'91 K5 Four Wheel Camper

[beags86]

You complaining?
Looks like the best day at work ever!




What some of us wouldn't do to play with blazers, winches, tractors and tow trucks....and get paid for it...

 

[campfire]

Neat story, Rob. Seems your blazer has done work duty before this? You should start charging them rental fees.

 

[6872xtc]

That's what kept me working for a heavy wrecker service for so long, doing stuff that others didn't know how to do. It makes the work day less boring.
And you just proved that you don't have to have a winch big rated for the weight that you hook to, just enough to make it move!

You should give the Blazer a pat on the dash!!!! Tell it good boy!!!

 

[ZooMad75]

You complaining?
Looks like the best day at work ever!




What some of us wouldn't do to play with blazers, winches, tractors and tow trucks....and get paid for it...

No complaints. Up to that point it was a crap day. But playing rescue made it all better.

Neat story, Rob. Seems your blazer has done work duty before this? You should start charging them rental fees.

If he does it again he's getting tagged for it. I might have flattened my Cable in the process, but I'm probably the cause of that.

That's what kept me working for a heavy wrecker service for so long, doing stuff that others didn't know how to do. It makes the work day less boring.
And you just proved that you don't have to have a winch big rated for the weight that you hook to, just enough to make it move!

You should give the Blazer a pat on the dash!!!! Tell it good boy!!!

Oh I did. It worked like it was supposed to. It really made me happy how well it did. No complaints.

 

[ZooMad75]

Looks like Photobucket gave me the finger and locked up everybody's free account. I refuse to pay $400 to allow 3rd party hosting. So I'm moving my stuff to flickr and here. Sorry, it will take a while to update all the photo links I had in photobucket.

 

[campfire]

Looks like Photobucket gave me the finger and locked up everybody's free account. I refuse to pay $400 to allow 3rd party hosting. So I'm moving my stuff to flickr and here. Sorry, it will take a while to update all the photo links I had in photobucket.

Sounds like extortion?

 

[ZooMad75]

Ok, so after a second day at the exhaust guy he came back with the typical, oh you got 2 to 3 inches of clearance anywhere along the right side pipe so we aren't sure why you are having the problems. Rather than loose my mind I offered up a different idea. How about taking some temp measurements, find out where the hot spots are so we know for sure where the problem is. Then rather than making one big SWAG (swinging wild ass guess) at what to change we can make adjustments based on some hard data. He was at least receptive to it.

On my way home driving the K5 from work I stopped off at Harbor Freight and grabbed a temp gun. So here's where it's getting confusing. Ambient temp is in the low 90's at the time of checking in the driveway. Truck had been driven in those temps for almost an hour. Checking with the engine idling in the heat I found anywhere along the inside of the frame rail on the feed and return lines the temps were 110-130*. At the same time the pipe and muffler area that isn't wrapped with header tape is only running 50-80* hotter than the fuel lines. But the Temps of the pipe that is wrapped is actually over 300*. Even going to the front of the exhaust before the wrap and 8" below the manifold connection is running at half the temp that the wrapped pipe is 2" from the edge of the wrap.

What the hell? I'm baffled that the area with the header wrap is running so much hotter than the pipe without. Either my cheapie temp gun is getting fooled by the wrap or I'm completely misguided by the concept of what the exhaust wrap is supposed to be doing.

Even with that being said, with the wrapped pipe section measuring 300* the fuel lines still don't measure any hotter than 135*. Coming back to the rear after the muffler, the tailpipe is running around 110* as is the fuel lines and it matches the temp I measured on the concrete below. Measuring the corner of the fuel tank where the tailpipe is closest, the temp of the tank matches everything else back there at 110*.

I can't say my testing so far is an "apples to apples" comparison to the conditions we encountered during the trip. Ambient temps were close but the overall heat soak wasn't the same. I barely put an hour drive time on it vs. 4 hours or greater like we did on the trip. I'm just confused by the odd high measurements on the wrapped section of pipe.

 

[6872xtc]

Is the wrap black? Or is the pipe next to the wrap a dark shade?
I imagine that the fuel lines and exhaust are silver. That makes a HUGE difference in how those temp guns read. I don't know why, but I have seen it lots before.
Just a thought.

 

[ZooMad75]

Is the wrap black? Or is the pipe next to the wrap a dark shade?
I imagine that the fuel lines and exhaust are silver. That makes a HUGE difference in how those temp guns read. I don't know why, but I have seen it lots before.
Just a thought.

Funny thing you ask... The wrap was kinda creamy tan color and has now darkened a bit. The fuel lines actually got painted black when the chassis was cleaned up. With the laser dot on the fuel line the reading seems accurate. Its a similar value to the black frame behind it.

I might grab one of my tech's guns that they got off one of the tool trucks before I go off making changes.

 

[Truckman4life]

Haven't read your whole thread but how is your fuel system set up? Do you have proper line sizes and a good return flow and no restrictions? Maybe a simple fuel cooler would fix it like those finned power steering coolers or something.

 

[ZooMad75]

Haven't read your whole thread but how is your fuel system set up? Do you have proper line sizes and a good return flow and no restrictions? Maybe a simple fuel cooler would fix it like those finned power steering coolers or something.

Fuel system is stock 91 stuff up to the fuel filter. From there forward on the feed and return lines we used lines from Workhorse that Larry has used on both of his 8.1 projects. Sizing is correct. The thing is, I don't think 130-140* degree temps is out of the question when running where they are. I'm thinking further wrap on the exhaust and possible shielding to the lines is the plan of attack but I want to validate this higher temp reading on the wrap vs the bare pipe.

 

[beags86]

Read this.. don't take your cheapy gun to mean the holy word.
A few years ago I started making my welders throw those damn things in the trash. To much variance and not enough accuracy.
Just food for thought.

http://blog2.thermoworks.com/2012/03/infrared-thermometry/

 

[campfire]

Read this.. don't take your cheapy gun to mean the holy word.
A few years ago I started making my welders throw those damn things in the trash. To much variance and not enough accuracy.
Just food for thought.

http://blog2.thermoworks.com/2012/03/infrared-thermometry/

This. Material choice makes a huge difference. Many materials do not radiate very well. Insulation is particularly bad a this because...wait for it...avoiding heat transfer is the entire point of insulation. It will be somewhat warmer inside the insulated pipe, and the material change will confuse the IR gun. Double uncertainty.

 

[campfire]

One other thought...if you're using lines sized for Larry's 8.1L on your 5.3L, you will be cycling fuel more slowly than he is, yes? I wouldn't think that would be significant, but it's something to think about.

 

[Bent77]

One other thought...if you're using lines sized for Larry's 8.1L on your 5.3L, you will be cycling fuel more slowly than he is, yes? I wouldn't think that would be significant, but it's something to think about.

Should actually be cycling fast since it's using less. But it begets the topic of how the returning fuel plays into the equation

Rob is the return working properly? Is it returned to the tank or to the pump?

 

[beags86]

Well obviously it's worse when he has less fuel. So it's working.

I would put a fuel cooler on it. Some would probably say it's a band aid. Unless it works.
And you know, Because racecar.

 

[campfire]

Should actually be cycling fast since it's using less. But it begets the topic of how the returning fuel plays into the equation

Rob is the return working properly? Is it returned to the tank or to the pump?

I thought his pump was sized for his application? I guess I don't know enough about the overall system to effectively open my pie-hole.

 

[Bent77]

I thought his pump was sized for his application? I guess I don't know enough about the overall system to effectively open my pie-hole.

He just uses less of the fuel provided, so it circulates more back to the tank. We understood what you meant

 

[campfire]

He just uses less of the fuel provided, so it circulates more back to the tank. We understood what you meant

Glad somebody did.

 

[ZooMad75]

Thanks for the input guys.

Read this.. don't take your cheapy gun to mean the holy word.
A few years ago I started making my welders throw those damn things in the trash. To much variance and not enough accuracy.
Just food for thought.

http://blog2.thermoworks.com/2012/03/infrared-thermometry/

I figured I was getting wonky readings for a reason, just wasn't sure why. That link explained a lot.

This. Material choice makes a huge difference. Many materials do not radiate very well. Insulation is particularly bad a this because...wait for it...avoiding heat transfer is the entire point of insulation. It will be somewhat warmer inside the insulated pipe, and the material change will confuse the IR gun. Double uncertainty.

Makes sense.

One other thought...if you're using lines sized for Larry's 8.1L on your 5.3L, you will be cycling fuel more slowly than he is, yes? I wouldn't think that would be significant, but it's something to think about.

Let me get a little more detailed on the lines. #1- It's stock TBI lines from the pump to the fuel filter. #2- The Workhorse lines are indeed for an 8.1, but directly match the feed and return points on the 5.3 fuel rail. Meaning, the lines aren't any different than if I lifted them from a 2002 Silverado.

Should actually be cycling fast since it's using less. But it begets the topic of how the returning fuel plays into the equation

Rob is the return working properly? Is it returned to the tank or to the pump?

Return seems to be doing its job. Since the rear lines are stock TBI stuff the return line comes right back to the sending unit and dumps into the tank from there.

Well obviously it's worse when he has less fuel. So it's working.

I would put a fuel cooler on it. Some would probably say it's a band aid. Unless it works.
And you know, Because racecar.

That's an idea that I'll keep in mind.

I thought his pump was sized for his application? I guess I don't know enough about the overall system to effectively open my pie-hole.

I'm using an AC Delco EP341 pump as the ECM I'm running requires less fuel pressure than a stock 5.3. I ended up dialing up the pressure to 51 psi late in the trip in order to try and calm the problem down.

He just uses less of the fuel provided, so it circulates more back to the tank. We understood what you meant

I'm sure with the lower pressure mine runs, its probably returning an average amount of fuel back. I know it's working as my problem gets more pronounced when the volume in the tank is less. With less fuel to dissipate the heat the pump runs hotter.

So let me throw this out there.. The idea in my head is to go ahead and wrap the rest of the pipe up to the muffler. Then add some insulation for both the fuel feed and return. I had a customer of mine suggest just splitting rubber fuel line and wrapping it around the hard lines. Cheap and simple. Thoughts?