Just bought a 1971 521 for 5 large ($500)

[Elkie]

Valve lapping compund, don't skip it. Which valve is it, not sure I ever saw that. Depending which one it is, with the engine at tdc  #1 the valve may be compressed and difficult to remove w/o pulling the cam. The cam gear is keyed to the cam, with three possible configurations. Check the timing marks on it before you pull it apart to make sure it is still within spec, otherwise it would be a good time to adjust for slack in the timing chain.

[pwrcat4000]

#3 intake

 

[pwrcat4000]

For my own reference

Clean the threaded holes in the block. Clean the bolts and lightly oil the threads, put a drop of oil under the top of the bolt head against the washer. Clean the block and head surfaces as clean as you can. Be careful with the soft aluminum head. Use a dry gasket, DO NOT use any coatings or sealer on it. Torque down in this sequence:

 

FRONT

ENGINE

 

7...8

3...4

1...2

5...6

9..10

 

Engine (L-series)

lb f ft

Camshaft locate plates bolts

4.3 - 6.5

 

Camshaft sprocket bolt

87 - 116

 

Carburetor nuts

4 - 7

 

 

Cylinder head bolts

 

First turn

29

 

Second turn

43

 

 

Third turn (late - L16 1973 on, L18, L20b)*

47 - 62

 

 

1975-80 L20b

61

[pwrcat4000]

Good news bad news

Thanks to all your help I changed the #3 intake valve. All the valves were working perfectly even the one I thought was bent. I looked at all of them and the seats while I had the head off. they were carboned up especially #3 where I had the dead plug, but the #3 intake valve moved freely (Weird)

I went ahead and replaced #3 because I could see where it hit the top of the piston Put it all back exactly like it was. I had a rubber coolant hose tear and squirting on the front of the motor and replaced it immediately and topped off the coolant. The tool worked great and it is timed exactly and (I mean exactly)

like it was when I took it apart. That is were the Good news stops.

 

Got it running it runs exactly the same... horrible. So I replaced all the plugs with NKG's.

No effect

Checked all the plug wires for spark with the truck running they all spark.

But the truck still idles like crap. sounds like it has an exhaust leak but I cant find a leak. I plan to look at the down pipe see if it needs Whatever... dough-nut?

It shudders in first unless I have the RPM up.

Just like it did before.

I turned the dizzy all the way CLOCKWISE and it runs slightly smoother.

The vacuum advance is now hitting the thermostat housing I can not turn it CLOCKWISE any more.

 

I am unsure what else to do pretty irritated tonight here at midnight.

 

I plan to recheck all the rocker arm gaps tomorrow... it is getting cold here in Kansas and my 8 1/2 year old has had enough of working on cars today)

I cannot see any timing marks on the crank only 2 pulleys and the indicator, don't know what to do about that.

 

Cap?

Rotor?

Plug Wires?

Replace vacuum advance pod?

Timing Chain?

It has 104,000 on it but the chain does not have bright links so I am assuming it is not the original?

Could it have slipped a tooth? it seemed to be a little loose

 

(but I really don't have any reference except a GM V8)

 

Like I said if I crank the dizzy all the way CLOCKWISE it gets slightly smoother.

[wayno]

You need to go back to the basics, put the engine at TDC.

Pull the valve cover and look at the cam lobes, number one cylinder cam lobes should look like the photo below, they should be at 10am and 2pm

I don't have a photo, but where ever your rotor is pointed will be #1, the L16 would be at 10am, while the L20b would be at 4pm standing on the drivers side of the truck looking at the side of the engine, if it doesn't point at a distributor cap wire, then you need to turn it till it does, if you cannot get it to point at a wire, then it is off and needs to be adjusted.

Once all this is confirmed good, and it still doesn't run right, then it is something else that is wrong.

TDC, 10am/2pm, rotor points to a wire post which is number one plug wire.

[pwrcat4000]

Wayno,

I will pull the Valve cover tomorrow and the dist cap and take a look!

[banzai510(hainz)]

Hopefully that ink pen mark isn't anything!!!!!!!!!!

 

go back to my vid and rewatch it. To me you put the oil spindal in off a tooth

 

Did you time it with a light? that's would spot it instantly!!!!!!!!!!!!!!

 

if the cam timming marks are fine then recheck the dist  where its pointing to at TDC Zero

[pwrcat4000]

Would not start tis AM so I adjusted the distributor back to the middle mark and put it on the battery charger got it started on choke took it up to temp then I checked all the rocker gaps at temp then I had to re adjust the #3 intake valve, it was way tight. <-- might have been some of the problem especially it was letting gas by
This afternoon I started it up and sea-foamed the truck. and it smoked like a mofo hoping it it cleaning any carbon deposits I missed. Anyway it is running really good now aside from the exhaust leak at the down pipe idles is still a little rough but the power is back so I am going to wait and see, for now. oh and i am getting a new air filter mine is definitely done.

 

banzai510(hainz)

First of all thanks for the video(s) that was super helpful.

The pen marks I assumed those were just where the oil has stained the sprocket but you are probably right.  I am going to put a timing light on it tomorrow (If I can find it) and see if it is hitting the mark, I am thinking it may just need some tweaking but if that does not do the trick or the timing is way off then I will pull the cover again and get some more pictures at TDC see if any thing moved.

[banzai510(hainz)]

I don't know whay you guys to the hard stuff 1st.

Timming light will ck if dist is lined up . cause you said you cranked the dist to get it to run. So if you remove the screw and turn it more it will be better if you can see it with a timming light.

 

seafoam and all others is a waist of time execp the valve lash.

 

If you watch my vid then you know what a L16 crank timming marks are

 

cam timming the before and after I cant tell what changed as I don't see really the first photo marks but looks close enough to run .  the 2nd photo looks right on. So to me its a distributor issue as long as the valve lash is ok .  I will assume the sparkplugs ect.. is fine

[pwrcat4000]

banzai510(hainz)
Thanks for your help and as before the great video. I am old and had trouble finding the mark in the day light  it was WAY retarded I have it advanced a little right now I think 2 marks but I can't remember. 

 

I had the truck running smoothly and aside form the exhaust leak (fixing Monday) running perfectly started turning the idle back down since I had it up to keep it running at stop lights and what not adjusted went fro a dive and everything went great until (don't worry happy ending) the damn thing started flooding pulled the glass and checked the float seemed fine put it back together (removed the Red RTV that some one had put on it) but the bowl was still overflowing pulled the needle and seat found a real nice piece of black fuel line. 3 feet of fuel line later all fixed up.

 

Now the only problems I have left are the E brake and the key switch has started acting up.
 

[Charlie69]

Congrats! Enjoy!

[pwrcat4000]

ignition switch fixed thanks to Datzunmike's post

http://community.ratsun.net/topic/64931-1973-datsun-620-push-start-button-schematic-help/?p=1183306

Instated a momentary switch on the dash next to the key.

Also replaced my 4" door speakers so I can "JAM OUT" LOL

 

[pwrcat4000]

Are these worth the money has anyone tried them they look like they would work but I am not sure.  I may try some barnyard engineering before I drop $70.  Unless some one on here can give me a positive report on these!

 

http://www.ebay.com/itm/Datsun-520-521-N-S-Truck-set-rear-parking-hand-brake-cable-kit-/361168839626?hash=item54175723ca:g:E-UAAOSw~uhUotyC&vxp=mtr#vi-ilComp

 

[4perrev]

Looks like she's coming along nicely. Not sure bout the cables. Mines still busted and I use a block as an e-brake!!

[pwrcat4000]

Well I don't know if it was a sense of adventure (or maybe it was the Bourbon) but I bought the cables late last night.

I will report back as to how they work out when I get them via canoe from Asia. 

[bilzbobaggins]

Well I don't know if it was a sense of adventure (or maybe it was the Bourbon) but I bought the cables late last night.

I will report back as to how they work out when I get them via canoe from Asia. 

 

Alcohol and ordering car parts is fun.  Thats how I got five speedometer cables.  At least they are all made in Japan.   :rofl:

[4perrev]

Alcohol and ordering car parts is fun.  Thats how I got five speedometer cables.  At least they are all made in Japan.   :rofl:

You know you've really gone wrong when the parts you're ordering show up at somebody else's house. Then their truck runs and looks better than yours!!!

[pwrcat4000]

Well the GD MF CS F exhaust manifold is still leaking underside of the center ports. I took it and had it trued up at the machine shop put it back together with new gasket and it is a little better but still leaks on the underside of the center ports I tightened from the inside out and the Bottom up although those bolts are a mother to get to even with a wiggle joint. So tonight I bought some high-heat sealant ( I used to use this on my headers back in 85 man) I don't know if it will do the trick or not but I am going to apply it tomorrow, hopefully, and then it takes 12 - 24 to cure. Maybe I should use my L16 manifold or just buy some headers if they even make them for this motor but I am not made of money even if I was I would be just pennies and nickels.

Thoughts?

[4perrev]

Did you get those nuts tight? It's a little weird to get in there, but can be done with some crafty universal joints. Just don't go to tight or you'll hate yourself for days and beyond, I promise you that! Is the pipe below the header putting torque on the header? Did you remove the pipe from the header before bolting the header to the head? If not, remove the pipe and install the header, then try and straighten the rest on the pipe to minimize the torque when connecting to the header. If none of that works, they do have headers around. Craigslist, eBay or members may have them. Troy Ermish has them, but pricey if you want to venture there.

[pwrcat4000]

4perrev

I tightened everything prior to connecting the down pipe the nuts are really tight I even loosened the top bolt and tightened the 2 lower bolts they are really tight. So tight I worry about pulling the studs out of the head. Did not have time to use the sealant today maybe tomorrow. I have my L16 manifold but it did not have the heat shield on it so i used the L20B manifold from what I have read the L16 flows better plus no smog stuff to plug other than the manifold leak it is running great I am even considering ordering the wing window gaskets because i can actually begin to hear wind noise when I am off throttle.

[4perrev]

Stupid questions maybe. Square head ports to square header? If the header was milled flat, it should fit without leaks.

[pwrcat4000]

4perrev,

I don't know I will look at it when I take it back apart I think it is a u53? head It all seems to be the the factory 620 stuff??? the other ports don't leak.

[4perrev]

Crack in the header, perhaps? When it's cold, you could use a spray bottle with soapy water to spray around the header to see where it's actually coming from. Only do it when it's cold, otherwise it will just evaporate as soon as it touches the hot a$$ exhaust. That is, if you don't know where she's leaking?

[pwrcat4000]

Good tip,

When I first start it I can actually feel the exhaust gas coming out from the Centerport on the underside of the exhaust manifold little puffs of air I can also hear it it might be difficult for me to spray soapy water since I'm working against gravity there I think I just need to pull it maybe get it planed I still haven't had time to try the red heat sealant it's such a pain in the butt to take all that crap off and then have it not work like last time besides my hands are still healing

[4perrev]

That's the beauty of Datsuns.........They are never complete.....Always making them better!!