Smog questions

[BeachKidd]

I'm going to be putting a new weber carb on my 78' 620 with an L20b. I am looking into eliminating the smog while I'm in there. What parts stay and which ones go? Does the egr get eliminated as well? I'm just kind of confused and need some guidance. Thanks!

[laotsu]

if you have a square port head it's best to get an L16 intake and early non smog exhaust manifold. pull the smog pump and the evap stuff. the worst is the mated L20b square port head exhaust/intake manifold.

[datzenmike]

Only the '75-'77 U67 square port head had the mated intake and exhaust manifolds. BeacKidd has a '78 which is a W58 rould port head.

 

Beach Kidd you really should finish filling out your profile and include the year of your truck.

 

 

As to the emissions equipment it's easier to disable them than to remove them. Removal can lead to vacuum leaks and broken bolts and for what? it won't run any better.

[Stoffregen Motorsports]

Some engines actually benefit from an operational EGR. Is this the case with W58? I don't know.

[datzenmike]

Well you can replace the '78 intake with an earlier L16/18 intake that does not have the EGR plumping on it but does retain the PCV fitting. Never delete the PCV. The problem with the earlier L16/18 intake is that it's smaller that the one you have so the dilemma is do you want to go for looks or proper air flow an a larger engine? The alternative is unbolting the EGR manifold from the intake and covering it with a fabricated plate... but now the PCV has also been deleted. You could drill and tap it to accept the PCV valve. Most cover plates look hokey and home made, and a source for vacuum leaks. Pick one way or the other and the thermal vacuum valve TVV can also be removed from the thermostat housing and done away with... but you will need a metric pipe plug to fill the hole. Last will be removing the SS pipe connecting the EGR manifold to the exhaust manifold and another metric pipe plug to block off the exhaust leak..... All this bother worth it for looks?

 

Now the air pump and belt can be removed, with it's hoses and air filter. The metal pipe plumbing into the exhaust manifold can also be unbolted and the holes sealed with metric pipe plugs.

 

Anti backfire valve and hoses are next. Seal the vacuum line. Backfiring and exhaust rumble on deceleration is now normal.

 

Charcoal canister and hoses from the fuel tank and the vacuum purge signal hoses must be sealed to prevent smell or vacuum  leaks.

 

The air filter housing already does not fit the weber and this is where the sensor for the air mix valve was on the snorkel. This mixes warmed air from the exhaust manifold and prevents carb icing, but it's a small price to pay for a neater engine compartment.

 

 

All this is ill advised as the engine is designed to run properly with everything. It will not run better without it. Many people believe the emissions system is robbing you of some hidden power but really it has almost no effect. Some things actually improve mileage. For others it's just fear of the unknown so get rid of it.

[BeachKidd]

Thank you mike!

[datzenmike]

Now start rippin".

[Stoffregen Motorsports]

You don't have to remove the air injection rail from the exhaust manifold, you can just cut the tubes off close to the manifold and then plug weld the tube stubs in the manifold. For the t-stat housing, it's easier to tap the hole to NPT and have a large variety of plugs available to you, some from the hardware store. I doubt you local Home Depot will have a BSPT plug.

 

The A46 manifolds work better than the large-port, late-model smog intake manifolds. You need to consider the valve size and the cam. They are not big enough to warrant a large port intake.

 

I like an OEM look in my engine bay so I will cut the bottom out of a stock air cleaner housing and fab a plate to fit the Weber and weld it in. Gives it that sleeper look.

[datzenmike]

I believe the only British pipe thread left on the L20B is the oil sender. I bought metric pipe thread plugs for the air injection tubes.

 

[laotsu]

That thread on  the fuckin oil sender is a bitch

[datzenmike]

1/4 BSP

[Stoffregen Motorsports]

You can tap that to 1/8 NPT real easy. Just coat a tap with grease and tap it. The grease will catch all the chips.

 

BSP is a non-tapered thread. BSPT is tapered, hence the T.

[laotsu]

You can tap that to 1/8 NPT real easy. Just coat a tap with grease and tap it. The grease will catch all the chips.

 

BSP is a non-tapered thread. BSPT is tapered, hence the T.

I shoulda done that 

 

see I have a Oil filter adapter from a 280Zx on my LZ2.05 and it interferes with the oil sender in it's natural position. So I ordered a BSPT 45° fitting, which would have worked perfectly. But the adapter threads are fatter in taper than the block. So the oil filter sticks straight up now and is fun to make a mess with during an oil change. I just punch a hole in the end and let it drain before removal.

[Stoffregen Motorsports]

Bummer. I can't understand why they position the filter in that way.

[laotsu]

Bummer. I can't understand why they position the filter in that way.

280Zx has two extra cylinders so the block is longer 

[Stoffregen Motorsports]

Right. I was speaking in larger terms. Why would any manufacturer position the oil filter that way?

[laotsu]

no, they have it down and to teh back, I had to turn it pointing up to avoid the oil sender the 45 was to allow the adapter to sit in it's natural position

[Stoffregen Motorsports]

Oh, I completely misunderstood. Sorry.

[datzenmike]

I shoulda done that 

 

see I have a Oil filter adapter from a 280Zx on my LZ2.05 and it interferes with the oil sender in it's natural position. So I ordered a BSPT 45° fitting, which would have worked perfectly. But the adapter threads are fatter in taper than the block. So the oil filter sticks straight up now and is fun to make a mess with during an oil change. I just punch a hole in the end and let it drain before removal.

 

This oil filter adapter... is it for the oil cooler option? Can you not clock it to another position?

 

[laotsu]

only two of the positions allow the oil filter to point down, the one you have it in in the picture conflicts with the alternator, the other position causes the return line lug to be very close to the oil sender. there's enough room to put a 45 in and it would all work. I spent $50 in shipping and parts getting 1/4" BSPT. None of them worked, they hold the sender unit just fine but wont thread into the block because their threads are too broad for the hole

[Stoffregen Motorsports]

Major threadjack...sorry.

 

You do have a couple more options to get it to fit.

You could go buy the BSPT die and run it down on the adapter to shrink the threads.

 

You could get a BSPT tap and run it into the block a bit.

 

You could use a 1/8 NPT to -3 (or -4) AN nipple, a stainless hose, then a union mounted on the fender well where you mount the sender. This option I use a lot. It gets the sender out of the way, it takes the weight off the adapter (I have seen adapter fittings snap from the weight of the sender mixed with the vibrations of the engine). Another reason this last option is cool is that you could mount a tee or a distribution block on the fender well and attach the sender plus a small gauge (so you can read oil PSI in the engine bay), a low oil pressure switch, a hose for a mechanical gauge, etc. Lots of options with the tee setup.

 

This is a Toyota V6 on which I relocated the sender unit .

 

This is a good illustration of what NOT to do.

[datzenmike]

Here's a better look...

 

 

There is only one small bolt and therefore it can't possibly be there to clamp the adapter down. It's purpose is just to align the adapter so it misses the engine mount or the alternator. Actually you can forgo the mounting bolt and use the main through bolt that has the inlet fitting to clamp everything down. Just position the filter where ever you want.

 

If really worried about the adapter moving you could notch the adapter where you want it and slip a bolt into one of the spare holes to hold it.

[laotsu]

yeah so in that pic you see there's no room for the wire to the sender, that was the issue with that position. as I have it now the small bolt isn't used but the oil filter doesn't have any room to point down because of motor mounts and stuff. 

[laotsu]

I've never found an adapter that fit the block. He got his smog answers so we're just using this thread to exercise the oil cooler adapter demons.

[datzenmike]

You're bailing?

 

That thread on the fuckin oil sender is a bitch

 

This is a Z22 block. Only the very late '70s had the smaller oil filter boss with the 4 bolt holes in them. Luckily the zx L28 block was the same as the Z22.