Jump to content
Jon's AD3 720

1983 720 4x4 King Cab Build Thread

Recommended Posts

Yup. The Z24 is notorious for blowing head gaskets every 100K. There's no way around this but to replace.

 

So if you didn't know about re-torquing the head bolts once a year to help prevent this then here's another tip.... Do NOT remove the cam sprocket until you know how to block the timing chain tensioner from falling out. Find out. Failure to do this adds hours of extra unnecessary removal of the front of the engine to correct.  

  • Like 1
  • Thanks 1

Share this post


Link to post

I have seen your previous posts about blocking the chain tensioner I will buy that plastic wedge tool. Let the fun begin. 

  • Like 2

Share this post


Link to post

Head gasket. Had similar symptoms on my truck last year. Don't fret though! Head gaskets on these trucks are pretty easy. Heck, I did it with no experience other than doing brake jobs. In fact, I think I did the head gasket on my truck before I ever touched the brakes 😂

 

On a serious note, as I recall there are no coolant channels in the exhaust manifold so you definitely have a fairly sizable head gasket failure. Either way, you'll end up replacing that gasket when you do the head gasket. Intake, exhaust, and head gaskets are all still available from Nissan. While you're there I highly recommend doing the water pump because its so easy, and if you plan on having this truck for the long term it wouldn't hurt to do the timing components. Lastly, taking the head to a machine shop to get it leveled is a wise investment. Shouldn't be too expensive either because it's a simple inline four. 

 

I wish you were in Minnesota because I'd be johnny-on-the-spot to help you tear this thing up. Once you do it once, getting all of the components off takes like an hour with 10 minutes spent enjoying a cold one. 

Edited by MaxChlan
  • Like 1
  • Thanks 1

Share this post


Link to post

The exhaust is stupid easy to get at and unbolt. Just pull it to the side. Get some help lifting and you can simply leave the intake right on the head. Saves a lot of work and if you really feel the need to replace the intake gasket, it's way easier off the vehicle. You will need to disconnect the EGR tube from the exhaust to the intake behind the carburetor.

 

Make sure the head surface is flat with a straight edge. You're allowed 0.004" max warp or 'low spot'. I've surfaced a head with a thick glass door from a stereo cabinet with 80 grit sand paper glued to it. Just push and pull it back and forth.

 

Dark is high area...

 

YKZTnho.jpg

8LxmuPG.jpg 

 

 

yz0S5ca.jpg

 

aPly8lR.jpg

 

 

58T2nP2.jpg

 

Cost $7 for the sand paper.

 

 

 

Clean head and block surface spotless. Clean out the bolt holes in the block. Head bolts are reusable if in good shape. Head gasket does not need re-torquing for a year. Re-torque the head when cold. Only loosen one bolt at a time and torque to 60 ft. lbs. Then do the next bolt, any order you like.

Cost $7 for the sand paper.

  • Like 3

Share this post


Link to post

i know i have read it before, but i can not find the thread. mike i think you said that buying OEM gaskets will get much better longer lasting results over cheaper aftermarket brands. where do i order those (intake, head, exhaust, and valve cover), and does anyone know part numbers for those?

  • Like 1

Share this post


Link to post

finally got time to tackle this head. i thought i would see more damage to the head gasket as well as the exhaust manifold gasket seeing as how i had coolant in the oil as well as coolant squirting out between the head and the exhaust manifold.

t8SE9kH.jpg

I still need to test the head for warpage. intake valves look good. exhaust valves have very minor pitting. the seating surfaces look good. (i forgot to get a picture of this) i have not inspected the valve seats yet. (tonight). i will have the head dye penetrant tested this weekend for cracks since my head gasket had no visible damage.

 

Questions:

 

if a coolant passageway opening interfaces with a metal inner ring of the head gasket is that a source of gasket compromise? there are also coolant passageways in the head and block that do not have corresponding holes through the gasket. is this normal? (shown in picture above. teardrop imprints in the filter.)

 

some of the threaded holes in the head that bolt the exhaust manifold on are stripped out. should i high temp epoxy studs in these locations? it appears that is what the previous owner has done on some of the exhaust and intake holes. ( shown above. guessing the three posts on my head aren't factory done) Or should i up-size the hole and re-tap  and use larger hardware?

 

what is the torque spec for the Intake, Exhaust, head, and rocker arm bolts? besides replacing the head bolts, is it advised to replace any of the other bolts?

 

does anyone have the part number for the aluminum valve cover gasket? NAPA gave me the rubber one which i believe is for the stamped steel cover not the cast aluminum one. from my research i need a cork rubber gasket. i have the raw gasket material and i could make one if needed.

 

any help would be greatly appreciated.

 

 

getting started

NN92M1X.jpg

 

"Milky" mess

UF82pIP.jpg

 

rdHTuDq.jpg

 

vTK3TyX.jpg

 

cleaned up somewhat. still need to finish prepping block surface.

u4sffzr.jpg

 

bought a wedge off amazon that didnt work for shit. ended up making my own out of wood.

UyhEXc1.jpg

 

 

I47iQ28.jpg

 

Cf3H3XY.jpg

 

pretty filthy valves.

ynKJca5.jpg

 

 

ss0ILp3.jpg

 

 

keeping things organized.

qcPnEbm.jpg

  • Like 3

Share this post


Link to post

got it running. fired right up after cranking for half a second. runs smooth (correct timing). need to adjust the idle and throttle cable a little bit, but that is easy enough. it smoked pretty good after it warmed up, but i expected that after all the spilled oil and coolant from disassembly. i only replaced intake exhaust head and valve gaskets. new valve oil seals, and new spark plugs.

 

the smoke out of the exhaust pipe stopped eventually, but would smoke heavily when i went to drive it.( under strain) i have only driven it around the block. there is a noticeable ticking coming from the motor. i adjust the valve lash to 0.012" COLD when assembling and i know i need to adjust it to 0.012" when it is warm and i will do so this weekend.

questions:

 

what could this ticking be? valve against rocker arm? it couldn't be valve against piston right?

 

is this smoke/steam coming out of the exhaust normal? could water be getting sucked in past the intake gasket?

 

what is the torque on the intake bolts. i couldn't find it in the owners shop manual.

 

i will try to post a video of it running so you can hear the ticking sound.

 

 

  • Like 1

Share this post


Link to post

Blue smoke is normal from changing a head gasket but should stop once everything burns off. Water vapor from the blown gasket probably cooled, condensed and pooled in the pipes and muffler. May take a little longer to get hot enough to boil away as steam.

 

Ticking is almost sure to be a loose valve adjustment. Set the valve lash hot. Thoroughly warm the engine and quickly set to TDC compression stroke #1, close... doesn't need to be exact. Remove wires in the way and valve cover.

I = Intake

E = Exhaust

 

Set the following valves...

 

I & E on #1

I on #2

E on #3

 

Turn engine exactly ONE turn and set to TDC exhaust stroke #1 to set the remaining valves...

 

E on #2

I on #3

I & E on #4..... done. With practice can be done in well under 10 min and long before the engine cools, just have everything ready.

 

 

Intake and exhaust mounting bolts are 9-12 ft lbs. Don't over tighten and strip the threads in the head.

  • Like 4

Share this post


Link to post

Sweet truck, I'm enjoying the build thread updates. I'm also in WA (Vancouver). You get the ticking figured out?

  • Like 1

Share this post


Link to post

ok. first of all, thank you mike for the help and advice.

 

secondly, a couple more issues. took the truck up in the mountains and it did great on the way up. On the way down trying to regulate my speed with compression so i didn't overheat my breaks my truck started to smoke a lot. smoke from burning oil. is this oil being sucked past the rings into the cylinder?

 

additionally 15 miles from home my voltage light came on and the gauge was reading 18 V. my thought is that either my sensor is bad or my voltage regulator is bad. i will check voltage at the battery terminals with a multi meter when engine running and see if the gauge and the multi meter match. if matches it is the regulator. if they do not match it is the sensorhas anyone else experienced this issue?

  • Like 1

Share this post


Link to post

The smoking is probably oil getting by the valves. When using the engine to regulate your speed going down hill, it creates vacuum and pulls oil down by the valves.

  • Like 1

Share this post


Link to post

Valve lash won’t make a difference. It’s pulling oil by the valve seals and guides.

  • Like 1

Share this post


Link to post

i just replaced the valve seals and a mechanic said that the guides were tight enough when he machined my valves and seats. it is what it is at this point then unless i replace my valve guides or replace the head right? There is a chance that i didn't seat one of my seals all the way? would this only be happening on exhaust valves? or both exhaust and intake?

  • Like 1

Share this post


Link to post

i am having an over charging issue. gauge is reading 18 volts. i have heard that this can be a result of bad ground connections. i am also thinking i should get my alternator tested to see if the voltage regulator is bad.

 

i also checked my voltage at the battery and it is over charging so it isn't a bad gauge.

 

has anyone experienced this issue?

Edited by Jon's AD3 720
  • Like 1

Share this post


Link to post

Yes. Replaced the alternator and no more problem. Internal regulator was bad.

  • Like 2

Share this post


Link to post

yesterday my turn signals/blinkers stopped working. all 4 of them worked perfectly before. haven't done anything to the truck recently that would have caused this...that i know of. The turn signal lights inside the cab on the gauge cluster stopped working as well. is this a bad switch in the steering column or a relay or something? any advice would be great. thank you.

 

-Jon

  • Like 1

Share this post


Link to post

Do your hazards work?  A common issue on these trucks as they age is the hazard switch gets touchy.  If hazards work fine, then mess with the switch to see if you can get the blinkers working.

  • Like 1

Share this post


Link to post

That was it. thank you. Now that you told me that i should have known because i think i have had this problem in the past and someone on here told me the same solution. thanks again.

  • Like 2

Share this post


Link to post

Do a compression test to confirm headgaskets fail and not just intake manifold gasket and then pull head. Fresh rebuilt motor+no headgaskets retorque=headgaskets fail. Also oil additive is terrible, sea foam fuel additive ok but I have never seen it do anything usefull. Heat is nearly essential at times when we approach 0 degrees F and recommended by all.

  • Like 1

Share this post


Link to post

Just stopping by to say the truck looks great man! Where are you located? Was seeing if I could rob some parts from the trucks you’re robbing parts from 😏

  • Like 1

Share this post


Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.