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Best intake to use for 6CTA8.3 external charge air cooler (intercooler) installation?

Mudog715

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So I picked up a couple of the (RG31?) MRAP cooling packs with the aluminum intercooler up front and stacked aluminum radiator / transmission oil cooler. I'm trying to line up the parts to complete this conversion on my M931a2, replacing the liquid-air cooler in the intake. I know others have just gutted and reworked the stock part, but I'd rather leave it intact and just replace it with the proper Cummins part. My research has led me to Cummins #3922646 along with the matching upper air tube, possibly a stock part from a '96 F700 Ford. Would this be the best option? If so, anyone have one to sell or know where I can find one? I've searched the internet and all the leads ended up being dead-ends.

The alternative option I found is a different design with a flat top cover (kind of like on 6BTs) with a rectangular flange on top where the air tube would connect. These seem to be available as new castings from China relatively cheap. However I would still need to find the air tube-to-rectangular-port adapter, which I haven't even found a picture of...although I suppose fabricating one wouldn't be too hard to do. Thoughts or suggestions? Thanks!
 

Mudog715

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These are the pics I've found of the 3922646 intake:
CUMMINS_6CTA-8.3_INTAKE-MANIFOLD_254076_1_390988_4.jpgCUMMINS_6CTA-8.3_INTAKE-MANIFOLD_254076_1_390988_3.jpgCUMMINS_6CTA-8.3_INTAKE-MANIFOLD_254076_1_390988_2.jpgCUMMINS_6CTA-8.3_INTAKE-MANIFOLD_254076_1_390988_1.jpg3922646_1.png3922646.jpg

This is the top cover I found with the rectangular port, Cummins 3354397 (NEW China castings):
6CTA intake new_1.jpg6CTA intake new_2.jpg6CTA intake new_3.jpg
 
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Mudog715

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I also found this style, presumably for an ISC. It has an integral intake pre-heater so presumably I could eliminate the ether system:
Cummins ISC Intake Manifold 4941008_1.jpgCummins ISC Intake Manifold 4941008_2.jpgCummins ISC Intake Manifold 4941008_3.jpg
The bolt pattern looks the same as the CTA (I know CTA & ISC are closely related but not what the component-level differences are), so presumably this would work on the CTA? The only problem is it uses a weird upper intake with EGR ports (pictured below), which I'm not too keen on... I suppose I could fabricate a custom air horn to fit this as well, unless somebody knows of a factory version without the EGR?
Cummins 4941737_4.jpgCummins 4941737_3.jpgCummins 4941737_2.jpg
 

simp5782

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I think Marty made his

You can use one off an ISC I believe just plug or weld the EGR ports
 

Mudog715

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Thanks Wes. Yes the Cummins #3925453 is what Marty used but I could never find a decent pic of it to see what it looks like. From what I can gather it is similar to the #3922646 (first one I listed) with the intake tube cast as one piece instead of a removable, bolt-on part. I kinda eliminated it because I couldn't find one used and Marty said he had to cut and rotate the intake tube to make it work. Since I'm assuming it's cast aluminum, that would require an AC TIG setup to reattach which I don't have. The #3922646 has a round flange between the plate and intake tube which I assumed would be trivial to drill new holes to re-clock.

I'm actually leaning towards using the ISC intake cover with the integral intake heater. I like the idea of eliminating the ether system and I can fab up the intake tube to rectangular flange or modify the stock elbow with the EGR ports. Anyone see a reason NOT to use this part? Will the intake heater add much of a restriction?

FWIW, I'm using the same 2930015576211 RG31 Cooling Pack as Marty.
 

Jbulach

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IMG_0902.jpg
This is on an 8.3 in a cab over I have, if you need any better pics or want me to look for part numbers, let me know if it could help you out.
 

Mudog715

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Ok guys thanks for the info and pics. The #3927879 intake tube looks to fit the #3354397 intake plate (2nd style in my 1st post), so if pick up that style plate I now know what OE intake tube fits it:
Cummins_C8.3_Intake-Manifold_1821960_1_24416830_2.jpg6CTA intake new_3.jpg

I looked again at the ISC intake plate with the heater grid compared to the stock CTA charge cooler intake. I don't think the ISC part will fit the CTA. The bolt pattern/spacing is different, didn't catch that before. Here they are next to each other for comparison:
Screen Shot 2021-04-12 at 8.24.27 PM.png

So I'm back to trying to find the #3922646 (round flange between tube and base) or #3354397 base and #3927879 intake tube. Anyone have one of those setups they want to part with? :cool:
 

Mudog715

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So all the leads on that site I had previously exhausted except for one, and I had been trying for several days to reach them and get a quote. Finally heard back today and gave them payment info, hopefully it shows up next week. The style I bought was the one with the round flange pointing straight up, bolted to a 90° elbow to where the CAC hose attaches.

Prior to that I chased down several leads and every "listing" I found was either sold, they couldn't find it, or my personal favorite "we don't sell engine parts off engines" even though they had an ad specifically listing an engine part... ugh.
 

Mudog715

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So all the leads on that site I had previously exhausted except for one, and I had been trying for several days to reach them and get a quote. Finally heard back today and gave them payment info, hopefully it shows up next week. The style I bought was the one with the round flange pointing straight up, bolted to a 90° elbow to where the CAC hose attaches.

Prior to that I chased down several leads and every "listing" I found was either sold, they couldn't find it, or my personal favorite "we don't sell engine parts off engines" even though they had an ad specifically listing an engine part... ugh.
Well, turns out I spoke too soon... just got a call back this morning telling me the intake they thought they had (that was listed on the truck parts search) was left in the vehicle when it was crushed a few weeks ago. Nothing else usable comes up on the search Wes gave me, nor on google searches... Soooo, back to the drawing board. If anyone here has one to sell I'm buying :)
Screen Shot 2021-04-16 at 10.39.51 AM.pngScreen Shot 2021-04-16 at 10.40.02 AM.png
 

Mudog715

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Alright, finally tracked one down. I actually just ordered the Cummins 3354397 China reproduction (plate with large rectangular port, would still need to find or fabricate the matching air tube). About 15 minutes later I got a call from one of the places that I previously called. They found a #3925453 in their core pile. $239 later it's on its way to me! I'll have to cut and re-clock the intake tube like profo and , but at least I found one. Now to gather all the hoses, reducers, and other fittings I need to plumb this cooling pack in the truck. Great fun! Thanks for the advice guys!
 
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Mudog715

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pretty sure this is 3925453 that I put on mine when I put in CAC.
That looks like the one profo used and matches the pics of the #3925453 I just bought. Are you going to cut and clock the inlet tube like profo did or make the connection a different way? It seems like turning it about 45° counter-clockwise would work. I also thought about just cutting the 90° off and having a vertical inlet, then using my intake tubing to make the 90° down to meet it. Until I have the cooling pack physically in the truck it's hard to tell exactly what's going to work best. I would like to minimize the hose-clamp connections as much as possible.
 
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