Emiko, my new 520 work truck

[datzenmike]

Why are you removing the head????? Thought you were just changing the valve guide seals???

[hucklefish]

1 hour ago, datzenmike said:

Why are you removing the head????? Thought you were just changing the valve guide seals???

Because I thought I was halfway there with 6 out of 11 head nuts loosened, and it would be good to know the condition of the cylinders and have a new head gasket. Now I'm not so sure. A local mechanic who has a 510 recommended I just retorque the head nuts and proceed with only replacing the valve seals after all. Since I haven't managed to actually loosen the head yet, even though all 11 head nuts are off, he thinks it'll probably be fine, and I should quit digging the hole deeper. If I keep going I'll probably end up thinking I might as well rebuild the engine, and since I don't have a proper shop for that, I think he's right.

I'm having fun - just wish I'd done it in high school when I only thought I didn't have enough time.

[datzenmike]

I have learned the hard way not to fix what isn't broken. It runs, leave it alone.

[Stoffregen Motorsports]

20 hours ago, hucklefish said:

It tees into the dipstick tube. Maybe a return line once connected to the PCV tube?

Actually, I believe that's a crankcase vent.

[Stoffregen Motorsports]

It's probably stuck around the studs. Spray some penetrating oil or WD40 around the studs and let it soak in. Or try removing the studs. But...if you break one, you's heading way down the rabbit hole.

 

If you have access to a blasting cabinet, take a few minutes, while the head is off, to decarbonize the combustion chambers and ports. Also, wire wheel the deposits off the valves. Give the head and block surfaces a good block sanding with WD40 before you reinstall the head. You will probably want to chase the stud holes too. Notice if any of them are "wet" holes and use sealant on them if they are.

[hucklefish]

On 6/28/2023 at 10:23 AM, Stoffregen Motorsports said:

Actually, I believe that's a crankcase vent.

So should the upper end of it be connected to whatever's connected to the elbow on top of the valve cover? Isn't that supposed to be connected to the air cleaner housing? So maybe I need a short bent hose between the air cleaner and the valve cover, with a tee in the middle of it to connect the hose from the dipstick tube?

In the parts manual, it looks like the J13 only had a single bent hose from the valve cover to the air cleaner. I've looked at every engine block in the online parts manuals, and I don't see that dipstick breather tube on any of them, or anything like it connecting anywhere up higher. Maybe it was from a later engine? Or maybe I have a newer J13 made for the Japanese or Mexican market after 1968? Or a forklift motor?

 

This evening the neighbor stopped by and talked for a bit, not high this time, I think. He says crankcase ventilation needs to be correct because of how it affects "blowby," which is important for valve lubrication. I think that sounds right, and I assume it's important for cylinder wall lubrication also, right?

 

Neighbor also told me last time that the vacuum valve (my guess) below is some kind of emissions control thing, but this time he says, "that's your fast idle." I wonder if he means it's a valve to pull the throttle off the fast idle cam.

The yellow arrows are vacuum ports, and the other two arrows are bullet electrical connectors (blue is female, red is male). None of these were connected to anything when I bought it.

 

[bananahamuck]

On 6/27/2023 at 4:58 PM, hucklefish said:

Head is good and stuck. I've squirted lots of penetrant down alongside the headstuds, tapped with a hammer on bosses and protrusions on the sides of the head , tried a pry bar wherever there's a bit of head casting overlapping something below, tried driving a cold chisel in at the joint in a couple spots... I'm headed to the hardware store to get some new poly rope to stuff in the cylinder and see if pushing up on it with a piston will move the head.

Anybody have any other advice?

 

Will do, thanks. I've been laying bolts and nuts in order as I take them off, but I think it's time to get a piece of cardboard and start labeling it.

 

 

put nuts back on a head studs few turns , put spark plugs in ,, take push rods out .. spin engine over, compression should pop it up 

Edited July 7, 2023 by bananahamuck

[Stoffregen Motorsports]

9 hours ago, hucklefish said:

So should the upper end of it be connected to whatever's connected to the elbow on top of the valve cover? Isn't that supposed to be connected to the air cleaner housing? So maybe I need a short bent hose between the air cleaner and the valve cover, with a tee in the middle of it to connect the hose from the dipstick tube?

In the parts manual, it looks like the J13 only had a single bent hose from the valve cover to the air cleaner. I've looked at every engine block in the online parts manuals, and I don't see that dipstick breather tube on any of them, or anything like it connecting anywhere up higher. Maybe it was from a later engine? Or maybe I have a newer J13 made for the Japanese or Mexican market after 1968? Or a forklift motor?

 

This evening the neighbor stopped by and talked for a bit, not high this time, I think. He says crankcase ventilation needs to be correct because of how it affects "blowby," which is important for valve lubrication. I think that sounds right, and I assume it's important for cylinder wall lubrication also, right?

 

Neighbor also told me last time that the vacuum valve (my guess) below is some kind of emissions control thing, but this time he says, "that's your fast idle." I wonder if he means it's a valve to pull the throttle off the fast idle cam.

The yellow arrows are vacuum ports, and the other two arrows are bullet electrical connectors (blue is female, red is male). None of these were connected to anything when I bought it.

 

 

I was thinking the same thing. Maybe that dipstick tube is from an A15 or as you say, a later year. It could tee into the valve cover breather hose if you want to hook it up.

 

Crankcase breathing does have an affect on oil consumption and leaks. You could rig up a PCV system and connect it to the valve cover breather. There needs to be another breather port lower in the block (or timing cover) to complete the circuit. The dipstick vent could suffice.

 

Fast idle solenoids did not come into play until the late '60s. The valve you have there looks like an idle up solenoid on a Chevy truck, so maybe that's what your neighbor is referring to.

[hucklefish]

3 hours ago, Stoffregen Motorsports said:

 

Fast idle solenoids did not come into play until the late '60s.

Did you mean '80s? This is a '68 truck.

I didn't see anything like it on the other model parts list diagrams when I was looking for the dipstick breather tube last night, but I wasn't specifically looking for it. I see it also looks like some vacuum operated EGR valve solenoids, so maybe that's why he first thought it was emission control. It's not an idle stop solenoid - that could only be operated by ignition cutoff, not vacuum, right?

[Stoffregen Motorsports]

Idle air control valves on fuel injected engines work by creating a vacuum leak. This looks like an IAC, but it can't be. A carburetor would not allow for the extra air by adding more fuel, and I've not seen that before.

 

The early idle up solenoids, either vacuum or electric, worked by pushing the throttle linkage.

[hucklefish]

Is there anything else this could be besides the rear crankshaft pilot bushing? And if the answer is no, how critical is it to the operation of my truck? Dumb question I suppose, but I only discovered it on the shop floor this morning, and I've driven it about 70 miles since removing and replacing the transmission, which I think is the only time it could have come out.

 

[Crashtd420]

Looks like the pilot bushing to me....

 

I think its important but I'm sure smarter people will confirm....

I believe it supports the center shaft of the transmission... 

[datzenmike]

Supports and aligns the clutch disk to the center line of the crank shaft. They are cintered powdered bronze porous and soft. They are pressed into the crankshaft and don't normally fall out, in fact you have to split them lengthwise and pull them out. 

 

If not forced into alignment the disc can be off center and vibrate when driving. Clutch may chatter when engaging. They are quite universal and the J13 is the same as the L16 and even used in the '95 300zx turbo Z32. 32202-30000 like $5.

 

I would check and if the old one is still there might as well change it. There are several ways to remove, most are very messy and like the Gordian knot. Cut to the chase....  slit with screwdriver and fish out the pieces. Tap new one into place with hammer and block of wood. Remember they are soft and permanently lubricated so NO GREASE or oil!. If missing, the transmission mainshaft may, or will eventually, have lightly damaged the crankshaft hole. Should be a snug fit. 

 

 

 

[KELMO]

I just did this removal that DM has pictured above, only not quite as cleanly. There are tools out there to help with driving the bushing in. Just be careful not to pound the bushing in too far.

Another method is to fill the hole with axle grease and use the driver tool to push it out with a couple smacks on the driver with a hammer. This has worked well for me in the past but that was on "A" motors. For the "L" motor, I had to split the bushing.

Edited July 11, 2023 by KELMO

[Stoffregen Motorsports]

14 hours ago, hucklefish said:

Is there anything else this could be besides the rear crankshaft pilot bushing? And if the answer is no, how critical is it to the operation of my truck? Dumb question I suppose, but I only discovered it on the shop floor this morning, and I've driven it about 70 miles since removing and replacing the transmission, which I think is the only time it could have come out.

 

You need that bushing. Bad things can happen without it.

[hucklefish]

2 hours ago, Stoffregen Motorsports said:

You need that bushing. Bad things can happen without it.

Well, ****. Now I have to remove the transmission again just to see if there's one in there.

I certainly didn't take it out, and it doesn't seem likely to just fall out on its own while removing the transmission. So I'm guessing this one I found on the floor is an old one that somehow got lodged and has been riding somewhere on the frame or edge of the engine block for the last several thousand miles. But then why would it be more likely to fall out when the previous owner worked on it than when I worked on it, and how else could it get to where I found it?

[Crashtd420]

Possibly got stuck on the transmission when removing....

Was it difficult to remove the transmission from the block?

[datzenmike]

All good questions but an abundance of caution is required here. Order a new one and it's either missing, or it's there and as you have a new one and it's apart replace it.

 

 

Grease is messy as hell, use bread. Best of all and doesn't need any special tool or tight fitting dowel is to split them with screwdriver.

[hucklefish]

Just now, Crashtd420 said:

Was it difficult to remove the transmission from the block?

Yes, but I have an answer I like better now. I think the J13 has a needle bearing for the crankshaft transmission pilot shaft, and this part I found is a starter pilot bushing.

 

Here's the starter pilot bushing in the parts diagram (https://www.carpartsmanual.com/datsun/pickup-1965-1972/electrical-1300-(j13)/starter-motor), and I see a bushing with the same dimensions and part number, that looks similar to mine on eBay (https://www.ebay.com/itm/293567243922).

Nissan 23319-10600 bushing on eBay:

 

Here's the crankshaft rear bushing/bearing in the parts diagram (https://www.carpartsmanual.com/datsun/pickup-1965-1972/engine-1300-(j13)/piston-crankshaft), and I see needle bearings with the same part number on eBay (https://www.ebay.com/itm/275330355542).

[hucklefish]

12 minutes ago, datzenmike said:

All good questions but an abundance of caution is required here. Order a new one and it's either missing, or it's there and as you have a new one and it's apart replace it.

Agreed, but I'd appreciate your opinion of my theory that it's the starter pilot bushing and the J13 has a needle bearing in the rear of the crankshaft. I don't know how or when the starter pilot bushing could have just fallen out either, but it seems more likely than the crankshaft rear bushing. I'll order both and have extra spares.

[Stoffregen Motorsports]

They don't always have a needle bearing for a pilot. Even if the book shows it, they are a standard part and could have been replaced with God knows what at any given time.

 

You're right, it does look like a starter bushing.

[hucklefish]

It was the starter bushing.

[Crashtd420]

12 hours ago, hucklefish said:

It was the starter bushing.

That much better then having to pull the transmission back out....

 

[datzenmike]

Learn something every day.

 

23319-10600 also used on all A series starters.

 

[hucklefish]

The bolt that goes up into the bottom of the carburetor between the barrels is just holding the top and bottom together, and not any kind of jet or other adjustment, right? I found it extremely loose when I was going to put the carb back on, and just tightened it. It's running fine now, and the parts diagram just calls that a bolt and washer - parts 22 and 24 here: https://www.carpartsmanual.com/datsun/pickup-1965-1972/engine-1300-(j13)/carburetor/exc-ltu-(from-may-68)

Thanks