Offenhauser intake manifold on the 2f engine,

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steffan said:
Based on the race shop that rebuilt my engine, the heads (small ports etc) on the 2F are the biggest limiting factor for power. I can’t imagine that manifold would help much as it would all get restricted in the head
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Pretty much true of any head/manifold selection. The worst intake manifold outflow the better heads. The key is to keep reducing the restrictions on flow, within reason.
 
timmyisinthewell said:
I bought the Man-A-Fre combo #2 back in the day, and as I recall I got from 9 to 12 mpg. I can't really tell you if there was much of a difference from stock in mpg or performance. Of course that was forty six years ago.

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trainbufftony said:
They aren't really speed equipment.
Speed equipment is built in a machine shop, not bought in a catalog.
These are dress up kits.
People still to this day put dress up kits on their cars. Usually they run worse afterwards, and often they won't pass a smog with the kit. In my experience as a mechanic I've never seen an instance where someone replaced a single carb with dual carbs and had it run better.
Dual carbs make the same air travel through a wider set of holes which reduces its velocity and it's ability to fill the cylinders completely at low RPM.
F engines don't run at high Rpm due to their stroke, so you need to concern yourself with low RPM power.
Low rpm power is what gets you crawled safely out of obstacles. Low RPM power is the landcruisers strength.
Let's recap:
No dress up kit in the world is going to make the F into a high rpm engine.
More carburetor decreases air velocity at low RPM.
If you're trying to 4wheel the thing, I'd hang the fancy intake on the wall, run stock.
If you just drive around town and to car shows, put the dress up kit on it and show off..
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If it doesn't go fast, chrome it!!!
 
trainbufftony said:
They aren't really speed equipment.
Speed equipment is built in a machine shop, not bought in a catalog.
These are dress up kits.
People still to this day put dress up kits on their cars. Usually they run worse afterwards, and often they won't pass a smog with the kit. In my experience as a mechanic I've never seen an instance where someone replaced a single carb with dual carbs and had it run better.
Dual carbs make the same air travel through a wider set of holes which reduces its velocity and it's ability to fill the cylinders completely at low RPM.
F engines don't run at high Rpm due to their stroke, so you need to concern yourself with low RPM power.
Low rpm power is what gets you crawled safely out of obstacles. Low RPM power is the landcruisers strength.
Let's recap:
No dress up kit in the world is going to make the F into a high rpm engine.
More carburetor decreases air velocity at low RPM.
If you're trying to 4wheel the thing, I'd hang the fancy intake on the wall, run stock.
If you just drive around town and to car shows, put the dress up kit on it and show off.
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Agree with most of what you said except more carbs reducing velocity. Maximum cylinder fill is a given but velocity is enhanced in smaller individual venturis. Max cylinder will not using pressure enhancement i should have added.
 
AirFuelRatioMan said:
Good that you read not to install a Weber 38/38. Not because it is a bad carb, I’ve ran them for over a decade and not once have I had a single issue. That said, the 32/36 AND 38/38 were made for engines no bigger than 2.3 liters. The accelerator pump shot is not sufficient for an engine bigger than 2.3l, and a lean sag will be experienced that can not be tuned out. This is why many claim that Webers like lots of advance, which is hog wash. The extra advance is helping a very lean air/fuel mix to better combust, that is all. Also, most end up jetting the idle circuit pig rich to compensate as well.

A 4 barrel is not too much carb for the 2F. The primary’s on a 4 barrel are smaller than a Weber 38/38 and Holley 350, and the secondaries will only open when a restriction is present. At least, if you are running vacuum secondaries. CFM calculators should be thrown out the window when sizing a carb for a straight six. The intake stroke pulses the carb, this can be seen when running multiple carbs where each throat feeds it’s own cylinder. The 2F requires 700 cc’s to be filled per intake stroke, a Chevy 350 requires 712. At any given rpm it takes the same amount of time and volume to fill the 4.2 l6 as it does the 5.7 v8. Therefore if a v8 of similar cylinder volume requires or runs best with a 600-650 cfm carb, the same can be said for the l6.

This has been shown with 650-750 cfm carbs on Ford 300s and also Chevy 292s. If using an “average” cfm calculator on a straight six, your cfm will show you need a much smaller carb and will become a restriction to the engine.

All that said, if no change is made to the cylinder head and exhaust, and the restriction occurs elsewhere, any benefit from the larger carb will be greatly reduced.

Anyway, I do believe Offy will still make the C series manifold upon demand. They are listed on Summit Racing, and have a ship date so…….

Lastly, the C series specifically states to run a 500+ cfm carb. The DP states 500cfm or less.

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Great information on sizing carbs on the 2F motor. Unfortunately our Aisan 2 barrel is running 31/35, even less than the Webers.
 
Hello everyone,

I have another specific question.
And my cylinder head is almost finished now.
Unfortunately, my camshaft is no longer in good condition.
I've read so much about camshafts here, but I'm still not quite sure what to do next.
Maybe I've already read way too much...🫣🫣🙆🙆
I actually intend to send my camshaft to Delta Cams in Tacoma.
What I'm not sure about, however, is which camshaft profile I should have ground.
There are two profiles: the 250° profile and the 262° profile.
Which one would you recommend based on your experience?
I definitely don't want the torque to shift too far into the upper rev range.
It's definitely not meant to be a race car, but more of a power cruiser.
I hope you can give me some good advice so I can send my camshaft on its journey to Tacoma.

It's already packed...😎✌️

Thank you so much in advance and have a nice day everyone,

Jürgen
 
Landcruiserfj45 said:
Hello everyone,

I have another specific question.
And my cylinder head is almost finished now.
Unfortunately, my camshaft is no longer in good condition.
I've read so much about camshafts here, but I'm still not quite sure what to do next.
Maybe I've already read way too much...🫣🫣🙆🙆
I actually intend to send my camshaft to Delta Cams in Tacoma.
What I'm not sure about, however, is which camshaft profile I should have ground.
There are two profiles: the 250° profile and the 262° profile.
Which one would you recommend based on your experience?
I definitely don't want the torque to shift too far into the upper rev range.
It's definitely not meant to be a race car, but more of a power cruiser.
I hope you can give me some good advice so I can send my camshaft on its journey to Tacoma.

It's already packed...😎✌️

Thank you so much in advance and have a nice day everyone,

Jürgen
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Cam2.webp
 
Landcruiserfj45 said:
"However,I'm not so sure anymore whether that's really a good idea,because I've read a lot now and some people say that it should be really great and others write that it's better not to do it.
Now of course I'm a little unsettled."
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Yes. This will be true for every question that you ask. Welcome to Mud! :)
 
Landcruiserfj45 said:
Hello to the 2f engine professionals here,

i'm thinking about getting the Offenhauser intake manifold for my 2f engine.
I have at least two questions about this.
And does anyone of you know where i can get an Offenhauser intake manifold,or maybe one of you even has one for sale ?
Because here in germany there is absolutely no chance of finding one.
But...and now the professionals are asked here...is it recommended to screw an offenhauser 4-fold intake manifold onto the 2f ?
There would also be a header and an electronic distributor.
Would that to be a good think,or would you feel that in terms of performance or rather less ?
I would be happy to get some answers.
It doesn't matter whether it's positive or negative...


Kind regards and thank you in advance,

Jürgen

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There are actually two different Offy 4 bbl manifold for the Toyota FJ40 motors. One is a dual port and the other is a "C" single port manifold. The dual port separates the primary and secondary flows in an attempt to insure better velocity and possibly torque and mileage.
 
Landcruiserfj45 said:
Hello to the 2f engine professionals here,

i'm thinking about getting the Offenhauser intake manifold for my 2f engine.
I have at least two questions about this.
And does anyone of you know where i can get an Offenhauser intake manifold,or maybe one of you even has one for sale ?
Because here in germany there is absolutely no chance of finding one.
But...and now the professionals are asked here...is it recommended to screw an offenhauser 4-fold intake manifold onto the 2f ?
There would also be a header and an electronic distributor.
Would that to be a good think,or would you feel that in terms of performance or rather less ?
I would be happy to get some answers.
It doesn't matter whether it's positive or negative...


Kind regards and thank you in advance,

Jürgen

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View attachment 3653911
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Additionally a small 390 or 465 cfm Holley vacuum secondary carburetor is not too much for a warmed over 2F motor.
 
charliemeyer007 said:
Actually part freeway at then 55mph for about 50 miles out, then about 70 miles idling along in second gear road hunting varmints, then back to the same gas pump I filled up at on the way out. I did this for many years and always got 25mpg for the trip.
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New here. That is amazing mpg. I normally run at 2800 to 3000 on the freeway and obviously less on 2 lane roads and in town. I average about 12+ mpg.
 
That is why I never wanted to change anything. I do think my new chinasium delco is working good now. Next I need to pull the carb and rot it out in the heated ultrasonic cleaner. Plus fix the odometer and a few other issues. I'm not pulling as much vacuum - intake gaskets might be loose - or the gauge is getting tired.
 
charliemeyer007 said:
That is why I never wanted to change anything. I do think my new chinasium delco is working good now. Next I need to pull the carb and rot it out in the heated ultrasonic cleaner. Plus fix the odometer and a few other issues. I'm not pulling as much vacuum - intake gaskets might be loose - or the gauge is getting tired.
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Biggest problem i have had with the stock carb is non functioning vacuum secondary. Paper clip trick will let you know if yours is functioning. Replace diaphragm and clean out ports is all it usually takes.

Of course you need to know which year carb you have.
 
rex in bama said:
I should be picking mine up from the shop this week - ended up pulling the offy manifold and Holley 350 and taking it back stock (well, with headers staying put). Very interested to see how she runs in comparison (and maybe listing for sale the old set-up here soon).
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I know this is an old thread, but didn't you decide on a cam? My 2F has the MAF offering and it has been fine the last 30k miles.
 
AirFuelRatioMan said:
Too bad you didn’t put a proper 4 barrel on the Offy. I may be picking up a C Series and slapping a QuickFuel Slayer 600 on her. Fully adjustable idle feed restrictors, air bleeds, secondary jets and accelerator pump. Oh and, a simplistic screw adjustable vacuum secondary 😎😎

If you decide to sell the Offy please let me know.
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Did you ever find the Offy intake? Curious as to how well your combo worked out.
I ran across dual-port Offy and 390 4bbl on N 81 FJ40 years ago. It ran great.
I have an Offenhauser "C" with a 465 Holley sitting on a shelf to be installed on my current 78 FJ40.
 
AirFuelRatioMan said:
I wouldn’t say backwards, in many cases stock is rock. However, running Yukon gears, Grizzly lockers, and RCV axles will greatly exceed off road performance and strength far beyond what Toyota originally built.

I also run GM HEI with a Toyota electronic dizzy, as IMHO, it is the highest performing most reliable setup I can achieve. Not to mention replacement parts are dirt cheap.

I have no loyalty to Toyota brand, instead like to take the best of all things available to me. Interestingly, our straight six motors were based off of GM Stovebolt engines :)

Regardless, I changed carbs because I could not manage to find jets for the darn thing. Looked everywhere, all I found were rebuild kits. I’m at 9000 feet and have big elevation changes to deal with, so I went with something that was far simpler to tune, to obtain jets for, etc.
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Have you considered fuel injection for your FJ?
 
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