Just replaced the head gasket on my Nissan motor

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mrsnak
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Posts: 188
Joined: Thu Jul 10, 2008 2:16 am
Location: Ventura, California
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Just replaced the head gasket on my Nissan motor

Post by mrsnak »

Thought I'd share my experience with replacing the head gasket on the Nissan B210 motor that is fitted to my 1961 Moggy pickup.
I cobbled this post from a few I made on a Nissan forum (not a huge amount of help, BTW). Quite a learning experience.
Was driving one day and engine began running poorer than it had been, then saw the big white plume of moist smoke. Knew exactly what it was. The creamy "snot" in the radiator and under the oil filler cap only confirmed it. Hadn't tackled any motor in well over 20 years, so though this would be fun project:

Got the head off and found the culprit.

Needed to take off the manifolds because someone welded an angled pipe right where the manifold bolts to the pipe, making it impossible (without cutting the pipe) to remove because the bolted stud on one side came right down to the pipe.

That being said, the gasket blew because the intake manifold was cracked (and broke off upon removable) at #4 piston. The ensuing vacuum leak overheated that area. (broken area circled)
Everything else looks good.

My problem - how many bolts hold the intake manifold to the exhaust?
I thought it was just the two (circled) Didn't see any others. Turns out the intake and exhaust also bolted together in such a way that you really need to take it off the head on the bench

The break was clean and I'd like to get it welded. Impossible to find a used one. After considerable searching, could not find one anywhere in the U.S. Ironically, I could find the exhaust easily.

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This was really a situation where I needed to remove the manifolds on the bench, rather than in the car.
Was really shooting the dark trying to find all the bolts. Ended up cutting the exhaust underneath the car so I could bring the entire unit out. Could not unbolt the manifold because one of the manifold studs actually touched the pipe (someone welded it so that it would fit) When I did reassembly, I put a shorter stud on the one that touched:

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Got a friend of mine to photocopy some pages from a good B210 repair manual as well as found myself a Clymer book, and got all the tolerances and torque settings.

Imagine my newbie surprise to find out that I had a 1400 motor from about 1980.
Didn't realize "A14" was stamped on the block until someone alerted me.
This was after (of course) I got an A13 gasket set - mostly good except the bore is larger on the A14. It was the cracked manifold that caused the head gasket to blow, and I caught it so quickly, no other damage was done. Overall engine temperature stayed cool, so no warpage at all in the head. Had it mic'd just to be sure. Both the block and the head cleaned up very nicely.

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Got my intake manifold welded up and milled the intake and exhaust together to get a smooth fit. The welder did a great job with the aluminum manifold with only minor warpage.

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Easy solution for where I cut the exhaust, now I can simply unbolt from here if ever I need to do this again (hopefully not) in the future:

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Anyway, got it back together myself and here was the moment of truth:

Morris running - YouTube

All in all, this could have been easier had I known more about the Nissan manifold assembly, the the person who did the original motor conversion could have done a better job. I think I would have tried to raise the motor higher and remounted the radiator a little lower and out more. The fan pulls from the lower 2/3rds of the Morris radiator and is very close to the fan. I also would have rerouted the exhaust to go out more, rather than down along the engine and bell housing.

My 1400 motor has new-found life and quite a bit of spunk for the truck.
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