Air Box for the Scout

[Steve Graham]

Air Box for the Scout lowers egt

Finely got a "roundtoit" and built a air box for the Scout. The engine now draws outside air from the base of the windshield and from behind the front grill. My cool down time mimics my 92 Dodge, only takes a minute or less to drop below 350 F. Around town and below 65 mph on the freeway the egts have dropped 100 F.



Steve

 

[mberry]

Looks really nice Steve! Thanks for the pictures. How's the Willy's coming along?

 

[Steve Graham]

The Willys would be farther along if I could keep the Scout out of the bar! Can't complain though, the clutch replacement that got it into the barn is the first change since the build up.

I'm just about done with the sheet metal on the Willys, only have the drivers side fire wall to do, reinforce and then its the sound deadening for the firewall and cowl.



Steve

 

[driverswanted]

Steve,

I am curious what your outside temperatures are during your test measurements. Also what is your EGT on the highway at about 65 and are you measuring that before or after turbo?

 

[Steve Graham]

The outside air temps have been from 90-100 deg F when I first made the measurement. At 65 the Scout is turning approximately 2000 rpm. This is at the end of the economy range and starting the power range for fueling. At 70+mph the egt will be at 700-750 climbing to 850 on hills. These measurement are down stream from the turbo, about 3 inches. If you know of any way to attach a probe upstream let me know, I'd like to do it.



Steve

 

[LOtero]

BAD ***** SCOUT are there any pics of the build? Ive got a 72 scout project rockcrawler. a cummins in a scout is just about a dream rig for me. bet that thing is indestructable.

 

[Steve Graham]

BAD ***** SCOUT are there any pics of the build? Ive got a 72 scout project rockcrawler. a cummins in a scout is just about a dream rig for me. bet that thing is indestructable.

Check my signature for all the pics of the buildup.

Yea the Cummins is almost indestructable, it's the rest, axles ect, and drive shafts I worry about now. Still have the D44's but have a D60 for the rear and HD D44 eight bolts going in when I get the time.



Steve



The link to the Scout Repower in my sig had gone bad, it's fixed now.

 

[driverswanted]

Steve,

I drilled and tapped right where number one and the forward cylinder come together back at number one. I must be about 3" away from number one piston. My exhaust flange is tilted with the forward edge raised so it opens up the rear side above the flange for some drilling and tapping. I work with stainless sheathed thermocouples a lot at work and knew I could squeeze it in there.

 

[Steve Graham]

You know what I'm going to ask for next, pictures! I would have thought that those areas of the manifold would be too thin to mount a screw in thermocouple? My first idea was to add a block between the turbo and manifold and then drill and tap for the probe, but you would need extra length studs, it might work.



And the bad news about the airbox installation, I'm picking up a drone from the turbo during acceleration and when shifting. Seems that the fresh air vent on the passenger side is in the same cavity and this drone is piped right into the cab. The short term fix is close the vent! I may have to block the air from the base of the windshield and just use the air from behind the grill.

Steve

 

[dieselcruiserhead]

Nice Steve, nice to see pics. I am hoping the snorkel will do the same for me. I have always been "anti-snorkel" mostly because 99% of the yahoos who have will not use them but it seems like a good solution for me for right now. .

 

[dieselcruiserhead]

Steve I can't believe I missed these all of these years but those are some great photos of your 4BT swap(s)! I dig the Willy's as well too! Andre

 

[driverswanted]

Steve,

Have not forgotten the pics of temperature sensor location. Just busy changing from a 3. 21 to 3. 55 this last weekend. Much nicer driving with the 3. 55. should be able to cut back even more on fuel now that it has such nice pull-away at higher road speeds.

 

[driverswanted]

Steve,

Here's the best photo I was able to squeeze in and get of my thermocouple. I used 1/4" npt tap into the exhaust manifold. The TC is 1/8" 316L or 304 sheathed.

 

[Steve Graham]

Barry,

Thanks for the photo.

Is the TC mounted underneath? I'm having a hard time placing the photo on the engine.

Steve

 

[driverswanted]

Sorry Steve, I should have pointed out references. The turbo exhaust housing is in view at the bottom and the firewall end of the exhaust manifold is at the top of the picture. You can see the compression fitting and it's threaded end in the forground of the exhaust/turbo flange. The thermocouple is entering the exhaust manifold from below; entering the underside of exhaust manifold where the engine's front cylinder exhaust joins number one cylinder's exhaust. The thermocouple drops down one inch out of the exhaust manifold and turns back toward firewall to clear the turbo exhaust housing.



Hope this clear it up better.

 

[Steve Graham]

Thanks,

Thats more better! I'll bet you had the exhaust manifold off to drill and tap?

Steve

 

[driverswanted]

Yep. I had it plugged until I robbed the system monitor out of my '91 6BTA one ton. I knew I was going to sell that truck so I had drilled and tapped the 4BT manifold for the future swap before everything was bolted together.

BTW. like my 3. 55 gears. Running 1906 rpm @65mph. One inch shorter tire should bring my rpm/mph numbers right in line with yours. At 70 mph I'm turning 2046 rpm. I'd like to have that 2000 closer to 65mph. Seems to have nice acceleration i. e. turbo spool up at 2000 and lets me pass other vehicles quickly; including hills.

 

[Steve Graham]

I think I'm going to half to do the drill and tap on the top, no plans to remove the manifold soon.

My gearing is calculated out to 1870rpm at 65 with new tires, 1900 at 65 is what I read while driving. Sounds like your right where I'm at.

Steve