Can we make a exhaust/intake manifold sticky?

[g-man]

I think I may not have actually answered your question. The riser at the front end of the exhaust pipe?

The riser being the center of the exhaust manifold where air "rises" to come up to the heater control valve and lets hot air up to the bottom fo the intake. Basically the flat sections where the intake and exhaust are bolted together. Once separated the intake can be put on a flat surface but the exhaust manifold is countoured in a way that prevents the flat area from laying flat on a surface

 

[g-man]

This video helped me to understand. Looks like it can be done with a carbide tipped mill machine...(not sure what this type of machine is called) with shorter passes.

how does a machine shop mill exhaust manifolds - Search Videos

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[FishTacos]

The riser being the center of the exhaust manifold where air "rises" to come up to the heater control valve and lets hot air up to the bottom fo the intake. Basically the flat sections where the intake and exhaust are bolted together. Once separated the intake can be put on a flat surface but the exhaust manifold is countoured in a way that prevents the flat area from laying flat on a surface

Generally this is not an area of concern to the machinist. You can't really remove much material here because if you do the bolt holes that allow attachment to the head will become misaligned. It's pretty rare to have a leak here anyway. I never use the remflex gasket in this spot for that very reason. OEM only here because thickness is important. Some say OEM gaskets everywhere on the I/E manifold but I have had good luck with the Remflex between intake and head and I like them for the EGR tube or block off plate. The torque values are lower with Remflex, so keep that in mind.

 

[FishTacos]

This video helped me to understand. Looks like it can be done with a carbide tipped mill machine...(not sure what this type of machine is called) with shorter passes.

how does a machine shop mill exhaust manifolds - Search Videos

Watch videos instantly on Bing—enjoy direct playback, discover related clips, and dive into trending content all in one place.

www.bing.com

Unless you have access to a vertical mill I wouldn't touch that area with a tool. You can check it with a correctly sized piece of known flat channel or aluminum billet. You would have to get something like that made. Probably not worth it. Like I said, that spot is not a common leak point.

 

[Dekeman]

I talked to the parts guy at Toyota and told him my story and he said “You can fix it. Land cruisers are easy to work on”.

In retrospect, I think THE BEST part about owning a FJ60 is working on it and learning all about it and becoming a good mechanic while doing so. The vehicle is rewarding to drive off road for sure, but it’s the eventual repairs done on your own that really make this vehicle rewarding.

Exactly what I needed to hear, thank you. I keep saying the 60 is easy to work on - everything is accessible and mostly straighforward when you have a diagram. Love fixing it as much as driving it, which is a good thing because I've mostly done the former. And thanks to you and many others here, I've done plenty on the truck with great success.

 

[Dekeman]

Thanks for the tips @g-man

 

[g-man]

Generally this is not an area of concern to the machinist. You can't really remove much material here because if you do the bolt holes that allow attachment to the head will become misaligned. It's pretty rare to have a leak here anyway. I never use the remflex gasket in this spot for that very reason. OEM only here because thickness is important. Some say OEM gaskets everywhere on the I/E manifold but I have had good luck with the Remflex between intake and head and I like them for the EGR tube or block off plate. The torque values are lower with Remflex, so keep that in mind.

This IS where my leak was. I just cleaned up the surface with a die grinder and abrasive pad (like scotchbrite). Then bolted everything together. Shined a flashlight up in there and didn't see any light coming through. Fingers crossed. Off to the machine shop to re-surface the flanges that bolt to the head and maybe spot facing if he can do it.

 

[FishTacos]

This IS where my leak was. I just cleaned up the surface with a die grinder and abrasive pad (like scotchbrite). Then bolted everything together. Shined a flashlight up in there and didn't see any light coming through. Fingers crossed. Off to the machine shop to re-surface the flanges that bolt to the head and maybe spot facing if he can do it.

Huh...how about that. Glad you got that sorted. Good luck at the machinist.

 

[F226continental]

There is kind of a process to get the manifolds flat and together.
1. loosely bolt intake and exhaust together (with new gasket)
2. With no gasket snug up intake and exhaust to head
3. now tighten intake and exhaust manifolds together with proper torque
4. take assembly off head, flip over on a bench and with a good file start to work the high places. Keep at it it’s just cast iron and aluminum it will be flat in short order, with a good straight edge.

anyone can do this give it a try

I’ve done at least 6 this way. No problems ever
i was a toolmaker in a past life

Posted this a while back, maybe helpful

 

[g-man]

There is kind of a process to get the manifolds flat and together.
1. loosely bolt intake and exhaust together (with new gasket)
2. With no gasket snug up intake and exhaust to head
3. now tighten intake and exhaust manifolds together with proper torque
4. take assembly off head, flip over on a bench and with a good file start to work the high places. Keep at it it’s just cast iron and aluminum it will be flat in short order, with a good straight edge.

anyone can do this give it a try

I’ve done at least 6 this way. No problems ever
i was a toolmaker in a past life

1. did that
2. did that, I used a spare head that I placed on my bench for easier access.
3. proper torque? not sure that there are any torque specs for bolting the intake to the manifold. I did it CAREFULLY...so as not to strip the aluminum threads.
4. If I put a file on it ...it will most surely get messed up. Took it to a shop to machine flat.
thanks for this info. I think putting it on the head first before tightening things up helped to get the bolt holes at the flanges correct distance/opening. And this got things close to flat.

I did put the block off plate in, flipping the heater flapper to open/warm position and holding it from the exhaust pipe hole. The block off plate pins the flap in the hot position. I realize it will take longer to warm up on cold mornings. But hey, I'll use the choke and let it sit in the driveway for a while. Not like I'm driving it to work every morning. AND...I'll never have to worry about the dreaded crack in the intake.

I used hi temp anti seize on the long bolts that thread into the cast iron exhaust manifold. Did not bother with the front small bolts that thread into the aluminum. That's unlikely to seize.

 

[g-man]

I also duct taped my horn joints instead of jb weld before heading off to the machine shop. The machinist was glad I had not tacked them with jb weld. He says he slightly turns the horns downward while the piece is on the belt sander and he wants them to be able to move a little. May want to check with your machinist on how he wants you to tack these before you take them to him.

 

[FishTacos]

I also duct taped my horn joints instead of jb weld before heading off to the machine shop. The machinist was glad I had not tacked them with jb weld. He says he slightly turns the horns downward while the piece is on the belt sander and he wants them to be able to move a little. May want to check with your machinist on how he wants you to tack these before you take them to him.

You may want to find a different machinist.

Belt sander is a terrible idea.

Wanting them "to be able to move a little" while "machining" them is an even worse idea.

 

[Spike Strip]

Just thought I'd drop this here: Not mine, but a pretty good video for people refreshing their Exh/Intake .

Some things I'd avoid, like non-JIS hardware and separating the manifolds if you're not going to surface, but a good look for what you're getting into for people who have never done it before:

 

[g-man]

You may want to find a different machinist.

Belt sander is a terrible idea.

Wanting them "to be able to move a little" while "machining" them is an even worse idea.

My machinist was using the guides that are on the horns and the exhaust manifold center section to line them up. When he puts the piece on the table sander he pushes them to get these sections flat. Circled in red here:

 

[FishTacos]

My machinist was using the guides that are on the horns and the exhaust manifold center section to line them up. When he puts the piece on the table sander he pushes them to get these sections flat. Circled in red here:

View attachment 2883828

Ok.

The outcome is all that matters. I've never heard of a machinist doing it that way. Hope it works out.

The I/E assembly is not easy to hold. If you find a machinist that does these frequently, they usually have a fixture that holds all four pieces in place (or the center section fixed together and the two horns in an aligned and fixed position). Then a fly cutter is chucked into a mill and the fixtured workpiece is fed past the fly cutter taking very light cuts until all imperfections are removed. After that a final process mills the points of contact where the washers interface with the manifold to ensure even clamping pressure.

As long as your machinist achieves alignment, flatness, and uniformity of attachment points you will be fine.

 

[Spike Strip]

Milling is the preferred method, but the proper type machinist's belt sander works, too.

 

[FishTacos]

That's a cool video.

And I should have said, I'm not aware of a machinist doing THESE manifolds that way. I think the problem with that (and as a side note, it's also a problem with the fly cutter) is that because you have two different materials (softish aluminum and much harder cast ferrous material) the two don't respond to material removal in the same way. If the fly cutter is told to take big cuts, you end up with distortion because the aluminum acts like butter. And if you have the horns improperly fixed you can run into even bigger problems when you bolt it up.

This is all academic and I'm sure it will work out.

 

[roadstr6]

I did a set of manifolds about a year ago because the bronze bushings the thermo-flapper pivots on were leaking. I ordered a block-off kit, but after pulling the manifolds, I decided not to separate them to install the block-off plate, but instead just plasma out the flapper and remove it and the shaft. I had my machine shop tap threads in the flapper shaft holes and install set screws to plug the holes. My machinist also used a belt sander like the video above to flatten the sealing surface. I have run these manifolds for 5K miles now with the flapper removed and no block-off plate. There have been no leaks, no cracks and no problems whatsoever. My thought is that the flapper only causes a problem when it fails in the "cold" position and super heats the intake causing a crack. With no flapper at all, the exhaust naturally flows downward and does not appear to have any detrimental effects on the intake manifold. The only thing I have noticed is that the exhaust note is a little throatier without the flapper there to obstruct the flow. It sounds nice.

 

[reddog90]

My truck has a little less than 130k miles and my heat control valve operates just fine when tested with a torch. I removed the manifolds to make sure I didn't have a cracked intake and replace the gaskets, and thought I would install a heat riser block off plate from Cruiser Outfitters while they were split to prevent any future issues. This block off plate blocks the travel of the flapper plate as it heats up though.

Should I:
Remove the entire heat control valve assembly and plug or weld the holes left behind in the manifold, then reassemble with the heat riser block off plate?
Remove just the flapper plate and leave the heat control valve shaft in place, then reassemble with the heat riser block off plate?
Heat the coil spring to fully rotate the flapper plate directing heat away from the intake manifold, then reassemble with the heat riser block off plate?
Or reassemble without the heat riser block off plate and hope the heat control valve doesn't s*** the bed while I own the truck?

 

[OSS]

From my understanding from a machinist who’s worked on dozens of Land Cruiser 2F manifolds, the aluminum intake cracks because the Heat Control valve can occasionally stick in the Cold position.
Because of this, every single 2F manifold that goes through his shop gets the Heat Control Valve removed and NO block off plate is used.

I brought a SOR manifold block off plate in for him to install and he was adamant that it wasn’t a good idea - to the point that he wouldn’t install it.
He knew what it was and said they don’t install those. You don’t want to use it.

Who was I to argue with an experienced expert who did all the engine rebuilds for TLC4x4.com and also for rebuilds for local Toyota dealerships?