Head, not sure if head gasket or head cracked at this stage.

[restorerestore]

Have water in oil, cyls 2-6 fine, nr 1 plug wet, water in oil. Suspect it is head gasket but not sure.

Do not have place to do head gasket nor tools, etc, so will have to pay to have done by local NAPA or such (use their head gasket set?) Have had work on truck done there, great place, mechanic i former Datsun shop. Est is 525 plus tax, is that reasonable?

IF worse case is head cracked, what is real cost for replacement head. Need to go cheap as 73 on SS, so not a lot of spare cash. Thoughts?

Have had 78Z for 25 years, used to do most work self, but back no longer accepts such things. Ole machine and I still run pretty good despite age.

[Jeff G 78]

$525 sounds about right to do the head gasket job. If the head is warped, only let them mill it if they know what they are doing. Milling the bottom-only will seal the head to the block, but the warp will still be in the head. N47 heads are cheap, so if the head has issues, try to find a good used one. I would expect to pay about $100 - $150 for a good used N47. I would verify that it measures flat and is full thickness though prior to purchase. The head should be 108mm tall from the valve cover surface to the bottom. Be sure to have them replace the valve seals while apart. It's much easier off the car and they are likely shot on your current head as well as any used head you would buy.

Has the engine ever overheated prior to the dead cylinder? If not, it could be a simple head gasket job.

Good luck.

[240260280z]

Cracks usually occur in 3&4 (exhaust ports are side by side) and in 6 (hottest due to distance from rad and cool water flow).

Heads with liners seem more prone to cracking.

I would agree with you that the #1 is probably head gasket.

Pulling the head is easy if you have some tools. This can save you money. If you can pull and re-install the head, the only thing you will have to pay for is a gasket and machine work.

http://www.classiczcars.com/forums/tech-pubs-howto/42420-77-280z-head-removal-%5Bstep-step-photos%5D.html

[restorerestore]

Cracks usually occur in 3&4 (exhaust ports are side by side) and in 6 (hottest due to distance from rad and cool water flow).

Heads with liners seem more prone to cracking.

I would agree with you that the #1 is probably head gasket.

Pulling the head is easy if you have some tools. This can save you money. If you can pull and re-install the head, the only thing you will have to pay for is a gasket and machine work.

Sorry but do not really have proper place nor tools anymore, am 73 and do not have proper back anymore either. Biggest worry is any wear on alum from any steam/exhaust going over the head areas, Sounds silly but why are intake removed when gasket replaced as they seem OK, in fact could almost pull head to replace gasket with header in place if loosened at header pipe/exhaust point and slide out carefully (Maybe)?

Sounds silly but I think I saw a head pulled on a in line 4 somewhere in that manner, was also ovh cam. But will save the pennies and get it done soon, miss the little lady, Wife has a 1993 240 SX convert, was first car she ever bought new, loves it dearly, Has auto trans and that went out, so it is next big project when the pennies there. as on SS and limited income, regardless of what gov says about inflation low, we find it not true. Thanks again for data, kind of miss the days when I could do all my own work, just physically not quite there at 73 and wife is "mid 60's" and do miss her SX, now not doing much more then plug./oil changes

[Jeff G 78]

Yes, the head can be pulled with the intake and exhaust in place as long as the exhaust manifold is stock. 6-into-1 headers are a different story since they wrap under the tunnel. Pulling the head and manifolds as an assembly are harder on the back since the weight goes way up. If the head needs any work, the shop will want the manifolds off anyways, so it's usually not worth leaving them on. It's very possible that they will find a broken stud at the rear of the head when they remove the exhaust manifold. If that's the case, they will need the manifold off to install a Heli-Coil.

Good luck with the repairs on both car!