Jump to content

My First 720. And First Datsun!


Brohemius

Recommended Posts

So I took the plunge into the world of Datsun, And so far i love it.

 

Got this 1981 720 from denmarkboy at a fair price.

20150303_174818_HDR_zpsxefatwzh.jpg

 

Having some rough idle and major stalling issues so I replaced all the vacuum lines.

This is before, i forgot to take a photo farther to the right.20150306_132201_zpsya2sejkx.jpg

 

New lines

20150306_145840_zpsofakllnb.jpg

 

New lines installed.20150306_161743_HDR_zpslecqzg5e.jpg

 

20150306_163413_HDR_zpsh24zcs7p.jpg

 

And heres all the crusty old line that was removed.20150306_161904_HDR_zpsug33lhef.jpg

 

While initially inspecting the vacuum lines i found this open nipple that i have no idea what is for... I cant find any open lines or another nipple that i should connect it to with line. Any help on that would be great.

20150306_161817_HDR_zpsnvarvlun.jpg

 

And lastly, the truck is having some strange stalling issues. On some days everytime i pop the clutch in or put it in nuetral or even at a dead stop idling, the engine stalls or i have to feather the throttle for it to stay running. Ive messed around with the idle control screw to keep it idling barely higher so it doesnt die, but to no avail. Im not sure what would cause this, maybe carb related? It is running very rich...

 

lots of help from Rhino13 today. Thanks brother.

 

Glad to be a part of this forum! Will update with an engine bay cleaning soon.

  • Like 4
Link to comment
  • Replies 183
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Welcome! Denmarkboy is the right guy to buy a Datsun from. Congrats.

 

Can you get some more pics of the stuff around that open spot?

Good call on replacing all the lines. It sounds like a vacuum leak if its running rich and still stalling. Find out what's supposed to plug that end (or plug it and see if that fixes your idle) if it doesn't you can put a hose in you ear and use the other end to listen for hissing around the connections.

  • Like 2
Link to comment

If the truck sat fire any length of time, sea foam it or carb clean it. I have one that sat all winter, ran fine before but does that now. I seafoamed it a little which helped, but I think it needs more. And new gas.

  • Like 1
Link to comment

Thanks for the warm welcome everyone!

 

So i plugged that open hole with my finger and i could instantly hear it run better. Going to get a line plug in about 20 mins. If it has that much effect on the engine should it be going to something? Or does that tell me its supposed to be plugged?

 

Ill put up more photos later today jones.

 

update soon with a drive report also, after plugging it and driving around a bit.

 

Lockleaf i have a can ready to use, i have heard great things about seafoam and i have heard lots of bad also. What do all you datsun vets say about the foam? And if i were to use it what vacuum line feeds all cylinders most evenly?

Most people use the brake booster line, but i wasnt sure if that is the best line for this engine.

  • Like 2
Link to comment

While initially inspecting the vacuum lines i found this open nipple that i have no idea what is for... I cant find any open lines or another nipple that i should connect it to with line. Any help on that would be great.

20150306_161817_HDR_zpsnvarvlun.jpg

I believe that connects to the vacuum motor in the air filter snorkel. It's a gate that mixes cold and warmed air from the exhaust manifold controlled by a temp sensor in the air filter that regulates it. Easily pulled off when removing the air filter housing.

  • Like 2
Link to comment

I always just use the vacuum booster line like you said. I also just slowly pour it down the carb while the truck is running. When it starts to stumble and tries to die, stop and let it ruin till it rubs smooth again, then start pouring slowly again. I've used it for years, never had a complaint. I've also been selling it across the parts counter for 8 years and sold hundredsf if not thousands of cans. I've had one guy complain and many guys thank me for the recommendation, for whatever you think that is worth.

  • Like 1
Link to comment

So i seafoamed the old beast. It smoked like crazy... And now runs a little smoother. Gonna do it again in a few days.

 

The stalling issue has stopped, for now atleast. Gonna replace all plugs and check the distributor cap and probably replace it also. Basically gonna do a full tune up bit by bit.

 

The only other issue at the moment that is concerning is a "chuggy" feeling tranny. When cruising in 2nd or 3rd at a constant speed i get a slight chug. Kinda jumpy feeling. Maybe its just trying to regulate and barely applying throttle in bursts?

  • Like 1
Link to comment

If equipped with an auto trans check the vaccum actuator , or throttle cable to the trans, (if so equipped) this will engage the TCC (torque converter clutch and cause a rich condition in some, and stall the vehicle out). Idk if Datsun added a TCC yet at this point so I may be full of crap, but just somthing I've leanrned with this.

 

Also, fuel filters in these trucks of age get dirty, there is one in the pump itself you can clean , and another outside. It is located just infront of the passenger rear wheel on the frame under a cover plate.

  • Like 1
Link to comment

Its a manual trans.

 

I really want to take care of the dieseling as it happens 95% of the time when i shut it down. Not sure what to do about it. I guess its running rich and thats the problem?

Check your anti-dieseling solenoid on the carb. Make sure the wires are properly connected & make sure the fuse is good. Also, w/ engine off, turn the key to engage the battery (but don't start it) and listen for a click in your carb - that's the solenoid. Last, unscrew the solenoid, clean out any gunk in the hole on the carb and/or inside the solenoid, and make sure there is a spring and a needle inside it.

 

If still dieseling after that, lean it out and make sure your timing is right (could be too far advanced.)

  • Like 1
Link to comment

Mine did that for a bit then I had to tinker with the carb and it finally stopped, used to back fire pretty bad too. The blue wire on mine has been cut, thinking of re attaching it to see if the choke still works, just haven't gotten around to it yet. 

Link to comment

I seafoamed it again and the dieseling has diminished but still happens. Just less extreme and not as frequent.

 

Im going to clean the engine bay soon and repaint all the accents as close to the original blue as i can. Also gonna paint the valve cover im just debating if i should match it to the light blue accents or do red to match the truck.

 

Also gonna do new plugs, fuel pump and filter, air filter, and anything else i can think of. Also gonna rebuild the carb soon. I want 30mpg lol!!

Link to comment

Ok went to get an alignment today and discovered some issues.

 

The idler arm bushing is gone, as a result im guessing the idler arm is warped from being used without a bushing.20150316_161322_HDR_zps9od1zsg9.jpg

 

And i found this major rubbing going on behind the idler arm. 20150316_162618_zpswnpv6fou.jpg

 

20150316_161348_HDR_zpsw2d12mhu.jpg

Heres a view from the top where the bushing rubs.20150316_161411_zpst2iw4k8m.jpg

 

So now to get some new bushing and maybe an idler arm... And to make that section not rub.

 

Also what is this little connector called? I need a new or lightly used one.20150316_161250_HDR_zpsb238o6tm.jpg

 

20150316_161254_HDR_zpskmtrzo1x.jpg

Link to comment

I would just buy a new idler arm myself.

Also I would loosen the bolts holding the idler arm and see if you can get the arm to drop a little by twisting it down on the end of the idler arm, it's tight there on my 720, but not that tight.

Ok so i ordered a bushing set for the idler arm, and also a left outer tie rod. Hopefully the bushings even that arm in the back and it doesnt rub.

Pictures of the fun coming tomorrow!

Link to comment

So today i dealt with the major front end issues. Atleast for a week or so until i can get a new idler arm and wheel bearings and tie rod ends. 20150317_135740_HDR_zpssxc185pc.jpg

 

Showing the melted bushing again.20150317_142321_zpskns8i5ke.jpg

 

I was able to just pull the bottom bolt off and then slide the outer collar off without having to take the entire idler arm assembly off. (cleaned the shit off also)20150317_143353_zpsw9cztqoj.jpg

 

Inside view of the idler arm collar.20150317_143404_zps43gieu3x.jpg

 

New bushings installed and all greased up inside.20150317_145259_zpsszskv7mu.jpg

 

The bushings evened out the rub and it looks to just barely clear now.20150317_151408_zpsrksrsezx.jpg

  • Like 4
Link to comment

Thanks charlie!! The ac does indeed work i just want to find a boot in better shape. last time i unplugged that one 20% of it turned to dust. And i want to wash my engine bbay, so i want my connections to be water resistant atleast.

 

Also thank you to everyone else who posted advice for me!

Very very much appreciated!

 

Trip to the coast yesterday.20150319_181358_zps7p65hdmy.jpg

  • Like 3
Link to comment

A problem has appeared in the last two days.

WWhen i leave the truck for a few hours sometimes it wont start or even turn over, just a "click" sound that i havnt found the source of.

But if i try to start it in rapid succession, as in turn the key "click" turn it back and turn it again and repeat like 5 or more times quickly. If i dont do it quickly it doesnt do shit just the "click". It seems the rapid on and off of the key is what helps...

Please help as this one worries me. ive had alot of hell with starters in the past and my mind instantly thinks starter.

  • Like 1
Link to comment

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.