New Guy Here! 73 Datsun 620

[Crashtd420]

12 hours ago, El Padrino said:

 

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

That may have been an incorrect statement.... 

If the clutch is stuck then the engine would be fine to spin but you wouldn't be able to shift.... 

I guess only if stuck in gear would the e brake matter.... 

 

[datzenmike]

Get the clutch working, you're going to need it eventually anyway. Bleed it at the slave and keep reservoir full.

[Stoffregen Motorsports]

Don't give up yet. It may still be doable without pulling the motor.

 

The big question here is why. Why does the engine not turn. We've all been assuming that it is stuck from the rings being rusted to the cylinder wall. Maybe it's time to have a look at the cylinders. Do you have access to a bore-scope? They are way more common than you might think. If you can find one, stuff the camera down each spark plug hole for a look-see. If no bore-scope is used, you can still see a lot with a flashlight and a good pair of eyes.

 

Next, if the bores look good, pull the oil pan. There may be signs of rust in the crankcase, or you may find a mechanical obstruction, like a rod cap that fell off. Or even something wedged in the timing gear on the crank. If everything looks good there, and you still haven't found the problem, time to move to the third option.

 

Cylinder head removal in the truck may reveal a lot. Now be careful here - assuming the bores are rusty from a blown gasket or cracked block, the head bolts may be rusted too. If you break one trying to remove the head, you've just entered a world of pain. If they break loose but are then sticky, squirt some WD40 down each head bolt shank, and hopefully it will reach the threads. If they don't break loose at all, you may need some heat or a big hammer, or both. nce you get the head off, you can now see into the cylinder to look for signs of a piston sticking to the bore. The tell signs are a sort of grey-black wiping pattern with a smearing of aluminum.

 

Once you can identify the problem, the solution may be self evident. In any case, you don't need to pull the motor yet. That is, unless you want to. I myself prefer to do this sort of work on an engine stand, but my shop is fully outfitted and it's easy for me to do. Leaving the engine in the truck may be the wiser choice for you at this point.

 

The bright side to having the head off is that, if the motor does need to come out, it's a lot easier to do with the head out of the way.

 

Oh, forgot to mention, leave the manifolds on the head and remove them as a unit with the head. If the manifold bolts break while trying to diagnose a stuck motor, you've just introduced another issue to be resolved.

 

 

[El Padrino]

On 12/2/2023 at 12:31 PM, Stoffregen Motorsports said:

Don't give up yet. It may still be doable without pulling the motor.

 

The big question here is why. Why does the engine not turn. We've all been assuming that it is stuck from the rings being rusted to the cylinder wall. Maybe it's time to have a look at the cylinders. Do you have access to a bore-scope? They are way more common than you might think. If you can find one, stuff the camera down each spark plug hole for a look-see. If no bore-scope is used, you can still see a lot with a flashlight and a good pair of eyes.

 

Next, if the bores look good, pull the oil pan. There may be signs of rust in the crankcase, or you may find a mechanical obstruction, like a rod cap that fell off. Or even something wedged in the timing gear on the crank. If everything looks good there, and you still haven't found the problem, time to move to the third option.

 

Cylinder head removal in the truck may reveal a lot. Now be careful here - assuming the bores are rusty from a blown gasket or cracked block, the head bolts may be rusted too. If you break one trying to remove the head, you've just entered a world of pain. If they break loose but are then sticky, squirt some WD40 down each head bolt shank, and hopefully it will reach the threads. If they don't break loose at all, you may need some heat or a big hammer, or both. nce you get the head off, you can now see into the cylinder to look for signs of a piston sticking to the bore. The tell signs are a sort of grey-black wiping pattern with a smearing of aluminum.

 

Once you can identify the problem, the solution may be self evident. In any case, you don't need to pull the motor yet. That is, unless you want to. I myself prefer to do this sort of work on an engine stand, but my shop is fully outfitted and it's easy for me to do. Leaving the engine in the truck may be the wiser choice for you at this point.

 

The bright side to having the head off is that, if the motor does need to come out, it's a lot easier to do with the head out of the way.

 

Oh, forgot to mention, leave the manifolds on the head and remove them as a unit with the head. If the manifold bolts break while trying to diagnose a stuck motor, you've just introduced another issue to be resolved.

 

 

Definitely not giving up on it. It’s important to me to keep the OG motor in the truck.

 

I do not have access to a bore scope. But I was looking at a couple on Amazon that hook to my iPhone.

 

I plan on letting the motor soak all this week and going to check it out again on Friday when I’m off. If no movement I plan on tearing in to the motor more. Taking the oil pan off like u suggested is a good starting point. I plan on getting the head off and seeing what else I can see if the oil pan reveals nothing.

 

i appreciate all ur info and tips. I’ll report back when I have an update!

[Ooph!]

11 hours ago, El Padrino said:

Definitely not giving up on it. It’s important to me to keep the OG motor in the truck.

 

I do not have access to a bore scope. But I was looking at a couple on Amazon that hook to my iPhone.

 

I plan on letting the motor soak all this week and going to check it out again on Friday when I’m off. If no movement I plan on tearing in to the motor more. Taking the oil pan off like u suggested is a good starting point. I plan on getting the head off and seeing what else I can see if the oil pan reveals nothing.

 

i appreciate all ur info and tips. I’ll report back when I have an update!

 

I have an older USB phone type bore scope camera I think cost $15 5 years ago.

The focal distance on mine is about 2.5 inches, takes a reasonable overall picture but difficult to line up in the cylinder to see a specific area because the cable isn't stiff and has no way to steer it other than twisting the cable . Certainly better than removing a head when you just need to see the overall condition.

 

[Stoffregen Motorsports]

8 hours ago, Ooph! said:

 

I have an older USB phone type bore scope camera I think cost $15 5 years ago.

The focal distance on mine is about 2.5 inches, takes a reasonable overall picture but difficult to line up in the cylinder to see a specific area because the cable isn't stiff and has no way to steer it other than twisting the cable . Certainly better than removing a head when you just need to see the overall condition.

 

You could always tape a piece of coat hanger or welding wire to it to stiffen it up. Put a bend in the end of the wire and twist to steer the camera.

[El Padrino]

Well I was able to get back out and check to see if the motor would finally spin. NOPE! I had a friend come over and we could not get it to spin.

 

I did order a bore scope and it’s on its way. I did take a long screwdriver and lightly scraped the cylinder walls and around the top of the piston and cyl 2 is pretty chunky. It seems as tho there’s a good bit of rust. Cyl 1 and 4 seem better and 3 was slightly better then 2.

 

Im gonna let it sit a little more and I’m ordering a flywheel wrench to see if I can get the motor to spin that way.

 

Guess we’ll see… 

[datzenmike]

Rusty cylinders. Even if you get it to spin what compression do you expect. I would just take the head off and check it. If the bores are pitted it will need over boring and over size pistons and rings and you have a new engine.

[El Padrino]

13 hours ago, datzenmike said:

Rusty cylinders. Even if you get it to spin what compression do you expect. I would just take the head off and check it. If the bores are pitted it will need over boring and over size pistons and rings and you have a new engine.

 

Yea idk… this will be the 1st time I’ve ever done or dealt with anything like this. Talking to another friend of mine he basically said the same thing. Compression is going to be garbage and the motor will need rebuilt.

 

So I guess my question to u all is where is the best place to order a rebuild kit?

 

I ran across California Datsun and they have a kit for around $800… 

[datzenmike]

You can source the parts yourself but it will take time.

 

Full gasket set. Should include valve seals

Over size pistons and rings

Main and rod bearings

Timing chain kit

 

Head may need rebuilding, valve job... $$$

 

Machine shop costs to over bore $$$

 

If you pay to have someone else assemble everything $$$$$$$$$$$ easy to get hosed on this.

 

 

Might be cheaper to find a good running used L series engine. L18 or even L20B if you have never done this before.

 

[Ooph!]

I've never been to your area but I'd bet there are still a few old fashioned machine shops somewhere near you.

Go see a couple and get an idea if they know what they are doing and honest and take it to them, they will also source the parts and get the proper ones so you don't waste money and time buying things beforehand that end up not needed. You might even be able to talk them into guiding you in the rebuild and assembly at their shop.

[Stoffregen Motorsports]

17 hours ago, datzenmike said:

Rusty cylinders. Even if you get it to spin what compression do you expect. I would just take the head off and check it. If the bores are pitted it will need over boring and over size pistons and rings and you have a new engine.

Yeah, I think it has come to this. A stuck motor, by all the engine building rules, needs to come apart to get at the very minimum, honed and new rings. I got lucky with my AMC 360 in my Cherokee last year. It was stuck, but very lightly and I was surprised to find that it runs great. I was not expecting that.

 

I've torn down motors that were stuck so bad that the pistons had to be beaten out of the cylinders with a sledge hammer. Hopefully this Datsun motor isn't that bad.

[datzenmike]

For all we know a rod has welded itself to the crank.

 

Pull the oil filter off and cut it open. If a bearing has spun, the oil will be glittery with metal particles. Save yourself the bother of a tear down.

[El Padrino]

Thanks for the replies!

I’ve got a guy who owns an engine shop that is willing to come to my garage to take a look at the motor. I explained everything to him so we shall see what happens next. However I’ll probably have to wait till after New Years with Christmas and stuff right around the corner.

 

Plenty of other stuff to do to the truck in the meantime. Floor boards need re done as well as the rockers.