2FE Piston to Cylinder Head Clearance (1 Viewer)

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Hello all, long time lurker but first thread here so bear with me.
I did a bunch of searching but can't seem to find a spec online or in the FSM.

My GF and I are building up a 2fe with a 83 2f block bored .040 over with .060 shaved off the deck and a 89 3FE head for her 84 FJ60.

I am wondering if anyone has any guidance on what the safe squish clearance (piston to cylinder head) is for this type of motor is. My machine shop says .035-.040 is a general minimum.

The bottom end is built up and the highest part of the piston is at .022 above the deck, trying to decide whether to pull it apart and shave down the pistons.

Also, does anyone know for sure what the compressed thickness of a factory 3fe head gasket is? HG measures .070-.072 uncompressed and my shop says the toyota HG's usually compress down to .062.

And lastly, let me take the opportunity to say thanks. This build wouldn't be possible without the volumes of wisdom and information already on this site.


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Onur

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I just had my block done as well on my 2F and my machine shop decked about .013 off the top. He said it would be fine with my head and block (both 2F specific--but should be same for 3F-E head as well).
 

DickM

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Sorry, I can't answer your specific questions. The shop that did the work for my 2FE build took .020 off of the deck. When we talked about it, they thought this was a good, safe compromise number for the overall performance based on the other stuff that was done.
 
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thanks for the input, I double checked, we took .040 off the deck on this motor these are also aftermarket pistons so I really need the squish clearance spec. to put it another way, the minimum safe distance between the piston at tdc and bottom of cylinder head.
 
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so the short answer is... if you have to ask, its too close.

going back over the build specs I realized I was working off the assumption that the 2f and 3fe had the same combustion chamber size, which I should have realized was obviously not the case.

Measured the combustion chamber volume at 77cc, found two different estimates for the head gasket combustion chamber area (16 and 12cc) in previous threads. With a .030 shave off the pistons for a piston to deck clearance of .008 should yield a final compression ratio of either 8.6 or 8.96 depending on which HG volume is correct. Either I can live with.

This compressions ratio calculator was super helpful if you find yourself in similar circumstances.

Thanks for all the input.
 
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I measured about 12cc for the head gasket volume- it seems to compress down to 1.5mm.

And I agree with your head volume- a relatively uncut head seems to be 77mm with new or decent (little cut) valves.

The short version, I found, was that you really don't want to cut any more than you have to to clean
up a 2FE- the compression gets to 9:1 pretty darned quickly on even just a 'freshen up' rebuild.

t
 

pappy

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Stock 2F block, with stock 3FE head increases the compression significantly. If you shaved .060" off the deck, you will ping, bad. When I had my 2FE built I specifically told the machinist to mill only what was necessary to get the surfaces flat. I don't know how much that was, and I ping on medium grade at sea level.
 
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not quite that much shaved, probably .040 between the deck and block, and now .030 off the pistons should come in right at 9:1 based on my calcs.

So when you're down in the lowlands, is pulling timing an option to compensate for the denser air? I know the international disto on the 2f has a knob to adjust timing to compensate for gas quality, but imagine that's not as straightforward with the 3f distro.

and hey, let me just say thanks for putting that 2fe pdf together, made all the difference through this process, and its completeness is what made us feel comfortable enough to undertake the project. oh and I really like your vehicle choices :clap:
 

Mace

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Squish clearance is not much of an issue. The compression (as previously noted) is.
 

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