84 720 Z24 head gasket coolant holes missing?

[Dattsunal]

I have a 1984 720 with a z24 engine that was purchased as a long block from Marshall engines in 2014. I have been having head gasket problems with this particular engine from that company. The original engine that was in the truck never had a head gasket problem, it had high mileage but I wish I would have kept it I just didn't have room for it anywhere. 

The last time the head gasket blew it was between cylinders one and two. 

This time the head gasket blue between cylinders two and three. 

 

Looking at the head gasket, the cylinder head, and the block, it appears to me that there are some coolant holes that are being blocked by the head gasket. It's as if not all the holes were punched in the head gasket for a specific reason? 

 

Basically that's my question, why do I see coolant passages in the block and the cylinder head, but the head gasket is blocking a few of them on the intake side?

 

Any help on this subject would be greatly appreciated, it seems to me that all coolant passages should be open to flow between the block and the head, unless of course there is a specific flow of coolant. 

Thanks, 

Dattsunal, 

 

 

[datzenmike]

I've never seen a head gasket that all the holes lined up with those in the head or the block. Sometimes there's a coolant hole in the head but not in the block.

 

Once the block or head casting is decided on it may be found out later that it cools one or all cylinders to well and it's cheaper to change the gasket to seal off the flow than to re-design the blocks.

[Dattsunal]

Ok thanks for the information. Took me a little longer to do the job this time as I am now retired and looking at 65. Definitely was not in a hurry to get it done quickly this time. I read some feedback about the Permatex Copper Spray. So this time I'm using that product on the head gasket. Will be interesting to see if it helps me to cure the problem on this engine. 

 

The most annoying problem I have right now is the clutch fan on the water pump. The last time I did a head gasket I put in a new thermostat and a new water pump. Turns out the clutch won't release the fan so it's constantly turning and it's loud. The water pump that was there before was fairly new and it had the same problem. So now that's two water pumps with a clutch that is not releasing the fan when the engine is cold. The water pumps that I used in the past didn't have this problem. 

Have you ever seen this issue?

 

Dattsunal

 

[datzenmike]

You don't need copper spray. You've effectively glued your head onto the block, hope that you don't have to remove it again. 

 

The clutch does no release but it does slip at all times. Maximum speeds is 1,800-2,200 after which the engine keeps revving but it does not. There is a sensor inside the clutch fan that releases more oil internally and this can add 200 or so more RPMs if it's running hot. This will reset only after the engine shuts off and it cools.

 

To test the clutch fan try turning it with the engine off. There should be firm resistance but it should turn smoothly. If you give it a strong spin with your finger it should stop immediately and not spin freely. If it does the above, it can be considered to be working properly.

[Dattsunal]

Ok thanks for letting me know. For about 8 years I was running two electric fans. I had purchased them on RockAuto and basically the thermostat was wired to have power all the time. So on a hot day the fans would run until the radiator was cool. That was nice because I didn't have to hear the fan on the water pump. 

I'm thinking I would like to go back to the electric fan. Do you know if an electric fan from a newer frontier would fit? 20 years ago when I used to live in New Hampshire, I had access to a couple of junk yards so that would be easy for me to find one. Now living in Manitoba really don't have access. 

[datzenmike]

Any fan you find was not made to fit but with all the thousands of electric fans out there something can be made to. I have two from a Subaru but they didn't fit side by side, too wide. I switched one's wiring so it was behind the radiator and pulled air through, the other one pushed normally from the front, and they overlap about 3-4". The 190F ? temperature sender was from a 200sx and it too will run independent of the ignition on it's own fuse and will run briefly after the engine is turned off. If left idling long enough the fan comes on for 10 seconds and off for 30 and continues that way.

 

All I did was cut the clutch fan off but leave at least 1/8" of shaft in front of the pulley.

 

Manitoba? I slept in my car on Feb 13th in Brandon. It was cold.

[Dattsunal]

Yeah that's how I had done my two fans, one in the back one in the front. Eventually the one in the front died. So that's why I went back to the Nissan standard. Maybe in the future I can get the boys at Westman salvage to let me walk through their yard and find something that might work so I can go back to electric. Until then I will deal with the noise because I don't really drive it that much. 

The manufacturer date of my truck is December of 83, it was built in Smyrna Tennessee for the Texas market. 

I got it out of a private junkyard in Rhode Island, back in 1999. 

In Quebec I picked up another king cab four wheel drive, that was well taken care of. Apparently it blew a head gasket and the older gentleman started to take it apart but then decided it would be better to sell it. That particular truck was built in Japan for the Canadian market and it has the same manufacturing date as my Texas truck. 

About 2 years ago a guy in Brandon Manitoba had a 1984 two-wheel drive King cab Datsun truck which he bought brand new. Unfortunately it rusted out pretty bad because it was never oil undercoated like my trucks. 

But the engine and automatic transmission work perfectly. So I picked that up and hopefully I will swap that engine and transmission into the Canadian King cab 4x4. 

Right here in Carberry Manitoba my neighbor across the street had a 1984 king cab two-wheel drive that he bought from brand new. 

He never had any problems with it. He got really old and had to go into a care home. I wanted to buy that truck too but my partner said that I have too many! 🤣 You and I both know you can never have too many!

Anyhow thanks for your input I really appreciate it.