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Temperature sensor/gauge?

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rratselad
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Temperature sensor/gauge?

Post #1 by rratselad » Fri Jun 19, 2020 7:13 pm

I had my engine rebuilt ~3 years ago and reused the existing temp sensor in the block. I don't know how old the temp sensor is, but it could be original. The radiator/coolant thermostat was new. The van may have ~300-500 miles on it since that rebuild.

When I pulled my van out of storage this year and ran it around, the temperature on the dash gauge seems lower than I ever remember it being. Here's what I'm seeing:

Gauge picture

If memory serves, the gauge used to show dead-center in the middle of the white/center range when the van was warmed up. Now it never reaches the white/center range and sits on the cold side.

I've taken the wire off the sensor and ran it to ground. The gauge immediately went to hot and pegged.

I'm hoping not to pull the coolant system apart, but am wondering if there's anything else short of a full coolant drain that I can do to troubleshoot? I'm concerned that the thermostat may be stuck open, although, standing near/around the motor it seems like it gets quite warm. If I have to drain the coolant, I guess I should just replace the thermostat and temperature sending sending units at the same time...? Am I missing anything easier?

Thanks!

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Re: Temperature sensor/gauge?

Post #2 by bubba22349 » Fri Jun 19, 2020 7:32 pm

Yes that is a bit low on temp gauge from your description and trouble shooting I would doubt that there's anything wrong with either the gauge or its sender. Do you remember what temp Thermostat you installed? My best guess is that it's the wrong temp Thermostat or its stuck open as you are thinking. it can be checked or changed though without a full coolant dump, only a small amount of coolant needs to be drained from the radiator to get just below the T Stat. Best of luck :thumbup: :nod:
Even a bad day Drag Racing is still better than a good day at work!

Current project is a 1988 John Deere 420 Garden Tractor I need a few small parts to get it fixed, plus some cosmetic items, maybe a few attachments, if you happen to have or know of JD 420 parts would welcome the help!

My Ex-Inline 6 Fleet 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

rratselad
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Re: Temperature sensor/gauge?

Post #3 by rratselad » Fri Jun 19, 2020 7:43 pm

I could be wrong - can't find my paperwork from back then ( :? ), but I thought I used a 195 degree thermostat. As best I can tell, that's OE temp for a 1970 240. Any thoughts? Also have you used any of the fail-safe thermostats? Are they worth it?

Thanks!

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Re: Temperature sensor/gauge?

Post #4 by bubba22349 » Fri Jun 19, 2020 7:53 pm

Yes if it's a 195 that's the correct one to use. No I have mostly used the standard T Stat's that are in a Blue and Yellow box the brand name i think is "Stat" it is a very old company that I have used for many decades or I also use the Motorcraft and Robert Shaw, can't give any recommendations on those fail safe type though. :nod:
Even a bad day Drag Racing is still better than a good day at work!

Current project is a 1988 John Deere 420 Garden Tractor I need a few small parts to get it fixed, plus some cosmetic items, maybe a few attachments, if you happen to have or know of JD 420 parts would welcome the help!

My Ex-Inline 6 Fleet 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: Temperature sensor/gauge?

Post #5 by Broncomike » Fri Jun 19, 2020 10:12 pm

We're the gauges, real gauges back then? I know the temp gauge in the 80+ trucks are just an idiot light with a needle but i don't know when that started. Id check it with another gauge. Even just a cheap one from the local parts store.

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Re: Temperature sensor/gauge?

Post #6 by Angelking » Sun Jun 21, 2020 3:41 pm

Broncomike wrote:We're the gauges, real gauges back then? I know the temp gauge in the 80+ trucks are just an idiot light with a needle but i don't know when that started. Id check it with another gauge. Even just a cheap one from the local parts store.


I was planning a Stewart Warner guage for the engine itself.



AK

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Re: Temperature sensor/gauge?

Post #7 by blprice74 » Sun Jun 21, 2020 9:55 pm

Broncomike wrote:We're the gauges, real gauges back then? I know the temp gauge in the 80+ trucks are just an idiot light with a needle but i don't know when that started. Id check it with another gauge. Even just a cheap one from the local parts store.


Agree...I never could make much of that gauge. I put in one that actually shows the temp and replaced the sending unit. Never really understood why it was installed like that.

Brandon
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Re: Temperature sensor/gauge?

Post #8 by sqrbckguy38 » Sun Jun 21, 2020 11:51 pm

I don't recommend those fail safe t-stats. I used to manage a parts store, saw a lot of them come back for warranty, especially Dodges. They would get stuck open the first time hot air passed by them while bleeding a cooling system. To be fair, it's not always the t-stats fault, but I just grew to not recommend them.
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Re: Temperature sensor/gauge?

Post #9 by sdiesel » Mon Jun 22, 2020 8:32 am

A problem of air in the system sometimes means the coolant level does not consistently reach the sensor resulting in readings that are inaccurate.

I reccomend motorcraft only for t stat. Mount it in such a way that the jiggle valve is at 12 o' clock.
a long love affair with the 300 six.
my lastest and final fling is a fresh 300 in an 88 ford f350 dually 4X flatbed

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Re: Temperature sensor/gauge?

Post #10 by Angelking » Wed Jun 24, 2020 3:35 pm

Am assuming this would be the oil pressure sending unit for a light?


Image

THanks

AK

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Re: Temperature sensor/gauge?

Post #11 by wallen7 » Wed Jun 24, 2020 4:42 pm

That would be for a temp sender or gauge

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Re: Temperature sensor/gauge?

Post #12 by Angelking » Wed Jun 24, 2020 4:47 pm

wallen7 wrote:That would be for a temp sender or gauge


For oil or water? There is an oil pressure sending unit for a guage I believe on the opposite side.

AK

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Re: Temperature sensor/gauge?

Post #13 by bubba22349 » Wed Jun 24, 2020 5:15 pm

X2 that's a water temp gauge sender there on the passenger side rear of the engine. Oil pressure gauge or light has a White wire with a Red stripe located on the drivers side of engine about 1/2 way between the oil filter and the bell housing. :nod:
Even a bad day Drag Racing is still better than a good day at work!

Current project is a 1988 John Deere 420 Garden Tractor I need a few small parts to get it fixed, plus some cosmetic items, maybe a few attachments, if you happen to have or know of JD 420 parts would welcome the help!

My Ex-Inline 6 Fleet 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: Temperature sensor/gauge?

Post #14 by Angelking » Wed Jun 24, 2020 6:59 pm

bubba22349 wrote:X2 that's a water temp gauge sender there on the passenger side rear of the engine. Oil pressure gauge or light has a White wire with a Red stripe located on the drivers side of engine about 1/2 way between the oil filter and the bell housing. :nod:


Thank you.\

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Re: Temperature sensor/gauge?

Post #15 by Broncomike » Fri Jun 26, 2020 3:33 pm

While we're on the subject, what's an acceptable max temp? It was 80-85 degrees yesterday and on some longer highway climbs, I was hitting 210 degrees. Doesn't usually run more than 195-200.

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Re: Temperature sensor/gauge?

Post #16 by bubba22349 » Fri Jun 26, 2020 3:49 pm

IN my OPIN 210 up to 215 degrees is still ok if your nervous about it you can always use the heater core temporarily as a little extra engine cooling on a long grade I have done this many times over the years. Do you have a radiator shroud on your truck? Best of luck :nod: :thumbup:
Even a bad day Drag Racing is still better than a good day at work!

Current project is a 1988 John Deere 420 Garden Tractor I need a few small parts to get it fixed, plus some cosmetic items, maybe a few attachments, if you happen to have or know of JD 420 parts would welcome the help!

My Ex-Inline 6 Fleet 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: Temperature sensor/gauge?

Post #17 by THE FRENCHTOWN FLYER » Fri Jun 26, 2020 4:39 pm

A rad shroud and a coolant recovery bottle both help.
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Re: Temperature sensor/gauge?

Post #18 by Broncomike » Fri Jun 26, 2020 4:40 pm

I do have a shroud and recovery tank. Although only about half the fan is covered and I think about 3/4 is supposed to be in the shroud. I may try to shim the shroud back a bit.

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Re: Temperature sensor/gauge?

Post #19 by bubba22349 » Fri Jun 26, 2020 5:47 pm

The fan 1/2 way into the shroud is correct for a fixed blade fan, if it's a flex type fan than its 3/4 of the way into the shroud since the blade angles changes with the engines RPM. You would not want to move the shroud back or it won't seal properly to the radiator core and then loses the fans full pulling effect, it's much better to use a fan spacer to correct it. Best of luck :thumbup: :nod:
Even a bad day Drag Racing is still better than a good day at work!

Current project is a 1988 John Deere 420 Garden Tractor I need a few small parts to get it fixed, plus some cosmetic items, maybe a few attachments, if you happen to have or know of JD 420 parts would welcome the help!

My Ex-Inline 6 Fleet 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: Temperature sensor/gauge?

Post #20 by Broncomike » Fri Jun 26, 2020 5:57 pm

It's a fixed with a proper clutch. Thank you!

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Re: Temperature sensor/gauge?

Post #21 by bubba22349 » Fri Jun 26, 2020 6:23 pm

:beer: That's excellent, to me the fixed blade fan with a clutch unit is a very good set up. :thumbup: :nod:
Even a bad day Drag Racing is still better than a good day at work!

Current project is a 1988 John Deere 420 Garden Tractor I need a few small parts to get it fixed, plus some cosmetic items, maybe a few attachments, if you happen to have or know of JD 420 parts would welcome the help!

My Ex-Inline 6 Fleet 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: Temperature sensor/gauge?

Post #22 by THE FRENCHTOWN FLYER » Fri Jun 26, 2020 10:26 pm

Are you sure the clutch is working?
Is there an audible change in the pitch of the fan when temps rise to the max as the clutch engages?
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Re: Temperature sensor/gauge?

Post #23 by Broncomike » Fri Jun 26, 2020 11:46 pm

I haven't really noticed, between the exhaust and road noise, it's hard to tell. It's been on there for maybe 10k miles but then again, I've had newer parts fail.

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Re: Temperature sensor/gauge?

Post #24 by BigBlue94 » Sun Jun 28, 2020 3:03 pm

Ive had mine at 240° for what seemed like an eternity on Hells Revenge trail in Moab, and have no permanent issues. Though i wouldnt recommend more than about 220°. A proper fitting shroud helps a lot. I have a 3" thick universal aluminum radiator in my 85 bronco, and the shroud for a 87 fit great. Its nice and thin and doesnt interfere with the triple v-belts. Going up the rocky mountains, I maintained 195° or lower. Thats with a 180° thermostat, and big tires and gears.

Ive since moved on to a couple of junkyard electric fans so that I dont see that 240° again while off-roading. As well as wrapping the coated headers, adding a plastic carb spacer, carb heat shield, fuel line insulation, heat extraction fan in the hood, and adding a cold air intake to the carb. Those last two required an "off-road only" spare hood so i didnt cut holes in my nice one.

My overheating issues came primarily from long tube headers under a carburetor, and very little airflow, especially seeing 4000 rpms.
1985 Bronco. 309ci I6, NP435, 4.56 gears, Detroit locker and tru-trac, 4" lift, and 37" swamper tires. The 309 is 9.75:1 CR with a Schneider 140H cam, 4bbl, roller rockers, larger valves, and headers.

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Re: Temperature sensor/gauge?

Post #25 by Broncomike » Sun Jun 28, 2020 8:49 pm

I may go to a 180 degree stat, I've always run a 195. I think a coolant flush wouldn't hurt but I'll get a spare heater core before I do that. Electric fans are in the list eventually but not in the budget for a while. My Bronco is running a little lean and I don't think that's helping the situation. I think it's a fuel supply issue so I started another thread about a fuel pump swap since I'm installing an efi block in the near future.

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Re: Temperature sensor/gauge?

Post #26 by BigBlue94 » Mon Jun 29, 2020 12:33 pm

Broncomike wrote:I may go to a 180 degree stat, I've always run a 195. I think a coolant flush wouldn't hurt but I'll get a spare heater core before I do that. Electric fans are in the list eventually but not in the budget for a while. My Bronco is running a little lean and I don't think that's helping the situation. I think it's a fuel supply issue so I started another thread about a fuel pump swap since I'm installing an efi block in the near future.


Im in the plains where heat is high, humidity is high, and cold is about 10°. Always have run a 180 stat and 10w30 oil.

Running lean will definitely cause heat to build up.

Like i said, I am running a pair of junkyard electric fans out of a ford windstar. Just hook em up to a drill battery in the yard to make sure they work and arent noisy. Only got about 50 bucks in them and the wiring, relays, and switches.
1985 Bronco. 309ci I6, NP435, 4.56 gears, Detroit locker and tru-trac, 4" lift, and 37" swamper tires. The 309 is 9.75:1 CR with a Schneider 140H cam, 4bbl, roller rockers, larger valves, and headers.

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Re: Temperature sensor/gauge?

Post #27 by Broncomike » Mon Jun 29, 2020 5:11 pm

Do you have them run to a temp switch or just an on/off? If a temp switch, what are you running and what temp do you have them switching on and off?

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Re: Temperature sensor/gauge?

Post #28 by BigBlue94 » Thu Jul 02, 2020 7:15 pm

Broncomike wrote:Do you have them run to a temp switch or just an on/off? If a temp switch, what are you running and what temp do you have them switching on and off?


No, just on a toggle switch. One for each fan.

If you look on like summits website, you can find a few different ranges for on/off controllers. Not sure but I'd think on at 180, off at 160 or so. But I dont really know.
1985 Bronco. 309ci I6, NP435, 4.56 gears, Detroit locker and tru-trac, 4" lift, and 37" swamper tires. The 309 is 9.75:1 CR with a Schneider 140H cam, 4bbl, roller rockers, larger valves, and headers.

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Re: Temperature sensor/gauge?

Post #29 by rratselad » Sat Jul 18, 2020 3:19 pm

Hey all,

Family, kids, etc. have kept me from doing much with this, but I'm hoping to run a new development by you. First, I appreciate all of the input. It's definitely helped me think through what is going on.

My 240 is in a 1970 van, so it's way easier for me to change out the temp sensor than it is to try and get at the front of the motor. The thermostat is new(-ish), but the sensor could be from 1969 (build date). So I ordered a Motorcraft sensor from RockAuto and threw it in when I had a few seconds to myself, then replaced a tiny bit of coolant that I lost in the process.

Nothing else on the van has changed other than the sensor and I'm seeing WAY higher readings on the gauge. Here's a pic:
Image

After shutting the van down, there's heat soak and I can hear fuel moving in the carb from time to time. My gut feeling is that the new sensor is way more accurate than the old one. The next question is what to do about the heat?

This vehicle isn't the easiest to work on, with the front of the engine near impossible to get to and the rest of it under a doghouse. I envy those that have a normal hood where they can get to most things!
Image

The van still has a 1969 OE fixed (non-clutch) 5 blade cooling fan and a ~2" spacer. If you look at the fan out of the vehicle, it looks pretty weird. Visually, the 5 blades don't look balanced, but that's probably not relevant.

I'd love to keep the van semi-OE and with minimal mods, if possible. At the same time, I want to do this right the first time. I've read good things about people swapping out OE fans (not just Fords, but a variety of mfgs) with Flex-a-lite 6-blade fans. The fan itself is pretty cheap,but I'll likely have to drain the coolant system and remove the radiator to swap the fans. Any thoughts on whether these Flex-a-lite fans are worth the trouble? Anything else I'm missing or other suggestions? Thanks!

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Re: Temperature sensor/gauge?

Post #30 by sdiesel » Sat Jul 18, 2020 3:36 pm

I have not found the non OE to perform any better than OE
My 460 and my 351 had 5 blade fans with wide paddles.

If the sensing unit is giving accurate info, then you have a different cooling problem; collapsing hose, blockage
Air in the system etc.
Adding fan to solve an overheat,usually means there is trouble afoot., On the other hand, adding fan to handle heavier load is perfectly acceptable, even so much as a fan from a Cummins Dodge.
An upstream pusher fan ,may help too.

Last of course u grounded ur wire to verify gauge is good
a long love affair with the 300 six.
my lastest and final fling is a fresh 300 in an 88 ford f350 dually 4X flatbed

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Re: Temperature sensor/gauge?

Post #31 by rratselad » Sat Jul 18, 2020 3:51 pm

One of the first things I did was ground the wire to the sensor and the gauge pinned to the hot side.

I’m wondering if there is a design flaw or problem with the Econoline vans with Carter YFs and (Over)heating? Before the motor was rebuilt, there was a ton of carbon in the intake and head. Everything I’ve read seems to indicate that this is consistent with a heat soak problem. It doesn’t help that the OE exhaust manifold is directly under the carburetor. In another thread, someone suggested that they had added extra fans to alleviate the heat soak issue with a Carter YF. Unfortunately, I don’t have room to mount extra fans like that and I’m also trying to maintain an OE appearance (again, where reasonable). Thanks!

sdiesel wrote:I have not found the non OE to perform any better than OE
My 460 and my 351 had 5 blade fans with wide paddles.

If the sensing unit is giving accurate info, then you have a different cooling problem; collapsing hose, blockage
Air in the system etc.
Adding fan to solve an overheat,usually means there is trouble afoot., On the other hand, adding fan to handle heavier load is perfectly acceptable, even so much as a fan from a Cummins Dodge.
An upstream pusher fan ,may help too.

Last of course u grounded ur wire to verify gauge is good

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Re: Temperature sensor/gauge?

Post #32 by THE FRENCHTOWN FLYER » Sat Jul 18, 2020 4:37 pm

I have become a believer in adding a fuel return line. Tee it in before the carb, run the return line with an .080" restriction in it back to the tank (or fuel filler tube if that is easier (direct the fuel down into the tank)). Keep it away from the exhaust. Many big block luxury cars use return lines.
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Re: Temperature sensor/gauge?

Post #33 by rratselad » Sun Jul 19, 2020 8:29 am

Frenchtown - would be unreasonable to plumb the "return" back into the supply line, with restriction you noted, within the engine compartment? Basically, tee the fuel line right above the pump and plumb it to a tee right before the fuel pump? It seems like this would allow the system to depressurize when turned off. I'm guessing this would allow too much fuel to drain out of the line between the pump and carb when the vehicle isn't used for a few days?

Also, how do you feel about the carb spacers? I might be able to get away with a very small one, like 1/8." There's a 2014 post here about them that I hesitate to revive given how old it is:

viewtopic.php?t=71698#

THE FRENCHTOWN FLYER wrote:I have become a believer in adding a fuel return line. Tee it in before the carb, run the return line with an .080" restriction in it back to the tank (or fuel filler tube if that is easier (direct the fuel down into the tank)). Keep it away from the exhaust. Many big block luxury cars use return lines.

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Re: Temperature sensor/gauge?

Post #34 by THE FRENCHTOWN FLYER » Sun Jul 19, 2020 4:08 pm

Plumbing the return line back to the supply side has its merits insofar as you will be cooling the hot spots with recirculating fuel, but it probably won't keep the fuel as cool as drawing from the big tank reservoir.

An insulating spacer can help. Its on my list to add a spacer plate to my truck under the carb to reduce the amount of heat convection coming off the manifold.
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Re: Temperature sensor/gauge?

Post #35 by rratselad » Sun Jul 26, 2020 2:02 pm

Has anyone found a source for the phenolic spacers for a 1bbl? Should it be the same spacer for an Autolite 1100 and for the Carter YF?

Update 8/31/2020:
The Carter YF needs its own spacer:

https://www.dashman.net/product.html?id=357
https://www.dashman.net/product.html?id=358

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Re: Temperature sensor/gauge?

Post #36 by rratselad » Mon Aug 31, 2020 10:52 am

So, I found a phenolic spacer for the Carter YF and the van runs a ton better! I'm still ending up with some heat-soak after shutdown.

When the van is running, I can hold onto the carb while driving and it's really cool! After shutdown the carb gets hot and I can hear the fuel boiling/percolating after a few minutes. The van restarts relatively easily, but the reason why I care is that the boil-off seems to go down into the manifold and leaves heavy carbon deposits at the base of the manifold, even after only ~1000 miles of driving.

I could be wrong, but after watching what happens it seems like the heat is coming up through the studs in the manifold. Any ideas on how to mitigate that?

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Re: Temperature sensor/gauge?

Post #37 by THE FRENCHTOWN FLYER » Mon Aug 31, 2020 11:26 am

rratselad wrote:I could be wrong, but after watching what happens it seems like the heat is coming up through the studs in the manifold. Any ideas on how to mitigate that?

Maybe use phenolic washers under the nuts too?

I have vapor lock issues on my 460 V8 powered pickup. I have found that the best way to get it to restart after a hot soak is to leave the electric fuel pump OFF.
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Re: Temperature sensor/gauge?

Post #38 by rratselad » Mon Aug 31, 2020 2:04 pm

That's an interesting idea. I guess I'll have to figure out where to source those.

Is there any reason to (or not to) put a lower temp thermostat in? Perhaps, if I lower the overall operating temp, there will be less heat to soak? Right now I'm running an OE 195 degree unit. It looks like there are 180's available. Is this too cool and will I end up with different problems?

Update - Aside from the questions above, I was just looking over the system and noticed that it has a 7lb radiator cap. No clue why it's that low - I inherited it that way. Rockauto and the local NAPA says I should have a 13lb cap. Worth trying this too/first?

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Re: Temperature sensor/gauge?

Post #39 by bubba22349 » Thu Sep 03, 2020 4:59 pm

In my OPIN changing the thermostat from a 195 to 180 isn't going to help you, the facts are there isn't a good reason to change to the lower rated thermostat this is because its 15 degree quicker opening time isn't likely to change the over all operating temperature of the engine to any extent. Both the 180 and 195 at their rated temperature opening will essentially will have the same coolant flow through rate. If the current 195 thermostat is opening at or near its rated temperature than its already doing the job that was designed to do which is to help in quickly warming up the engine to its rated operating temperature which helps the engines best performance and economy. Yes changing your radiator cap pressure back to the higher factory rated pressure cap maybe be worth trying, it will raise the coolants boiling point to a higher tempature. Good luck :thumbup: :nod:
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