"Orange Crush" 78 620

[RedStar620]

I recently bought a 1978 620 at a local junkyard. It had been sitting since 1988 and hadn't been fired up since then. Some parts were missing, like the radiator, fan, fan clutch and water pump. The paint is all original with some surface rust and it does have some small rot holes, one in the hood, another in the cab roof and a third in the tailgate. This truck has the automatic transmission and not to mention factory A/C!  I have no idea how many 620s had the AT with factory A/C. The center console is missing as well, but the A/C controls are still there. Does the 620 have a center console just for the A/C version, or they all the same? I just got it running a few weeks ago and it runs good. The fuel tank has a hole in it and I'm working on that.

[datzenmike]

Get a picture hosting account (free if no frills) and save any pictures you plan to send here. Copy the picture info and bring here and past it in your post.

 

Automatics were not that popular in trucks or small cars until millennials came along. The good thing about the Datsun automatics is that they are so boring to drive that you soon stop abusing them and just drive them. They last forever and are survivors!   

 

The AC is probably dealer installed, lots were. The first factory AC option in the 620 was '79. A '79 with AC has a compressor bolted to the side of the head where the fuel pump would be and instead uses an electric pump mounted on the right frame just forward of the rear wheel just like the 720s. I don't believe there is a special AC console.

[Rat-a-tat-Dat]

On my 720 (1980), the center console panel has the upper lever sliding to the far left to initiate a/c. Of course, move the bottom (lower control) lever to the left as well for the cooler air, lol.

[RedStar620]

15 hours ago, datzenmike said:

Get a picture hosting account (free if no frills) and save any pictures you plan to send here. Copy the picture info and bring here and past it in your post.

 

Automatics were not that popular in trucks or small cars until millennials came along. The good thing about the Datsun automatics is that they are so boring to drive that you soon stop abusing them and just drive them. They last forever and are survivors!   

 

The AC is probably dealer installed, lots were. The first factory AC option in the 620 was '79. A '79 with AC has a compressor bolted to the side of the head where the fuel pump would be and instead uses an electric pump mounted on the right frame just forward of the rear wheel just like the 720s. I don't believe there is a special AC console.

 

I checked the data plate in the driver's side door jamb and the build date is stated as June 1978 (although it has "9/78") stamped above it; would that mean that the truck is a '79?

[datzenmike]

Probably had some June data plates left over, I would go by the stamp.

 

 

The '79 model year began July '78 with car number 37,500.....

 

A '78 will have a 'remote igniter' distributor that looks like this under the cap...

 

 

The '79 uses a Matchbox' model like this...

[RedStar620]

The distributor is the 1978 style with the remote ignitor, so was it possibly swapped out? The last six digits of the VIN are 365427, so would it make this truck a 1979?

[demo243]

More photos! 

 

Got an orange '78 620 myself. Following this one.

[RedStar620]

The A/C system is clearly a factory install with the electric fuel pump and a York type A/C compressor mounted on the RH side of the engine. Yet the truck is a '78!

[Jersey]

Mike, my ‘75 service bulletin is showing that 1974 was the last of the dealer installed A/C units in the 620. 1975 and on they were all installed at the factory before shipment of the vehicle. As per the bulletin, this was done to eliminate the possibility of deterioration in emission control performance, due to an incorrect mounting of the A/C in the field.

[RedStar620]

On 1/3/2020 at 11:07 AM, Jersey said:

Mike, my ‘75 service bulletin is showing that 1974 was the last of the dealer installed A/C units in the 620. 1975 and on they were all installed at the factory before shipment of the vehicle. As per the bulletin, this was done to eliminate the possibility of deterioration in emission control performance, due to an incorrect mounting of the A/C in the field.

I have a second 1978 620 and it has the dealer add-on A/C that mounts under the dash, similar to the early factory set-up. The compressor was mounted on the LH side and was not a York type. There are no vents in the center of the dash, just the two side vents and the vents below the dash. Is it possible that dealer A/C continued past 1975?

[RedStar620]

I know it's been a while, but here's an update.

 

The other 620 (the blue and grey one, named "Ol' Reliable") blew a head gasket after it got too hot (thermostat housing gasket was leaking). I sent the head out for resurfacing and had it checked for cracks, and what do you know, it was cracked at the number two cylinder. So that 620 is now being used as a parts truck for the orange 620. The fuel tank has been fixed and no longer leaks. After sitting for a while, the engine would not run (it did run before). After fixing a sticking valve and swapping the carburetor (it's a 32/36, basically a Weber knockoff) from the other truck ), it fired up and runs great. 

[banzai510(hainz)]

7 hours ago, RedStar620 said:

it fired up and runs great. 

Fucking GREAT!!!!!!!!!!!!!!

[RedStar620]

We're not done yet. I'm getting the seat bolted in. I found out that the consoles are the same, A/C or non A/C. There is a panel (the one that has a slot in it) that pops out and the A/C controls mount to the back in that space as there are four screw towers. Trying to get this done before tomorrow when rain comes!

[RedStar620]

Bad news: the rear main seal was leaking so severely that the engine ran out of oil and locked up. Going to swap over the rebuilt engine from the other truck. Before the engine locked up, it had this strange problem. If I gave it too much throttle, the truck started bucking back and forth, but if I let off the throttle, the bucking went away and the engine ran fine. What would cause this?

[datzenmike]

 

 

On 1/3/2020 at 9:07 AM, Jersey said:

Mike, my ‘75 service bulletin is showing that 1974 was the last of the dealer installed A/C units in the 620. 1975 and on they were all installed at the factory before shipment of the vehicle. As per the bulletin, this was done to eliminate the possibility of deterioration in emission control performance, due to an incorrect mounting of the A/C in the field.

 

Perhaps this was the plan in '75. My info shows factory optional air conditioner available '77 and on with the York compressor. 

 

 

 

On 9/8/2021 at 10:12 AM, RedStar620 said:

 

 

The other 620 (the blue and grey one, named "Ol' Reliable") blew a head gasket after it got too hot (thermostat housing gasket was leaking). 

 

This is why there is a temperature gauge in the dash. The steam and noise should have told you too stop. Radiator should be checked weekly. Wet spot under the truck should be checked out.

.

 

1 hour ago, RedStar620 said:

Bad news: the rear main seal was leaking so severely that the engine ran out of oil and locked up. 

 

This is why there is a low oil pressure light that comes on. Also it's up to the owner to check the oil weekly.

[RedStar620]

Correction: the engine did not lock up, but when I drained the oil, there was a silver and copper color to it. I think the crank bearings are shot from the lack of oil. Still planning to swap in the short block from the other truck, as it has been rebuilt. As for the rear main seal leak, I had been checking and adding oil, but the leak got worse and worse.

[RedStar620]

Got the engine out and tearing it down to get the cylinder head off. Carb is off and working on getting the intake and exhaust manifolds off.

[EDM620]

On 1/20/2022 at 2:00 PM, RedStar620 said:

If I gave it too much throttle, the truck started bucking back and forth, but if I let off the throttle, the bucking went away and the engine ran fine. What would cause this?

Check your mounts incl trans for excessive movement. Under heavy throttle the engine might be tipping back and binding up the driveshaft u-joints or carrier bearing.

[RedStar620]

Got the head off and stripped down and cleaned up so it can be sent off to the machine shop. The head gasket was not blown and the camshaft and rockers looked really good with no wear on either despite the low oil condition. The thermo-reactor ports in the head (it's a W58 head) were intact. I noticed quite a bit of orange sealant on the front cover gasket and intake manifold gasket sealing surfaces. Was this a factory job or was someone in there before? The head gasket said "NO RETORQUE" on it. Was this an original head gasket?

 

As for the mounts, I have brand-new motor mounts.

[RedStar620]

Sent the head off to the machine shop. I may rebuild the other engine's lower end with new rod and crank bearings and new rear main seal later on, as it's an otherwise good block. Now waiting on the head...

[RedStar620]

I looked at the engine block and I noticed an "M1" code on the side of the block behind the driver's side engine mount. Has anyone heard of an M1 L20B block?

[datzenmike]

I have a Z24 block .... M3

I have  a Z22 from a 720 block... nothing on it.

Have an L20B from a 620 don't know the year but had silver paint on it with nothing on either side, an L20B definitely from a '79 620 and says M2 and another L20B block but can't get to it.

 

This tells me that I have too much shit laying around.

 

The M1 sounds familiar. My 710 has an L20B I'll take a look tomorrow. It would be a '76. I think the M1 is a later casting.

[RedStar620]

Got the head back from the shop. The plan is this: drop the head on the other engine (in the blue truck), pull that engine out and drop it in the orange truck.

[carterb]

When do we get to see pictures of this awesome project?