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Opel Tinkerer and Rescuer
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Discussion Starter #1 (Edited)
For those wanting an easy to install thermostat housing that allows use of the Standard GT radiator house, and a standard thermostat.. but is running a 2.2 or a 2.4L head and EFI. This would work for anyone doing a 2.2L/2.4L head with custom EFI or the Motronic Opel setup as it is compact and has both ports for the EFI sensor and the gauge cluster sensor.

I am working with a fellow in Europe that has 3D modeled such a thing.. It wouldn't have all the ports and require all the gymnastics the standard 75 GT/E housing and the 2.2/2.4L housings require. He originally created it and 3D printed it for use on a 16V conversion. They aren't cheap as they are CNC MIlled from Billet Aluminum.. ($200 and shipping from Europe and we will need to get 10 made, if we are to get them made at all. Curious how many would be interested. I am in for 3.

You can see in the pictures the original 2.4L uses a funky hose then goes to another hose. We found this setup does not seem to report the temperature a 100% accurate to the dash, and it gets in the way. of linkage and intake a bit. Look a lot cleaner and would avoid needing special lower radiator hose(s). The Standard GT/Kadett/Manta one would work.
 

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Opel Rallier since 1977
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1,712 Posts
Charles,

Can you describe where the bypass function is in this setup? I think I see some extra fitting points but am not sure what they are for.

Tnx, Mark B.
 

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Opel Tinkerer and Rescuer
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Discussion Starter #4 (Edited)
No bypass. The 2.2/2.4 head doesnt have a place for it.

If I got it right:

The Standard 1.9L head/housing the water pump when "idle" bypasses the radiator and runs the water through the engine and the port on the side of the head.

The 1.9L EFI ( GTE) Setup does the same but does it in the housing.

The 2.4L EFI Setup bypasses the water pump through the Radiator, and this allows the head and engine to get up to temperature faster. It also causes the water at the housing to be lower temp and thus gives you a lower temp reading at the temp gauge.

The solution is a simple one a few small 2mm holes around the thermostat flange.

It will allow air to get to the top to avoid cavitation. In this cause, with some holes in the thermostat itself, you bypass through the motor again but with less flow. Just enough to not worry about cavitation and air being captured in the system.
 

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Opel Rallier since 1977
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1,712 Posts
Yes the 1.9 does the bypass from the t-stat housing forward chamber through the O-ring between the head and timing cover and into the pump cavity in the timing cover. The 1.9 EFI does it in the different housing and I assume you are correct on the 2.4 .

But the bypass is not there for bleeding air.. it is there to make sure there is always a small amount of fluid flow even when cold to avoid hot spots in the engine (like around the tops of the combustion chambers). The bypass flow is a more than what you can get with just a couple of small holes drilled in the t-stat flange so I think this needs to be figured out.

If you added a tapped hole near the temp sensor area then you could tee a small length of hose from there to a Tee in the heater hose line that comes out of the lower rad hose connection to the water pump. Maybe that is why there is a 2nd tapped hole in the top of the housing, 1 for the temp sensor and a 2nd for connecting a small bypass hose?
 

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Opel Tinkerer and Rescuer
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Discussion Starter #6
1 for the temp sensor and a 2nd for connecting a small bypass hose?
Nope thats for the EFI Temp sensor.

He has been running a version of this on the 16Vs in racing applications, without any more bypass than a few holes.

I would think if you are getting hot spots in the head the t-stat would be open.

But is something to consider.
 

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Opel Rallier since 1977
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Well, bypasses are there for a good reason.... I certainly haven't looked at every cooling system but can't recall any one without a bypass function. The older ones have small bypass hoses or something like the 1.9 setup. Newer cars have it in the heater core..... coolant flows through the core all the time. (There is no heater core shut off valve like on our old cars.... a blend door is used to control the flow of the heated air instead.)

Perhaps just setup a tee on the temps sensor and tee into the heater hose will do it. No changes needed.
 

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Just Some Dude in Jersey
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14,402 Posts
Wah! Ha! Ha! Ha!

I notice that you've positioned your motor so that the back of the engine is partially outside the garage and you've erected a baseball batting cage around it. Gee, I wonder why you did that.......?

Wah! Ha! Ha! Ha!

:veryhappy


As far as bypass, Gil suggested that I simply drill some holes around the periphery of the 'stat. Worked great for me. This subject came up a few years ago and I recall Heliman saying that he drills bypass holes in the 'stats of all his cars.
 

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Opel Tinkerer and Rescuer
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Discussion Starter #10

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Opeler
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Charles, is there any reason to have this machined in Europe?
Unless there is an IP issue with the drawings, wouldn't it be more cost effective to have them manufactured in the US?
It would save a bit on shipping, etc.

Also, it's a bit hard to tell from the pictures but the anodized red version seems to have a heater port on the back side.

Chris

BTW, this is interesting, cleans up a jumbled mess of hoses :)
 

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Opel Tinkerer and Rescuer
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Discussion Starter #12 (Edited)
Charles, is there any reason to have this machined in Europe?
Unless there is an IP issue with the drawings, wouldn't it be more cost effective to have them manufactured in the US?
It would save a bit on shipping, etc.

Also, it's a bit hard to tell from the pictures but the anodized red version seems to have a heater port on the back side.

Chris

BTW, this is interesting, cleans up a jumbled mess of hoses :)
I think it is more to do with IP.. and your right does seem to be a port for heat in the back ( win / win ) (See above added pic )

Well, bypasses are there for a good reason.... I certainly haven't looked at every cooling system but can't recall any one without a bypass function. The older ones have small bypass hoses or something like the 1.9 setup. Newer cars have it in the heater core..... coolant flows through the core all the time. (There is no heater core shut off valve like on our old cars.... a blend door is used to control the flow of the heated air instead.)

Perhaps just setup a tee on the temps sensor and tee into the heater hose will do it. No changes needed.
Actually as running through the heater core would work.. then that's the easiest way, just use the port on the rear of the block.

A Tee heater control valve instead of a one way..

Should be suction from rad, and heater core to the block, out from the rear port to the heater and back to heater core.



Could even do it electronically to turn on the heat.. ( Gordo )



Omega-Omega Electronic Coolant Control 12V 5/8in - 31-60027-31-60027

This could all be plumbed pretty easily and hidden.
 

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Opel Tinkerer and Rescuer
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Discussion Starter #14
Charles, do you think this will work in conjunction with Keith's A/C kit for the GT?

Wes
Yes, I would assume so. It would allow for stock routing and use of the GT hoses.
 

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Opel Tinkerer and Rescuer
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7,442 Posts
Discussion Starter #15
It is originally intended to be used with dual side drafts which explains the lack of EFI sensor ports.
When you compare the two, while "expensive" at $200.

The one we will get will be CNC'd from Billet Aluminum, so it will both look cool and be functional. :)

For only about $100 more, and some here have that in just a few chrome doo-dads under their hood.

Being it has the missing heater connection the GTE/2.2/2.4 water housings have ( That can be blocked off as well ). It makes it flexible for routing.

As noted, seems the 2.4Ls I have built have had less than optimal heat to the heater, and they never show the temp correctly given the location of the gauge in the housing ( So I think the gauge sensing unit isn't the same as the cars that use this sending unit ). It should fix a lot of those things.
 
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Opel Tinkerer and Rescuer
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Discussion Starter #17
Charles, put me down for one, please.

Wes
That gets us 6.. and I think he has one or two europeans.. be nice to get this wrapped up sooner than later. So a certain someone can have his water housing before we finish installing the motor.
 

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Opel Tinkerer and Rescuer
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Discussion Starter #19 (Edited)
I'm in for one.
Great.. ! Once I get confirmation from him and that we are in production I will get with you all.

I am going ahead and committing to the lot of 10. That way I have them later and get them in production sooner.
 

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Just Some Dude in Jersey
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14,402 Posts
As previously stated on Facebook, I'm in for one. Even though I have my previous 1.9 style + adapter + chrome and will receive the FI one back from the chromers in about a month.

I wish I had the engine and the FI stuff here to do comparisons and offer alternative ideas. As I see it there's 2 issues preventing the use of the 1.9 style + adapter: Clearance between the housing and the throttle assembly and the seemingly anal need for super accurate temperature reading for the FI.

For one thing, is the clearance issue still an issue with the use of the new smaller throttle body? I live where it's cold and I want the heater function and I want it to be simple like it is now with the 1.9 housing + adapter. If I have to use the cockamamie FI housing, I'll have to use the rear block outlet for the heater(or a T-fitting in a hose somewhere), which comes uncomfortably close to the exhaust. I have bypass holes in my present thermostat and the whole system presently works great. If

If that's cleared up by the use of the shorter TB assembly and I have clearance, bypass, and heater function, then that leaves just the temperature sensing for the FI to be straightened out. Okay, I'm not holding water in my engine until just the water in the block is up to full operating temp and the thermostat starts to open, instead, all the water in my system slowly mixes until it's all at operating temp. If I didn't have constantly active bypass, as soon as the engine water gets hot enough to open the thermostat, that water will drop in temp as it mixes with the cold water in the external hoses and the radiator. This means a flux in temp will happen, which the FI may react to and adjust for. If I am able to use my present set up, then all the water will pretty much all get to operating temp at the same time. One way or the other, all the water in the cooling system will pretty much take about 15-20 minutes to reach full operating temp on a cold day, regardless of whether I use the 1.9 or the FI thermostat or the new fangled new one.

So, if I have clearance, via the use of the new throttle body, then I should be able to use my 1.9 + adapter set up. Then the only issue remaining would be finding a way to add a second temperature sensor for either the dash gauge or for the FI computer. On the 1.9 set up there is only one place for it. Could I do a splice of wires for both the dash gauge AND the FI to that one sensor or could I add a second sensor somewhere in the system? I'm sure I could do one or the other.

Everything depends on the clearance issue. I won't know that until my engine gets here and I can test fit things.......
 
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