Ollin Magnetic Digiscoping System

Big ol Burban?

Back a page or so there was some talk of tire size for the Burban. Not sure if you have a lift or how much clearance you have, or gears for that matter. If you have a 4.11 or 4.56 rear gear Coker makes a very good off road/highway 900x16. Lots of ground clearance, I ran them on an old Dodge power wagon and was very happy. Well, not Coker but the old Firestone 900x16's.
 
This week was spent dry fitting exhaust headers and finalized where the engine would sit.

The headers fit mostly good but are very close to the front drive shaft. They need to go to Jet Hot to get coated to try and help reduce heat transfer. Also the cross y pipe was too close to the transmission oil pan. So…

I decided to cut it apart and reroute it along side the transmission between it and the frame. I have one very roughly tacked together and still working on the other. Once done they will go get tug welded by a professional, then sent to get coated.


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Been really hot this week and not much progress has been made. I’ve been plugging away at the exhaust. Got it to where it has to go under the rear driveshaft. I opted for that crossing verses under the transmission oil pan. I want to keep the extra heat out of the transmission. The drive shaft is 1.5” short since I changed to a shorter transmission.

Now I’m at a crossroads, to lift or not to lift that is the question.

I don’t want the extra height but I would like to get the front pinion lower and further from the header. Tuff country offers a 4” and that is as small as I can go to move the pinion down. All the leveling kits leave it in place and don’t help with the issue.

Here is a done one with a 4”. Looks pretty nice but it will be another 2k into this build.


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All you professional welders should be happy to know that I scrapped the header extension and redid another one. This time with the right 308 wire and gas. The new one will not be an embarrassment when I take it to the welding shop to get it Tig welded together. That last one was bad but necessary as I put it together and cut it apart several times.
 
Been really hot this week and not much progress has been made. I’ve been plugging away at the exhaust. Got it to where it has to go under the rear driveshaft. I opted for that crossing verses under the transmission oil pan. I want to keep the extra heat out of the transmission. The drive shaft is 1.5” short since I changed to a shorter transmission.

Now I’m at a crossroads, to lift or not to lift that is the question.

I don’t want the extra height but I would like to get the front pinion lower and further from the header. Tuff country offers a 4” and that is as small as I can go to move the pinion down. All the leveling kits leave it in place and don’t help with the issue.

Here is a done one with a 4”. Looks pretty nice but it will be another 2k into this build.


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Perhaps if you lift it there would be enough room for the exhaust to be routed above the driveshaft. I think if it were under the driveshaft it's just asking for trouble.
I had an '85 Suburban although it was a 1500 with a straight front axle but until I put a 4" lift on it would drag the tail regularly going through washes and whatnot.
 
Perhaps if you lift it there would be enough room for the exhaust to be routed above the driveshaft. I think if it were under the driveshaft it's just asking for trouble.
I had an '85 Suburban although it was a 1500 with a straight front axle but until I put a 4" lift on it would drag the tail regularly going through washes and whatnot.
It is flush with the bottom of frame cross member under the tail shaft of the transfer case. I left it where I could skid plate the frame and have a flat bottom.

I ordered the muffler and will take some pics once I figure how that will sit.

I thought a lot about your concern as I was deciding where it should go.

If I wanted to run true duals the equalizer pipe could have ran further back and over the drive shaft. But to merge them and keep a single 3” tailpipe it would have to cross at the transmission or back where I did it.

Pics will show it better when it cools off.
 
I'll wait for the pictures but I can't imagine running the exhaust under a driveshaft. There is a little bit of movement there up and down and it could interfere. I would do everything I could to keep it as high as possible. Aftermarket heat shielding may help any concern of heat transfer.
 
I'll wait for the pictures but I can't imagine running the exhaust under a driveshaft. There is a little bit of movement there up and down and it could interfere. I would do everything I could to keep it as high as possible. Aftermarket heat shielding may help any concern of heat transfer.
If you go back and look at the exhaust pics you can see how close the joint is to the header. I would say there is about 3/4” to 1” clearance. I am going to try and cut a heat shield but with it that tight I’m not sure how much it will do without rattling or catching on the yoke.

Also from the factory the front drive shaft is over the exhaust and the lowest point of the truck under the transmission pan.
 
Perhaps if you lift it there would be enough room for the exhaust to be routed above the driveshaft. I think if it were under the driveshaft it's just asking for trouble.
I had an '85 Suburban although it was a 1500 with a straight front axle but until I put a 4" lift on it would drag the tail regularly going through washes and whatnot.
I'll wait for the pictures but I can't imagine running the exhaust under a driveshaft. There is a little bit of movement there up and down and it could interfere. I would do everything I could to keep it as high as possible. Aftermarket heat shielding may help any concern of heat transfer.

Here is what is on my mind from where I left off. The 45 on the exhaust would go back up to a 90 to send it into the muffler. I just need to decide muffler placement to finish that section.


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So, I put the Burban up on 5” blocks to see how it would sit with a lift. 4” light and 1” for the extra tire height.

If feels like driving a skyscraper. So the lift is out of the equation. I did some research on header shims and possibly adding a spacer in between the header and head. Seems the easiest way is to tilt the engine with a shim between the block and motor mount.

I used the engine crane and lifted on one side of the motor and watched the header clearance. It does give me about an extra 1/2” from the pinion if I use a 1/8” shim. That should allow me to manufacture a heat shield to fit in between.
 
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