1F or 2F what should I do?

[sscsksl]

I have a 71 40 with a 1F motor and 3sp that runs just OK. I also have a 75 40 with a 2F motor and 4sp. The 75 is only good for a few parts, so my question is:

Is a 75 2F motor and trans worth rebuilding to put into the 71?

I have a PTO wench, is this going to be a problem.

I checked the FAQ and did not see this addressed.

Thanks for your help.

 

[Pighead]

I have a 71 40 with a 1F motor and 3sp that runs just OK. I also have a 75 40 with a 2F motor and 4sp. The 75 is only good for a few parts, so my question is:

Is a 75 2F motor and trans worth rebuilding to put into the 71?

I have a PTO wench, is this going to be a problem.

I checked the FAQ and did not see this addressed.

Thanks for your help.

A) That's more than 1 question.

2) Yes.

III) Wench questions are handled in the chat section.

 

[texfj40]

I have a 71 with a completely rebuilt original engine that had only 256k original miles...with original 3 speed. Ran perfectly all these years. Now I have 40 more years of the manufacturers original engine that does a superb job for what the fj40 was designed to do. It is up to you if you want to keep it original or make a hot rod out of it.

 

[joemck7]

I wouldnt say that a 2f is a "hotrod" by any means, but there is something to be said about keeping things original. I had a 74 with a 3spd/F engine and it really felt like a tractor. It was great for getting around town but >50mph was not nearly as good as the 4spd/2F that I currently have.

I think that a well tuned and maintained 1F or 2F will be great and really the question is what you are going to be doing with the truck? A lot of people mistake the differences between 1F and 2F to be the engine when in fact it is the difference between the 3spd and 4spd.

 

[IDave]

2F hot rod. Heh-heh.

I would definitely keep the 2F and swap it in when the 1F dies unless you love original. You can make a 2F work with all of your 3 speed stuff.

 

[fj40er]

Do what I did use the 2F block and put the F head on it. I then board my motor 30 over, and yes it runs great, a ton of power. And the best thing is "Its A TOYOTA" not a chevota. I love my 6cyl.

 

[Pighead]

Do what I did use the 2F block and put the F head on it. I then board my motor 30 over, and yes it runs great, a ton of power. And the best thing is "Its A TOYOTA" not a chevota. I love my 6cyl.

I don't know if that works real well, putting a '71 F head on a 2F...how do you get oil up to the rockers? Instead, maybe do what I did, put a late F/1.5F head on the 2F block...still not what I would call "a ton of power", but not too shabby.

 

[sscsksl]

Is the head on a 1F better than the one on a 2F? If so why?

Is the block on a 2F better than the 1F? If so why?

Trying to learn here...

 

[Pighead]

Is the head on a 1F better than the one on a 2F? If so why?

Is the block on a 2F better than the 1F? If so why?

Trying to learn here...

"Is the head on a 1F better than the one on a 2F? If so why?'
Not necessarily, just different. Also, familiarize yourself with the differences between early F and late F engines.

"Is the block on a 2F better than the 1F? If so why?"
Yes. Bigger displacement, improved oiling, bigger manifold studs, bigger motor mount bolts...just is.

 

[IDave]

It is not a simple thing to put a 1F head onto a 2F, because of the oiling systems. I wouldn't go there myself unless I was completely comfortable with the issues involved.

 

[sscsksl]

Great info thank you!

 

[Pighead]

It is not a simple thing to put a 1F head onto a 2F, because of the oiling systems. I wouldn't go there myself unless I was completely comfortable with the issues involved.

Right. Unless it's a late F 1F head. Then it's a bolt-on...

 

[IDave]

Right. Unless it's a late F 1F head. Then it's a bolt-on...

F 1/2 engines are really just baby 2Fs. I've got one in my barn and I'm waiting for it to grow up.

 

[sscsksl]

For the 4sp, do I just need to install a PTO gear?

 

[MuskieFJ]

Why we are talking engines, what are the years of the "F", "F 1/2", and "2F"? I have a 9/72 and an 8/74 and am curious as what I have in them. I just assumed there were both 1F engines and wanted to know if either were the F 1/2. Thanks!

 

[dmaddox]

block stamp will say F or 2F down on the number pad.

My old F (F-135) runs like a champ. I think you need to change the direction of this thread to fixing your F - or start a new one on dialing it in/tuning it with more information on what your definition of "runs OK" is to see if we can help you save money and time by getting your F running right.

F or 2F not a huge difference and I am happy with my OLD siamese F

this f 1/2 is a transition year where the heads are a bit different, on an F block. So, post the numbers off the head for a more exact definition. No offense, but does it really matter? Or were you just curious?

 

[sscsksl]

No offense taken, I appreciate the help.
1971 FJ40 block stamp says F 274973
1975 FJ40 not available now to look at, but it definitely has a different shape motor, assuming it is a 2F.

The question on the heads stemmed out of curiosity from a response received, mentioning swapping head.

If there is not a marked difference between an F motor and a 2F motor, I would assume to keep the one in there. I would like to swap the 3sp for the 4sp but install a PTO gear so that I can keep my stock wench.

As far as runs OK: I had the carb completely rebuilt by a mechanic and it ran better, but still not great. Coughs sputters and dies often.

What do you recommend?

 

[tlc_4play]

Is a 75 2F motor and trans worth rebuilding to put into the 71?

Its a no brainer, rebuild and install the 2F

 

[My wife said no FJ!]

Did you mention what your plans are for this rig, cause if so I missed it.

 

[Trollhole]

Cannot put just any F head on a 2f block.
Cannot put a 1.5 F head on just any 2F block.


Per Mark W (and my summary added in)

Pre '68 F engines used siamesed exhaust ports and a deep "bathtub" style combustion chamber. They're pretty much on their own so far as interchanging anything. So don't be installing anything pre '68 on anything after '68.

From then until '72 the F engine used a flattop piston and a closed combustion chamber.

'73 and '74 F engines used an open combustion chamber and a very small dome on the piston.

'75-'80 US variant 2Fs used an open chamber and a domed piston.

'81 and later 2Fs used a closed chamber and a flat top piston.


A '73-'74 F head will be a bolt on swap to any of the 2F, producing more compression on the '75-'80 blocks.

A pre '73 F head will swap to the later 2F engines ('81 and later) once the rocker arm oiling is addressed. There will be piston/head interference on the early 2Fs. So you cannot use a pre '73 f head on a '75-'80

You can install an early 2F head on a late 2F engine. You will loose compression. So don't do it!

You can install any 2F head on the pre-'73 F engines. Again, you will loose compression, especially if you install an early 2F head with the open chamber. So don't do it!

Do it right once or don't do it at all.