78 620, L20B foreign matter in combustion chamber.

[flatcat19]

I always use the round side up. Even on the engines I build at work.

[Crashtd420]

I should of noticed this earlier but while I was cleaning the head studs I discovered this guy, I’m leaning towards not reusing this, any suggestion on replacing?

APR studs are about $130, just seeing

Good that you caught that....

 

If you decide on arp studs they list them under nissan l20b.. not datsun....

 

 

If you get in a jam and cant get replacement bolts locally, I should have a complete set of used head studs in my garage.... I'll send them to you for the cost of shipping ... I used arp studs on my engine so there really is no reason for me to keep them... I'm going to work on my datsun soon this morning send me a pm if interested and I'll get them out clean them off and send you some pics....

[datzenmike]

It's reusable as the good threads are the bottom ones that were in the block. After all it was holding that way for years. Looks like corrosion. No harm in replacing them though.

 

The machine process for punching washers makes them that shape. Flat side down, you can see the machining imprint from the head transferred to the bottom of the washer.

[Stoffregen Motorsports]

I would get a used set of 280zx head bolts, or any other late model L series. Look for an indented ring around the hex. Those are among the strongest OEM head bolts and will do the job. I find ARP head studs to be an unnecessary hassle.

[distributorguy]

ARPs are a pain.  If necessary they are great, but 99.99% of Datsun engines don't need them.  Studs are a necessity with aluminum blocks so you don't pull threads up in the block while trying to tighten them.  In iron blocks, the stresses aren't as punishing on the block threads.  

[Atikin9000]

Well got my gasket set, opened it up and the head gasket was bent.

 

 

 

Should I get a new set or is this going to be ok?

[datzenmike]

You're good. The front only seals in fumes and some small oil spray. It's not even kinked.

[Atikin9000]

You're good. The front only seals in fumes and some small oil spray. It's not even kinked.

Thanks Mike.

 

 

Regardless, ordered this form rock auto, can’t really be mad at them for shipping process but the box had no sort of protection.

[wayno]

As long as the holes in the front line up with the holes in the timing cover you should be good.

When I make a head gasket for my LZ23 engines I cut that part off the L block head gasket and put it on the L block timing cover, I then ad a little gasket maker where the two gaskets touch each other on both sides.

[distributorguy]

That's not bent.  Its fine.  They're good until they're so kinked that they can't be bent back into the correct orientation.  Besides, the twisted part is just for the timing cover not the compression rings.  

[Atikin9000]

I picked up a couple of new studs locally, thanks to every one that offered to help. Hopefully it will be running soon.

[Atikin9000]

There’s a v6 4x4 hardbody local to me with one of these in it. Are they adaptable to the 620?

 

 

 

 

Got one of these for free too, wondering if any one has wired one in before.

 

 

[datzenmike]

Looks like an H 233 lsd. In the WD21 they only came in 4.375 and 4.625. Look on the pass side inner fender below the hood hinge for the engine tag. Bottom line far right HF37 for a 3.70 or HF39 for a 3.90 ratio... maybe even HF43 or HF46

 

 

I have one from a WD21 Pathfinder and it's way too wide.

[Atikin9000]

 

Does the distributor timing look good?

 

I saw in another thread on here that it should be about 4 o’clock.

[racerx]

Is rotor pointing at #1 cylinder at tdc?

[datzenmike]

Well the vacuum advance does look like it's turned awkwardly into the valve cover..... but at the end of the day all you want is the timing to be easily adjustable to 12 degrees. Position of the distributor, rotor or the wires are really secondary.

 

If you want to check what it was set to at the factory and maybe adjust it so yours is the same generally as everyone else you can...

 

Set the crank to TDC on the compression stroke... looks like already there.

Remove the two 10mm? bolts holding the distributor base to the timing cover. Don't worry the timing is set and the distributor will only fit in the one position.

With the distributor out look down the hole and you should see this...

 

 

Note the large and small half moon on either side of that 'screw driver blade' on the oil pump/distributor drive spindle. If the drive spindle is oriented like this you are good to go. 

 

If it isn't at that 11:28 position moving it there might move the vacuum advance to a slightly better position but that's about all it will do. It will run exactly the same.

 

 

Let's check this first, and go from there.

 

 

 

.

[Atikin9000]

Well the vacuum advance does look like it's turned awkwardly into the valve cover..... but at the end of the day all you want is the timing to be easily adjustable to 12 degrees. Position of the distributor, rotor or the wires are really secondary.

 

If you want to check what it was set to at the factory and maybe adjust it so yours is the same generally as everyone else you can...

 

Set the crank to TDC on the compression stroke... looks like already there.

Remove the two 10mm? bolts holding the distributor base to the timing cover. Don't worry the timing is set and the distributor will only fit in the one position.

With the distributor out look down the hole and you should see this...

 

 

Note the large and small half moon on either side of that 'screw driver blade' on the oil pump/distributor drive spindle. If the drive spindle is oriented like this you are good to go.

 

If it isn't at that 11:28 position moving it there might move the vacuum advance to a slightly better position but that's about all it will do. It will run exactly the same.

 

 

Let's check this first, and go from there.

 

 

 

.

 

I’ll pop it off and check.

 

 

Is rotor pointing at #1 cylinder at tdc?

 

According to the book it’s pointing to #2

[Atikin9000]

 

Also set the head today.

[datzenmike]

I’ll pop it off and check.

 

 

 

 

According to the book it’s pointing to #2

 

As long as the #1 plug is there and the others following, it will be fine. I mean it must have run like this...

[racerx]

I’ll pop it off and check. ...put the dist. Cap w wires on the distribuutor then lift it up and see where the rotor is pointing towards.

 

 

 

 

According to the book it’s pointing to #2

[racerx]

U don't need the book, put the dist back w wires and lift it up, then see where the rotor is pointing.

[wayno]

It doesn't matter where the rotor is pointed as long as it is pointing directly at a plug wire post on the cap and you have some adjustment room to time it, that post will be number one spark plug wire, and the firing order is 1, 3, 4, 2 counter clockwise.

Normally #1 is at 3:30ish standing on the drivers side looking at the distributor rotor, yours appears to be close to that, it has to point directly at a post on the cap and still have enough adjustment to time the engine properly.

 

The engine has to be at TDC, if it is not at TDC you are just guessing and that will catch up with you sooner or later. likely sooner.

[racerx]

If things are not lined up, won't his timing mark on the pulley be off?

[datzenmike]

Was this engine running? If all you've done is set to TDC and removed the head it will still run when done.

[Atikin9000]

Was this engine running? If all you've done is set to TDC and removed the head it will still run when done.

It was running and just like you said I just pulled the head off.

 

Also the pulley mark is at 0