Jump to content

New to me 620


Justin620datsun

Recommended Posts

  • Replies 68
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Ok. I dont plan on doing anything major to it just making it more...daily driving friendly.  Anyways today...I got off work drove home and my truck has been "dieseling " since I got it I cleaned the carb out and adjusted the idle and it helped a little. But today it backfired and almost gave me a heart attack.  Not the first time I've had a truck do this though. Where do I start to fix it? The gas attendant didn't find it very funny...?

Link to comment

is stock carb or stock?

most weber aftermarket carbs dont have a anti desieling selinoid so the idle jet is not closed when shutting down thus sucking gas in and a hot open chamber is prone to detonation. stoch Hitachi carb have this.

 

back fire? I would try to adjust the timming. see wht it is and back it down a little bit.

if a weber carb there is a mixture scre on the side at the base. one can turn it in or out and the motor will have a sweet spot.

 

 

this is just me, on a hot day I will rev the motor up and take a small cup of water and drip water in the carb and rev it so it dont shut off and give it a piston cleaning.might help clean the carbon.

Link to comment

I believe its a stock carb. And the timing might be off I'll look on here to find a way to tell. Also the water trick I did it to my 79 Toyota pickup I had when it did the same thing and it fixed it. I'm unsure of the timing situation and I dont want to mess it up to where I can't put it back. I'll do some research.  

Link to comment

Little update. Cleaned up the plug(spider webs and dirt) now seems like start fine. I'll be doing plugs and wires in a few days. And brand recommendations for those? I heard ngk for plugs? I love the looks I get in this thing. I'll mess with the timing as well to get it running better. I also found some hoses that are "plugged" under the air cleaner should they be plugged in somewhere? They are plugged with bolts. I'll get pictures when I get off work.

Link to comment

get photos. Some OK to plug others not esp the crank case vent tube

NGK wire setNE 64 plug wires, NGK B6  or Nippondenso plugs and if possible get the Standard Motor product dist cap with the brass contacks. Rock auto has photos and part number. Thry used to sell the zBlue streak Version with Copper but cant find anymore. I run them and had them for 8yrs on same motor

Edited by banzai510(hainz)
Link to comment

Idle is WAY too high. Should be 650-750.

 

That high it's not running on the idle circuit which has a solenoid that shuts off the gas with the key. This solenoid controls only the idle.

 

In the air filter snorkel is a vacuum powered servo motor that opens and closes a flap gate door against a spring. This door mixes cold air from in front of the rad with warmed air from the hot exhaust. The intent is to provide the engine with a tightly controlled air temperature all year round. The engine warms faster, runs better and gets better mileage if the air temp is constant. It also eliminates carb icing in cold damp weather like freezing rain.  During full throttle the intake vacuum drops and the door closes off the heated air and only cooler outside air is drawn into the engine for full power.

Link to comment

Ok sounds good thank you. So another question.  If I get the timing dialed in and it doesn't stop the dieseling what's my next step? I heard seafoam but I don't know if I want to do that.  And also I adjusted the idle and it made the dieseling less...violent. again I got gas today and the attendant about jumped out of his socks.  How do I check what it is idling at? You said 650-750? How do u measure that? 

Link to comment

Does the VIN number on the title match the VIN plate on the door or in the engine compartment? If not it's the wrong title for the truck.

 

Since there are antenna mounting holes on the passenger side it could be a 78 or earlier cab/truck vs. a 79.

 

The AC rubber delete plugs are still in the firewall, and there is no AC Drier or bracket on the passenger inner fender. There are no monster cast iron AC brackets on the engine either.    This truck/cab probably never had AC. But it is possible the cab was swapped as DZMike said. 

 

I don't know why it would have the stock electric fuel pump without  AC, unless they did a really fantastic job of removing all the elements, and putting back all the delete rubbers/plates?   Are there center vents in the dash, or does it have a radio or a delete plate? Post a picture of the dash. 

 

Is there a condenser (skinny looking radiator ) mounted in front of the radiator on the grill side of the radiator support bracket?  The 78 and 79's with AC had an 8 blade fan vs. a 7 blade fan on the trucks without AC. How many blades on your plastic fan?

 

FYI:  Datsun AC was installed on 620 trucks as early as 1978 either at the factory or at the dealer (and the 78 had the Datsun electric fuel pump like that one,) possibly back to 1976. I researched this once and can't remember what cut off date I found.

 

There is an AC section in the 78 Factory Service Manual, but I don't have a 77 or 76 manual to check if there is an AC section in it.

 

Does anybody have a 76 and/or 77 Datsun Factory Service Manual who can tell us if there is or isn't an AC section in it?

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.