Hey you would happen to have a part number for the griffin "exact fit" aluminum radiator that you used?
CK5
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71K5 - BP71K5's Just for fun build
- Thread starter bp71k5
- Start date
bp71k5
3/4 ton status
Yep, it's this one:
Griffin 8-00013
Griffin 8-00013
I think that trimming will turn out better than mine did... Trying to keep ~12" of that subtle body line at the front of the fender was a royal pain!
Brian,
If you saw some of the last photos in my build thread it clear that I've got the same issue to deal with. Here's my hypothesis:
Try using a DS rear patch panel (behind rear wheel opening) as the replacement for the PS front area you are concerned about. The curve appears to be a lot more gentle, and would make the opening more symmetrical.
The hard part about sectioning the fender over a couple inches like you indicated is that the filler piece is going to create a really awkward transition.... Not really curved, and not really straight. Unless you were considering some sort of "pizza sliced" fenderlip I don't think you will like the appearance of that mod.
-G
If you saw some of the last photos in my build thread it clear that I've got the same issue to deal with. Here's my hypothesis:
Try using a DS rear patch panel (behind rear wheel opening) as the replacement for the PS front area you are concerned about. The curve appears to be a lot more gentle, and would make the opening more symmetrical.
The hard part about sectioning the fender over a couple inches like you indicated is that the filler piece is going to create a really awkward transition.... Not really curved, and not really straight. Unless you were considering some sort of "pizza sliced" fenderlip I don't think you will like the appearance of that mod.
-G
bp71k5
3/4 ton status
Just to ensure the idea is clear, the idea is to cut the front half of the opening out and move it forward 2.5". The new joint in front of the wheel well should match up ok. The hard part is the gap that's left at the rear.
It's tough to see in the photo but I've got the cut line a few inches past the
top of the wheel opening toward the rear. Once the front half was moved forward, the idea would be to cut and disgard about 8" from the back side of the moved panel leaving a 10" hole right at the top of the wheel well. The area up there seems small enough for me to fabricate a patch that has a smooth curve transition.
Clear as mud?
And Greg, I'll take a look at the idea of a patch panel from the drivers side, it sounds like it could be a decent alternative.
It's tough to see in the photo but I've got the cut line a few inches past the
top of the wheel opening toward the rear. Once the front half was moved forward, the idea would be to cut and disgard about 8" from the back side of the moved panel leaving a 10" hole right at the top of the wheel well. The area up there seems small enough for me to fabricate a patch that has a smooth curve transition.
Clear as mud?
And Greg, I'll take a look at the idea of a patch panel from the drivers side, it sounds like it could be a decent alternative.
bp71k5
3/4 ton status
Yea, if I only needed an inch of clearance the trimming would work ok. I realistically need to remove 2.5" at a minimum and theres just not enough space to do that while keeping the curve smooth.
Keep your total "uptravel" in mind when planning for the fender clearance... it really doesn't take much in the rear, unless you are running a low-lift / big-tire combo...
Visual aide:
I'm designing for 6" of uptravel which is acutally quite a lot. The tire is 38", but at 6" of uptravel it doesn't need a 38" wide opening to tuck in there. You can see by the red lines that it's maybe 34"(?) across.
That also assumes that the axle is traveling up equally on both sides (like landing off some big jump). If the axle is articulating, then the tire is angling inward and is even less likely to hit the outer fenderlip. With leafsprings, your axle is also going to move back a couple of inches as the spring flattens and the shackle rotates back. Admittedly, it's a lot harder to cycle a leafspring suspension in your garage to see how all the clearances work... that's one thing that is a lot easier with links for sure.
The final thing I drew on here (in yellow) was my idea for flipping that rear sheetmetal to the front edge of the rear wheelwell. You can see pretty clearly that the rear curve has substantially better clearrance, so grafting one of those onto the front edge might be all you need. I've seen a lot of really ugly attempts at opening up a 1st Gen fender.... and to preserve the "look" correctly could end up being a crapload of work.
-G
Visual aide:
I'm designing for 6" of uptravel which is acutally quite a lot. The tire is 38", but at 6" of uptravel it doesn't need a 38" wide opening to tuck in there. You can see by the red lines that it's maybe 34"(?) across.
That also assumes that the axle is traveling up equally on both sides (like landing off some big jump). If the axle is articulating, then the tire is angling inward and is even less likely to hit the outer fenderlip. With leafsprings, your axle is also going to move back a couple of inches as the spring flattens and the shackle rotates back. Admittedly, it's a lot harder to cycle a leafspring suspension in your garage to see how all the clearances work... that's one thing that is a lot easier with links for sure.
The final thing I drew on here (in yellow) was my idea for flipping that rear sheetmetal to the front edge of the rear wheelwell. You can see pretty clearly that the rear curve has substantially better clearrance, so grafting one of those onto the front edge might be all you need. I've seen a lot of really ugly attempts at opening up a 1st Gen fender.... and to preserve the "look" correctly could end up being a crapload of work.
-G
Hey Brian,
I think that you have the 2.5 or just a little less and you can still have a nice arch. I don't have anything here to measure off of any more, but that sounds about the same amount that I took out when I did mine.
Here are a couple of pics. I pretty much maxed out the cut to still give me a nice arch IMO. Hooked onto the jamb area, it comes in about 17 1/4". I also sent you a PM when Greg had some questions about the flip flop, turn around, rear quarter patch panel. Both Ideas, the pie cut and the flip patch came out really close.
bp71k5
3/4 ton status
Update: 11/23/2012
Today my wife suggested we take the kids and go down to Hollister and do some wheeling around down there.
The first pile of junk we tried to conquer stopped us before we even got started. My rear fender just dug into the tires within the first three feet. But this guy made short work of it even though I thought he would tip.
So we took an easy trail up to the quarry and had turkey sandwich lunch on the tailgate. Nice weather and pleasant scenery.
Today my wife suggested we take the kids and go down to Hollister and do some wheeling around down there.
The first pile of junk we tried to conquer stopped us before we even got started. My rear fender just dug into the tires within the first three feet. But this guy made short work of it even though I thought he would tip.
So we took an easy trail up to the quarry and had turkey sandwich lunch on the tailgate. Nice weather and pleasant scenery.
Last edited by a moderator:
Rock on brother! 
Any day spent on a trail is a victory. Bringing the family along is even better.....
I miss having access to a place like Hollister Hills.
Of course I miss having a truck that runs also.
-G
Any day spent on a trail is a victory. Bringing the family along is even better.....
I miss having access to a place like Hollister Hills.
Of course I miss having a truck that runs also.
-G
bp71k5
3/4 ton status
It was a good black friday, much better than going to the mall, even though thats more suited to my low fender clearance. My wife says I need to take care of that before we go back out there again.
bp71k5
3/4 ton status
I also found on the drive down there that my coolant wouldn't get above 165. Looks like the radiator cools a little too good. I may have to add some dampers for cold weather driving to at least get it up to 195. The other problem is my gas mileage just too another dive as well with I'm assuming the bigger tires. Now I have to plan my trips so there's no more than 125 miles between gas stations. 
K5 Jess
1/2 ton status
Nice!
Brian,
Wouldn't that be a thermostat issue? The motor couldn't sit at 165 with a 185-190 thermostat in there.....
A "cold" motor might explain the fuel economy problem too.
-G
Wouldn't that be a thermostat issue? The motor couldn't sit at 165 with a 185-190 thermostat in there.....
A "cold" motor might explain the fuel economy problem too.
-G
That was my thought. Maybe it's sticking open? Does it actually heat up and then cool down to 160 or is it always cold? Might just be too cold of a thermo unless its a new problem.
bp71k5
3/4 ton status
That's a good point. It runs pretty close to temp when I'm idling or moving slow, but the freeway drive is where I was seeing the low temp. I just assumed it was the extra airflow cooling it off. I'll have to check the computers temp sensor and see if that is not seeing the same temp as the gauge.
From what I've been taught, the cooling system is constantly opening and closing the thermostat to modulate temperature.
If there is super cold coolant from the radiator, it flows into the engine and causes the thermostat to close. Once the temperature rises above the threshold, the thermostat opens and the hot water flows out, and cool water from the radiator fills the motor up again.
Obviously, its not quite that perfect (hot vs cold water) since the thermostat doesn't open or close instantaneously but a properly functioning cooling system will go through those open/close cycles.
I'd guess you've got a stuck thermostat or a "too cold" thermostat in there... Sounds like a easy fix.
-G
If there is super cold coolant from the radiator, it flows into the engine and causes the thermostat to close. Once the temperature rises above the threshold, the thermostat opens and the hot water flows out, and cool water from the radiator fills the motor up again.
Obviously, its not quite that perfect (hot vs cold water) since the thermostat doesn't open or close instantaneously but a properly functioning cooling system will go through those open/close cycles.
I'd guess you've got a stuck thermostat or a "too cold" thermostat in there... Sounds like a easy fix.
-G
bp71k5
3/4 ton status
Update 02/09/2013
Been working really slowly clearancing the fenders. Here's the method I ultimately chose.
But as I was sanding down the paint to get good metal to weld with, I kept having to grind farther and farther cause I kept hitting bondo.
The entire wheel well was damaged underneath 1/4" of bondo at least.
Must have been a CB antenna mounted?
I started out thinking I could probably hammer the dents out and clean it up, but then found worse stuff... it's hard to see but it looks like they fill some holes with brazed brass...
Ugh. So I decided a patch panel was a better option.
I ordered one from eBay, but the guy sold me the wrong side. I also noticed that the thin bead along the edge of the wheel opening wasn't there. Rather than having the guy send me the correct side, I just got a refund and ordered a different one from GMC Pauls because their listing specifically says the bead is there.
Here's the difference. The beaded one is also a much heavier gauge steel and so I'm much happier with it. Not sure when I'll be able to actually install it, but that's where I am at the moment.
Been working really slowly clearancing the fenders. Here's the method I ultimately chose.
But as I was sanding down the paint to get good metal to weld with, I kept having to grind farther and farther cause I kept hitting bondo.
The entire wheel well was damaged underneath 1/4" of bondo at least.
Must have been a CB antenna mounted?
I started out thinking I could probably hammer the dents out and clean it up, but then found worse stuff... it's hard to see but it looks like they fill some holes with brazed brass...
Ugh. So I decided a patch panel was a better option.
I ordered one from eBay, but the guy sold me the wrong side. I also noticed that the thin bead along the edge of the wheel opening wasn't there. Rather than having the guy send me the correct side, I just got a refund and ordered a different one from GMC Pauls because their listing specifically says the bead is there.
Here's the difference. The beaded one is also a much heavier gauge steel and so I'm much happier with it. Not sure when I'll be able to actually install it, but that's where I am at the moment.
These freakin' trucks can be real heartbreakers sometimes......
Good info on those replacement panels though. I got my last batch from Tri-Pro but from what I've heard they are no longer around. Looks like GMCPauls has the "good stuff"....
Good to see you back at it.
-G
Good info on those replacement panels though. I got my last batch from Tri-Pro but from what I've heard they are no longer around. Looks like GMCPauls has the "good stuff"....
Good to see you back at it.
-G
bp71k5
3/4 ton status
Yea, I knew there was some bondo, but not quite that much.
I just decided to get outside and cut some away.
And rough trimmed the patch to check alignment.
Then took my son out for a ride around the lake in his big wheel. I dug out my old skate board for the first time in 15 years. Pretty relaxing day so far.
I just decided to get outside and cut some away.
And rough trimmed the patch to check alignment.
Then took my son out for a ride around the lake in his big wheel. I dug out my old skate board for the first time in 15 years. Pretty relaxing day so far.
