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L20b emissions delete


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Hey guys, I'm working on a 76 620. I have a Webber showing up tomorrow but I want to delete all the emissions crap while I'm in there. Couldn't find a good breakdown with the search on how, so figured I'd ask someone to point me to a couple good threads to read since I'm sure it's been posted a million times somewhere. 

 

Thanks in advance. 

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Just know in advance that a poorly deleted emissions system can cause more problems than it's worth.  If you are expecting it to run better or make more power you're wasting your time. The emissions systems on old Datsuns have no effect at full throttle.

 

You can get rid of the EGR that is piggybacked onto the intake by removing it and making a cover or block off plate. These tend to look pretty hokey and unless you tap it you loose your PCV valve which is important for keeping your engine oil clean and prevent smells escaping into the cabin.  With a little work and some JB weld you can grind away on the intake and turn this...

 

CFOY8X4.jpg

 

into this...

 

wPXiRYX.jpg

 

Looks just like the earlier L16 intake but has the larger L20B runners and no EGR. Kept the PCV valve too.

 

 

The EGR signal from the carburetor passes through a thermal vacuum valve TVV on the thermostat housing. Remove and replace with a pipe plug.

 

 fkfCFt9.jpg

 

The air pump can be removed and all the hoses and pipes. The metal pipes in the exhaust manifold can be unscrewed and removed and the holes plugged with these for a clean look...

 

xVkEyEu.jpg

 

Unless going to all this trouble it will look worse than just leaving it alone. No-one can see what you've done anyway.

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That's exactly what I need to know, what to keep and what to plug up! I'm more concerned with a clean engine that's easier to work on. Everything is so corroded that it will be easier to remove it than replace it at this point. Thanks Mike! You're a life saver buddy. I'll be posting updates on Instagram at @contained_chaoschaos180

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So, I got the webber in today and deleted a bunch of clutter. She idles way better now but I'm getting a grinding noise from the front of the motor. I have a water pump on the way and I'll check the chain tensioner also. I'm going to look for a place to host photos so I can post pics of what I have done so far. 

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After a free temporary plugs here and there, she idles great!

e7J4ebz.jpg

 

 

TQaAula.jpg

 

 

Had to shave a little off the adapter plate and gasket. 

ewimsEP.jpgokagUJw.jpg

 

 

Here's the before pic. 

xe2Kk9Q.jpg

 

Now that it's all been test fitted and it works, I'll be disconnecting and pulling the engine to do gaskets and investigate the engine deeper. Also want to do cleanup and paint. 

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Plugs are metric thread. I just pulled them from another newer KA24E intake. The exhaust plugs I took one of the pipes with me to a fastener store and matched it to the one shown.

 

I see someone has already deleted the EGR but the bolt on manifold is still there. When removing it try hard to keep the PCV valve and the block vent connected.

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On 6/6/2019 at 5:35 AM, datzenmike said:

Plugs are metric thread. I just pulled them from another newer KA24E intake. The exhaust plugs I took one of the pipes with me to a fastener store and matched it to the one shown.

 

I see someone has already deleted the EGR but the bolt on manifold is still there. When removing it try hard to keep the PCV valve and the block vent connected.

Thanks Mike. The carb came with the block off plate so I removed what I could of the system and plugged anything I thought looked like it would cause a vacuum leak. Some plugs are temporary just so I could get it to idle and check some other things. More permanent solution coming soon and I plan to delete that rail on the manifold also. 

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2 hours ago, Eric said:

All L20B's have the emissions stuf on it? Or can i just buy a non emissions stuff L20B manifold and install that? Will clean up the engine bay a lot.

 

Pierce manifold sells a new intake, their website says it's for an L20b....

https://www.piercemanifolds.com/product_p/99002.825.htm

 

Not sure of its non emissions or not.... I would email them or call or maybe there are some other pics of that manifold on line.....

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On 6/5/2019 at 6:05 AM, datzenmike said:

Just know in advance that a poorly deleted emissions system can cause more problems than it's worth.  If you are expecting it to run better or make more power you're wasting your time. The emissions systems on old Datsuns have no effect at full throttle.

 

You can get rid of the EGR that is piggybacked onto the intake by removing it and making a cover or block off plate. These tend to look pretty hokey and unless you tap it you loose your PCV valve which is important for keeping your engine oil clean and prevent smells escaping into the cabin.  With a little work and some JB weld you can grind away on the intake and turn this...

 

CFOY8X4.jpg

 

into this...

 

wPXiRYX.jpg

 

Looks just like the earlier L16 intake but has the larger L20B runners and no EGR. Kept the PCV valve too.

 

 

 

Do what I did, above. $7 for some JB weld and I think I bought a tap for the PCV valve, probably $10. The rest was just hand grinding away the aluminum with a carbide burr. Couple of hours and it looks exactly like an earlier L16 intake but has the larger L20B ports.

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19 hours ago, Eric said:

pretty expensive manifolds, i'll go find something used first 🙂

 

$267 is expensive for a brand new intake manifold?

 

Considering a DGV adapter is $30-$40, you deduct that from the too expensive part. How much would you pay fore a nice manifold that meets all your criteria?

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2 hours ago, Stoffregen Motorsports said:

$267 is expensive for a brand new intake manifold?

 

Considering a DGV adapter is $30-$40, you deduct that from the too expensive part. How much would you pay fore a nice manifold that meets all your criteria?

Well this is ratsun......

 

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2 hours ago, Stoffregen Motorsports said:

$267 is expensive for a brand new intake manifold?

 

Considering a DGV adapter is $30-$40, you deduct that from the too expensive part. How much would you pay fore a nice manifold that meets all your criteria?

 

Its not expensive for brand new manifold but thats not what i am looking for. I don't mind getting a used one for less money if it does the same thing

 

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  • 3 weeks later...
On 6/19/2019 at 6:52 PM, datzenmike said:

 

 

Do what I did, above. $7 for some JB weld and I think I bought a tap for the PCV valve, probably $10. The rest was just hand grinding away the aluminum with a carbide burr. Couple of hours and it looks exactly like an earlier L16 intake but has the larger L20B ports.

Datzenmike, I plan on doing exactly this to my intake manifold.  I am using the Weber carb.  Do I plumb in a vacuum line attachment as well as a PCV valve?  

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6 hours ago, Utahskier said:

Datzenmike, I plan on doing exactly this to my intake manifold.  I am using the Weber carb.  Do I plumb in a vacuum line attachment as well as a PCV valve?  

 

At the time I did need a vacuum source for the ATC (auto temp control) on the air filter housing snorkel and for the purge for the charcoal canister. Why not have one and if not used just seal it for now? 

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  • 1 year later...
On 6/6/2019 at 5:35 AM, datzenmike said:

Plugs are metric thread. I just pulled them from another newer KA24E intake. The exhaust plugs I took one of the pipes with me to a fastener store and matched it to the one shown.

 

I see someone has already deleted the EGR but the bolt on manifold is still there. When removing it try hard to keep the PCV valve and the block vent connected.

So other than the pressure valve.The other hose intlet has to come over also?? Does it matter where I stick the pcv like where the old egr port is instead of drilling out the nasty little port it was in?

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