The head seems to leak even more after retorque Mostly from the front

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240zgoldie.blogspot.com

Wait ~ I thought it only leaked from the back???

If it's leaking in other places after an even retorque, you will need to pull it and replace the gasket. Might be a great time to have it planed (milled) flat and true at a machine shop, too.

I won't even ask if you tightened it to specifications, in proper sequence. Of course you did.

Wish this had been easier.

Frank

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1970 240Z

Head might be warped.

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-Chris

I did tightened it in proper sequence as told in FSM. Yea, i'll remove it asap, the photo guy told me that the photoshoot has been moved to next tuesday so i cant dismantle it AND i dont have the parts yet

edit: local machine shop promised to straighten it with fair price. 80$.

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240zgoldie.blogspot.com

Update: I have removed head with the help of my wife (!!) and now its time to take head to machine shop. In all the hustle i didnt look in which hole was the camshaft guide in cam sprocket, there is 3 holes in sprocket. Maybe someone can tell? The block itself was quite dirty and pistons are black from the top, but that dirt seems to go away if i clean enough.

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240zgoldie.blogspot.com

I wish I had that much workspace on MY bench!

#6 piston looks "washed clean". Did you find it that way, or did you wipe the carbon from it?

As long as the head is off the car, you should consider replacing the valve guide seals now, instead of waiting until they wear out. Replacing them while the head is on the car can be a tedious chore , and if you drop a valve into the cylinder during the procedure, you have to remove the head again to get it out anyway. I am told the valve guide seals from a Ford 4.0L V6 Explorer engine are identical to the Z set, but are tougher and cost less.

Use the 1st hole on the cam. If the chain seems loose, move to the 2nd hole. Will you replace the chain with a new one while you have the opportunity?

Frank

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1970 240Z

I will stick to the old chain.. Head is now in machine shop, they promised to look it next week. I was a bit frustrated because when i called them, they said nothing needs to be removed but when i took the head there, they said valve guides need to be taken off. Well i let them do it even if it costs a little more. They are pro's unlike i am. Now i concentrate on cleaning manifolds and carbs, also i need to remove air galley from exhaust manifold and get lots of new nuts and bolts.

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240zgoldie.blogspot.com

The correct holes in the cam sprocket aren't determined by how tight or how loose the chain seems to be. The way to determine which hole to use is to degree the cam with the sprocket and chain installed. It's a little complicated to explain; you should download (it's free) the factory service manual.

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71 on a rotisserie, two more in pieces in my shed...and a 69 1600 waiting for me to get to it

I do have FSM ( even though it seems that i havent) but my understanding of technical vocabulary is sometimes quite bad. I rather hear it from the "guys".

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240zgoldie.blogspot.com

Also...that "washed clean" look on #6 is typical of a blown head gasket; often the coolant leak has it all nice and clean when you take it apart. If you are interested in higher performance, you should polish the piston tops and combustion chambers to mirror-finish; the increased heat reflectivity and decreased sharp edge hot spots will let you run a little more timing advance without detonation problems. Also....you will benefit nicely from smoothing and polishing the intake and exhaust ports while you have it apart....a couple hours with a die grinder and some sandpaper rolls is safe and easy to do.

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71 on a rotisserie, two more in pieces in my shed...and a 69 1600 waiting for me to get to it

Yes i've been grinding those ports clean, luckily the machine shop cleaned the head quite well. It was warped about 0.2mm, not much but enough. I was wondering, now that i have new manifold gaskets, which way the come.. metal part towards head or towards manifold?

And how smooth should the block surface be? Its not that bumpy, only dirty looking. I want to get this Zee back on the road asap

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240zgoldie.blogspot.com

I forgot to update this thread so i might as well do it now. I've succesfully changed the head gasket (yeyy) and even managed to keep the timing correct. Actually now that i think, changing head gasket is quite easy task Been driving with new gasket for few weeks and Z seems to be in great shape. Although now it's off road for a week or so, i took my (new) distributor to one local engineer guy who modifies it to modern no-points dizzy. Hopefully it gives me a little more HP as my old dizzy was warped and the difference in timing between cylinders was quite big.

In cylinder no1 timing was 17 degrees and in cyl no6 it was 10. So when i hit the pedal to the metal, there is big ROAR but it accelerates as fast as old 70's diesel Mercedes.

Also i got some troubles with ignition switch base, i have 1 year old Chinese el-cheapo switch and it gave me a headache by switching off the car in tricky places. Also turning on was quite tricky until we changed ORIGINAL 40year old JAPANESE base back. Switch is new but the base is oem. Jeez, these guys can make cars! My engineer friend laughed his ass off when we fixed this issue.

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240zgoldie.blogspot.com

I just went thru this thread again as a result of reading the new post.

Mark is right. The TENSIONER will provide the right amount of tension
or slack no matter which hole is used. The choice of hole, as I recall,
is only for dialing in the desired degree of cam advance for whatever
type of driving you do, or whatever performance you should choose.

Thought might also be given to replacing the tensioner, and maybe even
the chain, chain guide, and other things, as long as the head is off. These
aren't parts that you would consider changing as often as your underwear
and socks, but maybe Mike would be so kind as to advise whether any of
those parts had ever been replaced in the past, so as to help determine
whether that might be necessary now or not.

FWIW,.....................All Z Best,.....................Kathy & Rick

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All Z Best,.......Kathy & Rick

1969 Z.CAR (#00013 10/69) 8/30/76
1969 ITSA.Z (#00171 11/69) 8/24/73
1970 OLD.Z (#06289 6/70) original owner
1971 510 2dr since 12/31/75
1969 1600 rdstr (our 160-Z)
1971 (#19851 1/71) sold
1975 75.Z (#01343 1/75)