Block plug??

[Stoffregen Motorsports]

Thinking more about this last night.

 

On quite a few of the Toyota engines, the temp sender for the gauge is located in or near the middle of the intake manifold, but the temp sensor for the ECU and the time switch for the cold start injector are in the t-stat housing. Why would they put them in those two specific locations? I suspect the temp sender for the gauge is in the manifold to give the driver a more general reading (without the bounce from the t-stat opening and closing), but the other sensors are in the t-stat housing because that's more indicative of what is actually going on in the engine's cooling system.

[510revisited]

11 hours ago, Stoffregen Motorsports said:

Thinking more about this last night.

 

On quite a few of the Toyota engines, the temp sender for the gauge is located in or near the middle of the intake manifold, but the temp sensor for the ECU and the time switch for the cold start injector are in the t-stat housing. Why would they put them in those two specific locations? I suspect the temp sender for the gauge is in the manifold to give the driver a more general reading (without the bounce from the t-stat opening and closing), but the other sensors are in the t-stat housing because that's more indicative of what is actually going on in the engine's cooling system.

This is why I was wanting to put the sensor into the intake. I figured the jump from hot to cold (ish) might fuck with the ECU and think the motor is cold. Or am I WAY wrong? Trial and error I guess. I do appreciate all the input. I'm also dying to get this thing done and see if it was a big waste of money, or if its gonna be ok.. I just love the idea of a "modern" l20b. I'm a purist at heart, but hate carbs. 

[distributorguy]

What's happening at the T-stat is real, and that's what the ECU is going to want to know.  It doesn't want the "dumbed down" version, which isn't even an option.  That plug in the block is at the bottom (coldest) part of the cooling system, and the intake is always going to run much cooler - by 10-25 degrees.  My EFI is run off a sensor at the T-stat housing, and its well tuned.  A 13.5:1 engine can idle at 650 rpm and has more low end torque than the stock motor - it'll actually do a burn out if you try, which is decent for a cam with a power range of 4500-9600 rpm.    

 

Just put it in the stat housing.  

[510revisited]

So here's where it stands. I bought the t housing as mentioned before. I tapped three out of four sensor holes. 2 at 3/8 not, one at 1/4not. The fourth had a plug in it already. Not gonna mess with it unless it's a problem. Now here is my question. I'm trying to route a line from lower rad, to t housing, to intake. How I'm setup now is from lower rad to a 90 degree -8 swivel an fitting that bolts onto the t housing via another an fitting. -8 to 3/8 not. Then from t housing to intake via a 1/4 elbow. Here is a pic for reference. 

This got me to thinking. Is this setup going to allow to much lower rad coolant into the housing and cool down the thermostat and my sensor too much, since it doesn't technically tee? Any and all help is appreciated. 

[datzenmike]

No that's not the way. The intake fitting goes past the thermostat housing and joins to the pipe down to the lower rad hose.

 

Like this...

 

 

Doesn't have to be perfect, you can use hoses and T fitting. It just has to work right.

[510revisited]

So like this?? 

Or this? 

Or either? Thanks again.

[datzenmike]

I like #2 better.

[510revisited]

Ok. I'll figure something out. Thanks mike

[datzenmike]

As to the two holes added for coolant flow out into the intake, this also promotes better circulation all along the left side of the head. Without them all hot water from the #4 has to move forward all the way to the front of the engine to get out via the thermostat housing. Surely the #1 cylinder and ports are much heated by the hot water from the other cylinders moving towards it from the back of the head. Both these holes are between and below both pair of intake ports.

 

 

Here's the L 6 cylinder head that someone has added coolant tubes to remove hot coolant.

[510revisited]

Ok. I would say that I'm officially in need of some help. I'll start from the beginning. I purchased a zx t housing as per Mike's advice. Worked out perfectly till I stripped the damn thing while tapping it for 3/8 npt. My bad. Next I bought another housing (officially my 3rd) which is for a zx as well. Apparently they had several types. And so I dont see this one working to well, because of the output placements. Before I tap this one I need some help. I want to run a bypass from lower rad to t housing to intake. As per factory. But without making a Lego looking connection out of a bajillion an fittings. I need to know what the hell my options are. Mind you, I would like to keep it neat looking. Any and all help is appreciated 

[distributorguy]

The heater hose outlet on the back of the head, opposite side works perfectly for this.  Enough coolant flows through that hose to push coolant through the back of the head, tested and proven at Bonneville.  Don't heat the intake.  That's a fine band-aid for  stock smog engine, but there are so many better ways to deal with carburetion.    

 

DO NOT overtighten fittings on the T-stat housing or it WILL crack, especially when you start making the holes bigger.  If it needs repair, get it welded and start over.  $30 project.  

 

Glad to see you finally came to your senses about the coolant sensor.  If you want detailed photos of what we're doing with the race motor for cooling/plumbing/efi/etc... its all street-worthy and I'd be happy to text or email you details.  612-804-5543

[datzenmike]

Heater hose fitting on back of head?? Hot water comes out of that for the heater. Connecting the thermostat housing to the heater outlet on the head is making a closed loop. Both are under same pressure from the water pump pressurizing the block.

 

Check your lower rad return line into the water pump. You should have this...

 

Hose on the left is the return from the heater and the smaller vertical hose (with clamp) is the by pass from the thermostat. Pretty sure just about all L 4s had this. It may be capped off by a previous owner. Run a hard line or hose up to the thermostat from this.

 

[510revisited]

4 hours ago, datzenmike said:

 

 

I'm trying to figure out a way to replicate that tube in this pic. I can fab and weld, but I've never welded little ass tube like that. I'm just trying to get an idea of what I can do. Maybe just bypass using a hardline and go with rubber? Idk. 

[datzenmike]

Rubber is fine but it won't last 50 years. Brass or copper and brazed?

[510revisited]

6 hours ago, datzenmike said:

Rubber is fine but it won't last 50 years. Brass or copper and brazed?

That's what I figured. I'm gonna look into it. What are the original pipes made of? 

[datzenmike]

 Steel tubing? and welded or forged together. They do rust.

 

[Stoffregen Motorsports]

Early L motors did not tee off to the t-stat housing. The line ran directly to the intake.

 

Small tubing... I have had the same problem with my LS swaps. There is one pipe I wanted to make, but I could find literally zero shops or manufacturers that were able to help. Even finding the supply of tubing proved futile. I did eventually find a limited selection of tubing at McMaster-Carr, but gave up on the project because I didn't want to rely on a soldered connection. I ended up finding the right size tee (5/8 to 5/8 with 1/2 tee) and making the rest up with preformed hoses from other applications.

 

One of the big hose manufacturers has a PDF of their complete hose line with pics and measurements and bend descriptions. It's a big file (about 100 pages) and I printed a copy for reference. I can't find the link though. I think it was Gates.

[datsunrides]

For small diameter tubing, I use stainless steel tubing. Now I have the ability to weld small tubing that makes it look cleaner, but you can get compression fittings for tees and adapters. McMaster Carr has some but a place like swagelok has many more options. If you do go this route, make sure you get double ferrule fittings for stainless. You can also do this with copper tubing/brass compression fittings, (or soldered/brazed fittings) but IMO is not as durable with engine vibration.

[Stoffregen Motorsports]

22 hours ago, datsunrides said:

For small diameter tubing, I use stainless steel tubing. Now I have the ability to weld small tubing that makes it look cleaner, but you can get compression fittings for tees and adapters. McMaster Carr has some but a place like swagelok has many more options. If you do go this route, make sure you get double ferrule fittings for stainless. You can also do this with copper tubing/brass compression fittings, (or soldered/brazed fittings) but IMO is not as durable with engine vibration.

I am going for an OEM look, so compression fittings won't do it for me. I did find some weld fittings on the Swagelock website that look interesting.

 

I do have tubing bead rollers that can form a bead on small tubing, and that helps, but still trying to figure out the tee section.

[datsunrides]

I have found that if you desire a bead for the hose to go over, the first stage of a double flare looks pretty much like OEM.