FJ40 1976 Sluggish/Strained Starts Hot Engine 2F…Exploring Heat Shields, Carb Cooling Fan. (2 Viewers)

hobbes

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My 87 2F has the fuel return on the fuel pump. Better, I think, was the older style on the carb. Either way, it’s recommended to have something.

I’ve got an OEM carb rebuilt by JimC, use non-ethanol fuel, and have no issues in southern FL. Not as severe a test as the desert southwest, I know. When the engine is hot I just put the petal to the floor and hit the starter. That said, I do use 3FE headers, so my intake is undoubtedly cooler.
 
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ToyotaMatt

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I have a 1976 South American FJ40 with 2F Engine running a Chinese made H3662 aftermarket 21100-61012 carb. No smog. I’m exploring my options to eliminate the sluggish/strained starting when hot in preparation for summer driving. My SA FJ40 was built in 4/76 and has original rebuilt engine. I’m considering adding the following:
  • Carb cooling fan 16362-61020 Fan No. 2 (California Spec) click here
  • Carb heat shield 21912-61012 (shield for mechanical linkage) click here
  • Exhaust Manifold Insulator Heat Shield NO. 1 17167-61010 click here
  • Exhaust Manifold Insulator Heat Shield NO. 2 17168-61010 click here
  • Exhaust Manifold Insulator NO. 3 17169-61011 (still available from Toyota click here )
I‘ve not fully researched this yet but wondering:

A) why these SA trucks had no exhaust shields or cooling fans?

B) will just the shields be enough to help with hot starts?

Below are the shields I need and shots of my carb set up.

View attachment 2636389
View attachment 2636390


your on the right path Paul starting with the static fundamentals of SUPER HEATED FUEL ATOM-IONIZATION symptoms


i can help in one key area , now

then once you obtain a drivers side Squirrel cage type black metal carb cooling fan off a FJ40 , NOT a fj60 there NOT compatible mounting .fyi

i can then go into great technical detail , about a manual Timer VS a manual Pull Switch options pros cons etc...

for engaging your late model 40 carb cooling fan circuit

i like to say never say never , but your PERIOD correct Front BIB style california spec. only ENGINE cooling fan option , has 2 major flaws :

- NLA anywhere on earth

- the fan is a general engine bay cooling fan assy , NOT a carb dedicated cooling with a duct jetting cool fresh air on the float bowl itself .........

- this is a huge difference here , the California fan WILL NOT Address your atom-ionization symptoms properly at all

in my opinion ...



see link below :

include all needed mounting hardware complimentary too OEM too of course ......... :cool:

PM me for you PROMO discount code as well , I WANT to Help out here make this right in any way i can , i have properly updated my 1983 FJ43L-KC Columbia spec. , in my above prescribed fashion , and a manual spring loaded 30 minute wind up timer .........

30 - 60 minutes of constant fan ON power KEY OFF , will NEVER drain your battery at all NO WAY !



 

Ackcruisers

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Thanks for this @ToyotaMatt. I wondered why the “BIB“ style fan was called a “carb cooling fan” as it flows air across the engine bay vs directed to the carb. The 16362-61020 Fan No. 2 (California Spec) was very short lived and was replaced by 16360-61023 click here 9/77- 1/80.

My louvered vent on driver side does not have the metal bracket inside to mount the 16360-61023 style fan. Has anyone retrofitted a bracket? (Photo by @psmbfuer )
327841DA-629A-47C0-88A8-EA3F4C3585D3.jpeg
 

ToyotaMatt

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Thanks for this @ToyotaMatt. I wondered why the “BIB“ style fan was called a “carb cooling fan” as it flows air across the engine bay vs directed to the carb. The 16362-61020 Fan No. 2 (California Spec) was very short lived and was replaced by 16360-61023 click here 9/77- 1/80.

My louvered vent on driver side does not have the metal bracket inside to mount the 16360-61023 style fan. Has anyone retrofitted a bracket? (Photo by @psmbfuer )
View attachment 2640970


looks like a trip to home depot sheet metal isle and some 18guage

you vise and a mapp gas torch

BANG done
 

Dizzy

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I agree. However, my 2F, previous Fs, ran/run really bad when it is cold - all with headers. As bad as 8 mpg, now back at 12 mpg. A hot start isn't as bad as a not-properly-atomized condition that could last for months. Although, I'm pretty sure that I recall Ackcruisers signing off for the year with the road salts last winter/fall?
 

Ackcruisers

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I agree. However, my 2F, previous Fs, ran/run really bad when it is cold - all with headers. As bad as 8 mpg, now back at 12 mpg. A hot start isn't as bad as a not-properly-atomized condition that could last for months. Although, I'm pretty sure that I recall Ackcruisers signing off for the year with the road salts last winter/fall?
I did sign off for the season in December prior to first snow fall here in New England. I do want ability to run truck year round.
 
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I have a used carb fan from a 60 if you want it, or two bilge pump fans from a Grady-White(these you can mount just about anywhere)
If you don't mind losing a little authenticity, a good set of headers will solve your heat problem immediately--never to return.(my '77 has been been running this way for >10 years--no issues--then again, I'm in Fla. so I don't have to deal with really cold weather-usu I get 13+ mpg at a steady 55 mph on trips)
Dizzy would have way more experience than I do with the weather related fuel consumpotion
 

Dizzy

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I love my 'Aussie' header. But, some of what I experience in the winter is carb-related. It hates running the choke for fast-idle, too lean is the symptom (I'm overtly contradicting the pros, and 2F-vets, here). My current engine has low compression, and vac. The Aisan air horn makes an obscene mess of securing the venturis, relative to other carbs, and the minimal use of the choke butterfly seems to almost starve the main circuit, there is the bucking lean. Sure, the factory manual wants me to warm up the engine, but, I don't have the time, really. Plus, it is not just out of the driveway, but ten miles out on the trail. Once started, the engine responds well to a lot of fast-idle and less choke. No problem here, just an observation. But, as a side note, the ICE, in general, isn't as efficient at my 6,900' of altitude.

In my previous post, I was thinking that the thing about headers, or 3FE exhaust, is that you are hacking the factory design. It might be a good thing, but, why give up something that was, by the factory, considered a positive, in the name of progress? My factory transmission hump tar insulator was a gooey melted mess when I got the truck, and it had headers. The cab is super hot from now until fall, and I generally consider headers to be an unintentional heat-exchanger. I just came really close to getting the fiberglass gear covers, for heat insulation alone. I'd consider the exhaust block-off plate from Cruiser Outfitters, and using it with a '75 manifold, but my manifold needs an EGR plug, and I need to get the down-pipe flange, plus my intakes are kinda in rough shape for more heat, so, in general I'm kinda envious of anyone who can easily run a mostly stock set-up.
 

1MOA

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Before you do anything run 3 tanks of ethanol free gas through it and see if it clears up. With modern fuel blends and 10% ethanol in your fuel coupled with a chinese knock off carb that has unknown "qualities"

An engine can only burn the vaporized portions of the gasoline.
Depending on the time of the year and local regulations, ten percent of the fuel should be evaporated when the temperature reaches the 122°F to 158°F range, 50 percent of the fuel should be evaporated when the temperature reaches the 170°F to 250°F range and 90 percent of the fuel should be evaporated when the temperature reaches the 365°F to 374°F range.

The under hood temperature of many vehicles will reach 230°F or higher during a hot soak (after the engine is shut off) so 50% of the gasoline (the most volatile parts of the fuel) in the carburetor may boil off. This heating and subsequent boil off of fuel components can and does wreak havoc on fuel curves and ignition timing requirements of a carburetor equipped engine plus it will create vapor lock issues if the gasoline boils in fuel lines or the carburetor bowl(s).
If your gasoline is burning off beofre you start it as it sits hot you are left with the "garbage" ( esters, and agents) it try and fire the engine not to mention the gunk that ethanol leaves in your fuel system.
 
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Ackcruisers

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B) will just the shields be enough to help with hot starts?

In my opinion (and 30 years of farting around with hot starts), they will do nothing to stop hot soak or vapor lock. The rear-most manifold shield is to stop heat from getting to the firewall. The front manifold shield is the heat stove for winter starting. The shields between the the ex and intake are part of the heater riser system for cold starting.

I took apart my manifolds and had 1" of metal milled off the bottom of the intake manifold, and made a 5/16" steel plate to seal off the exhaust manifold. This large air gap between the manifolds prevents some of the exhaust heat from cooking your intake. I also switched to TBI fuel injection, which was the real cure to endless hot starting issues.

The OEM design of having the exhaust manifold directly below the carb. will always create heat problems on summer days. A carb fan (I still have and use mine) is a good idea. Our crap gasoline (with Ethanol or not) is designed to control emissions, not to allow 50 year old trucks to run well. I added EFI (AFI TBI) to my truck so that I could drive it on hot days without a near-death experience every time I pulled out of a gas station or after parking the truck for a few minutes on a hot day.

Steve
I think the metal plate idea is smart. I just found this video that shows a heat riser spring in action.
.

Also, Kurt from Cruiser Outfitters has a block off plate. This thread click here explains it very well. I believe my problem will be solved with the plate and cooling fan combo.
 

Dizzy

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I'm one step behind. I was thinking about your carb. I just installed a new OEM non-USA 2F carb in place of the old '75 smogerator. In a rush, work is busy.. It ran great. Then I filled the tank, 11mpg, but much of that the idle was a bit high. Not bad, for the kind of driving that I was doing. I did a lean-best adjustment at the gas station. Then it wouldn't start. With the old carb, the idle adjustment didn't matter much, I figured that it was because the throttle plate was beyond the intended idle spot (less dense air at my elevation), and at the next progression hole. I enriched it by 1.5 turns, ran, and started like a charm. What I'm getting at is if the starter isn't moving the engine at a high enough rpm, vacuum won't be great enough to get it enough fuel until if your throttle plate is really closed. I'm trying to stay at the lowest non-USA spec for that that I can - I love to not hear so much engine at the stop light, or when I'm cruising in neutral, plus, I'm going for fuel range on the stock tank.

Try enriching the idle mix screw is my solution to the lean start.
 

Ackcruisers

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I'm one step behind. I was thinking about your carb. I just installed a new OEM non-USA 2F carb in place of the old '75 smogerator. In a rush, work is busy.. It ran great. Then I filled the tank, 11mpg, but much of that the idle was a bit high. Not bad, for the kind of driving that I was doing. I did a lean-best adjustment at the gas station. Then it wouldn't start. With the old carb, the idle adjustment didn't matter much, I figured that it was because the throttle plate was beyond the intended idle spot (less dense air at my elevation), and at the next progression hole. I enriched it by 1.5 turns, ran, and started like a charm. What I'm getting at is if the starter isn't moving the engine at a high enough rpm, vacuum won't be great enough to get it enough fuel until if your throttle plate is really closed. I'm trying to stay at the lowest non-USA spec for that that I can - I love to not hear so much engine at the stop light, or when I'm cruising in neutral, plus, I'm going for fuel range on the stock tank.

Try enriching the idle mix screw is my solution to the lean start.
Thanks for this. I am considering getting a new gear reduction starter as the one that came with my truck is a little tired. The starter is still available from Toyota 28100-60070-84. Click here. My truck starts perfectly when cold with proper choke and idles to non USA spec. The only time I have a difficult time starting is when the truck has been running for a while and turn it off for 5 minutes then try to start it again. The truck will start without any "real" problem but it just is sluggish requiring a few turns of starter/flywheel. Your suggestion of the starter is a good one. With a stronger starter, the gas that may have boiled off will be replenished faster.
 

Dizzy

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Well, the (traditional) hot start is perhaps a rich condition. The factory manual suggest an open throttle to work with that.

In my post, yesterday, I loosely concluded that my condition was too lean. My carb setting is probably out of wack, as there isn't enough density of air, here at 7,000.' However, I wouldn't expect a starter to spin the motor at like 500 or 600 rpm. However, that is where we are setting our idle mix screws.
 

Dizzy

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20210427_075724.jpg


I was suggesting that the slow jet (#16) seems to basically meter out the fuel for the idle circuit. The idle mix screw can almost be closed completely if the throttle plate is at the dotted line as it is illustrated above, and it will still idle, getting fuel from the above progression hole. However, the vacuum created by the starter, and the vacuum from the engine running is totally different. In other words, I would consider the idle mix, and idle speed settings, as they might affect air / fuel balance at a certain rpm.
 

GA Architect

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I'd second the 3FE exhaust manifold modification as @hobbes pointed out above. I'll be doing that modification for my '71 FJ40 build with the '76 2F that's in there now. BTW, the 3FE manifolds are equipped with heat shields as well.
I know it has been done before, but another well documented process & procedure is always helpful. :)
 

4Cruisers

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I know it has been done before, but another well documented process & procedure is always helpful. :)
Will do. I spent a lot of time researching the needed hardware, came up with a parts list, and made a drawing. I bought all of the hardware and put together a kit. It'll be later this year before I get to the project.
 

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