I would have to go with the too tight and not having the ability to flop around a bit.
CK5
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71K5 - BP71K5's Just for fun build
- Thread starter bp71k5
- Start date
bp71k5
3/4 ton status
Update 3/19/2015
Radiator repair seems to be holding so far. The electric fan bracket is still not bolted to the upper bracket so the radiator isn't overly clamped down for the past week and a half. California is a pot-hole-Mecca so this thing has been getting a workout hitting several hundred potholes at 50mph. No leaks yet.
In other news, my gas mileage is down to 8.3mpg on the freeway. Switching from 35"AT tires to 37"MT seems to have cut 2-3mpg from my mileage. I'm wondering if the motor size and truck weight is just at its limit for efficiency or whether the TBI system can be tuned to squeeze a little more mileage out of it.
Radiator repair seems to be holding so far. The electric fan bracket is still not bolted to the upper bracket so the radiator isn't overly clamped down for the past week and a half. California is a pot-hole-Mecca so this thing has been getting a workout hitting several hundred potholes at 50mph. No leaks yet.
In other news, my gas mileage is down to 8.3mpg on the freeway. Switching from 35"AT tires to 37"MT seems to have cut 2-3mpg from my mileage. I'm wondering if the motor size and truck weight is just at its limit for efficiency or whether the TBI system can be tuned to squeeze a little more mileage out of it.
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On your mileage are you using the odometer to calculate miles traveled? If so the change in circumference of the tire will make the odometer read inaccurately. Which will throw the miles traveled off and ultimately miles per gallon unless you changed the gear to account for the change.
But the weight and size of the new tire will affect the mileage in a negative way. But for a 6000 pound non-aerodynamic brick 8 MPG is about normal.
I hope you have the radiator problem fixed this time!!!
But the weight and size of the new tire will affect the mileage in a negative way. But for a 6000 pound non-aerodynamic brick 8 MPG is about normal.
I hope you have the radiator problem fixed this time!!!
bp71k5
3/4 ton status
I re calibrated my speedo so it's accurate and matches all the gps speed apps on my phone so I'm guessing it's accurate enough. Just seems kinda dumb to have a small block TBI when an 8.1L big block modern fuel injected motor couldn't make much worse mileage could it?
- Joined
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[hushed whispers]........join.........us...........Brian............we.........have........cookies...........[/hushed whispers]
-G
[chanting] big block...............big block.............big block.......big block [chanting] 
Sounds like I don't even need to provide input on this one...
bp71k5
3/4 ton status
Ok, you guys got a laugh out of me. Haha
[cough] duramax [cough]
bp71k5
3/4 ton status
Update 3/23/2015:
I can't afford to get the kind of cookies you guys are selling.
I did a little testing for radiator leaks yesterday and lifted each tire up off the ground a decent amount to see if I could find any places where the radiator mounts are doing something to the radiator. After jacking up each tire about a foot, the radiator has the exact same amount of movement as it does sitting on the ground. I don't see anything weird. I also tweaked the fan shroud mounts to make sure they aren't aren't forcing the top mounts to clamp down on it any more. Will have to test that and see how it does. I did see a few drops of green fluid on one of the lower mounts though. I could find any obvious leaks though so maybe it was just leftover from the previous leak. It's all washed really well make sure any green fluid that shows up now will for sure be a leak.
I can't afford to get the kind of cookies you guys are selling.
I did a little testing for radiator leaks yesterday and lifted each tire up off the ground a decent amount to see if I could find any places where the radiator mounts are doing something to the radiator. After jacking up each tire about a foot, the radiator has the exact same amount of movement as it does sitting on the ground. I don't see anything weird. I also tweaked the fan shroud mounts to make sure they aren't aren't forcing the top mounts to clamp down on it any more. Will have to test that and see how it does. I did see a few drops of green fluid on one of the lower mounts though. I could find any obvious leaks though so maybe it was just leftover from the previous leak. It's all washed really well make sure any green fluid that shows up now will for sure be a leak.
bp71k5
3/4 ton status
Update 4/23/2015:
Well, it's leaking again in the lower spot I found earlier. Looks like the side tank is separating from the center fin area. Any advice for new radiator brands and/or mounting bracket design? I'm even maybe open to ditching the core support and bending some tube like all the cool kids.
Well, it's leaking again in the lower spot I found earlier. Looks like the side tank is separating from the center fin area. Any advice for new radiator brands and/or mounting bracket design? I'm even maybe open to ditching the core support and bending some tube like all the cool kids.
What are you using for a radiator.
just found a pic
is it brass/ copper ?
is it brass/ copper ?
bp71k5
3/4 ton status
Yea, all metal no plastic. Just an oreily's "Heavy duty" replacement radiator. 
The lower radiator mounts are little metal cups that hold a rubber "U" shaped cushion and they are screwed onto a sheet metal tray that's part of the core support and that tray feels kinda flimsy. It's possible the frame is moving around more and pushing on that tray and I just can't see it when I use a floor jack to cycle the suspension.
The lower radiator mounts are little metal cups that hold a rubber "U" shaped cushion and they are screwed onto a sheet metal tray that's part of the core support and that tray feels kinda flimsy. It's possible the frame is moving around more and pushing on that tray and I just can't see it when I use a floor jack to cycle the suspension.
bp71k5
3/4 ton status
Sheesh, pacfab has an turnkey 8.1L on the website for $3500. It's not a bad deal, but thats gonna have to wait.
My Ron Davis hasn't leaked a single drop of fluid in over 5 years.
Also, it hasn't HELD a drop of fluid. And my 502 uses less fuel than a Prius...!
-G
I'm running one of these --> http://entropyrad.com/ Mind you, I don't have a lot of time on it, but it has more time than Greg's. Looks to be extremely well made. All of the welds are super clean.
something to keep in mind too is RJFguitar's experience with them... It might not be as "turnkey" as you'd think.
