Mexacali Express ('72 K10/LQ4/TH350 Retrofit)

[Low Elco]

Hopping on this train- lots of good info here! Bookmarked! You oughta PM KRUE and USMCchevy to add this to the FAQ stickies!

[67cheby]

nicely done, very informative thread !

[Bomp]

Note pad...check
bookmarked.check
subscribed....check

[jpstaub]

Click here to download a copy of the CAD file needed to make the custom engine brackets for the Pacific Fabrication cross member referenced in a previous post.

Once you download the file upload the file at Big Blue Saw on any other cutting service you'd like. Big Blue Saw is really easy to deal with but there are other services out there including guys with CNC plasma cutters in their garages. Big Blue Saw will display what the cut parts will look like. They should closely match the picture below.



Choose your material. 0.25" steel is recommended based on the thickness of the original parts. In my opinion cold or hot doesn't really matter for this application. To each his own however.

If guys want to crank out 10,000 sets so be it. All I ask is that any modifications to the original file be posted in turn so that others out here can benefit. A $5 donation to the beer kitty is welcome. Shoot me a PM for contact details.

Disclaimer: This file is offered without warranty or guarantee of suitability. If you assemble the parts that means you're taking full responsibility for how well or poorly the assembly operates. If you can't weld find someone who can. The part finish from CNC waterjet cutting is so good that assembly adds very little to the overall cost.

[jpstaub]

For those of you who can check the oil level in the engine every once in a while there's no need for the oil level sensor as originally equipped. Discount Hydraulic Hose has what you need. Use part no. 9029-20x1.5. The installed plug is shown below.



For those that want to use something else as long as it's 20mm x 1.5pitch it'll work.

[jpstaub]

For those with the factory oil pressure indicator, Auto Meter Part No. 2268 will hook you up with an 1/8" NPT outlet which happens to be the thread size of the stock oil pressure line setup. The installed fitting is shown below.



For the oil light guys, the thread size of Part No. 2268 is 16mm x 1.5pitch. I bet VDO makes a pressure switch that can be used with the stock '72 wiring harness. A little speculation on my part but worth the effort to chase it down I think.

[jpstaub]

The LQ4's I've worked with have come with plugs where you'd get the vacuum for the power brake booster. To correct that problem use Vacuum Booster Fitting part no. 12559760. The picture below shows one installed (it's the piece with the red ring around it).



The first time I installed the fitting it took me a while to figure out how. The fitting makes use of the Chinese handcuff method. No kidding. That's the easiest way to describe it.

1. Push the red ring in as far as it will go with the tip of your finger.

2. Apply pressure to the red ring while sliding the plug fitting out.

3. Wipe a layer of light lubricant on the booster fitting (there's an o'ring inside the vacuum port).

4. Slide the booster fitting in and you're done.

[jpstaub]

In an earlier post I stated that LQ4's or other LSX engines that came with 4l80e's are suitable for TH350/700R4 swaps with no additional parts; just flex plate bolt hole elongation. If you're not sure what a 4l80e setup looks like the picture below will help you out.



Notice the small ring inside the middle of the flex plate. That's a crank spacer unique to LSX engines using 4l80e's. It's designed to catch the snout of 4l80e torque converters. Happily the crank spacer will also catch the snout of TH350 and 700R4 torque converters. And those flex plate bolts (part no. 12563533 or 19257940), cheaper than Corvette exhaust manifold bolts at $4.75 each but no steal. Do your best to get all the original fasteners that you can with the engine. It's pretty easy to bleed cash on unique factory fasteners that are difficult if not impossible to find outside the stealership.

If you elect to use a flex plate out of a parts yard it will probably come with the spacer since it's captured by the flex plate. The last flex plate I got was $35 out the door with spacer.

[jpstaub]

Where to put the computer? It's a pretty sizable box that I chose to hide under the air filter in front of the driver's side inner fender. The steel mounting material came with the air filter kit which is referenced in an earlier post. You have to do some cutting. No buying is involved other than the fasteners and plastic stand offs.



You can see the orientation of the computer in the next photo below. Aside from hiding the computer the mounting location maintains the proper orientation of the wiring harness connectors. That way I didn't have to do a lot of creative twisting of the connectors to attach them to the computer. Minimizing twisting and strain is good for long term durability.

[jpstaub]

To move power from the battery to the truck fusible links came installed out of the factory. An LSX adds to the load on that link. Most people who don't replace the link during the course of their swap will end up replacing it after it gives up the ghost a time or two. A MIDI fuse holder is a nice clean way to install a high amperage fuse. Littelfuse part no. 04980900Z is what I've been using. Waytek has the same fuse as part no. 46008. An 80A fuse is part no. 46385 which I used to run the additional LSX loads and an electric cooling fan that pulls approximately 25A steady state. More than anything else, the 80A fuse is meant to protect the fuse/relay panel which is rated at a max of 80A.

The installed fuse holder is shown below. It's right above the coolant reservoir cap in the photo.

[jpstaub]

Going LSX means thinking about power management if you plan on keeping electronic fuel injection. As a result you'll need a fuse/relay panel. The best thing going that guys like us can get hold of is Cooper Bussman's mini fuse and micro relay panel. It's compact, weather tight for engine compartment mounting, and holds enough relays and fuses to get the job done all in one spot. Part no. 15303-6-2-4 is what you're after. Waytek sells these dolls at a really reasonable price.

The picture below shows a panel stuffed with micro relays.



Click here for additional technical information on the panel like what terminals to use, electrical ratings, bolt sizes, etc.

[jpstaub]

If you mount the fuse/relay panel close to where the computer is mounted you'll have very little to do in terms of power wire length modification aside from cutting. Less modification means spending less time on wiring, a part of the build most people don't enjoy.

The picture below shows the optional mounting brackets (part no. 46085 at Waytek) to the right of the computer next to the radiator.



In the picture below you can see the top of the fuse/relay panel cover to the left of the air cleaner. There's enough room to get fat fingers in there to change a fuse or relay but if you're not looking for the panel it's not noticeable.

[jpstaub]

As far as I can tell, Spal makes some of the best electric cooling fans on the market. I've used part no. 30102082 twice. Guys down south or those that spend a lot of time at high power and low speed or that have crap radiators may need something more.

For mounts I don't do anything fancy but I do mount the fan permanently. Mounting fans with pull-through-radiator plastic fasteners is a sure way to destroy your radiator over the long term. That may be good if you're running a crap radiator but eventually you'll want to protect your investment.

I modify a rubber Spal fan gasket (part no. 30130074) and hold the fan to the radiator using Spal mounting brackets (part no. 30130011) with plastic stand offs and associated fasteners. Note: by mounting the fan to the radiator you can do all your fab work on a horizontal bench which keeps blood pressure low.

I know that I'm not pulling air through the entire radiator with my mounting technique. However, I haven't reached a point where the fan can't keep up with the heat load.

[jpstaub]

I've been avoiding the wiring discussion but no more. This post is the first key to the castle as far as wiring is concerned when using LQ4's that came from Express 3500 vans with a TH350/700R4. At all costs remain organized and keep the harness bundled together.

The first order of business is to get yourself up to speed on general wiring harness practice. LT1Swap.com is the best place I've seen for this. There's a lot of good information about how to modify a wiring harness to make it stand alone. On top of that, you can get your computer reprogrammed at a very reasonable price through Brendan, the guy that runs the site.

OK. Now you're ready to rock and roll. Awesome. Along with Brendan's instructions click here for a pinout table I put together specifically for van based LQ4's. It's labeled for a 2004 model but it's based on a 2006 model with minor wire color modifications. So, it ought to work for other years if you don't have a 2004 engine. The bottom table is a fuse block connector pinout which is a help when identifying which power wires go where. If in doubt use a multimeter to ring (test continuity) of a connection. Near zero resistance means you have the right beginning and end of a wire. Large resistance means you have the wrong beginning and end of a wire although it's possible that a wire is broken.

When clipping power wires from the fuse blocks I group and label the wires (tip: by using blank adhesive address labels you can group and label quickly). By doing that I set myself up for one of the largest steps in the process which involves linking everything up in the fuse/relay block.

[jpstaub]

The harness should be looking a lot thinner than it started after you get rid of all the crap that goes along with a computer controlled transmission. Hopefully all your power wires are labeled. The next order of business is to stuff the fuse/relay block according to the file in the previous post. It's also included below.

6.0L K-10 Vortec Retrofit Wiring.pdf

The order in which you stuff the fuse/relay block is all a matter of personal preference. As far as the diagram is concerned, the blue bars indicate that terminals are tied together or should be tied together. If you're using the fuse/relay block referenced in an earlier post you don't have to worry about tying relay pins 87 together. The fuse/relay block comes that way out of the factory. You just have to position the relays in the block so pins 87 are in the correct location. (If you're not familiar with relays the pins are numbered and the numbers molded into the plastic shell tell you which pin is which).

When joining multiple fuses to one relay source I recommend running one heavy gage wire away from the fuse/relay block, joining lengths of wire together using a crimped butt connector and solder, then running the respective wires to their associated fuses. This keeps a giant ball of connections from developing at the fuse/relay block.

Note: to avoid problems with wiring over the long term it's best to solder all butt connector type connections.

[eagleuh1]

One of mthe best, most complete writeups I've ever seen. Thanks for taking the time and effort. Especially on the file for te motor mounts. Kudo's. Jim

[Low Elco]

Dang, this is a lot of good info! Almost makes me want to dive in!

[jpstaub]

Safety is a topic that doesn't get a lot of play in the performance world at times. I don't mind. I like to be as much of a hazard as the next guy. But I do recognize that passengers may expect not be turned into a block of carbon as a result of high pressure fuel spray after a crash.

In the Vortec Retrofit Wiring document included in a previous post you'll see a "CRASH SWITCH" in the upper right hand corner. It's wired such that power is removed from the ECU in the event of a crash. By removing power from the ECU not only do the fuel pumps stop pumping but the ECU can no longer control spark or fuel injection disabling the engine. If you talk to accident investigators one item they will mention is that when people/police first arrive on the scene of a bad head-on crash the engine of the vehicle will be screaming because the driver's foot is jammed down on the accelerator pedal. Not to be morose, but with all the idiots out there texting instead of driving it's a good idea to think ahead because they're not.

Ford did us a solid by incorporating inertial crash switches in tens if not hundreds of thousands of vehicles. If you go to Ebay and type in "inertial crash switch" you're bond to have a selection to choose from. Usually they'll come with a wire pigtail which will save you some money and time sourcing a connector. A typical setup is shown below. If you'd rather have a new switch use part no. 1S3906. Connectors are commonly available.



So now that you're a little scared for your life how/where to install the switch? An image below covers the basics. Installing the switch upright will allow the metal ball in the switch to drop in a crash breaking the circuit. I like to put the switch in the cab on the throttle pedal bracket which keeps it out of the weather, out of the way, but accessible. It also allows me to run a lead from the little used "Glove Box & Spot LT" fuse on the stock fuse panel for power. Shown below is a Ford installation but it gets the idea across.



For guys that like to know how things work the image below shows how the switch is operated. If you'd like to test it out prior to installation smack the switch against your palm to activate the inertial release. Test with multimeter; circuit should be open. Reset the switch and test again; circuit should be closed.

[jpstaub]

For Key Power I use the original ignition wire. It's on when the key is on which is how we want Relays 1 and 2 activated. With the key off Relays 1 and 2 are deactivated and battery power is preserved. For a visual depiction see the retrofit wiring diagram in a previous post.

[jpstaub]

Type I circuit breakers are used in place of fuses for the fuel pumps and the electric fan. What gives?

A type I circuit breaker automatically resets power after it's amperage rating is exceeded. This is a good feature when using motor driven electrical devices. Motor driven electrical devices are, in general, known as inductive loads. This means when the device is first powered up it takes a certain period of time for the magnetic field and therefore the resistance in the load to build up to normal operating levels. Therefore, when power is first applied there is a spike in current well above the steady state rated operating current. Whhhhhat?

Believe me, I learned all that crap above the hard way. That super stout Spal electric fan I reference in an earlier post kept blowing 30A fuses. It would turn on once or twice then nothing (makes for sweaty palms and nervous glances at the temp gage when waiting at red lights which I always manage to hit). The reason was the spike in the current when the fan first turned on. A handful of spikes would melt the fuse. What about a fuse of higher rating? The mini fuses that make the Cooper Bussman RTMR panel so sexy have a max rating of...you guessed it, 30A.

In a roundabout way I finally stumbled on a reference explaining that OEMs use Type I circuit breakers whenever they're driving inductive loads: power windows, fuel pumps, electric fans, etc. Now you know.

The 30A Type I circuit breakers aren't all that common. Use part no. CB211-30 to get the treasure hunt started. Drillspot is where I got mine.

[Bomp]

Thanks for all the helpful info.
I have it bookmarked for when I get to that point in the build.
Keeping notes.

[jpstaub]

Stock harnesses come with two grounding ring terminals. Once all the extraneous stuff is removed from the harness there's no reason to keep both terminals. Merge all the ground wires together on one of the grounding rings and remove the other for a cleaner installation.

As far as installation is concerned, GM uses bellhousing stud bolts (part no. 15724226) to mount the transmission. Choose a place that looks good to you, throw a bellhousing stud bolt in and bolt your ring terminal on (they're perfectly sized for the stud). See below for a picture of the fastener.

[67cheby]

i think i am going to be getting alot of tips from your thread very soon ! I am going to be doing the same thing in my wifes Blazer, keep up all of the GREAT INFORMATION !

[jpstaub]

A man's choice of wiring connectors is about as personal as his choice in firearms. Well, only for a certain kind of man who most likely is not the life of the party.

There are a lot of connector systems out there. Hop on Mouser's website. It'll make your eyes bleed with the number of choices available. To narrow down the scope I got interested in what GM is using since I'm using GM's stuff (know thy enemy). Delphi and GM have been hand-in-glove for a long time. The original connectors on the trucks are primarily Delphi Series 56. And the connectors on the LSX harnesses are Delphi. All this means that Delphi stuff is relatively common, easy to source, easy to find replacements for, easy to work with, well documented, etc. for people who know what they're looking for and where to look.

I kid you not, this link to Delphi's Global Connection Systems Catalog will put an awesome amount of power in your hands. Those who would rather not learn anything will gladly continue to pay $20 for a lousy damn temperature sensor connector pigtail which is just the start. The global catalog gives you pictures AND part numbers. Without part numbers you're a lamb wondering around in the dark. Don't be a lamb. The wolves are out there looking for a quick buck.

Once you have a good feel for what you're after go to Mouser or Digi-Key. Type in the part number you're interested in. Bam! Now you know how to fish. Make sure to pay it forward.

[jpstaub]

Originally Posted by jpstaub

In the Vortec Retrofit Wiring document included in a previous post you'll see a "CRASH SWITCH" in the upper right hand corner.

"Upper right hand corner," should read "upper left hand corner."