New Guy Here! 73 Datsun 620

[El Padrino]

8 hours ago, vicdat said:

Nice find....the fuel lines and tank are likely super clogged and dirty after that long.

I suggest a bit of Marvel in the cylinders and use a small remote tank once you get it to hopefully turn over.....

Good Luck,

Vicdat 610

 

Yea i plan on running a fuel cell or getting a new tank. Marvel was put in the engine about 2 weeks ago. Hopefully that starts creeping in and things loosen up. I did not have my breaker bar or a socket big enough on me to really try and spin the motor. Im hoping to do that Wednesday some time.

 

Thanks

[datzenmike]

Try 'hitting' it with the starter a few bumps.

[El Padrino]

So things didn’t happen the way I planned yesterday. A 21mm is the biggest socket I had in my travel tool kit so I was unable to try and see if the motor would spin. So I need to get some other sockets and then go back tomorrow and see what happens.

[datzenmike]

I think a deep 27mm so it extends outside the pulley for the breaker bar. Try the starter first you may not need it.

[El Padrino]

3 hours ago, datzenmike said:

I think a deep 27mm so it extends outside the pulley for the breaker bar. Try the starter first you may not need it.

Ok… I will thanks for the advice. Hopefully I can get to it tomorrow.

[Stoffregen Motorsports]

1 1/16 works too.

[El Padrino]

Well I finally got a battery and tried to bump the starter and it did not turn the motor at all. The starter definitely tried tho. I also got the right socket and breaker bar. The motor did not budge but I got excited and heard a pop but it was just the bolt in the fly wheel getting tighter.

 

Ive never messed with anything else like this before so I don’t know what my next step should be.

[Stoffregen Motorsports]

Persistence. And lubrication. Dump some ATF or any liquid lube down the spark plug holes and let is sit for a day or more, then try again. If you can get it to move, then try rocking it back and forth, instead of just going all the way round.

 

If the bottom end is stuck, it's likely the top end will be either rusted, dry or both. Valves can rust and then stick and then hit the pistons when you turn the motor over, so remove the valve cover and douse the valvetrain with oil, then watch the valves move as you turn the motor.

[El Padrino]

4 hours ago, Stoffregen Motorsports said:

Persistence. And lubrication. Dump some ATF or any liquid lube down the spark plug holes and let is sit for a day or more, then try again. If you can get it to move, then try rocking it back and forth, instead of just going all the way round.

 

If the bottom end is stuck, it's likely the top end will be either rusted, dry or both. Valves can rust and then stick and then hit the pistons when you turn the motor over, so remove the valve cover and douse the valvetrain with oil, then watch the valves move as you turn the motor.

I did exactly that. I put PB Blaster in the spark plug holes. I can’t go back to the truck again until Friday at the earliest. So hopefully that stuff works its way down there. I finally got the valve cover off with the help of quite a few soft hits from my dead blow hammer. It’s not completely dry and that part looks good to me. But again this is the 1st time I’ve ever messed with a locked/froze motor. I wish I could get ahold of the person who the guy I got it from bought it off of to find out why they let the truck sit since 2008. 

Hopefully I can get the motor moving!

Thanks for the reply!

[datzenmike]

Well lets hope not but could be because he seized it up.

 

If you ever replace with a cork gasket rub engine oil on both sides first.

[El Padrino]

1 hour ago, datzenmike said:

Well lets hope not but could be because he seized it up.

 

If you ever replace with a cork gasket rub engine oil on both sides first.

Yea def if I get a cork gasket.

So would that motor be worth rebuilding or what would u all suggest for a motor??

[datzenmike]

The one year only '73 was an L16 and if it's buggered it will cost the same amount to rebuild the later and larger displacement L20B. Without any other changes it makes about 20 more HP. It is 3/4" taller but they were used in the later 620 so just use the L16 oil pan and engine brackets/mounts. The L16 flywheel won't fit it so if finding an L20B get a flywheel with it.

[El Padrino]

1 hour ago, datzenmike said:

The one year only '73 was an L16 and if it's buggered it will cost the same amount to rebuild the later and larger displacement L20B. Without any other changes it makes about 20 more HP. It is 3/4" taller but they were used in the later 620 so just use the L16 oil pan and engine brackets/mounts. The L16 flywheel won't fit it so if finding an L20B get a flywheel with it.

Right on… it was hard enough to find a 620 in my area. Prob gonna be super hard to find another engine. Hopefully this one is salvageable.

 

A friend of mine had a 620 back in 99-2000 and he said he put a NAPS motor in his. I guess they were in the 280z cars or something… guess I can do more research once I find out if the motor is bad.

 

Thanks again…

[KELMO]

9 hours ago, El Padrino said:

I guess they were in the 280z cars or something

No, that would be a straight 6 cylinder, NAPS Z motors were typically found in 720 trucks.

[datzenmike]

The EFI version NAPS Z20E and Z22E were in the '80-'83 S110 200sx and the CA20E/CA18ET in the later S12 were also called a NAPS engine. 

 

To install a Z series engine you would need the transmission also. I put a Z24 in my 620.

 

 

[Stoffregen Motorsports]

If the valve cover gasket didn't tear, I'd reuse it. The factory ones were best.

 

The bottom end could be frozen from liquid getting into the bores, or it could be seized from overheating. Or even worse, it could be seized from rod bearing damage.

 

A leaky head gasket can cause a piston to rust to the cylinder wall, well, the rings actually. If the rust isn't too deep, a simple ball hone can usually clean this up enough to run well again. If you have to beat the piston out of the bore with a hammer, you'll likely damage the piston, so let it soak and continue to spray it down and keep trying.

 

Overheating can cause the piston to smear into the steel of the bore. This can be repairable by simply honing the bore.

 

Broken or spun bearings so bad that the engine seizes... that's a lot of parts and labor to repair.

[El Padrino]

15 hours ago, datzenmike said:

The EFI version NAPS Z20E and Z22E were in the '80-'83 S110 200sx and the CA20E/CA18ET in the later S12 were also called a NAPS engine. 

 

To install a Z series engine you would need the transmission also. I put a Z24 in my 620.

 

 

Yea the Z24 engine is what I had in my 86 Hardbody.

[datzenmike]

Oh that's right the Z24i was in the '86.5- '89 D21 Hardbody and the '87-'89 WD21 Pathfinder.

[El Padrino]

11 hours ago, datzenmike said:

Oh that's right the Z24i was in the '86.5- '89 D21 Hardbody and the '87-'89 WD21 Pathfinder.

Yea mine was an 86.5! I tell people that and they look at me like I’m crazy.

[datzenmike]

Yeah the 720 ended some time in 11 '85 with car number 51,280. This would be 6 months into the '86 model year hence the half year moniker. 

 

The D21 started some time in 11 '85.

 

My information shows no 720 for '86 only the D21. The '86 720 information is lumped in with the '85 model year.

[El Padrino]

Well I went back over to the truck to see if I could spin the motor at all and NO DICE…

 

Before I left I put the breaker bar back on it and hooked a ratchet strap to it so that it would have constant pressure on it. 
 

Getting frustrated! I’d really like to keep the whole truck original as far as that goes.

[Crashtd420]

Thinking outside the box here....

 

Any chance the transmission is in gear? With the ebrake on. ....

Or possibly the clutch is stuck .....

 

Make sure sure your not in gear and try rolling the truck forward and back. ...

If it rolls free then it is the engine,  probably the rings.....

 

Worse case your pulling the engine for a rebuild.... even if you get it to spin and run its probably going to need a rebuild.

[El Padrino]

22 minutes ago, Crashtd420 said:

Thinking outside the box here....

 

Any chance the transmission is in gear? With the ebrake on. ....

Or possibly the clutch is stuck .....

 

Make sure sure your not in gear and try rolling the truck forward and back. ...

If it rolls free then it is the engine,  probably the rings.....

 

Worse case your pulling the engine for a rebuild.... even if you get it to spin and run its probably going to need a rebuild.

Appreciate ur input.

 

Yes the trans is in neutral. I also tried it with the trans in 2nd gear and rocked the truck back and forth pretty good trying to bump start the motor to spin.

 

You mentioned the e brake. Why would the e brake being pulled stop the motor from turning?

 

In neutral the truck has no issues rolling.

 

Thanks again

[datzenmike]

You could try having friends push the truck in the driveway while you have it in 4th with the clutch pedal down. Get up to speed and dump the clutch. Don't use lower gears or it will just drag the tires, might drag anyway.

[El Padrino]

8 hours ago, datzenmike said:

You could try having friends push the truck in the driveway while you have it in 4th with the clutch pedal down. Get up to speed and dump the clutch. Don't use lower gears or it will just drag the tires, might drag anyway.

The clutch doesn’t seem to engage or disengage. It goes straight to the floor with no pressure at all. My one friend suggested that as well.