Intake coolant lines, can they be deleted?

[Brandon H.]

I have a L20B im cleaning up, some fresh paint on the block, getting rid of useless stuff. I noticed with these motors, coolant runs through the intake, heard it improves gas mileage. I want this motor to be simple as possible. I want to ditch that crap, and tap and plug the intake. Is it needed? Will I run into problems with the exhaust being on the same side?

[datzenmike]

I have a L20B im cleaning up, some fresh paint on the block, getting rid of useless stuff. I noticed with these motors, coolant runs through the intake, heard it improves gas mileage. I want this motor to be simple as possible. I want to ditch that crap, and tap and plug the intake. Is it needed? Will I run into problems with the exhaust being on the same side?

 

You may think it's useless but Nissan spent a lot of money developing this system to improve drive ability in extremes of weather (hot to cold) and provide the best performance and economy. You want simple, do nothing with it, how simple is that? Not broken? don't fix it!

[Skib]

I delete them sometimes.

 

everything works fine if you just plug it all up and dont run it.

[Brandon H.]

You may think it's useless but Nissan spent a lot of money developing this system to improve drive ability in extremes of weather (hot to cold) and provide the best performance and economy. You want simple, do nothing with it, how simple is that? Not broken? don't fix it!

 

I want simple. Its a lifted truck with a solid axle swap, 4 speed tranny, divorced transfer case, fuel cell in the back. Wont drive it more then 25 miles on its longest drive. Mud toy.

 

I understand they did it for a reason, there are reasons for everything... even reasons to get rid of it. I have the engine bay stripped to nothing, motor out. I less hoses/lines/ect on this motor the better. Almost all the rubber hoses need replaced.

 

Will it kill performance or make it run like shit?

[Skib]

Will it kill performance or make it run like shit?

 

 

no its fine.

[datzenmike]

It will run without it but no advantage. The best reason is for an advantage, lacking that, why bother?

[Skib]

ya you dont gain anything by removing them but it will run just fine if you do, up to you

[HRH]

It's a definite plus if you're racing the shit out of the thing and you may need to quickly remove and reinstall manifolds/head, etc. I always use the U67 head for that reason. It's already deleted, they used a sandwich plate to warm the intake via the exhaust manifold. It's more efficient and better for operation to have it maintain temperature with the water temperature. If you're building a mud truck, I'd be tempted to leave that system intact when cold mud gets thrown on the manifold. Then again, I run mine in snow and it doesn't seem to mind cold snow/slush packing up. But it's also injected. Carbs are a little more annoyed by extremes.

[metalmonkey47]

I leave stuff like that alone. I figure, Nissan probably had a reason for putting it there, so theres no reason to remove it. Now, if it was emissions, sure kill it if you don't need it. But cooling lines... meh... like Mike said, if it ain't broke don't fix it!

[flatcat19]

Its a lifted truck with a solid axle swap, 4 speed tranny, divorced transfer case, fuel cell in the back.

 

And you're not showing us the oic's for what reason?

[Datsfrodo]

I removed mine, (kade motor) I noticed that in the mornings it takes a bit longer for my car to idle right, till it warms up. I can live with that.... Its on hot days that i feel i get what i want. by "cuting off" coolant flow to the throttle body my intake plenum stays a bit cooler. I think its something like for 10 degrees cooler you gain 1% hp(something like that). Honestly it not that much but i feel better knowing theres not hot coolant warming up the intake manifold. Thats just my two cents.

[datsunaholic]

It's not a good idea to remove it in cold climates, but you're not in a cold climate.

 

Other than that, he only disadvantage of removing it is if you don't plug the head too.

 

Why?

 

The coolant line in the manifold is slightly higher than the water jacket in the manifold itself, so it can force air out. With it plugged, it can form an air/steam pocket and that pocket can get REALLY hot if it migrates to the head vs being in the manifold. Causes a hot spot in the engine between #1 and #2 or (less likely) between #3 and #4. It doesn't happen very often, but the potential is there.

[Brandon H.]

It's not a good idea to remove it in cold climates, but you're not in a cold climate.

 

Other than that, he only disadvantage of removing it is if you don't plug the head too.

 

Why?

 

The coolant line in the manifold is slightly higher than the water jacket in the manifold itself, so it can force air out. With it plugged, it can form an air/steam pocket and that pocket can get REALLY hot if it migrates to the head vs being in the manifold. Causes a hot spot in the engine between #1 and #2 or (less likely) between #3 and #4. It doesn't happen very often, but the potential is there.

 

Awesome thanks a lot guys. Very good advice. So whats the best way to block it off? I was thinking to use a tap and tap the intake manifold, then thread a plug in (where the manifold bolts to the head).

 

Being taken apart

 

Also anyone know what tranny this is.... looking for gear ratio

[datzenmike]

F4W63 but no way to tell by looking if from a 510 sedan or from a 510 wagon/620 truck.

 

510 sedan:

1st... 3.382

2nd.. 2.013

3rd... 1.419

4th... 1.000

 

 

510 goon or 620 truck:

1st... 3.657

2nd.. 2.177

3rd... 1.415

4th... 1.000

 

Place in first and carefully count the turns on the input to get one complete output turn. If about, or just over, 3.5 turns then it's a 'wide ratio' 620/510 goon 4 speed.

[banzai510(hainz)]

I used a 14/pipe plug. 1/4 is mostly the size of the allen head. The hole should be close to not needind to be drilled. But ck on the hole size needed fot he correct tap size.

 

youll need to make sure the tap is not too long as youll need to thread it in a couple times till you get the taper right. As you might bottom out on the other side of the head(inside) till the pipe plug fits flush.

 

MY little cheat sheet here says 1/4-18 is the pipe plug and use a 7/16 drill bit if needed

[flatcat19]

That trucks bad.

Make an intro.

I want to talk about it.