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Unread 04-15-2013, 07:15 PM   #16
ForeverNoob
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Quote:
Originally Posted by 82JeepCJ7 View Post
FYI: Any of the threaded ports in the thermostat housing are going to be in the bypass system. The one in the intake will not see adequate flow until the thermostat opens.
So maybe my understanding of how water flows through this thing is wrong?

It flows from the intake to the radiator via the waterneck, no?

The area on my intake that houses the temp sensor gets hot before the waterneck. After the stat opens, the waterneck gets warmer, and so does the top hose. What am I misunderstanding?

Again, there is one and only one threaded port on my waterneck. It houses a ported vac switch for the vac advance. The vacuum advance switches from manifold to carb vacuum after the stat opens (which allows the switch to heat up), which should be long enough to open the choke, which in turn eliminates the need for more advanced timing because the fuel mixture leans out.

Also, mine is a 76 (assuming it's the factory motor, as the PO said it was. I haven't checked any numbers). Was something different between mine and yours?

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Unread 04-15-2013, 08:19 PM   #17
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i Had To Replace A Freeze Plug. Why Are These Words Capitalizing? ! Anyway, The Block Coolant passages Were Clogged From Crud And Old Stop Leak. Perhaps Your Block Has Similar Issue. Flushing Is Not going To Get The Solids Out. A Chisel Helped, But Cannot Reach Behind The Cylinders
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Unread 04-15-2013, 08:27 PM   #18
ForeverNoob
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For the sake of keeping the record:

My OE replacement temp sensor is reading the correct resistance throughout the operating range of temps based on the opening of the thermostat and ported vacuum switch. The gauge still buries. After pulling the gauge cluster, I can verify 12 volts to the temp gauge. As I understand, it should only be about 5 volts, regulated from the fuel gauge through the jumper wire. I assume the extra voltage with the correct resistance from the sensor is burying the gauge. I don't understand why I haven't fried my temp gauge. Considering replacing the whole shebang at this point because my odometer doesn't turn and I'm not sure I want to try to rebuild the gear drive for it...
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Unread 04-15-2013, 08:29 PM   #19
82JeepCJ7
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I can see the difference between our necks. You have the style with he port in the back, horizontally. The temperature sensor in your neck basically turns the vacuum on to the dizzy once the engine warms up. Many recommend tossing this and hooking directly to manifold vacuum.



Both styles of necks are interchangeable. I had to use the one with the hole facing strait up due to the large intake runner of the Offenhauser intake would not allow anything to be screwed into the back of the neck.

Due to the bypass hose from the water pump to the hose neck, there is always water flow in the engine regardless of engine temperature. This bypass hose allows water to go around the thermostat and keep everything flowing to prevent cavitation at the pump. It is because of this bypass, a engine block temperature gauge will read the water temp even before the thermostat opens.

You can see the bypass hole in the gasket.



Matt, some are there, others are in the cross over portion of the intake. That is where my factory sender is. I have two gauges hooked up, the factory and the aftermarket gauge.
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Unread 04-16-2013, 07:09 AM   #20
turbogus
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Perhaps after I complete the wiring for my fan setup I'll revisit the mechanical gauges' sender location. Around this 'consumer desert' that I live in it took a few tries to find a thermostat housing that didn't run the upper radiator hose into the distributor.
When I replaced the intake manifold gasket a while back I dropped the thermostat housing and a chunk broke free. Got a replacement at NAPA before I began this project. The angle of the new water neck was such that it ran into the PVC assy and the bypass hose now runs into the vacuum plenum for the distributor. Went back to NAPA, after they opened to check if they goofed the part no. they figured it was a reboxed item.
I checked out the NAPA website and they have a picture of the very thermostat housing I need. Twice ordered by the applicable part number from NAPA and twice the part is configured differently (Made in China) go figure, further the two NAPA parts were cast differently from one another

Ultimately, I went to Mac's Jeeparts and tore one off a Waggy, cleaned it up and that's what I've been using since.
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Unread 04-16-2013, 08:18 AM   #21
ForeverNoob
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Quote:
Originally Posted by 82JeepCJ7 View Post
I can see the difference between our necks. You have the style with he port in the back, horizontally. The temperature sensor in your neck basically turns the vacuum on to the dizzy once the engine warms up. Many recommend tossing this and hooking directly to manifold vacuum.
Yep. It switches from manifold vac (cold) to carb vac (warm). I've had someone else on the forum tell me to ditch the ported vacuum. I don't understand why. They just said it was problematic. The PO removed the CTO and had the dizzy hooked to carb vacuum. I replaced it, routed vac lines properly, and it seems to function fine, at least for now.
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Unread 04-16-2013, 08:31 AM   #22
Matt1981CJ7
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Full time manifold vac to the dizzy provides full vac advance at idle, which is when your engine needs the advanced timing for cooler combustion temps. This is how engines ran for decades.

Ported vac was developed for emissions purposes, at the expense of idle performance.

Matt
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Unread 12-03-2013, 06:48 PM   #23
ForeverNoob
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So I read a thread elsewhere on the forum recently on 'forum etiquette' and realized I am an offender. To put this one to rest, the end of the story goes like this: I replaced the entire speedo cluster, verified the correct voltage, and everything has been cool (pun intended) since. Thanks to all those who chimed in, and sorry to bump an old thread...
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Unread 12-03-2013, 08:32 PM   #24
Matt1981CJ7
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Thanks for the update, Noob.

I'm glad you got it working.

I'm curious, did you ever switch over to full-time manifold vac advance?

Matt
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Unread 12-03-2013, 09:05 PM   #25
ForeverNoob
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No, still running the ported vac switch. Hasn't caused any issues for me, so I haven't fussed with it... but I am still running a presto dizzy. Hoping to change that this spring/summer, but I can't say its going to happen for sure yet. Maybe I'll toy with it after the upgrade...
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Unread 12-03-2013, 09:26 PM   #26
Matt1981CJ7
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That's cool.

When you get around to upgrading your ignition, I encourage you to try manifold vac advance. Many of us have realized improved idle and low RPM performance, and easier cold starts with that setup.

Matt
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