F.5 head on 2F engine (5 Viewers)

[SergP]

I have two heads: 60051 (1974) and 61031 (1977)
I have read many threads here, but not many really had comparisons between F.5 and F2 heads. Especially with the pictures.
I try my best to summarize some information here. All my measurements are not 100% accurate, but give some idea of the size.
Just may be useful for anyone who thinking to replace the head from 2f to f.5 to increase compression.

Head: f.5 (1974) model year (60051)
Block: 2f with the dome top pistons.
Head gasket: 2F

 

[SergP]

some measurements:

 

[SergP]

distance from valve to the head surface:

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[SergP]

how it will fit on the 2F engine block..

 

[SergP]

For f.5 head 2f gasket fit very well.

Edit: correct # in image 60051

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[SergP]

I have finally done a compression test (cold engine)
from approximately 125psi ...it jumps to 165-170psi across the head (60051)

 

[JKIII FJ40]

are you running it now, have you noticed anything different? thanks for the info, should my F.5 ever die its good to know there are more options.

 

[Dave54000]

How did the that head work out on a 2f block

 

[SergP]

How did the that head work out on a 2f block

So far good... start well at cold.. vacuum 16-17in .. heating is normal..
but I have not run too far yet.

 

[Pighead]

How did the that head work out on a 2f block

As an aside, I've got sorta the same thing. '74 1.5F head on an early 2F block. Had some pinging issues at first, corrected with timing and octane adjustments.
I put this engine together 20 years ago, plenty of miles on it. Been promising it a valve job for about 10 years now, getting around to it now so I'm disassembling for taking it to the machine shop.

 

[Godwin]

Ran this combination in the FJ40. Fresh rebuilt '85 2F block with domed pistons, and '74 F head. Compression was 195 psi and I had to run premium, but it was a strong pulling 2F.

 

[Dave54000]

I am putting a 75 2f in my fj and just found out it has flat top pistons and has a 61030 open chamber head so I need to find a closed chamber head or mill down the 61030 or the 1974.5 head I have around 300 to 400 bucks

 

[BullHab]

Why didn't you just run your

Ran this combination in the FJ40. Fresh rebuilt '85 2F block with domed pistons, and '74 F head. Compression was 195 psi and I had to run premium, but it was a strong pulling 2F.

61040 closed chamber head on your domed piston block? Asking because I am considering placing the 61040 head on my 78 2f which comes with domed pistons. Seems like a good way to increase compression. Hoping to find someone who has done this.
Thank you.

 

[SergP]

Why didn't you just run your

61040 closed chamber head on your domed piston block? Asking because I am considering placing the 61040 head on my 78 2f which comes with domed pistons. Seems like a good way to increase compression. Hoping to find someone who has done this.
Thank you.

I believe '74 F head has only an open chamber head.

 

[SergP]

Why didn't you just run your

61040 closed chamber head on your domed piston block? Asking because I am considering placing the 61040 head on my 78 2f which comes with domed pistons. Seems like a good way to increase compression. Hoping to find someone who has done this.
Thank you.

Just make sure your domed piston doesn't hit the head.

 

[flx]

I believe '74 F head has only an open chamber head.

It depends of markets.

Non-US 74 F.5 head

60034 cast number

 

[BullHab]

I believe '74 F head has only an open chamber head.

Thank you, I thought it was a closed chamber head in that year. I appreciate the knowledge.

 

[BullHab]

View attachment 3931834
Just make sure your domed piston doesn't hit the head.

This is why I am asking if it was a viable solution. I want to take advantage of Toyota latest improvements and having latest head would seem to have more support. Looks like I am back to skimming and larger valves in a 61030 head.
Really appreciate learning more about these vehicles and powerplants.

 

[BullHab]

Ran this combination in the FJ40. Fresh rebuilt '85 2F block with domed pistons, and '74 F head. Compression was 195 psi and I had to run premium, but it was a strong pulling 2F.

Any problems with piston interference? As late ,61040, 2F motors were closed chamber, why switch to an earlier head? Was that 74 head open or closes configuration?
Thank you in advance.

 

[Godwin]

Any problems with piston interference? As late ,61040, 2F motors were closed chamber, why switch to an earlier head? Was that 74 head open or closes configuration?
Thank you in advance.

I did this ca. 25 years ago and don't have the head number anymore. As I recall the head was from a '74 so the later F with oiling. This was a combination that @Mark W had discussed on the old Land Cruiser Mailing List. Since I was rebuilding a 2F I decided to try it out to boost the hp of the 2F. I don't recall any piston interference issues. I ran this combination for about a year until the head cracked. I then installed a '77 2F head and think that I would have noticed any piston damage at the time if there had been any.