2f engine, pistons and head.

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It's been years since I was active in cruiserdom other than oit crewing with Canguro Racing but after my 1976 fj40 had been parked for 19 years I'm finally making progress in getting her back on the road. What I thought was simply a "rings didn't seat" issue on my motor with 2k miles on it turned out to be a poor machine job on the block. I didn't know any better at the time.

In the end I purchased a 1975 2f that the PO said just had a head job done on it. The compression was supposedly about 130 across the board but it was a $500 motor. I did a leak down on it tonight and every intake valve leaked, so off with it's head.

What I found was a 61030 head on a block with .020 flat top pistons. From my research this is a no go as the 61030 is an open chamber head and with the flat tops, there's no power. So what's the right option? New domed pistons? Mill the head down? Find a different head? I'm squirreling pretty hard on this poor girl as I ripped the body off the frame while she wasn't looking.

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No expert here. But, any head that has no major cracking, or has been inspected would be the ticket. I prefer old OEM to new aftermarket Match the head to the pistons, but, I hope this is correct, but just find the best head with the least effort. Don't mill down the head for better compression, just to maintain the plane. I'd say more, but, the tech section gets hijacked with lore of shopping.
 

Pighead

Stop calling it an FJ
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I forget what head number i have, but i know it's off a Late F engine. Pretty sure it's the open chamber head you mention. Back in 2004 when i rebuilt the 2F block, i was able to find Federal-Mogul domed pistons and Total Seal rings, .050 over, for it. It bumped compression pretty well, had some initial problems with pre-ignition but worked that out. Still running that engine in my Pig today.
 
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Sorry guys, It's been so long I had my notifications set wrong so I didn't see any responses coming through. I was talking to Kurt Williams as we were working on Monica, Canguro Baja race truck. He recomended finding a late model, closed chamber head. Now the hunt begins. I have two heads already, a 75 and a 76. They both need rebuilt so rebuilding a later model won't change the amount of work that has to be done.
 
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How do we identify a random head in the attic? Casting number? And tell me about the openchamber/closed chamber thing. Thanks.
 
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@island45 Good question. The key for me is in the picture I posted above. You can see how the whole area around the valves is indented into the head. That's the 61030 head. A kidney shaped indent looks to be a 61040. My engine should have had domed top pistons and use a 61030 head but a Previous owner used flat top pistons and should have changed to a 61040 head to use them. It sounds like I'm changing the head to a 61040 or changing back to dome topped pistons.

2f heads.PNG
 
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I've googled for the last hour unsuccesfully. Does anyone know the OEM thickness of a 1975 or 1976 head? If I remember right my original 1976 head was milled .100" when I did it 25 yrs ago. I just have no number to verify it against. Any thoughts?
 

fjc-man

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I couldn’t find a specification for head thickness either, so I went out in the garage and measured the one I have. I came up with 94.7mm and I couldn’t tell you if this head has ever been milled, but I don’t think so.
 
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That whole head milling for better compression vs. head milling for factory-defined flatness...
Must be an "old-schooler" upgrade, or were the castings too thick when they were new? Opinions?
 

Pighead

Stop calling it an FJ
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If I remember right my original 1976 head was milled .100" when I did it 25 yrs ago. I just have no number to verify it against. Any thoughts?
A good machinist will stamp, somewhere on the head, to indicate any work done.
 

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