New guy needs help head gasket blown

[stevef1972z]

So, I went and picked up my first 1972 240Z yesterday morning. Started fine at the car lot, idled nice, drove fine. It had been sitting for a while (18-24 months), so if figured something would happen on the way home. I had extra oil, water, tools galore. The first thirty miles were not too bad. Stoppped and put gas and carb cleaner in, wouldnt idle, found broken vacum lines and replaced them in the parking lot. I thought that was the problem for the trip.

Was I wrong! Got on the highway for the last 17 miles home, cruZing nothing major going on, just pleased with myself and the little car. Next thing I see is white smoke in the rearview and a climbing temp gauage. Shut her down as soon as I could find an off ramp, never pegged out the temp imagine around 230 though. Pull the dipstick and yep, milkshake!

I have a lot of stuff with the car, many new parts, and the body and interior are fantastic. Now I have some wrenches to turn. Is this a horrible job? The service manual and the Haynes say it can be done with the engine in the car but that the timing chain can be tricky.

Any advice? Things I need to look out for? All help needed.

[zbane]

It's actually a fairly straightforward procedure. Just make sure you have all the items you'll need beforehand (tools, gaskets, etc.). Regarding the timing chain, there really is no "trick" to it. Once you pull the head cover off, dab a spot of paint on the chain and sprocket. Once that is done, wedge a piece of wood/wide handle screwdriver (handle down)/pair of pliers (handle down)/etc... Basically, you just want to keep tension on the timing chain guide. If that slip, then you have a big project on your hands...

[Walter Moore]

When you take the head off of the car, check it very carefully for any signs of erosion, or pitting of the chambers. On mine the PO had apparently driven it for a long time with a small coolant leak into the #6 chamber, and it left a track in the head that the head gasket could not fill. It also pitted the chamber so badly that I had to have it welded up and re-machined in order to replace the valve seats. (The pitting had nearly bypassed the exhaust valve's seat)

Just a friendly warning. If there are visible tracks from a coolant passage to one of the chambers, you will want to have the head resurfaced before installing a new gasket.

[stevef1972z]

OK I will keep that in mind, looks like its going to be baptism by fire with this car.

Is there any one brand of head gasket I should be looking for over another, something that has had better luck than with other brands?

[z74z90]

www.blackdragonauto.com and www.zcarparts.com pretty much have the S30's covered. You might have local sources also. Welcome to the world of Z. Life will get better!

[z74z90]

Walter Moore...how come I have not seen you at a Indy Z Car Club meeting?? www.indyzcarclub.com

[stevef1972z]

OK intake and exhaust manifolds are off, and cleaned up. Working on getting the fuel pump and ac brackets off the passenger side of the engine, and it is ready to start taking off the head itself.

Felpro gasket set ordered, due in Wed. Still very confused with the service manual and Haynes manual on how to get the timing chain through the head without slipping and not making a mess of things. I understand a slider between the chain runs to keep them seperated and prevent the tensioner from shooting out, but how to keep the chain from coming off the crank has me nervous.

BTW how much does this head weigh? Dont want to kill myself getting it off.

Also, anyone have a good plan on how to get all of the milkshake out of the engine. I was going with lots of back to back oil changes.

[stevef1972z]

Head is off, and not too bad a job, looks like the timing chain stayed in place. Examination of the head does not look bad, head gasket was sorn completely away on number 6 and very worn on number two. So far so good, get the gaskets tomoroow evening and then start re assembly! Wish me luck!

[nhoddino]

Job is fairly strightforward. Just do a real thorough check of the head when you hav3e it off and make sure you do let the chain drop too far in. Not impossible to get out if you, just an extra step.

[240ZMan]

You should check the head for flatness before you put it back on. If it is warped, you'll be doing this job again much too soon.

If you don't have a flat bar, take it to a machine shop. It's pretty easy to check and they can do it while you wait. If it is tweaked a little (not uncommon for these heads), they can do a mild shave to clean it up.

[stevef1972z]

Everything is back on and she runs like a sweing machine! I am very happy the head checked out fine. Got the little beastie back together and its not making milkshakes out of the oil and not smoking. Oil is clean and engine smooth.

Now it has a new problem, the brakes in the rear are dragging. It does it after several miles, 2 or 3 miles and the brake light starts to flicker and it starts to drag the rear brakes. By the 4th mile the light is on full bore and there is little free wheeling...my guess is the parking brake pieces hanging up. Anything I should know about this?

[HotrodPez]

That light indicates a bias between front and rear, essentially letting you know if one half of the system is not holding pressure. Could be a proportioning valve?