Any tricks to pulling manifolds off l20b?

[villegs]

Putting smog free manifold and weber on the truck and i believe I've got all the bolts off but the little SOB will not budge. Are there hidden bolts that I am not seeing or should I break out the 5lb hammer? '77 620 btw..

[Guest DatsuNoob]

I pulled out the intake and exhaust manifold as one unit and junked em both as soon as I had the L16 intake and header. Probably easier to do it that way. I would refrain from any sluggo action just yet. Easiest to disconnect the exhaust collector at the downpipe and pull out the whole thing as one, atleast I thought so.

[datzenmike]

There are 4 bolts on the top, two on each runner. The bottom has our bolts that are shared with and clamp both the exhaust and the intake to the head. Hard to get at.

 

What motor is this?

[Guest DatsuNoob]

If you get all the bolts out the whole thing should just pop off, together since the intake and exhaust are pressed together. A good swivel joint and a couple short extensions make life so much easier for this. I assume from the title this is a smogged out L20b

[justin 620]

Best trick to taking them off is to make sure all the bolts are off, top 4 and bottom 4. Be sure to drain you water first.

[650savag]

buy a 12mm swivel socket. I tried to use a regular 12 mm socket with a swivel joint adapter and it would not reach the bottom, center bolts. I had to wind up going to sears and buying the 12 mm swivel socket. I think I had to bend or remove the heat shield under the carb. When you get all 8 bolts out, the intake/exhaust assy. will come off easy.

[deadmonkey]

After doing this a few times I think I have come up with an ok way of doing this

1) drain the fluid below the level of the intake and then a little more

2) take off air cleaner, carb and all emissions stuff and first two bolts of the fuel/vacuum rail

3) disconnect the 3 exhaust flang bolts and move the flange out of the way and make sure it comes loose. If it doesn't come loose it may be rusted on and will take some love to get it it to come off.

4) take off the collant hose if you haven't already (the small return line that goes from the intake, about 2nd cylinder,) and then take off that little threaded hose connector.

5) you should be able to get to all the bolts/nuts now. There are the "shared" bolts tht clamp down both the intake and the exhaust. You should be able to get to all of these with a 12mm and a wobble head and extension. Try both from below and from the top. It will fit, you justhave to get to it from the right angle. A couble of them you may not be able to get all the way out w/ the wobble head becasue it may bind... just use a wrench or finger to get the rest of the way.

 

Arrows pointing to "shared" bolts and the threaded hose connector

[mike]

If you get a 1/4 inch ratchet, extensions and 12mm swivel socket it makes it a lot easier too. The 3/8 stuff will get in the way. Except for head bolts and flywheel bolts, 1/4 inch is about all I use on datsun engines. It makes it easier to keep from overtorquing stuff, I can keep a smaller lighter tool kit with me and they are cheaper too :cool:

[mike]

...Oh yeah, if youve still got that heat shield on your manifold... good luck. I ended up drilling holes in mine and ripping it out of the way with a pair of pliers to get the intake/exh manifold off because the bolts were so rusty.

[villegs]

Finally got the carb off (do not remember it being that difficult on my 210) and found this.

Probably be why power seemed lacking and it ran a bit rich, that flash around the port is solid varnish and covered a good %50 percent of the opening eew.

[justin 620]

Holy crap, that's a lot of gunk!

[Guest DatsuNoob]

:sick: :poop: so you get the manifolds off then?

[JCR]

so being new to this

if you remove the L20 intake and replace it with a L16 no smog intake

then you need a header ??or can you reuse the stock L20 exhaust?

[ariascarlos1990]

so being new to this

if you remove the L20 intake and replace it with a L16 no smog intake

then you need a header ??or can you reuse the stock L20 exhaust?

 

depends if your manifolds are mated or not.

[datsunaholic]

If it's a '77 and stock, they are mated.

[Guest DatsuNoob]

Chances are if you have a smogged L20b you will most likely need to junk both the exh and int manifold. Like Carlos said, they're most likely pressed together. It looks like they are anyway. You could also find an L16 exh manifold since they're cast, and much thicker than any header tubing. I hear they handle heat a bit better, but either would work. I bought a long tube header for mine a long time ago, and hardly any noticeable difference in performance IMO. More of a pain in the ass trying to fit it up than it was worth really. The radiator had to be pulled, the motor mounts too, had to slide the motor forward off the yoke of the driveline a bit just so it would drop down in place, and when it did, it would tap the tortion bar at rough/cold idle or upon shutoff. Irritating. Finally got under there with some heat tape and wrapped the bar so it wouldnt ring anymore :lol: If you do find a header, I suggest a short tube with the removable downpipe for ease of installation.

[JCR]

thanks guys

it is stock so i think it is mated together

i'll look at it to be sure tomarrow

thanks again