3fe exhaust manifold on 1987 2f - fitting question (1 Viewer)

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Jan 16, 2006
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Good morning, I have a 1987 fj60 with an exhaust leak, and have been researching headers vs existing manifold vs the 3fe conversion. I am leaning towards the 3fe option but have a fitting question.

My understanding is the 3fe manifold is 15mm, and the existing intake manifold is 10mm, so some adjustments have to be made. Most recommendations are to shave the manifold down (thus decreasing the strength), or put in a half washer solution (seems jerry rigged to me) for proper fitting. Neither one of these seem ideal to me, so am looking for a different solution.

My question is this, would it be reasonable to fabricate a 5mm aluminum “shim” for the intake manifold to increase the thickness to match the exhaust manifold in order to mount them both? Maybe I’m overthinking this, but don’t want to create more problems in the long run.

Thanks for the thoughts.
 

Godwin

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I'm interested to see how you would fabricate an aluminum shim. Would this shim fit between the intake manifold and manifold gasket?

I'll give you a nudge toward going the 3FE route, after reading your post I checked the post I made on this mod 3FE exhaust on 2F head - https://forum.ih8mud.com/threads/3fe-exhaust-on-2f-head.955034/. I've had the 3FE manifold on for 6 years and guesstimate 100k miles and it is still leak free. I agree the half washer approach is jerry rigged, that's what I did and at the time it was the best approach for me. The JB welding is not that secure and if I pull the manifolds apart I expect that the 1/2 shims will fall out.

We need a good solution to installing the 3FE exhaust and maybe you'll be able to provide that.
 
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So, I measured the thickness of the 3FE exhaust manifold (16mm), and the thickness of the original intake manifold (10mm), and created three aluminum shims (6mm) to place b/w intake manifold and engine. The order I put everything on was engine, manifold gasket, shim, gasket paper, then manifold (with gasket maker applied to all pieces). Had to do a lot of shaping to get them to fit correctly, but they did the job. So far so good.

My next predicament now is to connect the manifolds to down pipes (which I don't have). Brought it to a muffler shop and they can build me the Y piece, but they said they don't have anything that will connect to the manifolds without blowing out a gasket. What did you do when connecting your manifolds to down pipes? Did you already have the down pipes? I found the down pipes on Cruiser Parts, but really only need the flange (Down Pipes) on the far left side.
 

HemiAlex

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Fit and finish was good, plus I no longer have to deal with any crusty pipes. With those, you can build an oem fit exhaust back to the tail pipe with the muffler shop only having to fab a y pipe.
 

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