Head gasket blown on 1986 Nisan 720

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sterlingstone
Posts: 5
Joined: Sat Aug 15, 2009 9:08 am
Car: 1986 Nissan 720 pickup

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I recently had an event while driving down the highway.

There is now a metal ping or pang on deceleration and started running roughly.

I did a compression check, cylinders one and two are near 160 PSIcylinders three and four only read 55psi. Does this sound like a blown head gasket.Note, no while smoke is emitted from the tailpipe and no milky residue in the oil or under the oil fill cap.

Thanks,

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flinterman2000
Posts: 1011
Joined: Mon May 04, 2009 5:32 pm
Car: 2000 Nissan Wingroad, 85 Datsun 720 Pick Up.

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Sure does sound like a blown gasket. Would not show signs on the filler cap or the radiator depending on where the bridge in the gasket is.

comrade_charlie
Posts: 15
Joined: Tue Aug 18, 2009 9:27 pm
Car: 1985 720, 1987 300zx, 1985 300zx

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If it is a blown headgaskets, They are easy to replace, I did one on a z24 in a d21

The d21 just had bad compression, cant remember if it was none or low like yours, but if 2 are the same bad compression id say its blown between those 2 cylinders like this d21's one was. and it was between 3 and 4 cylinder.

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Project Trucker
Posts: 166
Joined: Tue Aug 18, 2009 11:50 am
Car: Datsun 720 pickup

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you also might re time the timing belt on the front by aligning the dots

sterlingstone
Posts: 5
Joined: Sat Aug 15, 2009 9:08 am
Car: 1986 Nissan 720 pickup

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How is he easiest way..what things must be done to prevent the chain/adjuster from coming apart or falling in the engine?

Thanks.

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sterlingstone
Posts: 5
Joined: Sat Aug 15, 2009 9:08 am
Car: 1986 Nissan 720 pickup

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Can you see the dots without removing anything?

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Project Trucker
Posts: 166
Joined: Tue Aug 18, 2009 11:50 am
Car: Datsun 720 pickup

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go to the timing belt and look at the gear and there should be a little dot on it and adjust it with wrench with the other dot

i can go and check so i can tell you everthing on it if you need

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Project Trucker
Posts: 166
Joined: Tue Aug 18, 2009 11:50 am
Car: Datsun 720 pickup

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o and yes you can see the dots without removing anything unless your engine is really dirty

comrade_charlie
Posts: 15
Joined: Tue Aug 18, 2009 9:27 pm
Car: 1985 720, 1987 300zx, 1985 300zx

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When I did it, I just pulled the whole timing cover off, and did the timing after I got the head back on. Didnt have to pull the oil pan or anything like that, just have to go slow.

sterlingstone
Posts: 5
Joined: Sat Aug 15, 2009 9:08 am
Car: 1986 Nissan 720 pickup

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Please look, if you would.

Thanks

sterlingstone
Posts: 5
Joined: Sat Aug 15, 2009 9:08 am
Car: 1986 Nissan 720 pickup

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Please look, if you would.

Thanks

seang
Posts: 2028
Joined: Tue Dec 16, 2008 8:09 pm
Car: Ford Fiesta ST
Location: Michigan

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Project Trucker wrote:go to the timing belt and look at the gear and there should be a little dot on it and adjust it with wrench with the other dot

i can go and check so i can tell you everthing on it if you need
There is no timing belt, what the hell are you talking about

moredunes720
Posts: 73
Joined: Tue Jul 14, 2009 12:18 pm
Car: 1985 nissan 720 4x4

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yeah, i'm confused on this thread, this motor has a timing chain that has to be suspended to keep the tensioner from getting jacked up. I ran a piece of wire from it and hooked it to the hood hinge. I was in bfe when i fixed the head...so i could not fashion a wooden block like the chilton's suggests. lol the chain ended up fallling down in any way when i trailered it from bfe to my own house in bfe on the other side of the state, even with the wedge. What a learning experience that was.

flinterman2000
Posts: 1011
Joined: Mon May 04, 2009 5:32 pm
Car: 2000 Nissan Wingroad, 85 Datsun 720 Pick Up.

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A wedge shaped block 2 1/2" at the top would hold the chain and tensioner in place once the engine does not turn. Its easy to remove the head after that.


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