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brasssmunkye

'85 720 2WD blown headgasket :/

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so, i bought my 1985 720 not long ago, and it's been doing us pretty well, until the other day when it blew a headgasket while in town. 

truck never overheated or anything, i think the cooling system just needed to be flushed more often, especially considering we bought it after it had sat for a couple years.

 

took it to the shop, to make sure it was a blown head gasket, and now they are quoting us $2000-2300 for repairs,  that includes a new radiator, hoses, timing chain guide, machining the head a bit, and of course, the headgasket.

 

now, i am no mechanic, but i am pretty damn sure i can perform all of these repairs except the machining of the head (if it ends up being necessary) 

 

either way, does this seem like an unreasonable price? I'm in northern california for reference, and i paid $1200 for the truck to begin with. 

 

i'd really like some input on this, because i'm pretty bummed out about this situation. I was hoping this truck would last a while, and i can't exactly afford $2200 right now. So i would like to know what you guys think of doing the work myself, if it would be super difficult and time consuming or not (i'm not a mechanic, i do my work in my dirt/gravel driveway.) 

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That is what I hear other folks saying when they take their trucks to the shop, then they take it home and do it themselves for under a $100.00 in materials.

I also know of a couple guys that wait for these 720s to show up on Craigslist with a blown headgasket for $500.00, they buy them and replace the headgasket and sell it for a decent profit, do it yourself.

The napZ engine is known for blowing headgaskets, the Nissan fix for this is to re-torque the head every tune up one bolt at a time, loosen it and re-torque it in no particular order as long as all of them are done.

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Well if your paying someone else to do the work, expect to be gouged a little

 

What was the quote on time for R & R?

 

Parts?

 

Machine work on head?

 

Parts for head?

 

Is the head getting decked(flattening the gasket surface) or rebuilt?

 

 

 

 

Everything that the shop is installing HAS to marked up on their end,  that includes the price of the machine work, parts and labor.

 

 

 

 

 

 

 

Get a service manual and do it yourself

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Doing a head gasket is easy. Most important thing is to not drop the timing chain. Head doesn't need to be milled unless it is warped.

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Mill it. Deck it. Respect it.

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The last head gasket (Felpro at NAPA) I changed, cost me $28 up from $23 of 6 years before. This was an L series but the same amount of work, actually slightly more trouble I think. Took the head off in a couple of hours, cleaned it and put it on the next day after repairing two broken exhaust manifold studs. 

 

The Z24 will blow the gasket roughly every 100K unless you re torque the head bolts to keep it tight.

 

 

IF you plan to do this, just do not undo the cam sprocket until you find out how to secure the timing chain tensioner in place so it does not dislodge. If it falls out.... add 6 hours of work that's not needed. Securing the chain tensioner is almost no work at all but crucial to saving you so much time. If the head should need milling add $30 to $50 for the work.

 

$2,000 tells me they don't want your business.

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If it didn't over heat.. pull the head. Have it checked for flatness at a machine shop. Small skim of the head won't hurt. New head gasket, done deal.

 

That quote is a lot of money. I paid less than that to have heads done on a v8 range rover with a full valve job. That was before I could turn a wrench.

 

Get some tools and do the work yourself! We have walked people through these jobs before. If you are mildly mechanically inclined or know someone that is.. it can be done yourself.

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What size are the bolts/studs (M10 x1.5?) for the head, will the ARP kit for the ka24e work?  How about replacement studs for intake and exhaust manifold?  The fellow that last worked on my truck used a batch of bolts of which non matched another.  All seemed to have similar pitched threads thank God.  I would like to find studs, is the proper size stud M8 x 1.5 about 40mm?

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KAs use torque to yield bolts that must be thrown away after use. The Z series are totally reusable if undamaged. If worried about the head gasket simply re-torque each bolt separately once a year. This re-news and keeps the clamping force on the gasket. Loosen one bolt and tighten to 60 ft. lbs. then move to the nest bolt. Any order you like as long as only one bolt loose at a time. Do this on a cold engine.

 

For intake and exhaust, take a representative bolt into a hardware store that sells metric fasteners and buy all you need.

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KAs use torque to yield bolts that must be thrown away after use. The Z series are totally reusable if undamaged. If worried about the head gasket simply re-torque each bolt separately once a year. This re-news and keeps the clamping force on the gasket. Loosen one bolt and tighten to 60 ft. lbs. then move to the nest bolt. Any order you like as long as only one bolt loose at a time. Do this on a cold engine.

 

For intake and exhaust, take a representative bolt into a hardware store that sells metric fasteners and buy all you need.

Yea when I was checking my exhaust manifold and noticed that almost all of them were missing ??? took 1 bolt into my store and got replacements for a whopping .30 each and now im thinking my manifold is leaking because there are no gasket butting against the block?? idk it hasnt really bothered me..

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Get the gaskets and it should work, there pretty cheap.

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Some knot head used all kinds of different bolts. I don’t think there is a matching set. What is the thread pattern supposed to be?

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As others have said they are pretty easy to do. I would probably try to figure out if you really need that full kit of parts. Are you sure the radiator failed or is plugged? If you didn't overheat I would check for leaks, bad hoses, maybe test the temp sensor before just throwing extra parts at it. 

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Are they the same as the intake manifold bolts?

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captain, I believe they are the same as the intake bolts.

 

I thing the problem is I bought a set of studs that were the correct thread pattern, M8 x 1.25, but some idiot use a bolt with a similar but different thread pattern and that kept the studs from threading properly.  I just wanted to check before i get an M8 x 1.25 tap and try and clean up the problem.  

 

Thanks

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captain, I believe they are the same as the intake bolts.

 

I thing the problem is I bought a set of studs that were the correct thread pattern, M8 x 1.25, but some idiot use a bolt with a similar but different thread pattern and that kept the studs from threading properly.  I just wanted to check before i get an M8 x 1.25 tap and try and clean up the problem.  

 

Thanks

 

I can get you a correct thread and pitch but it wont be until Saturday because ill take a bolt off friday and match it up at my work. Im sure you will have an answer by then though. that sucks that the PO had not done it properly. Part of the reason im afraid of buying used trucks because of the hack jobs people come up with including myself. Hope that your tapping process doesn't have any problems :)

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Toxicrain, 

 

I tapped then M8 X1.25 it went smooth and seems to have fixed my problem.  I hear loud and clear that I am supposed to put a replacement head gasket on a clean oil free surface without any other product.  What about intake and exhaust manifold gaskets?  I really do not want to have to make the mess, but i want it installed correctly.  I see copper sprays and other stuff.   I am sure everyone has an opinion help me form mine.  I am a blank slate.....

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The whole point of a gasket is to seal any irregular metal surface marks. Gaskets are soft and crushed by the mounting bolts to make the seal. If the two surfaces are clean... the gasket will work. Trust your ability to clean two metal surfaces. I might use a sealer if the maker did but Nissan did not.

 

Now if you are a chevy owner that's different. None of the parts fit right and you have to trowel on 1/4" thick RTV to fill the gaps. Chevy owners prefer that orange or blue stuff most. I see it in wrecking yards all the time.

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i remember the gradual and sequential pattern of torquing of the head bolts.  How much torque on intake and exhaust manifold bolts?  I am using studs with some pretty cool looking brass plated "manifold nuts" that have a flange, and are self locking.  do i need a washer?   Just checking....

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I think they used washers on them. It would protect the soft intake aluminum.

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DM, thanks.  will pickup some washers......how much torque?  I saw it posted somewhere but cant find it with search feature and I do not have it in me to read all 44 plus pages of topics.......again.

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DM, thanks.  will pickup some washers......how much torque?  I saw it posted somewhere but cant find it with search feature and I do not have it in me to read all 44 plus pages of topics.......again.

I know this is probably naughty and I should be a bad influence, but......

I usually just make them tight, I check them at every tune up so I am not concerned.

 

Edit: Should say in the FSM, do you have one yet?

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12-14 ft lbs.

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Did my own head gasket for the price of the gasket. Just remember to read the book and block the timing chain otherwise front cover has to come off if you get slack in the timing chain. Bitch to get distributor and oil pump timed up on common drive gear.

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Bitch to get distributor and oil pump timed up on common drive gear.

 

Set to TDC compression on #1

Drive spindle should look like this when set right with distributor removed...

8Gj0vYy.jpg

 

 

You can achieve this by aligning the oil pump oil hole and the punch mark and install.

0996b43f8020986a.gif

 

 

... not so bad.

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