620 round port which header

[cruznude]

So,I'm ready to install motor but before I do I'm looking to get a header on there.  Now I have a round port w58 and I really don't want to change out heads and start getting all technical with the motor.  It runs well and have re-done everything from transmission to waterpump.  Now, I've installed a 32/36 Weber and am looking for the header.  Theres shorty headers but there only made for square port and then theres the other type or standard ones which are round. Which one would be best for my purpose and does the jet coating keep the engine compartment cooler?  Does anyone know of a shorty for a round port?

                                                  Thanks

[metalmonkey47]

You don't need a header for that motor. You'll end up loosing more then you gain. 

 

You can find an early L series exhaust manifold that's perfectly matched for the motor. 

[datzenmike]

First... headers are a waste of time unless going full race cam and multiple carbs. Otherwise you are paying $50 per HP (probably closer to $100) gained and that does not include the bullshit trouble to put them on and make them fit, the heat, the noise, the gasket leaks, the bolts coming loose.... and no one can see you have one anyway.  Six months later it will be all rusty and you'll  wish you hadn't thrown the old manifold away.

 

If you just have to have some kind of 'performance exhaust' consider the earlier 4 into 2  L16 exhaust manifold and a custom 2 into 1 down pipe...

 

Other than weight how is a header any better? That L16 manifold is over 40 years old, where will that header be in 5?

 

People throw them away cheap. Spend the money saved on an electronic distributor, and NO not one of those red MSG things. The '79-'80 matchbox distributor and matching coil, from an L20B is most desirable

 

Now as to the round vs. square ports. A round port W-58 head can be used on a square port exhaust manifold. It's not perfect but it will work. However a square port on a round exhaust should be avoided.

[Z-train]

I have two manifolds for sale in the classifieds.

[KlassicMotion]

What engine do you have?  Do you have an L16 with a W58 head, or an L20B with a W58 head? (I only ask, because after 30-40 years, you never know, you can only make assumptions)

 

I have an L20B with a Top-End Performance header.  It is designed for the square port head, and welded together pretty poorly.  I had to grind down all of the flange welds, open the ports back up, and in some areas, re-weld them, where they didn't get enough penetration.  I also had to have the flange surfaced to get it to sit flush against the head.

 

For the L20B, My opinion is that header works well with 2" pipe going all the way back to the muffler, and 1.75 tip off the muffler.

 

As a rule of thumb, the 4-1 headers are better for high-end hp.  A Y configuration like 4 into 2 into 1, which is what most of the early manifolds are, are best for low-end torque.  Most 4 cyl. lack low end torque.  There are multiple designs of the manifold Mike pictured.  The main thing to look for is the manifold that retains 2 independent chambers as it enters the lower flange.  An easy way to tell;  while looking in the bottom flange, if you stick your fingers in the two ports, you should not be able to touch them together.

 

Another thing to consider is the size of your pipe.  L20Bs like 2" pipe from the manifold back.  I wouldn't put any bigger than 1.75" on an L16.

 

Stick with the manifold you have.  Spend your money elsewhere.  Cast iron manifolds have advantages of being reliable.  Headers tend to break or leak....

[KlassicMotion]

Regardless of what you decide to run, with that w58 head, use Felpro MS 22801 intake/exhaust gasket (for '77-'80 Nissan L20B).  I've tried all the others, this one works the best for header or stock manifold.  Aside from a Nissan gasket of course...

[cruznude]

Y*es I have the L20b with the w58 and at first I looking at keeping the exaust manifold just the way it was but after stripping off all the smog etc, I had to disconnect those 4 tubes that go into it by the carb, plus disconnect the egr valve so I have issues with plugging up all these holes first.  I was thinking also about having my friend sandblast it and then I'd paint it with high temp paint.  I bought the dizzy from a 79 on ebay this week and know just to figure out what I want to do with the exhaust before I install motor.

[KlassicMotion]

So if you've got an L20B, then you have this manifold, I presume:

 

 

 

If you have a welder, weld them up.  If you don't (I didn't at the time, but I had an Oxy/Acetylene torch), I just cut my tubes about a 1/2 from the mani, and melted the tubes back into the plug.  I also used the scrap tubes from the rail system as my filler rod.  I did the same on the inside to limit turbulence:

 

[KlassicMotion]

Oh, yeah, don't get rid of any of the heat shielding!!  Leave the one on the intake and exhaust if it's not already gone...  If your looking for performance, keep your intake as cool as possible.

[datzenmike]

Regardless of what you decide to run, with that w58 head, use Felpro MS 22801 intake/exhaust gasket (for '77-'80 Nissan L20B).  I've tried all the others, this one works the best for header or stock manifold.  Aside from a Nissan gasket of course...

 

I'll assume this generic gasket has the coolant holes for the intake as they are necessary on all '78 and up L20Bs. On the '77 head the holes would be on the gasket but simply not used by the intake/head.

 

 

Oh, yeah, don't get rid of any of the heat shielding!! Leave the one on the intake and exhaust if it's not already gone... If your looking for performance, keep your intake as cool as possible.

Well it might provide some shielding but it's really to provide warm air to the snorkel on the air filter.

 

 

Y*es I have the L20b with the w58 and at first I looking at keeping the exaust manifold just the way it was but after stripping off all the smog etc, I had to disconnect those 4 tubes that go into it by the carb, plus disconnect the egr valve so I have issues with plugging up all these holes first. I was thinking also about having my friend sandblast it and then I'd paint it with high temp paint. I bought the dizzy from a 79 on ebay this week and know just to figure out what I want to do with the exhaust before I install motor.

 

Some thoughts on smog systems.

 

.

EGR uses inert exhaust gasses. In other words little to no oxygen content and it just takes up space in the combustion chamber. When mixed with the incoming fuel and air it dilutes it and reduces power and peak cylinder temps and pressures where most oxides of nitrogen are produced. It's not much and you probably won't even notice it. To make up the loss the throttle is simply opened very slightly further. EGR is not enabled on a motor that is still warming up, it is not on when idling and it is not on at wide open throttle so the excuse for removing it 'because it robs power' is laughable.

 

 

 

If you have a properly functioning PCV system then a catch can is no more needed that a rear spoiler. It's totally a 'race car' item to catch fluids from a possible blown motor and keep off the track. The PCV simply draws air in the valve cover to displace warm vapors from the crank case and routs them back into the motor to be burned. Under certain throttle conditions the flow can reverse and this is why the valve cover vent hose goes back to the inside of the air filter and any vapors are sucked into the carb directly. Running the valve cover hose to a catch can does a disservice to everyone as the fumes are vented into the atmosphere. Any oil or water collected has to be disposed of... usually thrown away. Again... where does it go? Better to leave the PCV system as it is. It's a remarkable and elegant way to reduce hydrocarbon emissions and extend engine life while being totally benign in operation.

Other than looks it's a waste of time removing the EGR and the problems introduced like leaks and making a hokey block off plate. If you do DO NOT get rid of the PCV valve.

[cruznude]

yes,I was loking at doing something like that on the manifold I have also Klassic and it looks like yours came out pretty good also.  Datzenmike, I understand all the PCV and EGR values but amongest putting on my weber,  it won't allow me to install the EGR back on as this round metal thing hits it.  I've made a real good block plate thats perfect fitting but should I do like others and install the PCV off the intake at the block off plate or can I install it in the plug on manifold?  Thanks guys for all the good info.

[datzenmike]

It will work anywhere but central would be best so all cylinders 'get some'.

[KlassicMotion]

I'll assume this generic gasket has the coolant holes for the intake as they are necessary on all '78 and up L20Bs. On the '77 head the holes would be on the gasket but simply not used by the intake/head.

 

 

 

Well it might provide some shielding but it's really to provide warm air to the snorkel on the air filter.

 

 

The gasket is the proper gasket for the late L20B. (the years I quoted were straight from the package.. I did fudge it though, it did specify a difference between 77 truck and car, one of them it did not list.  I was unaware of the difference.)

 

The main shielding I was referring to is the one that bolts to the bottom of the intake.  The one on the exhaust doesn't hurt either...

 

This pic was taken from my thread ( http://community.ratsun.net/topic/56764-i-love-my-weber-38-dges-heres-my-38-dges-install/ )

 

In it you can see what I did to block off the EGR system, and the heat shield I'm referring too.  Also, I deleted the EGR system because my header didn't allow for it. That thread also shows how I routed my PCV system.

 

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[datzenmike]

Good stuff.

 

I don't care if 'smog stuff' is deleted as long as it's done right. Too many times it's done for the wrong reason and simply fucked up by some inept person. Removal requires that it be done correctly or you end up with problems.

[cruznude]

Yes I've seen your thread and was surprised to see where you put the pcv and it seems to work well for you.  I'll look at your thread again.  Thanks

[cruznude]

Good stuff.

 

I don't care if 'smog stuff' is deleted as long as it's done right. Too many times it's done for the wrong reason and simply fucked up by some inept person. Removal requires that it be done correctly or you end up with problems.

 

Okay DM, I get that things shouldn't just be done and especially half assed.  If you were in my shoes and you wanted to remove the smog and just have a clean motor.  Where would you have started?  Where would you locate the PCV?  I'd like to show you a pic but I've always had trouble posting pics as I'm not too good at this.  What did you mean by central would be better?

[KlassicMotion]

Yes I've seen your thread and was surprised to see where you put the pcv and it seems to work well for you.  I'll look at your thread again.  Thanks

 

There was a hole there that needed to be plugged, so it seemed the easiest and most logical....  I didn't just drill the hole bigger, I drilled a bit lower, so the top of the hole that was already there, stayed in the same location.

[datzenmike]

 

This is good, and centered so all cylinders can pull from it.

[metalmonkey47]

Just FYI, Nissan (Nismo) makes a header gasket for L4's. 

[cruznude]

If deciding to go with a header, whats L 4? And do buy this at your local Nissan dealer?

[datzenmike]

L 4 = L series 4 cylinder.

 

If deciding to go with a header, whats L 4? And do buy this at your local Nissan dealer?

Well, don't throw the stock manifold away. You'll want it to put back on in a month. BTW don't mistake more noise for power gained from this.

[KlassicMotion]

If you do buy a header, and you do buy a header style gasket, versus the Nismo one or the one I recommemded;  I can't remember which one I tried, but one of these (I think the green one) was utter junk, and I had to just throw it away.  Although, as poorly put together the Top End header is, I wouldn't trust to buy the Top End gasket either.  Proceed with caution if you go this route.

 

http://www.ebay.com/itm/Datsun-510-521-610-620-L20B-L18-L16-Intake-Exhaust-Manifold-Header-Gasket-NEW-/400552400916?pt=Motors_Car_Truck_Parts_Accessories&hash=item5d42c89814&vxp=mtr

 

http://www.ebay.com/itm/Datsun-510-Exhaust-Header-GASKET-For-L16-L18-L20-510-and-Pickup-/310398259034?pt=Motors_Car_Truck_Parts_Accessories&hash=item48452d8f5a&vxp=mtr

[cruznude]

Was going to do the header thing and after all the input just decided to sandblast the stock exhaust manifold and paint it hi temp black.  The install went real well and Thanks to DM for all the good info (once again).  Klassic I took your advise and found some plugs that fit the manifold where you welded yours up and got that problem all solved.  Installed motor and and block off plate. Damm it looks so good. I might have to get the 14 year old next store to come over and do this photobucket thing for me.lol.  I can never do that damm thing.

[KlassicMotion]

:thumbup: