'72 K5 - AJ's Gray Matter Build

[AJs72K5]

2/22/23 - Chassis update - no real pics on this update. Art Morrison, like most of the chassis builders, turned out to be a bust for me. I spent an awful lot of time working with their engineers trying to design something they could / would build. At the end of the day, I felt like I was making too many compromises. Not bashing them. They just weren’t who I wanted to partner with at the end of the day.

That said, I’ve been working with someone else in the space and put down a deposit for a chassis build today. They build some premier parts for 2WD GM chassis and are expanding into the 4x4 space. I’m partnering with them on the design and will have K5 chassis #1. Very refreshing to have input on the product. And the owner is a cool dude. More to come soon. They asked me to keep it on the down low until we have design finalized.

 

[AJs72K5]

2/7/23 - Cagey. Still welding up holes in the sheetmetal. Nothing exciting to see there.

Onto the update.... Bringing it back old school. Y'all will remember this gem of a showbar. 3 inch tubing held to mounts with self-tapping sheetmetal screws. The "mounts" were bolted down with 3/8" bolts.

Made a call to our resident beadroller / fabricator, Adam Deuling (he's too Instagram famous for CK5 now) to whip up some cage plates.

Used them to solid mount the new Hogan Built cage

All of that said, engine tune is schedule for week from today. forthcoming soon... followed by fixing the seat and seatbelt mounts

 

[jaros44sr]

Nice cage, gotta feel more secure in the drivers seat

She's looking good

 

[folkenheath]

2/7/23 - Cagey.

All of that said, engine tune is schedule for week from today. forthcoming soon... followed by fixing the seat and seatbelt mounts

Cage looks nice!

What ECU do you have now, isn't it self tuning?

 

[AJs72K5]

Cage looks nice!

What ECU do you have now, isn't it self tuning?

FAST Sportsman ECU. The roller cam we did doesn’t make enough vacuum for self tuning.

 

[folkenheath]

With the sportsman can you turn the self tuning off below a certain RPM? Or is it just on or off?

The self tuning will still work above around ~2K RPM. Its only below that it will need "assistance"...

 

[AJs72K5]

With the sportsman can you turn the self tuning off below a certain RPM? Or is it just on or off?

The self tuning will still work above around ~2K RPM. Its only below that it will need "assistance"...

I had to go find the manual to answer this one, it's been a while. It's parameter driven... min and max RPM, CTS, and TPS

 

[folkenheath]

Then I would just reset the tune, and set the MIN learn RPM to 1500 or 2K for that cam. It's really only going to matter close to idle where the overlap confuses the ECU by mixing oxygen from the intake with the exhaust, the O2 sensor picks that up and the ECU tries to richen it out, but it's false data, and keeps getting worse. Once the flow increases with RPM it doesn't matter any more. Set your target A/F to around 12.8 to start it with., everywhere. You can always lean it out later at cruise once it's running good.

You may have to tune a few idle and low RPM cells manually below the min learn, but I think you'll find it will be pretty close if you have the correct settings to start the tune. To tune the idle fuel watch the MAP reading, more vacuum means it likes it, less vacuum means it didn't like it. Of course the way the engine runs and the smell will warn you if its way off.

If your cam was getting in the 310 - 330 duration (~280 - 290 @ 050) or higher, then I would say to put the min RPM up to 2500 even. Most cams can learn at idle too, but apparently not yours. Make sure you don't have a vacuum leak or an exhaust leak.

My truck cam is currently ~230/240 @ 050 (280/290 ADV) and it learns OK, a wider LSA helps the ECU with less overlap, mine is still 110 LSA from the carb.

So unless you have more duration than that it should learn OK, mines still the old FAST EZ-EFI, for now.

 

[AJs72K5]

3/18/23 - Babaganooshed!! Got the tune done! Engine is making good power and running smooth. Self learning is on, but only above 1700 rpm and 31% load. Tuner doesn’t like PCV valves… says they’re big vacuum leaks and wanted it removed - so I did.

Weather cleared and took the K5 out for a 15 mile cruise. Engine and tune felt great!

Pulled off to a side road and did a 6000 rpm burnout. Something let go in the transmission and it went into limp mode. Got it back home and pulled it today to send off the @Greg Ducato for a checkup. Can’t say enough good things about his customer service.

 

[Babaganoosh]

Well done, making me proud.

Actually that sucks, how much power you making? Curious to see what Greg says.

 

[AJs72K5]

Well done, making me proud.

Actually that sucks, how much power you making? Curious to see what Greg says.

My guess is over 500 at the crank. Simulations I ran when built said it’d make 550hp and torque. Engine isn’t dyno tuned. Guy I used tunes it for what the engine wants. Will need to do a dyno run at some point.

 

[Babaganoosh]

My guess is over 500 at the crank. Simulations I ran when built said it’d make 550hp and torque. Engine isn’t dyno tuned. Guy I used tunes it for what the engine wants. Will need to do a dyno run at some point.

Dyno just disappoints, Street tune with real load is where it’s at.

 

[AJs72K5]

4/5/23 - Transmission diagnosis

Talked to Dr. Ducato last week after he assessed the damage. Because I didn't put a dedicated ground on the case, the transmission was trying to ground itself to the internal bearings... ultimately they got eaten for lunch and sent metal everywhere in the case causing all of the clutches to fuse, etc. In layman's terms, directly from Greg, "this thing took a tremendous $hit all over itself."

After a full build / rebuild, transmission showed up today.... in the same box and pallet that I sent to him, which is the original box and pallet from when I bought it... recycling at it's best. Hopefully I can make some time and progress over the weekend on the install.

 

[centexk5]

A ground wire from the case to the frame? Gotta say that’s the first I’ve heard of that. Aluminum block?

 

[AJs72K5]

A ground wire from the case to the frame? Gotta say that’s the first I’ve heard of that. Aluminum block?

Yep, ground from the case to the frame. I made the assumption that the bolts would ground it to the iron block. Guess too much engine paint in the way.

 

[centexk5]

Definitely never heard of having to do that. Live and learn. Guess I’ll be putting one on mine now.

 

[folkenheath]

The engine block is normally a more direct ground than the frame because that's where the battery ground is connected directly to, unless you moved the battery to the back and grounded that to the frame. The transmission doesn't take much current to run the electronics.

I just make sure that the bellhousing surface is scraped clean to raw metal and free of paint on both the transmission and the engine block. The bellhousing surface should never be painted as it can not only remove the ground but also cause the bolts to not remain tight as the paint gets smashed and if the paint is thicker in spots could cause alignment issues.

A ground from the transmission to the frame surely can't hurt, so I am not saying don't add one. It bypasses any painting that people may have done. But its still important to have a clean bare metal bellhousing surface on both the trans and the engine block, that's all I am trying to say.

 

[centexk5]

Mine ain't perfectly clean and I'm not about to unbolt that big sob just to clean it haha.

 

[Babaganoosh]

I think I might just add one for chits and giggles.

 

[AJs72K5]

With the trans out and having access to the back of the block, I’ll be cleaning both surfaces and adding a ground strap just because.