Exhaust Manifold Replacement - Marine Torq Stainless Steel

[Woodski]

As for retorque needs on a set of manifolds, typically yes.  I have found the manifold to head joint can be finicky, it took me a couple of exhaust manifold gasket changes to get ones that don't relax the torque much.  My current go to's are the Mr. Gasket ones (PN will depend on your cylinder head exhaust port).  Dissimilar metals (aluminum, cast iron, stainless steel) all have different thermal expansion coefficients so you need to find a gasket that accepts a variation from side to side.

Agree, do not use loctite, I actually use anti seize to ensure the bolts stay free and don't corrode.

[foobared]

On 6/1/2023 at 8:22 AM, justgary said:

Anybody interested in reopening the group buy?

I am. I’m about to order new longblock for my mastercraft PS 190 w/5.7 TBI. 
 

please let me know when this might happen. I need to order asap. Thanks

[skisky89]

@wakesetta12Negative, no locktite on the bolts. I snugged them up after a day on the water (in June) and they're still tight. I used permatex instead of the included gasket.

[justgary]

24 minutes ago, scotcher3 said:

Are these available for a 2003 Malibu Response LXi with the Monsoon 335? I notice they don't have a option on their website - any ideas?

Do you have iron manifolds or aluminum ETX manifolds?  Both are available.

[justgary]

As a reminder to those who are looking for Marine Torq stainless manifolds, you can send an email with a description of your engine and manifolds (and a few photos of your manifolds) to [email protected].  Your manifolds will get drop shipped to you directly from Marine Torq.

[Louie Louie]

On 8/28/2023 at 9:20 AM, justgary said:

As a reminder to those who are looking for Marine Torq stainless manifolds, you can send an email with a description of your engine and manifolds (and a few photos of your manifolds) to [email protected].  Your manifolds will get drop shipped to you directly from Marine Torq.

96 indmar 320 monsoon efi

[justgary]

We have been working closely with Marine Torq lately to get a good replacement for ETX-CAT manifolds.  The result is that it should be fairly easy now to ask for the ETX-CAT replacement and not have to provide dimensions or other information.  The latest modification adds the water port at the other end, so if you like your crossover line, you can keep it!

The story I hear is that the early ETX-CAT manifolds crack or otherwise fail near the end of their life, but Indmar no longer uses them so they don't want to make a big order.  The foundry has put those castings on the back burner due to small order sizes, so replacements are getting very hard to find (if at all).

In any event, here is the result:

The scaling of this overlay may not be perfect, but you get the idea.  The pre-cat O2 sensor has room to fit properly over the plenum cover, and the outlet pipe angle is close enough to ETX-CAT to allow reuse of the old hose if it is still good enough.

[JustRi]

2011 Wakesetter 23 LSV

Would it be worth it to get manifolds without the Cats/O2 sensor IF(and big If) I could find someone to do the tuning of the ECM?

I can order the manifolds from Torq, or get the manifolds without the CATs/ O2 sensor locally.  As of right now I am on hold if the "tuner" at the boat shop can do the tuning as he's out sick and not responding to the shops texts. So I'm in a holding pattern.

What route would you guys go? Cats or NO Cats

[justgary]

Cats and O2 sensors are a separate thing.  You could dump the cats and keep the pre-cat O2 sensors and the boat would run just fine.  You might need to spoof the post-cat O2 sensors with a resistor to keep from getting a code, but I don't think they are used for feedback to the engine.

If it were me, I'd probably just keep the cats since the manifolds with them are cheap enough.  I would not try to retune the motor for no O2 sensors.

[kjr]

Why not retune the motor for the sensors? I'm gonna have to have my ecm re tuned for another motor any way? I'm wanting a 383 . Was a 340 monsoon. 

 

I'm wanting to run the metal manifolds and do away the 4 sensors on the end.

[justgary]

13 minutes ago, kjr said:

Why not retune the motor for the sensors? I'm gonna have to have my ecm re tuned for another motor any way? I'm wanting a 383 . Was a 340 monsoon. 

 

I'm wanting to run the metal manifolds and do away the 4 sensors on the end.

Going to a 383 should just be a reprogram since the tune is known.

Switching to a MEFI2 ECM with a Hammerhead tune would get rid of the O2 sensors.  It might be hard to do that and keep your current throttle body, etc.

I would stick with the O2 sensors and the closed-loop tune it gives you.

[NorwayVLX]

Hey guys

what fittings are you using to replace the exhaust elbow. The original elbow is too large for the new manifolds?

[justgary]

23 minutes ago, NorwayVLX said:

Hey guys

what fittings are you using to replace the exhaust elbow. The original elbow is too large for the new manifolds?

Which manifold and which engine do you have?

[Murphys]

I emailed MarineTorq on March 11 inquiring about exhaust manifolds for a boat. I quickly received an auto reply email indicating that they would contact me in one business day.

Still waiting 

[justgary]

13 minutes ago, Murphys said:

I emailed MarineTorq on March 11 inquiring about exhaust manifolds for a boat. I quickly received an auto reply email indicating that they would contact me in one business day.

Still waiting 

Send an email to [email protected] with your engine and year.

[Murphys]

1 hour ago, justgary said:

Send an email to [email protected] with your engine and year.

Will do. Thanks. 

[NorwayVLX]

On 4/5/2024 at 4:31 PM, justgary said:

Which manifold and which engine do you have?

2008 vtx with indmar 5.7L The manifolds are the HT63 with catalact  converter. The old engine has these additional metal bends that join the rubber exhaust and clamp to the original manifolds. How do I upload pictures maybe it’s easier to show the difference?

[NorwayVLX]

in the pic above with the overlay of old manifolds and new. My original only have one exhaust sensor. The second that’s on the exhaust elbow is where I need to find something to fit so the Rae water from the heat exchanger can be expelled through the exhaust if you understand what I mean. 

[justgary]

17 hours ago, NorwayVLX said:

in the pic above with the overlay of old manifolds and new. My original only have one exhaust sensor. The second that’s on the exhaust elbow is where I need to find something to fit so the Rae water from the heat exchanger can be expelled through the exhaust if you understand what I mean. 

Sorry about the delay in responding.  I'm trying to figure out if you need to plug an O2 sensor port, or you are trying to get the water around the catalyst and back into the exhaust stream.  Did you buy directly from Marine Torq?

Post photos by uploading them to a different hosting site and then linking them here.

Imgur.com is OK.  Upload one photo, click get link, then come back here and use the "other media" button and select "insert media from URL."  Now paste the link you got from Imgur and add ".jpg" to the end and press return.  The image should show up inline here.

[NorwayVLX]

Yes I bought direct from marinetorq. 
 

the port is the same size as the sensor but I only have one sensor and the original exhaust manifold that connects to the exhaust pipe has the waste water connection for expelling out through the back I believe. 

[justgary]

5 hours ago, NorwayVLX said:

Yes I bought direct from marinetorq. 
 

the port is the same size as the sensor but I only have one sensor and the original exhaust manifold that connects to the exhaust pipe has the waste water connection for expelling out through the back I believe. 

Perfect.  I'm still trying to figure out exactly what part you need.  Please pick one:

1.  I have everything but the proper size elbow for water.

2.  #1 plus I need to plug the post-cat port.

3.  #2 plus something else.

4.  None of those.

Please send your photos to [email protected] if you prefer to not post them here.

[Woodski]

@NorwayVLX - Perhaps this is information you already know, there are 2 configurations depending on model year of boat.  Early boats simply had one O2 sensor bung per manifold, newer boats have two,  one bung before O2 and one after on each manifold or side.  The bung thread size is same as a spark plug, if you only have one O2 sensor plug per side simply plug off the one not needed.  Make sure you plug off the correct one so you do not ruin the catalyst with water, the correct one will be farther downstream to avoid catalyst contamination.