How to put 2 piece exhaust manifold together?

[coldtaco]

How do you put the 2 piece 1HZ/1HD exhaust manifold together? I am assuming that you put the two o-rings into the two grooves at end of short piece. What do you do with the C-clips/snap rings? Do you put them over the o-rings in the grooves?
Thanks.

 

[coldtaco]

The o-rings are already installed.
The picture is just for those that have never seen this before

 

[coldtaco]

Nobody has EVER messed with this?

 

[Jan-78FJ40]

Nobody has EVER messed with this?

Of course.
and you are correct. rubber o rings into the groves, and compression rings over them, with the openings to opposite sites.
there is also a small sleeve in between the two parts. The manual shows this well.
cheers,
Jan

 

[coldtaco]

Thank you. Unfortunately I did not have the mental skill to 100% be sure that that is the way to install the two pieces. I did not find anything that said where those C-clips go just that you make sure the gaps are spaced opposite from one another.

 

[Tim-HJ61]

I did not find anything that said where those C-clips go just that you make sure the gaps are spaced opposite from one another.

That's how I do it, seems like a wise option. Like others have said, there is a small collar that needs to be installed too. That just sits in the end of the two cylinder section.

Best to assemble the turbo onto the manifold first, including the dump pipe, and have most of the head studs in place so you can slide the unwieldy heavy combination into place easily. I also have a piece of particle board that I lay across the top of the air filter housing/battery area so I can rest the manifold turbo combo, whilst I get myself into a better position for the final awkward manoeuvre.

Oh, and don't forget the head to manifold gasket/s too. Embarrassing to have to pull the whole thing off again, so I imagine....

Tim

 

[veiloctane]

I assume the rubber o-rings are there only for installation because the heat would just melt them away

 

[mudgudgeon]

I assume the rubber o-rings are there only for installation because the heat would just melt them away

They don't melt so much as harden and solidify.

When I've pulled these apart, getting the rings out can take chiselling them out with a small screw driver or punch, or zip disc in a grinder. Can be a total PITA

 

[veiloctane]

They don't melt so much as harden and solidify.

When I've pulled these apart, getting the rings out can take chiselling them out with a small screw driver or punch, or zip disc in a grinder. Can be a total PITA

Not in my current experience.

I reciently pulled off the turbo the rubber is no longer there

This was from running a turbo after a couple of days. I wouldn’t think the rubber would vaporize. that fast.

 

[oddballs]

Is there any reason this manifold is a 2 piece design. It seems odd to me but maybe that is just me?

 

[veiloctane]

Is there any reason this manifold is a 2 piece design. It seems odd to me but maybe that is just me?

The Toyota 1HD-T (4.2L turbo diesel engine, common in Land Cruisers like HDJ80/81) features a two-piece exhaust manifold: a front section (turbo side, ports 1-3 or similar) and a rear section (ports 4-6), connected via internal passages sealed with special rings.


Required Parts for the Joint


• Rubber O-rings (typically 2, high-heat resistant Viton or similar; they aid assembly and burn away after startup without issue).


• Metal compression/sealing rings (piston-style split rings, Toyota part 17151-17010 or equivalent; 2 required—these provide the permanent high-temp seal).


• A small metal sleeve/collar (aligns the two halves internally).


These seal the gas passage between the manifold halves to prevent leaks. Always replace them when separating the manifold (they often harden or require chiseling out).


Step-by-Step Installation of the Two-Piece Manifold


1. Preparation:


• Clean both manifold halves thoroughly (remove old rings, carbon, rust from grooves and ports).


• Inspect for cracks (common on 1HD-T manifolds).


• Have new multi-layer steel (MLS) exhaust manifold-to-head gaskets ready (Toyota 17173-17010 or equivalent).


2. Assemble the Two Halves:


• Place the rubber O-rings into the grooves on one manifold half (usually the rear).


• Install the small alignment sleeve/collar into the center passage.


• Place the metal compression/sealing rings over the O-rings. The split/gap in each metal ring should be positioned opposite (180° apart) from each other for best sealing.


• Carefully align and mate the two halves (they slide together with the rings compressing slightly).


• The rubber O-rings help hold everything during assembly but will vaporize from heat once running.


3. Install the Assembled Manifold to the Cylinder Head:


• Apply anti-seize to the studs/bolts.


• Place new manifold-to-head gaskets.


• Position the assembled manifold (with turbo if attached) onto the head studs.


• Hand-tighten the 12 nuts/bolts.


• Torque in a crisscross pattern (start from center, work outward):


• Typical spec: 39 Nm (29 ft-lb) initial.


• Some manuals note additional tightening on loose nuts to ~32 Nm.


• Re-check torque after a heat cycle.


4. Reconnect Components:


• Turbocharger (if removed): Torque to manifold ~52-60 Nm (check FSM for exact).


• Heat shields, EGR (if equipped), downpipe, etc.


• Use new gaskets where needed.


Tips and Warnings


• Work with the engine cold.


• The manifold is heavy—support it well.


• Common to snap studs—replace with a stud/nut kit if any are damaged.


• After startup, check for exhaust leaks (soot marks).


• Refer to the Toyota Factory Service Manual (FSM) for your model for exact diagrams/torque (highly recommended—the joint assembly is illustrated clearly).


Here are exploded diagrams and parts photos for reference:

Close-ups of the O-rings and metal sealing/compression rings: