Rocco's 77 K5 Blazer - Frame Off 6.2/6L80 Build

[RoccoK5]

Apart from the frame and core support, I had the fuel tank and t-case skid plates coated along with some misc odds and ends like brackets, battery tray, spring u-bolt plates, suspension parts, drag link, etc. Nice thing about it is they do all the prep work to get down to bare metal. IIRC, frame was around $500, and the core support with the other misc parts was around $300. I'm probably at around $1K total for all the coating, which I think is cheap, considering this includes prep and looks great.

One downside is that it's not as easy to touch up and difficult to grind down if you need to weld on it, but this truck won't be a dedicated trail rig and TBH I'm not too worried about it getting beat up too badly. We'll see.

Here's a pic of some other stuff I had done earlier in the year:

 

[Coontail]

What's the details on your spare tire carrier? Looking to do something pretty similar

Very nice job on your build!

 

[eclipse85k10]

Definitely cool to see it come together with the body off you get a clear view of the motor swap details and attention to detail. Nice build

 

[RoccoK5]

What's the details on your spare tire carrier? Looking to do something pretty similar

Very nice job on your build!

Thanks! Let me see if I can dig up some pics from when I built the carrier.

Definitely cool to see it come together with the body off you get a clear view of the motor swap details and attention to detail. Nice build

Thanks!

 

[RoccoK5]

Here are some details on the spare tire carrier I built a few years ago, before completely tearing down my truck.

The goal was to keep the stock bumper and support a 35" tire. I'd probably do things differently today (e.g. double-shear spindle, replace stock bumper), but here's what I ended up doing at the time:

I used a single shear spindle/hinge kit from Chassis Unlimited (p/n CU-59109) and got the latch idea (basically a door striker and latch) from Rock Hard 4x4's JK Patriot bumper (https://www.rockhard4x4.com/product_p/rh-5001.htm). I actually bought the latch parts from them. The spindle is supported by a 2"x3"x1/4" rec tube on the passenger side of the truck, which bolts up to the outer bumper bracket and frame. The carrier itself is made from 2"x2" square tube and 2"x3" rec tube, with a rubber bumper up against the tailgate to keep everything tight when latched. Here's what it looked like once I had welded up the bracket, support, and spindle and started mocking the rest:

Testing fitment with a 35"x12.50" tire:

I ended up angling the tire in toward the truck a bit to keep it a bit tidier:

Kinda hard to see in these pics, but I had to notch the factory bumper to make room for the spindle and latch. The striker for the latch is mounted on a bracket that bolts to the frame. I also added a spring-loaded pin to the spindle to keep the carrier from swinging closed from the open position.

 

[Chevy305]

What wheels and tires are those?

 

[RoccoK5]

What wheels and tires are those?

XD Series 807 17x9
BFG MT KM2 35x12.5x17

 

[RoccoK5]

Finally got the engine fired yesterday! Excited that everything worked well on the first shot. No codes, no wiring issues.

Before I was able to start the engine, I:

• Installed the freshly ceramic coated headers with new gaskets and O2 sensors.
• Installed cheap intake with new MAF sensor.
• Primed the engine with fresh oil.

Here's my priming setup:

Fed the oil in through the driver's side galley:

And a terrible quality vid of the prime:

 

[RoccoK5]

Started on the exhaust yesterday. Planning on 3" from headers into single (dual in, single out) muffler with a single 3" tailpipe. I am using regular, non aluminized mild steel tubing and will have the whole thing ceramic coated once it's done.

Routing the passenger side around the transfer case was tricky, but I think I've got it sorted out: I will most likely need to add a v-band clamp at the muffler so that section is separate, otherwise I won't be able to remove it without first dropping the t-case or crossmember. I will probably use two clamps at the front of the muffler so that the whole rear separates from the driver and passenger mid-pipes.

Waiting on the muffler to arrive then I can get the rest mocked up and tacked together, then fully welded.

 

[Jumppr]

Everything you've done so far is everything that I wanted to do when I originally started.......Looks good!

 

[RoccoK5]

Made a little more progress on the exhaust yesterday.

I started by hanging the muffler, which I should have done first, since I ended up having to tweak the mid-pipes to line up. Here's the hanger I came up with:

You can't really see in the pic, but I'm using an exhaust hanger grommet like this one to isolate the hanger from the frame bracket:

This keeps the muffler tucked up high and toward the passenger side. I added a v-band and tacked the driver's side pipe in place.

Next I need to finish up the passenger side pipe, then I can route the tailpipe and finish weld everything.

 

[RoccoK5]

Like everything else on this project, progress is super slow...if I have a couple free hours to do some work, half of that is spent getting everything I need out of the garage, and then cleaning everything up when I am done. I wish I had some indoor space for this, I think everything would be moving along much faster if I did. Oh well, maybe on the next one.

That being said, passenger side exhaust fit-up is finally done!

I'm pretty happy with how it came out, although the pipes are pretty close to the transfer case and the frame / rear brake line on the passenger side, and the fuel line runs right above the driver side. I'm planning on having everything ceramic coated which I think would keep the heat down somewhat, but I suppose I could wrap the pipes where they run close? Or am I overthinking it?

Anyway, I'm going to try to find time this week to weld everything up on the bench -- Hopefully I can keep the pipes from warping by welding small sections and moving around to keep from putting too much heat into them. We'll see how it goes. Then I can run the tailpipe, which should be a quick job, and then I can move onto the next thing on the list!

 

[Coontail]

That looks awesome! I like the hanger on the cross member a lot. What muffler did you go with?

As long as there's a decent air gap between the exhaust and the fuel line you should be alright, the ceramic coating should help quite a bit too

 

[6872xtc]

The more effort that you put into keeping the heat out of other components, the better off you will be. The transfer case oil may get hot and darken faster, but the problem that I have witnessed and heard about is too much heat in the fuel. It seems to show up as difficulty to start hot, or not starting unless it cools or the vapor is purged from the line. I have witnessed it on a TBI conversion with an external pump, hear about it on a 5.3 swap that I believe was an in tank pump.

 

[Coontail]

^ Very good points, you could use the waffle type heat shielding as a barrier between the fuel line and exhaust

 

[Chevy305]

heat shield sleeve over the fuel and brake lines, good to go

 

[RoccoK5]

That looks awesome! I like the hanger on the cross member a lot. What muffler did you go with?

As long as there's a decent air gap between the exhaust and the fuel line you should be alright, the ceramic coating should help quite a bit too

Thanks! I took a lot of inspiration from your build and the pics you posted of your exhaust. Muffler is a Magnaflow #12298 (5x8x18). Hoping for an aggressive but not ridiculously loud exhaust note, but we'll see!

As for the air gap, I have at least an inch or more all the way around. I may consider wrapping the pipes in spots, or sleeving the brake and fuel lines.

The more effort that you put into keeping the heat out of other components, the better off you will be. The transfer case oil may get hot and darken faster, but the problem that I have witnessed and heard about is too much heat in the fuel. It seems to show up as difficulty to start hot, or not starting unless it cools or the vapor is purged from the line. I have witnessed it on a TBI conversion with an external pump, hear about it on a 5.3 swap that I believe was an in tank pump.

Yeah, definitely don't want vapor lock!

^ Very good points, you could use the waffle type heat shielding as a barrier between the fuel line and exhaust

heat shield sleeve over the fuel and brake lines, good to go

I may wrap the exhaust in places and add some sleeving around the fuel and brake lines, couldn't hurt! I wonder if it's also worth adding a heat shield to the muffler?

 

[6872xtc]

@ZooMad75 could you give some experience of your problem?

 

[ZooMad75]

@ZooMad75 could you give some experience of your problem?

Well the short version is the that the heat of the exhaust was only part of my problem. More so it made it worse.

My actual problem turned out to be a kink in the 2" section of hose in the fuel sending unit from the pump to the pipe. However, when it was hot out and the engine under a load requiring more fuel volume, the kink in that little hose would cause the pump to deadhead and quit. With the proximity of my exhaust to the fuel line the resulting heat with no fuel pressure would cause the fuel to boil. This is why I was seeing the bubbles on the fuel pressure gauge discharge hose.

At first we thought the heat was causing the fuel to boil while driving. This was not the case. Fuel under 40+ psi of pressure can't boil from the heat off the exhaust. Fuel is no different from any other liquid in that when under pressure the boiling point increases. Now I looked high and low for what the temp would be at my pressure and I came up empty handed. But it isn't any different than the cooling system boiling at 250 degrees under pressure vs 212 normally.

I wrapped the exhaust. Added a shield and even moved the exhaust pipe over another inch. No change to the stalling condition. I dropped the tank to install a trailer hitch and looked inside. To my surprise we found the kinked hose. Replace the pump and the hose. Drove 2 more years with everything else the same and not once did it stall again. Even on the mojave road with 118° ambient heat.

It's worth making sure the exhaust is not too close but it takes a hell of a lot to actually vapor lock any modern fuel injected engine running 55psi fuel pressure.

 

[RoccoK5]

Thanks for the insight, @ZooMad75 ! Sounds like it was a fun problem to track down.

My other concern is that the fitting where the fuel line transitions from a hard line to a teflon hose is positioned right above the exhaust. Thinking I may rework the lines so that if it ever were to leak that it's not dumping fuel onto a hot pipe.