3FE vs 2/3F carb cyl. head (1 Viewer)

[Delancy]

Very interesting.

Confusing, actually.

What's the difference in a 2F and 3F head?

Nothing.
Starting in 1985, the 3F became world standard, and the one market (USA) that soldiered on with the 2F got the 3F cylinder head. Head gaskets are also the same.

Yes, the 2F manifolds bolt to a 3F head. That's how they come from the factory for 85-87 2F engines.
Also, 3F manifolds bolt to any 2F head, although if it is an 84-earlier 2F head, there will not be the extra bolt holes for the additional 3F manifold bolts.

Has your position on this maintained throughout the subsequent years beyond this original post?

Is that a nice way of asking a foremost authority on F engine compatibility "if he's sure"?

Is it possible that non-US 3F heads had variations beyond 87?

Loosely basing the inquisition on this:

Just an update on this thread :

I have a 3F carbed head ( Africa spec ) - It does not look like the 2F head but just like the 3F-E head without the injector pocket .

So I reckon it is possible to cut pockets into the 3F head if you want to retrofit the 3F-E intake manifold and convert it to eFI . Can someone tell me how deep , wide and how high the injector pockets are so I can make plans to cut these pockets . I can easily import a intake manifold but to import the head as well will be too expensive .

Pictures of 3F carbed cylinder head

Links seem to have expired on pics, but....

The 3F head with the kidney shape chamber seems to be more resistant to pre detonation than the 2F head with egg shape chamber .

Eluding to, at least, the latter 3F head castings to be a 3FE head, minus the injector pocket.

3F non US
11101-61050
11101-61060

85-87 US 2F
11101-61040

To further the data, it seemed logical to compare valves and camshafts (thanks, Onur), which the following resulted:

3FE and 3F share intake/exhaust valves.

2F, 3F, 3FE share camshafts.

2F is a different valve than either the 3F or 3FE.

Considering the 3FE valve differences are known, this would indicate that SOME variation of 3F head isn't the same as a 2F.

Right?

Any advantage with the 3F Int/Exh assy on a USA late 2F (with a 2F/3F head ) over the stock late 2F exhaust setup ?

Takers?

 

[Delancy]

Is it possible that non-US 3F heads beyond 87 had other variants?

 

[FJ40Jim]

Yes..

 

[cuencanolenny]

I am a little surprised that nowhere on Mud can I find where someone has measured the combustion chamber volume on the variety of F, 2F & 3F heads. I would do it, however, I don't have access to the heads.

 

[cmckown]

Trying to glean some more info from this thread! Yspen has pics that have expired of the same type head 11101-61050 that I have here.(I have a pic but it wont upload) I want to do the opposite of his idea and put this head on a 2F block. I can say that it looks just like the 3FE kidney shaped combustion chambers but does not have the injector style intake ports. I'm looking for the head cc's and anyones input. I'm thinking this will make a higher compression 2F. I think the 3FE head will cc the same.

 

[Delancy]

Yspen from South America??

Man, I won't swear, but thinking one of the lower octane heads that they compensated for by increasing displacement in the head.

I'll dig through notes tomorrow, as I made a ton.

Getting closer.... 3F head 2F block...kinda.

 

[cmckown]

check out this chart. I have 11101-61050. W/O emission control

 

[cmckown]

Cool Delancy! its coming along. 3f carb! Is it cable throttle? Is there some kinda riser under it? This is a generic pic of head I got off the web. I have yet to see the combustion chambers in person of the one here.

 

[cmckown]

What # head ya got there?

 

[CruiserShel]

Combustion chamber

Here's the combustion chamber for comparison.
The 3FE uses a tighter kidney-shape chamber which gives better turbulence and more squish. But at the cost of more valve shrouding. To keep the 3FE C.R. from being too high w/ the tighter chamber, the stock valves had very recessed faces.

Both heads benefit from the new flat faced valves, as that raises the CR, and reduces heat loss to the valve. Valves run hot, so reducing the temps of the valves, while increasing performance, is a good thing.


View attachment 127525View attachment 127526

Jim, I was just browsing your webpage. Is Reilly a flat coat retriever? I have one that looks like her.

 

[FJ40Jim]

He's the kind of dog you get for $20 at the county dog pound.

People who are knowledgeable about such things tell me he is a (or has a lot of) flat coat. I just know he's smart and generally well behaved.

 

[88red]

@FJ40Jim This looks like a good place to ask.
Are the valve seats are hardened on either of these heads?
I’m assuming the stainless valves are ground to 45deg. Do you resurface to 44.5 per FSM or does final lapping remove this in the end?
I’ve been wanting to tool up a bit to be able to rework the 3fe Instead of sending this all out to the machine shop. IE a set of seat cutters and possibly a used valve resurfacer to rebuild a couple heads I have sitting around.

 

[Spook50]

I came across this thread while looking for what exactly is different between 2F and 3FE heads. Very enlightening. Given this, what is the reason a late 2F exhaust header wouldn't work with a 3FE head? Or is it simply because it wouldn't be a bolt-in solution with the 3FE exhaust's downpipes?

And the more important question, @FJ40Jim are you (or anyone) selling upgraded 3FE heads? I may be in if for a head job next summer given the excessive amount of oil my PCV catch can is getting in the last few months (I have a couple suspicions but not 100% until I do a leakdown test), and would love to have an upgraded head to put on without waiting for my current head to be machined and rebuilt while I sit without a driveable vehicle. The thought of an upgraded head and the extra flow from it had me wondering about the adaptability of headers without the wild goose chase of looking for actual 3FE headers.

 

[Stumpalama]

I came across this thread while looking for what exactly is different between 2F and 3FE heads. Very enlightening. Given this, what is the reason a late 2F exhaust header wouldn't work with a 3FE head? Or is it simply because it wouldn't be a bolt-in solution with the 3FE exhaust's downpipes?

And the more important question, @FJ40Jim are you (or anyone) selling upgraded 3FE heads? I may be in if for a head job next summer given the excessive amount of oil my PCV catch can is getting in the last few months (I have a couple suspicions but not 100% until I do a leakdown test), and would love to have an upgraded head to put on without waiting for my current head to be machined and rebuilt while I sit without a driveable vehicle. The thought of an upgraded head and the extra flow from it had me wondering about the adaptability of headers without the wild goose chase of looking for actual 3FE headers.

For reference, here's some pics of the 85-later 2F or 3F cylinder head, and a 1988 3FE cylinder head. Both heads have been cleaned, milled and had valves changed to 1.50 & 1.84 stainless SBC parts.

Notice how the FI intake ports have a significantly raised gasket surface. It would be pretty much impossible to get the 3FE intake manifold to seal on a carb'ed head.

Also notice that the 3FE head uses 2 more dowel pins for locating the manifolds. Again, this might make it more difficult to retrofit a FI manifold on a carbed engine.
View attachment 127522View attachment 127523View attachment 127524

Gonna bump @Spook50 question since I am researching installing a Sniper EFI on my 2F. I have a 3FE head that I had Chevy SS valves installed into in preparation for a 2F-E conversion that I ditched for the Sniper plan.

Two simple questions: Will a 2F intake (3FE head locating pins removed) and header fit and properly seal on a 3FE head? If not, what are the issues that prevent this fitting up?

Edit: Found this:

I have a 1981 FJ40, so, based on the above information, does that mean I have the kidney shaped valve shrouds? If so, It may be worth the extra week or so and $$ to have the SS valve put into the 2F head.
I feel like Juan Epstein: "I'm so confused!"

 

[Spook50]

Gonna bump @Spook50 question since I am researching installing a Sniper EFI on my 2F. I have a 3FE head that I had Chevy SS valves installed into in preparation for a 2F-E conversion that I ditched for the Sniper plan.

Two simple questions: Will a 2F intake (3FE head locating pins removed) and header fit and properly seal on a 3FE head? If not, what are the issues that prevent this fitting up?

Edit: Found this: View attachment 2616909
I have a 1981 FJ40, so, based on the above information, does that mean I have the kidney shaped valve shrouds? If so, It may be worth the extra week or so and $$ to have the SS valve put into the 2F head.
I feel like Juan Epstein: "I'm so confused!"

Glad to see someone else with the same question as me.

As far as the SS Chevy valves, are they larger than the stock 3FE valves?

 

[Stumpalama]

Glad to see someone else with the same question as me.

As far as the SS Chevy valves, are they larger than the stock 3FE valves?

Yes, they are; and they are hardened.

 

[GLTHFJ60]

Gonna bump @Spook50 question since I am researching installing a Sniper EFI on my 2F. I have a 3FE head that I had Chevy SS valves installed into in preparation for a 2F-E conversion that I ditched for the Sniper plan.

Two simple questions: Will a 2F intake (3FE head locating pins removed) and header fit and properly seal on a 3FE head? If not, what are the issues that prevent this fitting up?

@mtweller might be able to chime in here, but 3FE heads have an extra scoop cut out in the intake runners (in the top) for the injectors. I *believe* that this scoop is too large to seal against a 2F intake, but I have not tried specifically. IIRC the 2F/3FE exhaust manifolds will swap between heads without issue.

3FE head:

2F head. Bad angle, but you can see that the intake runners don't have that large bulge in them:

 

[RockDoc]

Will a 2F intake (3FE head locating pins removed) and header fit and properly seal on a 3FE head? If not, what are the issues that prevent this fitting up?

This question has come up a few times.. the best indication I've seen is the last pic in @FJ40Jim original post of this thread. I seriously doubt the combination will seal, but I don't have a 2F intake or gasket to check against a 3FE head (would someone who does please check and post pics?)

 

[Stumpalama]

@mtweller might be able to chime in here, but 3FE heads have an extra scoop cut out in the intake runners (in the top) for the injectors. I *believe* that this scoop is too large to seal against a 2F intake, but I have not tried specifically.

3FE head:

View attachment 2617106

2F head. Bad angle, but you can see that the intake runners don't have that large bulge in them:

View attachment 2617108

That is the crux of my question... the ability to seal around the injector cutouts

3FE manifold gasket:

vs. the 2F manifold gasket:

I also understand the extra bolt locations and the different bolt size on the "ears". it appears that the 2F intake manifold itself may not be tall enough to cover the tops of the cutouts.

 

[Spook50]

That is the crux of my question... the ability to seal around the injector cutouts

3FE manifold gasket:
View attachment 2617116

vs. the 2F manifold gasket:

View attachment 2617117

I also understand the extra bolt locations and the different bolt size on the "ears". it appears that the 2F intake manifold itself may not be tall enough to cover the tops of the cutouts.

Those Remflex gaskets are outstanding, BTW. Used one on the 225 slant in my '74 Plymouth (notorious for manifold leaks) and never once had an issue afterwards.

As far as the bolt patterns go, though we're hunting different objectives here, it looks like (now someone correct me if I'm wrong) I could use a 3FE gasket, retain the extra bolts on my 3FE head, and possibly drill out the mounting flanges on a set of 2F headers to allow them to mount to a 3FE head (drilling them prior to having them ceramic coated). Connecting to the exhaust is a non issue for me since I'll be having a custom system built that can easily be located to mate to the header outlets.