Here's what I did for heater hoses/bypass valve on LSx swap
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Car: 1991 Z28 convertible built 3/1/1990
Engine: Cammed 6.0L LSX
Transmission: T56
Axle/Gears: custom Ford 8.8", 4.10 gears
Here's what I did for heater hoses/bypass valve on LSx swap
Since I recently decided to put a/c back on my car I needed to put a bypass valve inline on the heater hoses to keep the conditioned air from blowing across a hot heater core. You'll notice that the stock 3rd gen bypass valve has only 3 outlets and you need 4 for an LSx swap (2 to heater core, 2 to water pump).
The part number for the valve is 74781.
I plan on painting the two 90* brass fittings black so they don't stick out like sore thumbs, but I literally just finished this today and wanted to get it all mocked up. I also wish the vacuum port was facing rearwards but it is what it is.
The part number for the valve is 74781.
I plan on painting the two 90* brass fittings black so they don't stick out like sore thumbs, but I literally just finished this today and wanted to get it all mocked up. I also wish the vacuum port was facing rearwards but it is what it is.
Last edited by BlueZee28; 10-14-2014 at 11:23 AM.
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Re: Here's what I did for heater hoses/bypass valve on LSx swap
Great find, I would be interested in the part number. Vintage air has a one inlet one outlet valve. I could never get an answer supported by facts on whether or not the ls water pump needed constant circulation (heater lines) or could simply be turned off.
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Car: 1991 Z28 convertible built 3/1/1990
Engine: Cammed 6.0L LSX
Transmission: T56
Axle/Gears: custom Ford 8.8", 4.10 gears
Re: Here's what I did for heater hoses/bypass valve on LSx swap
I've looked for the box it came in and don't believe I have it anymore. I wish I knew what the number was too in case I ever need to replace it.
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Car: 1991 Z28 convertible built 3/1/1990
Engine: Cammed 6.0L LSX
Transmission: T56
Axle/Gears: custom Ford 8.8", 4.10 gears
Re: Here's what I did for heater hoses/bypass valve on LSx swap
On second thought it looks like it may be from a Ford Ranger, based on a Google image search.
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Car: 91 Firebird
Engine: 6.0
Transmission: T56
Axle/Gears: 3.73
Re: Here's what I did for heater hoses/bypass valve on LSx swap
Ghettocruiser did a similar swap about 4 yrs ago or so.
https://www.thirdgen.org/forums/ltx-...-valve-ls.html
I followed his lead and used some premade hoses that allowed for the hoses to follow the ac box rather than going over the top of the motor. The part numbers and pics are in that thread as well.
it works great and I am very happy with it.
Enjoy!
https://www.thirdgen.org/forums/ltx-...-valve-ls.html
I followed his lead and used some premade hoses that allowed for the hoses to follow the ac box rather than going over the top of the motor. The part numbers and pics are in that thread as well.
it works great and I am very happy with it.
Enjoy!
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Car: 92 Firebird
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Re: Here's what I did for heater hoses/bypass valve on LSx swap
It does need constant circulation. If you're plugging the HC lines, swap the LS1 t-stat for a SBC version. This way coolant continuously circulates through the WP and the t-stat still regulates in/out of the engine
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Car: 1991 Z28 convertible built 3/1/1990
Engine: Cammed 6.0L LSX
Transmission: T56
Axle/Gears: custom Ford 8.8", 4.10 gears
Re: Here's what I did for heater hoses/bypass valve on LSx swap
Ghettocruiser did a similar swap about 4 yrs ago or so.
https://www.thirdgen.org/forums/ltx-...-valve-ls.html
I followed his lead and used some premade hoses that allowed for the hoses to follow the ac box rather than going over the top of the motor. The part numbers and pics are in that thread as well.
it works great and I am very happy with it.
Enjoy!
https://www.thirdgen.org/forums/ltx-...-valve-ls.html
I followed his lead and used some premade hoses that allowed for the hoses to follow the ac box rather than going over the top of the motor. The part numbers and pics are in that thread as well.
it works great and I am very happy with it.
Enjoy!
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#8
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Car: '89 Firebird
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Re: Here's what I did for heater hoses/bypass valve on LSx swap
Still did a good job on your own car though.
Ghettocruiser did a similar swap about 4 yrs ago or so.
https://www.thirdgen.org/forums/ltx-...-valve-ls.html
https://www.thirdgen.org/forums/ltx-...-valve-ls.html
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Car: 1991 Z28 convertible built 3/1/1990
Engine: Cammed 6.0L LSX
Transmission: T56
Axle/Gears: custom Ford 8.8", 4.10 gears
Re: Here's what I did for heater hoses/bypass valve on LSx swap
Lol it ended up being the part number in the link above, I edited the original post so others can look it up at the parts store.
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Car: 87 IROC-Z
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Re: Here's what I did for heater hoses/bypass valve on LSx swap
Same part number as mine . Not sure if it's just mine but I had about 3 defective units since I did my swap .
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Car: 91 Formula
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Re: Here's what I did for heater hoses/bypass valve on LSx swap
Used the same valve, but bought some formed hoses to clear the engine.
I forget the numbers but Napa has 5/8" & 3/4" hose sections with tight formed 90's on them that you can use to clear the engine.
I forget the numbers but Napa has 5/8" & 3/4" hose sections with tight formed 90's on them that you can use to clear the engine.
#12
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Re: Here's what I did for heater hoses/bypass valve on LSx swap
Holy crap that was 4 years ago?!?!?
Time is going by WAY too fast...
My valve is still in and working great! When I rebuilt the 86, I considered using metal tubing for the heater hoses. Similar to the 4th gen setup. In fact, I still have the 4th gen heater hoses, and I looked at modifying them again. My main reason for just using the hoses..is that they are available locally for super cheap, and it makes for easy mounting of the heater control valve.
I too used the hoses with pre-bent 90* angles. Works great to get them out from behind the motor.
J.
Time is going by WAY too fast...
My valve is still in and working great! When I rebuilt the 86, I considered using metal tubing for the heater hoses. Similar to the 4th gen setup. In fact, I still have the 4th gen heater hoses, and I looked at modifying them again. My main reason for just using the hoses..is that they are available locally for super cheap, and it makes for easy mounting of the heater control valve.
I too used the hoses with pre-bent 90* angles. Works great to get them out from behind the motor.
J.
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Car: 1989 Iroc-Z
Engine: LS1
Transmission: Tick Stage 2 T56
Axle/Gears: 2.77
Re: Here's what I did for heater hoses/bypass valve on LSx swap
Holy crap that was 4 years ago?!?!?
Time is going by WAY too fast...
My valve is still in and working great! When I rebuilt the 86, I considered using metal tubing for the heater hoses. Similar to the 4th gen setup. In fact, I still have the 4th gen heater hoses, and I looked at modifying them again. My main reason for just using the hoses..is that they are available locally for super cheap, and it makes for easy mounting of the heater control valve.
I too used the hoses with pre-bent 90* angles. Works great to get them out from behind the motor.
J.
Time is going by WAY too fast...
My valve is still in and working great! When I rebuilt the 86, I considered using metal tubing for the heater hoses. Similar to the 4th gen setup. In fact, I still have the 4th gen heater hoses, and I looked at modifying them again. My main reason for just using the hoses..is that they are available locally for super cheap, and it makes for easy mounting of the heater control valve.
I too used the hoses with pre-bent 90* angles. Works great to get them out from behind the motor.
J.
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Re: Here's what I did for heater hoses/bypass valve on LSx swap
Yes, it does matter. Short tube goes to manifold vacuum, and long tube goes to heater coolant bypass valve or is capped.
The short tube doesn't actually connect directly to the manifold though. It goes to a vacuum check valve. The other two legs of the check valve go to the manifold and the vacuum ball (reservoir). The purpose of the check valve is to close off the line to manifold when manifold loses vacuum. The vacuum ball will allow the system to temporarily hold static pressure so the HVAC controls don't do funky things.
The short tube doesn't actually connect directly to the manifold though. It goes to a vacuum check valve. The other two legs of the check valve go to the manifold and the vacuum ball (reservoir). The purpose of the check valve is to close off the line to manifold when manifold loses vacuum. The vacuum ball will allow the system to temporarily hold static pressure so the HVAC controls don't do funky things.
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