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Deleteme

Member Since 13 Feb 2018
Offline Last Active Mar 28 2018 06:19 PM
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#1553281 1979 Datsun 620 Motorhome, upgrade & restore.

Posted by Deleteme on 23 March 2018 - 09:51 PM

That is one trippy alternator! What old hippie did you buy that from? It's so funky I like it. :rofl:

I get my little sister to paint parts I pull off :)
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I fixed the engine, busted the nuts off the BPT valve and plugged the hole.
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#1553163 1979 Datsun 620 Motorhome, upgrade & restore.

Posted by Deleteme on 23 March 2018 - 10:58 AM

You can see that massive crack in my last photo


#1553160 1979 Datsun 620 Motorhome, upgrade & restore.

Posted by Deleteme on 23 March 2018 - 10:54 AM

The BPT valve was cracked in half next to one of the mounting bolts.
The bolts we're so rusted, and one was hard to reach.
I used gasket maker to seal the crack and the idle slowed right down.
It ran so smooth.

Did not solve hesitation.
Sprayed carb cleaner in top of BPT valve, engine responded.
Hack sawed top of BPT valve off, sealed vacuum.
Runs like bag of shit and won't idle.
No longer hesitates.

Shouldn't effect engine at idle anyways. Wtf.

What is port for, that is next to the vacuum advance on the carb? it pushes air.
I have it capped.

Installed tachometer, "idles" at 900.

Turning idle mix screw does NOTHING.
Indicates I still have a leak?
Used carb cleaner method, intake manifold gasket suspect, but did not respond to dubious amounts of cleaner.


#1550756 1979 Datsun 620 Motorhome, upgrade & restore.

Posted by Deleteme on 10 March 2018 - 09:07 PM

Thanks man, I'll check on the electricals.
I think I could hear the sound of high voltage crackling when I took it for a spin.
But might've been loose stuff.

Do you guys replace the stock coil?


#1550735 1979 Datsun 620 Motorhome, upgrade & restore.

Posted by Deleteme on 10 March 2018 - 06:22 PM

Did the vacuum lines this way. Seems correct. Works fine.

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Still stumbles when a press the gas at a particular point, same issue as before I replaced the carb.

Thinking...timing.


#1550160 1979 Datsun 620 Motorhome, upgrade & restore.

Posted by Deleteme on 07 March 2018 - 07:26 PM

Success!

Turns out the rebuilt carburetor had a spring installed backwards, causing it to be in the way of the fast idle cam, so the cam would never step down.

Armed with a thermostat and it's housing gasket, coolent and hoses - plus a new 12 mm wrench - Should fix up fine.

Now for this wrench fabrication...

throttle getting stuck? Binding somewhere? Good idea to get a tach..really cheap.

Fast idle cam getting stuck against spring.


#1550044 1979 Datsun 620 Motorhome, upgrade & restore.

Posted by Deleteme on 07 March 2018 - 10:49 AM

Previously turned out fast idle screw, fast idling cam is on first cam step.

Looking at repair Manuel on AutoZone.
Eric the car guy might be helpful too.
I'll update on my endeavors...


#1550025 1979 Datsun 620 Motorhome, upgrade & restore.

Posted by Deleteme on 07 March 2018 - 10:01 AM

Well I did adjust that screw and mirrored the other carb. It stopped screaming.

It is still going too fast, setting the idle doesn't even come into play yet.
I can't figure out how to slow it down.

It's not getting any throttle, so wtf.
Fast idle...too fast.


#1549870 1979 Datsun 620 Motorhome, upgrade & restore.

Posted by Deleteme on 06 March 2018 - 02:40 PM

Thanks Mike, I'll go grab those in a bit.
Solved carb problem again.
I was wrong about the spring.

Turns out the bottom butterfly that's actuated by the throttle cable...well the adjusting screw is set too high.

The top choke mechanism...I don't understand. It's got a dial for lean and rich, and it is what makes the choke spring into place.
However...turned to the left it is springy, turned to the right and the choke flaps in the wind.
The original carb is set to the right and operates fine, springy. I don't understand.

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#1549850 1979 Datsun 620 Motorhome, upgrade & restore.

Posted by Deleteme on 06 March 2018 - 12:38 PM

Ok, found the problem: return spring for butterfly valve incorrectly installed. Appears to need more loops of spring, too loose and unsprung.


#1549838 1979 Datsun 620 Motorhome, upgrade & restore.

Posted by Deleteme on 06 March 2018 - 11:17 AM

I could not identify the leak after it hit the fan. Gonna go look again today.
It was I assume pure antifreeze, I added water when I saw it was low, perhaps the lower boiling point of water caused high steam pressure.

Where is the thermostat coolent opener thanglejag valve? the piece on the engine connected to the top radiator hose?

When I removed the fuel rail to get at the left carb bolt I learned the bolt holding the rail also bolts down a coolent senseing/distribution area.

Idle is not ok, I need to understand the choke mechanism, the one top butterfly, it opens too much when I start the pickup.

The butterfly goes from closed to open a few degrees, but it's enough to make it scream.


#1549719 1979 Datsun 620 Motorhome, upgrade & restore.

Posted by Deleteme on 05 March 2018 - 04:50 PM

Ya it turned out to be a fragment of throttle cable less than it needed, like a milimeter and also I was turning the air/fuel mixture screw and not the idle screw! And the choke mechanism doesn't hold it's place very well.
Had to hold the choke and push the throttle down after turning the idle screw out to the max.

But now I have sprung a leak. Bottom radiator hose was ice cold...top hose was hot. Overflow hose to resevoir was cold aswell.

The original carburetor is much more solid and less finicky. The choke mechanism on this new one is shit.


#1549695 1979 Datsun 620 Motorhome, upgrade & restore.

Posted by Deleteme on 05 March 2018 - 01:10 PM

Ok, wasn't the idle screw, now I need help.

Engine starts up and goes full throttle, what's the likely cause?
Air filter is off, did it with it on.
No missing vacuum's.
Gas below dot in fuel window.
WTF?


#1549675 1979 Datsun 620 Motorhome, upgrade & restore.

Posted by Deleteme on 05 March 2018 - 09:43 AM

Oh you know what... I'm probably gonna want to set the idle to a particular rpm.

I don't have a tachometer, any advice?
Smooth and not shaking the bolts out Perhaps.


#1549667 1979 Datsun 620 Motorhome, upgrade & restore.

Posted by Deleteme on 05 March 2018 - 09:06 AM

Hey...that's a pretty good idea!