to place the hardwood wedge. This is the only hesitation I have; I don't want to have to deal with resetting the timing chain. Does anyone have any photos or maybe a sketch of exactly how to wedge the timing chain?

I can't seem to find a good pic or diagram right off, but it's pretty easy.

When you pull the cam cover, look down in front of the cam gear, and you'll see how the cam chain comes up out of the front cover, thru the head, and passes over the cam gear. What you want to do, is to put the wedge down in front of the cam gear, and wedge it in between the two sides of the chain and force it outwards against the front cover to hold it in place. This will push both sides of the chain outwards, and will push back on the tensioner, which will give you some slack in the chain and allow you to take the cam gear off, while at the same time, holding the chain tension on the crank gear.

This is just my opinion, but since the correct tool is cheap, I'd use it instead of a piece of wood which can and will splinter sooner or later and can drop pieces of wood into the pan. I'd rather spend 12 bucks than have a piece of wood that may or may not be cut correctly and either slip (which means you end up pulling the front cover to re-install the chain on the tensioner) or splinter and clog up an oil gallery.

Also, if you don't cut the wood correctly, it can end up wedging the chain outwards against the bottom of the head, which will make it hard to pull the head. It needs to slide down between the chain, yet not wedge it until it is below the bottom of the head.

Are you pulling the head because you think you may have a blown head gasket ? Have you had the coolent systime pressure tested? Are you seeing any signs in the coolent of a leak, or in the oil ? Another thing is the coolent level droping? If the answer is yes to any of the questions , Pull the head. I agree with 2many on the wedge.

If you're still wondering, I'll take a scan from my L20A, L24 & L26 Factory service manual... it's only a line drawing but I'll also scan in the line drawing with dimensions of the tool used.

Let me know if you want me to do this.

I don't see any oil when I open the radiator, but the coolant level DOES drop. However, a good portion of that may be due to the water pump leak we discovered!

I haven't changed the oil yet, so no opportunity to see if there's water in the oil pan.

kyteler, if it wouldn't be any trouble to scan that diagram, it would be GREATLY appreciated! Even if, by some wonderful chance the head wouldn't have to be removed, I still want to know how to do it for the time when it HAS to be done.

Look at these three pictures and you'll see how the chain wedge works.

Here is the second scan.

And the third.

AWESOME! That's exactly what I needed to see. I'm the type who needs to exactly why something has to be done a certain way, and as they say a picture is worth a thousand words. Now I don't feel so apprehensive about removing the head (well, except for maybe a broken bolt or two!) Thanks a million

I too am edumacted! :stupid:

This, I did not know, but the photos give a good lesson.

Thanks sblake01

Maria,

SBlake01 pictures show exactly how the wedge works and where it goes. Like some others here I have been hesitant to use a wooden wedge in case of splintering.

I found that a common plastic tent peg (the ones used to secure tents to the ground so they don't fly away) work exceptionally well and eliminate the risk of splinters getting into the engine.

Cheers,

Peter

Those pictures I scanned were from an old 'Petersen's Complete Book of Datsun'. Datsun once sold that wedge through their parts department. The one I use is made of hard plastic. I bought it years ago, back in my 510 days, at a Beck/Arnley auto parts store. I don't think they're in business anymore. I remember seeing a pattern somewhere on the web for making one of these but I can't remember where. It's a very useful tool. I learned that the hard way the first time I tore down my 510!