1F (F 155) Intake Manifold / Exhaust Manifold Installation (1 Viewer)

[kylenine]

F 155 engine in my 40 (Mar. 1970). Rebuilt the carb (Small window SD-40) and decided to replace exhaust/intake manifold/valve cover gasket while I was at it. Cruiser had been sitting for ~25 years prior to my ownership. I've added ~1500 miles since.

Separated manifolds to check for cracks in the intake manifold. Plenty say not to do this to avoid resurfacing. No cracks on either manifold. Re-tapped and re-threaded any and all bolts, nuts and threads, cleaned both manifolds and head/block on driver's side.

Remflex gasket kit (Thickest to prevent leaks). Planning on finger-tightening the manifolds together then mounting them on the block, torquing the nuts to the block (30-35ft/lbs?) and then tightening the manifolds together(Torque spec?). It is recommended to bolt manifolds together and then get resurfaced but both hold up to a straight-edge nicely so I'm not too worried. No plans for a block-off plate because my flapper is intact and moves freely.

Am I on the right track or do I need to bolt them together and get them resurfaced? The ears on the manifolds had half washers on them. Are those OEM? Does anyone have any other insights on the installation? Leave the flapper in or take out? Thanks in advance!

 

[Pighead]

I think you're on the right track.
Pretty sure C washers were not OEM, someone else may have had trouble with a leak at one time.
I might just snug the manifolds up to the head, without a gasket and see how they match up.

 

[kylenine]

Thanks Pighead. Good idea.
Any thoughts on the flapper? 1F should be fine with or without it, right?
I think I'll leave it in if it's not going to hurt anything..

 

[OSS]

The machine shop that did all the engine work for tlc4x4 in Southern California removed the Heat Control Valve on every LC manifold assembly that went through their shop.
He told me they can stick. And when they do, the intake manifold overheats - then cracks. Mine had a hairline crack in it.

 

[73FJ40]

@kylenine

The thermstatic spring is long gone, so the flap isn't working as intended.

If it's frozen open, it probably won't hurt to leave it alone. Then you won't have to plug the holes left in the casting without the shaft .

If it's only partially open, get rid of it.

Attached is a picture of mine, which shows the OEM stop bracket, to use as a guide to check how much it's open.

 

[kylenine]

Mine isn't stuck either way. It is loose/free and goes to both extremes (See pics)
Seems like it would be a pain to plug the holes. I guess I could just tie it in it's open position but the exhaust should be holding it there anyways, right?

 

[73FJ40]

Mine isn't stuck either way. It is loose/free and goes to both extremes (See pics)
Seems like it would be a pain to plug the holes. I guess I could just tie it in it's open position but the exhaust should be holding it there anyways, right?

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Given the negative consequence of the valve if it somehow migrates to the cold position, I would at least wire it wide open, and forget about it.

Another option is to get a thermostatic spring and get this back in service for those cold Montana mornings.

 

[kylenine]

I actually ended up needing the half-washers on the intake manifold ears to make both manifold ears the same thickness. I can't imagine the intake manifold was machined down 1/16" but that is the only thing I can think of.

 

[65swb45]

That gasket between the intake and exhaust has obviously caused a serious mismatch between the ears of the intake and exhaust. That can’t be good for port alignment either.

 

[kylenine]

The gasket between the intake and exhaust wouldn't cause the ears to move forward or backwards; only up and down. No problems up and down for me. The bolts were loose between the manifolds allowing both of them to be bolted against the head. I'll try to attach a picture of what I mean tomorrow.

 

[ToyotaMatt]

The gasket between the intake and exhaust wouldn't cause the ears to move forward or backwards; only up and down. No problems up and down for me. The bolts were loose between the manifolds allowing both of them to be bolted against the head. I'll try to attach a picture of what I mean tomorrow.

if you remove the heat riser ,flapper , install a heat riser block off plate , and weld 2 short bolts in the OLD shaft holes from the outside :


you will intern gain horse power :

why ?


you have removed a restriction , plus manifolds will run cooler


this ain't BS

it works u will feel a tad more pep and have a cooler engine bay this summer


i swear by these steps on all past F and 2F engines manifolds i build


there is NOT a Negative to doing this except a required smog test in your area ......

 

[ToyotaMatt]

The gasket between the intake and exhaust wouldn't cause the ears to move forward or backwards; only up and down. No problems up and down for me. The bolts were loose between the manifolds allowing both of them to be bolted against the head. I'll try to attach a picture of what I mean tomorrow.

- you leave all the center vertical bolts and nuts loose :


- install the manifolds together :

- this allows a freedom of movement and forgiveness factor , they must be started with a few thread turns , that's it


- torque manifolds to head

- per fsm


- then your very last step by step will be to tighten the vertical sandwich bolts in a pleasing star pattern


- this is the only way i roll , its 100% successful 100% of the time

- its NOT in the fsm , sadly should have been a supplement ?

- this was a NO STUDS threads chafing either approach ........

longer block studs would help you out too in a major way ?

guides : 90080-12008

report back , i bet you win at getting this on 1st try ,


matt

 

[fjwagon]

This manifold set setup is touchy. They are super long and then you have aluminum and cast iron in the same area. They cool down at different rates but still close to get minimum warping but it will eventually warp. And hope you don't get water splashed on it. The question is...how bad will it warp. Sometimes they warp because the gasket has a leak and eventually the heat eats the gasket away. I have resurfaced in the the past. I will say it ran a lot better so i really did not have a choice. Its just part of the process. If are in tolerance I would not resurface it....yet. just watch it and let it settle. Hopefully you will not have to remove it. You are on the right track.

 

[ryanwk628]

Thanks Pighead. Good idea.
Any thoughts on the flapper? 1F should be fine with or without it, right?
I think I'll leave it in if it's not going to hurt anything..

I put a small tack weld on the outside to hold it in the open position on my manifold. PO had it just flapping loose