Ok, took off head and now I've got concerns. L20b

[banzai510(hainz)]

I dried telling him that already.

 

1/8 would be fine.. I did a 1/4 and was to big a hole

[G-Duax]

Yeah, 1/8th is all I ever used until moving to Texas, then only 2) 1/8 holes.

[Draker]

I guess I gotta get drilling myself.

[KoHeartsGPA]

There's a hole in mine, no need to take it apart then.

[datzenmike]

No........

A bypass hole in the thermostat it's self, not the housing.

 

 

 

This will work but the water goes directly into the rad. This displaced cold water out the lower rad hose into the warming engine further slowing the warm up. A LOT of water is going to flow through that small hole in 5 min. The by pass runs this slightly warmed water directly back into the warming engine. Cold rad water stays in the rad until the thermostat finally opens and there is flow.

 

If a hole in the thermostat was the best way, Nissan would have done this. Instead they went to a lot of trouble to develop the by pass system.

 

Not saying the drilled hole in the thermostat won't work, just not the best way.

[KoHeartsGPA]

I want it done right, and I'm gonna make it look purdy ;)

[banzai510(hainz)]

if running side drafts and the head holes are best plugged up this is the simpliest way to do it

[KoHeartsGPA]

I fixed my heater leaks and verified core is intact, so I'm going to plumb that back into system as well.

[datzenmike]

If running side drafts there would still be the by pass hole in the thermostat housing. THIS is the by pass. The water cooled/warmed intakes just used the already there by pass as an easy connection back to the cooling system. 

[Stoffregen Motorsports]

 

If a hole in the thermostat was the best way, Nissan would have done this. Instead they went to a lot of trouble to develop the by pass system.

 

They actually did have one, Mike. It has a jiggle valve in it. Drilling the hole is more of a cheap insurance policy than a real performance mod. I usually just clip off the jiggle valve.

 

The argument that the factory is always right has proven time and time again to be a misleading theory. Fact is, improvements can be made to just about anything. 

[Roadster-ka]

I always clip off the jiggle valve!

[KoHeartsGPA]

Cuz Ratsun.

[flatcat19]

I have an L16, no thermostat bypass...jiggle valve cut out, hole slightly enlarged.

 

I do want to do the bypass, just haven't tried to hunt it down yet.

[datzenmike]

I guess an L20B thermostat housing will have the fitting, but you will need to somehow T it into the coolant line from the intake.

 

 

Not really shown well is the by-pass hose from the thermostat housing just behind the vacuum advance hose. It T's into that rusty metal pipe from the intake. That metal pipe continues down across the front of the engine to the lower rad hose. This is a '76 L20B that didn't have the water cooled intake but I was able to get a '79 intake and the by-pass with the T.

 

That '79 intake with the EGR carefully removed looks way better that a block off plate huh?

[KoHeartsGPA]

Went to Bob's today and got my head :frantics:

 

 

 

 

And picked up my Victor Reinz at my uncle's house...

 

 

Can't wait to start assembly :frantics:

[flatcat19]

All that money spent and he didn't pull the liners out for ya?

[wayno]

Unless one is on a circle track it doesn't really matter, big valves, big intakes, closed chamber, all are big plus's, liners in exhaust, small negative on daily driver.

What's ya need two head gaskets for, maybe I am missing something.

[thisismatt]

Unless one is on a circle track it doesn't really matter, big valves, big intakes, closed chamber, all are big plus's, liners in exhaust, small negative on daily driver.

What's ya need two head gaskets for, maybe I am missing something.

 

 

Lower compression :thumbup:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

:rofl:

[datzenmike]

Stock L20B ....................................... 8.4

Above with closed chamber head..... 8.9

Above with two HGs.......................... 8.11

 

If closed chamber head was milled down the 8.11 would be slightly higher.

[Stoffregen Motorsports]

Why would you want the compression any lower than 9:1 ? Even with 87 octane, 9:1 is not even close to being a problem.

 

The exhaust ports become too large once you pull the liners. If you're going to run that head, it's better to leave them in.

[datzenmike]

Too big on an exhaust port? The U67 exhaust ports are as large and larger and square at the manifold. For all the work probably no gain removing them, and not easy: the valves have to come out, I've done this. There are raised bumps along the port length to support the liners away from the walls so they get, and stay hot. I ground them away. 

[banzai510(hainz)]

2 headgaskets??????????

 

called having a spare and getting them while they still out there

[KoHeartsGPA]

Unless one is on a circle track it doesn't really matter, big valves, big intakes, closed chamber, all are big plus's, liners in exhaust, small negative on daily driver.

What's ya need two head gaskets for, maybe I am missing something.

Spare HG, i like to hoard spare parts ;)

 

Why would you want the compression any lower than 9:1 ? Even with 87 octane, 9:1 is not even close to being a problem.

 

The exhaust ports become too large once you pull the liners. If you're going to run that head, it's better to leave them in.

This, unless I'm racing the thing its pointless to remove them, you really don't gain much unless you go ape shit balls to the walls with all the racing mods, and his word means much since he worked for Dave Rebello building racing engines, you guys should see his shop...heaven!

[scooter]

Looks good!

[KoHeartsGPA]

She's alive!!!