LL8 Engine Test Platform Project

rchalmers3

Gold Supporter
I had a spare TB frame and am in the process of using it as a basis for performing engine and transmission runs. I also wish to build a turbo exhaust system, and the accessibility provided by this fixture will be a welcome treat for this old tired body.
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I built the pedestals from scrap tube. I made one wheel adjustable in height.
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Rick
 

rchalmers3

Gold Supporter
Thread Starter
I painted the frame and brought it inside to assemble.
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The first engine to be run in is the 2006 I had rebuilt.
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The 4wd transmission is not coupled by a converter. For now I am using the trans solely as a mount, to get the engine all hooked up, running and tested. Later I'll put in a working 2wd unit. More on that later, much later!
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I retained the strut towers and threaded upper A arm bolts back into the towers, anticipating the turbo build project that will follow the run-in of this engine. I'll also mock up an outline of the firewall to create the absolute limits of the space I have to work within when making my first turbo kit.
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The next steps are to fit a battery and fuel system with an eye towards appropriate sizing and packaging. I believe I'll locate those items under the radiator. After the battery and fuel system are placed, I can fit the radiator. Then I'll then make up a stand alone harness for this 2006 engine.

Thanks guys for your interest, comments and encouragement. Again, I appreciate your willingness to share your experience with me as I become acquainted with the LL8 platform.
Rick
 
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TollKeeper

Gold Supporter
I think you might be better off on just using an actual firewall from a GMT360. Its not a matter of just space from the firewall to whatever, but other things that are also present (wiring looms, water cooling hoses, AC lines (if still equipped), Tranny lines, power steering lines, etc). It would also allow you to have a functional cluster so that you could watch for water temps, RPM, etc, at a glance without having to find the right window on a laptop.

Something like this... (but without the A-pillars or windshield) (Poor SS)
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rchalmers3

Gold Supporter
Thread Starter
I think you might be better off on just using an actual firewall from a GMT360.
TollKeeper,
Thanks for the suggestion, I should have considered that previously when I had the materials. My yard space is limited, so I have not kept any unused body parts around. My intention was to strip and use the bare minimum of materials needed, so I'll continue that direction.

I'm exploring the possibility of assembling a basic platform that is sufficiently flexible to run both the 2006-2007 and the 2008-2009 systems. The main connection piece is the under-hood fuse block. From my cursory inspection, most, but not all of the basic wiring systems overlap. I'll keep on it and post developments as they slowly occur.

Rick
 
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rchalmers3

Gold Supporter
Thread Starter
I added a few bits to the platform, however I need some materials for assembling the controls. Being that the holidays are upon us, package delivery is slow, so I'll be setting this project aside.
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The radiator is fitted and I have put together a pressure can for charging the oil galleys.
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I found a suitable battery location that uses the stock cables and built the tray from salvaged angle iron.
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Here's my idea of a no-cost fuel tank.
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The electrical wiring of the engine test bed wiring does not have to agree and meet up with a vehicle, so I have pulled out circuits that are not needed and have taken it upon myself to route the wiring in a manner that pleases me. The engine portion will exit off the rear driver side.
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My goal is to have a flexible wiring system comprised of independent harnesses for the engine, transmission and controls, connected via OEM harness connectors. At this juncture it appears that the 2006-2007 model will be doable. The 2008-2009 models, with the addition of the separate PCM may require a re-think!
A shout out to @lime-swap for his valuable assistance in obtaining the special bits required for this aspect of the project, and for his views on power mods utilizing the OEM controllers. Thanks bud.

Happy holidays gents, and thank you again for your interest, comments and suggestions.
 

MRRSM

Lifetime VIP Supporter
Nice Work, Rick... These New Additions to The Chalmers Atlas Engine Test Station are splendid.

Props to @limequat for helping you with the arcane Electronic Stuff, too!


FWIW... I was thinking of the possibility that you might consider adding in Four Points under your Frame fitted with Four Short Steel Tubes welded in cross-wise and using Thru-Bolts to hold on Four Short Angle Iron Sections. These Lifting Segments could be rotated around underneath the Four Sides supporting entire Frame and equally elevate those balanced locations ...But slightly Taller than your Wheeled Posts. They could be easily be worked into their places using Lengths of Steel Tube Welded onto the Upright Angle Supports of these "Iron Footers" and allow you to Slip in a Tire Iron for Leverage to move them into and out of position.

(Think "Parked Semi-Tractor Trailer" here...) :>)

The Wide, Plate Steel Feet could then be Pin-Locked into place through the Side Frames and thus, offer a Solid, Flat "Footer" for the Entire Loaded Frame to Rest Upon while the Engine is Running, Gyrating and Vibrating around just above. The less the Whole Rig Shakes during Operation the Better, so using these as a Temporary Foundation should allow the Engine,Transmission and Support Frame to be much more stable. Once the Test Motor-4L60E is Turned Off... the Footers could be Un-Pinned, Rotated around under the Frame and held up and out of the way using the Thru-Bolts, while the Wheeled Posts settle back down on the Deck and allow the entire Rig to Roll Around again.

PS:

With your Battery, Wiring and "Fuel Cell" all situated quite near to each other... an ABC Fire Extinguisher is a Handy Thing to have nearby.
 
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rchalmers3

Gold Supporter
Thread Starter
With your Battery, Wiring and "Fuel Cell" all situated quite near to each other... an ABC Fire Extinguisher is a Handy Thing to have nearby.

Now that comment made me laugh! It happens that I relocated here to the US South East a few years ago. into a log home. As in: ALL WOOD HOUSE. Finding home owners insurance companies who specialize in covering these unique homes has been... involved. And yes, I have 2 1/2 pound ABC'ers located on all levels of the house!

Thanks gents, and happy holidays to all,
Rick
 

MRRSM

Lifetime VIP Supporter
I'm sure you've already thought about this... But if not just yet ... if you intend on mounting an Analog Oil Pressure Gauge in Plain View with enough flexible hose length to 'Place, Zip Tie or Bracket' it anywhere very convenient:

https://www.amazon.com/dp/B08BFVCLH3/?tag=elightbars-20==

ANALOGOILPRESSUREGAUGE_.jpg

.... instead of placing the required M16 X 1.50 to NPT Adapter into the Engine Block HERE:

GM42LFRONTOILGALLERYPLUG2.jpg

You might consider using either of the Two Horizontal Oil Gallery Plugs situated HERE:

GM42LREAROILGALLERYPLUG.jpg

This approach would place the OP Gauge well away from the "Busy" area at the front of the Engine and eliminates having to route any Plastic or Copper Tubing snaked around the long engine block to avoid the Heat from the Exhaust Manifold or any other harness entanglements elsewhere.

This M16 X 1.5 to NPT Adapter is one of many made for the LS Motors and available for under $10.00 on Amazon:

LSENGINEOILPRESSUREADAPTER.jpg

Happy Holidays, Brother...
 
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rchalmers3

Gold Supporter
Thread Starter
Hiya fellas, I hope this message finds you well in the new year with these unique times. It's been a month since my previous installment. I believe I have all the bits needed to get this project running, and will spend some time on it in between feeding the wood stove and fireplace!

I fitted a control box to the radiator support. Seemed like the right place to position it. It's an ammo box loaded with cheap eBay switches and gauges.
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The on/off main switch is double pole/single throw. That feature gives me the create license to switch both power and ground. Since I'm winging it, I appreciate having options on switching relays! The black push button is for the starter..... I messed up on the position of that during the layout and didn't catch it until it was too late. There is a fuel pump switch, and an ignition main with individual kill switches for each cylinder.

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I retained the DBW throttle and fitted a friction bar for setting the engine speed. I also placed the ALDL connector in a familiar location under the "dash".
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Regarding extra instrumentation, the fuel gauge was a cheap, easy solution to add. I have ports for a mechanical water temp gauge at the water pipe above the thermostat and a sandwich plate at the oil filter for plumbing in an oil gauge and pre-oiler.
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As usual, the last mile of this project will be to complete the wiring. I have 75% of the wiring sorted, and I now have the last bits in hand to get it done. I will simplify a bit of the power distribution, as this application does not have the same requirements as a road vehicle. I believe it will be sufficient to have three relays, one for the starter, one for the fuel pump and a final one for all ignition operations. I will retain the park-neutral and transmission operations.
I look forward to having it all sorted, then pinning out each wire run one final time!
One detail I'll save for later is fitting a dash. I do have the wiring prepared, but I'm not sure where or how I'll place that piece. For now I'll use the ALDL and my Snap-On Verus.

This project has been fun, but I am realizing that I want to get it going and move on to the car build. My next post should be a report on having this thing making noise and carbon dioxide emissions.

Cheers gents.
 
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TollKeeper

Gold Supporter
Your almost to the point of turning it into a cool little go-kart!

Looks good man!
 

rchalmers3

Gold Supporter
Thread Starter
It's running.

I'm at 98% completion. I still need to fill the cooling system and run it in closed loop so I can monitor the entire system. When I'm satisfied with that, I'll wrap up the exposed wiring and make it a tidy package.

I encountered a few issues leading to the start up. First, I had the oil priming tank fed into the sandwich plate. That was a mistake some of you probably noticed in the previous images that I posted. I should have made it feed into the pressurized galley. As I had it hooked up, all it did was prime the filter and pick-up tube, so I pulled the plugs and cranked the engine numerous times for 30 seconds to build oil pressure repeatedly.

Next, I need to caution you: If you follow my design and mount a mechanical oil gauge in an ammo box, be sure to drill a few drain holes in the bottom of the box. I made one hella mess! The difference between almost tight and tight enough on those ferrule fittings is about 1/6 of a turn on the nut...

The last detail was small. The #4 cylinder was not contributing on the initial start. It took just a few minutes to sus the control circuit wire for #4 had backed out of the computer connector. While repairing this last issue, I was thankful to not having to be doing the diagnosis while laying over the engine!

It was suggested that I make a short video of the successful conclusion to this project. I did so, but I must warn you that my ancient phone makes videos look so 2001. Here is the link:

You folks have been a great inspiration to me as I follow my desire to develop my understanding of the GMT360 and LL8 engine. If you have any questions about this project thus far, or if you want to borrow the platform for your own project, let me know and I will make it available! Thank you for your continued encouragement. My next project will be preparing the body and chassis for racing. I will post up on those developments as they occur.

Rick
 

JayArr

Active Member
I have a couple of questions Rick.

First is how much of the wiring harness do I need to pull out of a junkyard Envoy? I'm going to use a purchased run in cart but will need to make an Envoy specific wiring harness. If I just grab everything from the engine compartment and back to the transmission will I have enough or do I need to get parts of the wiring harness from inside the cab as well?

Second is why you used a mechanical oil pressure gauge at all, isn't there an electronic one on the engine that can be monitored through OBDII? I've never like the mechanical ones because of the leak potential.
 

TollKeeper

Gold Supporter
I think I can answer the second question.. Since the factory sensor is just a on/off switch that the computer than estimates what the oil pressure is to go to the gauge cluster. I would imagine you would get the same false info from a OBD2 readout.

Not to mention, just a quick look over at a gauge is easier than pulling up a scan tool, and getting to the right PID.
 

Mooseman

Master Blaster
Moderator
Like @TollKeeper said, the OEM oil pressure gauge on these engines is fake.

Looking at the mechanical gauge, it goes up to almost 100 psi cold. Maybe that's partly the reason they can't use a real gauge because they only seem to go to a max of 80 psi.

Nice job on this project! Cool to see there is still interest in this engine despite having been out of production for 12 years.
 

rchalmers3

Gold Supporter
Thread Starter
I have a couple of questions Rick.

First is how much of the wiring harness do I need to pull out of a junkyard Envoy? I'm going to use a purchased run in cart but will need to make an Envoy specific wiring harness. If I just grab everything from the engine compartment and back to the transmission will I have enough or do I need to get parts of the wiring harness from inside the cab as well?

Second is why you used a mechanical oil pressure gauge at all, isn't there an electronic one on the engine that can be monitored through OBDII? I've never like the mechanical ones because of the leak potential.
Hiya @JayArr,

What year is your Envoy? That info may have me suggest a more complete reply, as the year models have different players in the engine/power train areas.

Inside the cabin are the DBW throttle, Instrument Panel and ALDL connector, so if you want the full Monte, I suggest you harvest at the least the wire section that goes from the underhood fuse block into the cabin.

Getting that entire loom with the throttle assembly out of a wrecking yard vehicle would be time consuming and tedious. That loom continues up and over the trans tunnel into the climate controls, and it also continues back to the rear fuse block. Just follow it into the drivers side of the cabin and extract the first 30% of the harness that has the throttle pedal, IP harness connector and ALDL.

As the others have mentioned, having analog oil pressure readings right there at the controls is a basic insurance policy. I used it to monitor oil pressure readings while cranking the engine while all electrics were off. I could not have done that with my Verus, nor with a instrument panel gauge.

Rick
 

JayArr

Active Member
Hi Rick

Thanks for the info, I'll get everything up to the tranny tunnel on the drivers side in the cabin.

My Envoy is an 05. and my spare engine is an 03 so I need to stick to those early years.

I see the advantages of the mechanical gauge, I'll put one on my stand as well, thanks.
 

rchalmers3

Gold Supporter
Thread Starter
Hi Rick

Thanks for the info, I'll get everything up to the tranny tunnel on the drivers side in the cabin.

My Envoy is an 05. and my spare engine is an 03 so I need to stick to those early years.

I see the advantages of the mechanical gauge, I'll put one on my stand as well, thanks.
@JayArr, A heads up!
Today I had the 100 PSI mechanical oil pressure gauge fail. When the engine is cold, the pressure is quite high, perhaps too much for a 100 PSI mechanical gauge. The cold egine oil pressure went up. up. more up, past 100 PSI and stayed there! And it's now reading over 100 PSI with the engine off!

I did a brief search and was unable to locate a 120 PSI mechanical gauge, so I did the next best thing: I have ordered a direct replacement (thank you Amazon Prime) and I'll let you know if the replacement gauge survives. Otherwise, if you cannot find a 120 PSI mechanical gauge, I suggest you go with an electrical 120 PSI oil pressure gauge. I may follow this advise myself if the replacement gauge fails.

Regarding your year model, your vehicle years do not have the separate PCM, so my suggestion about harvesting a portion of the body harness is accurate.

Rick
 
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ddgm

Registered Member
@JayArr, A heads up!
Today I had the 100 PSI mechanical oil pressure gauge fail. When the engine is cold, the pressure is quite high, perhaps too much for a 100 PSI mechanical gauge. The cold egine oil pressure went up. up. more up, past 100 PSI and stayed there! And it's now reading over 100 PSI with the engine off!

I did a brief search and was unable to locate a 120 PSI mechanical gauge, so I did the next best thing: I have ordered a direct replacement (thank you Amazon Prime) and I'll let you know if the replacement gauge survives. Otherwise, if you cannot find a 120 PSI mechanical gauge, I suggest you go with an electrical 120 PSI oil pressure gauge. I may follow this advise myself if the replacement gauge fails.

Regarding your year model, your vehicle years do not have the separate PCM, so my suggestion about harvesting a portion of the body harness is accurate.

Rick
Auto Meter makes mechanical oil pressure gauges up to 150 psi, looking at their site, I see 8 of them, ranging from $75 to $110. Have no idea of their worthiness but seem to have a great selection of gauges of all types.
 

rchalmers3

Gold Supporter
Thread Starter
Should not the oil pressure regulator have limited that to the specified 65 psi max??

Could that device be stuck?
Cheers, TJ. While I had the pump dis-assembled, I cleaned and inspected the oil pressure regulating piston, spring and bore, and saw no issues. On cold start (in cold weather) the indicated pressure is about 75 PSI at idle, and falls as the engine warms. If I rev the engine while cold, the pressure reaches the upper limits of the 100 PSI gauge. The break in oil I'm using is a mineral based 5-30w. Perhaps the synthetic oil will give different pressures?

I don't think the actual oil pressure exceeded 100PSI. I believe I watched the 100 PSI oil gauge sail off to heaven.

From my understanding, the oil pressure specification is a minimum, with no maximum or regulated pressure specification given. Therefore, I'm satisfied with the current readings, unless someone with more experience says different.

Rick
 

rchalmers3

Gold Supporter
Thread Starter
It's very lovely, indeed! Something about this platform in its most abstract and minimal form is beautiful. Also makes any maintenance job a breeze. Great work!
Cheers zaid3.

I want to wrap up this project with a few final thoughts and findings. The first thing to point out is that I was able to create this test platform with minimal cost. This particular project was created from the remains of other vehicles I purchased and parted out. I estimate I have less than $300 in additional purchased materials to bring it all together.

The ALDL is the best access to determining proper operations. That, along with the mechanical gauges, I see no reason to wire up the dash. Upon getting the platform running, I find I can trust the cheap mechanical gauge set, including the coolant temp and volt meter. The only additional information I could receive from a working dash is a tachometer and CEL. Also, I can't figure out where to place the dash, so I'm gonna leave it off for now.

I have two fault codes related to this project. One is related to a CEL circuit issue (no dash!) and the other is relates to the fuel pump circuit, which I rewired to create switched control. If I find it to be worthwhile, I'll take a moment to create the appropriate work arounds for these two codes in order to satisfy the ECM.

Something that limits the utility of this platform is a lack the ability to perform proper engine break in. There is no way to place a load on the engine. I like to wear in the piston rings by numerous long, loaded pulls up to max revs. So for now, this test platform is limited to mock up and testing. Eventually I'll figure out some way to put a brake behind the transmission to create the drag needed for proper engine break in. If you people have suggestions, I'd like to hear from you on that concept!

Again, thank you all for your contribution to my efforts,

Rick
 
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From my understanding, the oil pressure specification is a minimum, with no maximum or regulated pressure specification given.


Well I'm not sure this can be considered a specification but I have seen a few references like the one linked below that state this 65 psi as a maximum. I have an aftermarket mechanical pressure gauge on my 2002 4.2 with over 285000 miles and in cold weather I have seen mid 70s at say about 2500 or 3000 rpm and 60 psi at 620 rpm idle when cold (like 40 or 50 degree oil temps). At about 190 something degree oil temps I will drop to around 10 psi at idle and maybe mid 20s at 2000 rpm.

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rchalmers3

Gold Supporter
Thread Starter
Well I'm not sure this can be considered a specification but I have seen a few references like the one linked below that state this 65 psi as a maximum. I have an aftermarket mechanical pressure gauge on my 2002 4.2 with over 285000 miles and in cold weather I have seen mid 70s at say about 2500 or 3000 rpm and 60 psi at 620 rpm idle when cold (like 40 or 50 degree oil temps). At about 190 something degree oil temps I will drop to around 10 psi at idle and maybe mid 20s at 2000 rpm.
Thanks for that TJ,
I betcha my numbers are not too far off of yours. This is a freshened engine with all of about 15 minutes of idle operation. As I tried to explain earlier, I don't think the engine really created 100 PSI. I believe the gauge went bonkers when I revved the engine under conditions that create the highest possible pressure, prolly within 10% of the gauge max. I will continue to monitor the oil pressure as I develop a method to wear in the piston rings on the platform.

Rick

 

Mooseman

Master Blaster
Moderator
For any codes you want to get rid of, you can have them disabled via a tune. You will likely need one since you also need to disable VATS. Don't want to use a downstream O2 sensor? Delete the codes. Don't care for using the PCM to control your fuel pump? Delete the codes.
 

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