81 210 Head Gasket (looking for tips)

[Hawaiian620]

My 210 blew the head gasket on the way to cars and coffee this past Saturday. I've never done a head gasket before, so I'm looking for any tips. I should have every tool I need. 

 

Main goal is to get it running. Side quest is to delete all the emissions stuff and clean up the engine bay a bit. My main concern is not knowing were all the vacuum lines go. I've been taking pictures as I take stuff off for the most part. Going to try and work on it a little every day and get it going again by the next cars and coffee at the end of May. 

 

Thanks in advance for the assistance!

 

 

[datzenmike]

The A series is not known for blowing the head gasket. Just what makes you think it' a blown head gasket... before tearing it apart?????

 

Actually the OHV engine is very easy to do as there is no cam timing chain involvement. I have done this... in the mid '70 but I'll let someone else have a go. To save time and make it simpler I disconnected the exhaust down pipe and lifted the head off with the manifolds and carburetor attached. Less chance to strip or break a stud or bolt.

 

Head must be checked for flatness or it will just do it again in a few weeks. If so NOW would be easier to unbolt the manifolds when you can comfortably get at them and have a shop mill the head flat. 

[Hawaiian620]

It over heated, I pulled over and let it cool down. Drove again for a couple of minutes before over heating again. Second time the overflow cap blew completely off and landed by the air cleaner housing. I'm talking the cap and the strap holding it to the tank came off haha Let it cool down completely (40mins or so) while waiting for someone to bring coolant. Filled up then started it and noticed lots of white smoke from the tailpipe, checked the oil and it was diluted. Had it towed home.

 

Really hoping nothing else got damaged. It started easily and was able to back it into the garage. some noise from the engine, but I'm assuming that's because now the oil is a lot thinner than it should be. Not sure why it over heated in the first place. It has always ran to the left of middle or in the middle while sitting in traffic. Never noticed any leaks. I actually just fixed the transmission leak then drained and filled it on thursday. Never saw anything else leaking while I was looking around. 

 

Thanks for the info, Mike. I'll grab my level and check the head once I get everything else off. At least that's what I saw someone on youtube do. 

Edited April 27 by Hawaiian620

[datzenmike]

Cast iron blocks and aluminum heads do that when over heated. The head is almost for sure warped or now has a high spot that can't pinch and hold the gasket. It happens.

 

 I had an L series head that was given to me for blowing gaskets. I tried copper coat but it was no use. I don't recommend this but I used a sheet of glass and 180 sand paper. You can see where the high spots are...

 

There was a high spot mostly between 2 and 3.

 

 

 

Eventually... gone.

 

 

Took about 45 min. 

[Hawaiian620]

well shit. If I have to get the head machined, that'll have to wait till I save up funds. I'll continue getting to the block though. I'll have to drain the oil and coolant before I do anything else I think.

 

I read that I should replace the head studs, is that true? I found some A15 ARP studs for about $130.  

 

Here is what the oil cap looks like.

 

Just for my knowledge, does anyone what this part is? Has some wires and a vacuum hose. It was located by the carb. 

 

Edited April 28 by Hawaiian620
Fixing pictures

[Dguy210]

1 hour ago, Hawaiian620 said:

well shit. If I have to get the head machined, that'll have to wait till I save up funds. I'll continue getting to the block though. I'll have to drain the oil and coolant before I do anything else I think.

 

I read that I should replace the head studs, is that true? I found some A15 ARP studs for about $130.  

 

Here is what the oil cap looks like.

 

Just for my knowledge, does anyone what this part is? Has some wires and a vacuum hose. It was located by the carb. 

 

 

1.  You don't need to replace the head studs, the stock ones are fine (same bolts as used on even the Z series and KA). I've reused them many many times.

2. Check the flatness of the head before getting it sent out, really easy to do. 

3. Looks like the vac switch emissions equipment maybe. Most people remove it and cap the outlet on the manifold. If you intend to run it and really need to know there should be a listing in the service manual what it is (see thread below with link to service manual). Specifically this would be my best guess but I might be wrong:

 

 

 

Edited April 28 by Dguy210

[datzenmike]

That's the fuel shut of vacuum switch. Under certain conditions of coasting with foot off the gas the idle mixture is still being sucked into the engine even though it is not needed or being used. This gas is simply wasted out the tail pipe. The fuel shut off senses high intake manifold vacuum and uses the idle cut solenoid to shut of the idle mixture. This is an emissions device that actually saves gas!

 

Other things that work with the shut off is a transmission neutral switch and a clutch switch to prevent the engine stalling between shifts or if shifted into neutral while the shut off is active.

 

Head bolts are totally reusable if not damaged. I don't think Nissan switched to TTY torque to yield bolts till late '80s.

 

Once head is on get a gallon of cheap Wallmart oil and a cheap filter. Drive it for a day or two then do a proper oil change with a NAPA WIX oil filter and some 10w30 Shell Rotella T4 oil. T4 still has the high ZDDP anti scuff additive package that was used back in the early 80s when your engine was new. If you are using a regular oil made for today's engines it has half the ZDDPO that it used to. Push rod and solid lifters need this protection.  

[Hawaiian620]

8 minutes ago, Dguy210 said:

 

1.  You don't need to replace the head studs, the stock ones are fine (same bolts as used on even the Z series and KA). I've reused them many many times.

2. Check the flatness of the head before getting it sent out, really easy to do. 

3. Looks like the vac switch emissions equipment maybe. Most people remove it and cap the outlet on the manifold. If you intend to run it and really need to know there should be a listing in the service manual what it is (see thread below with link to service manual). Specifically this would be my best guess but I might be wrong:

 

6 minutes ago, datzenmike said:

That's the fuel shut of vacuum switch. Under certain conditions of coasting with foot off the gas the idle mixture is still being sucked into the engine even though it is not needed or being used. This gas is simply wasted out the tail pipe. The fuel shut off senses high intake manifold vacuum and uses the idle cut solenoid to shut of the idle mixture. This is an emissions device that actually saves gas!

 

Other things that work with the shut off is a transmission neutral switch and a clutch switch to prevent the engine stalling between shifts or if shifted into neutral while the shut off is active.

 

Head bolts are totally reusable if not damaged. I don't think Nissan switched to TTY torque to yield bolts till late '80s.

 

Once head is on get a gallon of cheap Wallmart oil and a cheap filter. Drive it for a day or two then do a proper oil change with a NAPA WIX oil filter and some 10w30 Shell Rotella T4 oil. T4 still has the high ZDDP anti scuff additive package that was used back in the early 80s when your engine was new. If you are using a regular oil made for today's engines it has half the ZDDPO that it used to. Push rod and solid lifters need this protection.  

 

Thank you both for the information! I knew I should've checked the repair manual regarding that part haha Sounds important! I'll drain the fluids in the next couple days and post some progress. Thanks again!

[Hawaiian620]

Got the oil and coolant drained and header unbolted. Working on getting all the other connections off before pulling the valve cover. Noticed the valve cover has Phillip heads, so I'll probably replace those with nicer hardware while it's off.  

 

Does anyone know of a hood strut kit like this for the 210? Not sure I could make this one work on the body side, so I figured I'd ask. Would be nice to get the hood prop out of the way.

Edited April 30 by Hawaiian620

[Hawaiian620]

Removed the valve cover and mostly everything connected to the head. Should hopefully be able to pull it off this weekend. 

Edited May 2 by Hawaiian620

[Hawaiian620]

[datzenmike]

The remaining water in what doesn't drain out will settle to bottom of the oil pan. After a drive and a long sit loosen the drain bung and see if any will come out. If not that milk shake will slowly evaporate from engine heat. Try buying some bulk cheap oil and just keep changing it and the filter.   

[Hawaiian620]

5 hours ago, datzenmike said:

The remaining water in what doesn't drain out will settle to bottom of the oil pan. After a drive and a long sit loosen the drain bung and see if any will come out. If not that milk shake will slowly evaporate from engine heat. Try buying some bulk cheap oil and just keep changing it and the filter.   

Thanks for the info. I'll make sure to do that. 

 

Got everything off. To me it looks like the rear is where the gasket failed, but obviously I could be wrong. 

[Hawaiian620]

This is what the studs look like. Am I still okay with cleaning them up and reusing them? I have a thread chaser kit I plan on using. 

 

Any thoughts on how I can clean up the engine bay? I'm going to wire wheel the rust areas under the brake booster, remove the heater hoses since it was leaking in the cabin, so I blocked it off with a bolt. Was thinking of painting the block, but don't want to mess with the dist. Open to any suggestions. Figured I'd do as much as I can while I have this much space. Thanks again!

 

Edited May 2 by Hawaiian620

[datzenmike]

 

Yup this is what steam will do. Sometimes the valves are clean also.

 

Head bolts are totally reusable if not damaged. TTY torque to yield bolts weren't used until the KA? engines. 

 

 

Looks clean enough.

[Hawaiian620]

31 minutes ago, datzenmike said:

 

Yup this is what steam will do. Sometimes the valves are clean also.

 

Head bolts are totally reusable if not damaged. TTY torque to yield bolts weren't used until the KA? engines. 

 

 

Looks clean enough.

 

Awesome. I'll do some research on how to check to see if anything warped and track down some gaskets

[datzenmike]

The block is cast iron but heads are aluminum and can warp. Clean that head surface then get a straight edge and place across the back at those head bolt holes. If you can slip a 0.004" feeler gauge under it the head needs to be milled flat. 

 

I doubt that it's warped at all. Sometimes gasket just blow.

 

Are you using antifreeze? 

[Hawaiian620]

15 hours ago, datzenmike said:

The block is cast iron but heads are aluminum and can warp. Clean that head surface then get a straight edge and place across the back at those head bolt holes. If you can slip a 0.004" feeler gauge under it the head needs to be milled flat. 

 

I doubt that it's warped at all. Sometimes gasket just blow.

 

Are you using antifreeze? 

Correct, I was using antifreeze. I'll check the head and report back. 

[Hawaiian620]

Is it okay to cap this port? It was for the heater, but the in-cabin hose sprung a leak in 2022, so I plugged it with a bolt. I won't ever use the heater again, so I'm hoping I can just cap this at the port. What would be the best way to do this?

 

The AC on the other hand came without a belt when I bought it in 2018, but everything seems to be intact, and the compressor doesn't make any weird sounds when I spin it by hand. I might throw a belt on later and see what happens. Maybe in just needs a recharge? I know nothing about AC systems. 

[Tom1200]

So I've been away from the site for several weeks but wanted to just chime in as the resident A-series guy.

 

First if you get an A-series engine really hot and then refire it, they will eat the head gasket followed quickly by melting the coolant passages at the surface of the head.

 

The head gaskets do indeed deteriorate; typically by the rear coolant passage and or between cylinders 2 and 3.  They will start to use a slight bit of water followed shortly thereafter by overheating. 

 

In 37 years of racing my 1200 I've had two fail due to corrosion (we aren't allowed to use water). Additionally when we got our JDM GX motor is had a bad head gasket. It had just started to fail.

 

One of the telltale signs is one of the spark plugs will be unusually clean. 

 

Happily the heads seem to be sturdy enough that I've only had one warp and that was on a motor that completely melted down (the head had large holes in the coolant passages).

 

As for the head bolts I've reused those for years, even on motors with 12-1 compression, without issue.

 

[datzenmike]

 

I don't know where the inlet heater hose connects to the engine but likely a fitting. Take to a hardware store and get a threaded bung fitting to plug it off.

 

That's the heater return hose. Just cut it off, plug the end with anything suitable and use a hose clamp

[Hawaiian620]

5 hours ago, datzenmike said:

I don't know where the inlet heater hose connects to the engine but likely a fitting. Take to a hardware store and get a threaded bung fitting to plug it off.

 

That's the heater return hose. Just cut it off, plug the end with anything suitable and use a hose clamp

 

I'll take a look for the inlet. I think I remember where it was. I saw autozone has the rubber coolant plugs for the return side. 

 

7 hours ago, Tom1200 said:

So I've been away from the site for several weeks but wanted to just chime in as the resident A-series guy.

 

 

 

 Thank you for the insight! I have to clean the block and head. Not really in a rush since my head gasket doesn't have an estimated arrival date yet. I've been cleaning the bay and some random parts in the meantime. I did a very rough check of the head with my straight edge and it seems fine, but I need to get some feeler gauges. 

[Hawaiian620]

I got all the old gasket scraped off and wiped it all down with brake cleaner. How can I clean off all the carbon build up? I saw I could use sea foam on the pistons by letting it soak for a few hours. Should I wipe some assembly type oil in the cylinders when I put everything together?

 

Still waiting on the head gasket. It's been somewhere in AZ since Thursday or Friday 😑

 

Anything else worth doing or cleaning while I'm waiting? I wiped down the engine bay and am going to repaint some parts that have surface rust or chipped paint. 

[datzenmike]

No sense cleaning the pistons and combustion chambers, they will look like that is a week. Leave the cylinders alone. They still have a micro film of lubricating oil from last time it ran and are lubricated by oil jets on the connecting rods as soon as you start it up

 

Run a straight edge across the head gasket surface. If you can slip a 0.004" feeler gauge under it it needs to be resurfaced at a shop.

 

While off, is as good a time as any to replace the valve seals. 

[Hawaiian620]

16 hours ago, datzenmike said:

No sense cleaning the pistons and combustion chambers, they will look like that is a week. Leave the cylinders alone. They still have a micro film of lubricating oil from last time it ran and are lubricated by oil jets on the connecting rods as soon as you start it up

 

Run a straight edge across the head gasket surface. If you can slip a 0.004" feeler gauge under it it needs to be resurfaced at a shop.

 

While off, is as good a time as any to replace the valve seals. 

Thanks again for the info! I ordered valve seals and the tool kit for it. Should be here on saturday. I still need to get feeler gauges.