Author Topic: Fuel lines next to exhaust pipe. How close is too close  (Read 3222 times)

Offline Papawoodi

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Fuel lines next to exhaust pipe. How close is too close
« on: February 04, 2019, 08:07:18 AM »
I just got my exhaust done a week back and yesterday while under the truck admiring it, I noticed the exhaust pipe on the passenger side near the transmission tail shaft was pretty close to the fuel lines. This is the section where the metal lines turn into rubber lines for about 6in and then back to metal.
My question is, how close is too close? It looks to be about 2in away right now. Is this ok or should I get it redone, or just use heat shield?
Trying to get my truck back on the road for me and my little boy to enjoy car shows, but don’t want to put us in danger nor lose my truck that I have owned since I was 16.
1985 C10 Silverado single cab SWB 350/700r4
1986 C10 Scottsdale Extended Cab project

Offline JohnnyPopper

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Re: Fuel lines next to exhaust pipe. How close is too close
« Reply #1 on: February 04, 2019, 06:40:01 PM »
That does sound close, especially if the rubber line is right there.

Curious if the metal line was cut at some point and then rejoined with a jumper hose??? Doesn't sound like a factory build, but I may be wrong.

In any event, shielding is a minimum, and replacing that section of metal line would be better.

Be safe with your boy!

1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction

Offline Papawoodi

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Re: Fuel lines next to exhaust pipe. How close is too close
« Reply #2 on: February 05, 2019, 07:19:30 AM »
Thanks for the reply... I could not say if they were cut at some point, but I have owned this truck since the early 90's. This is where the lines go from passenger side to the driver side, so I assumed it was factory. I guess if it was metal lines there I would not worry so much, because down the frame to the motor the exhaust is about 3" or 4" away.
Was reading a heat shield could be used. So I put some aluminum 2in piece on the frame rail to help block the heat some. Before I put this dual exhaust transmission brace in, it was had dual exhaust on it but never noticed how close it was then.
Might have to take it back to the exhaust place and get the pipes re routed or at least give them a call...
1985 C10 Silverado single cab SWB 350/700r4
1986 C10 Scottsdale Extended Cab project

Offline Irish_Alley

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Re: Fuel lines next to exhaust pipe. How close is too close
« Reply #3 on: February 05, 2019, 08:00:07 AM »
ive left an inch gap between the plastic skid plate under the tank and my exhaust pipe with no issues. i would feel safe with 2" but if you need some reassurance then go with a heat shield or replace the lines with the flexible stainless and mount them inside the frame
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline bd

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Re: Fuel lines next to exhaust pipe. How close is too close
« Reply #4 on: February 05, 2019, 08:44:13 AM »
Enshroud the lines in Thermo-Tec Sleeving if you're concerned.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline JohnnyPopper

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Re: Fuel lines next to exhaust pipe. How close is too close
« Reply #5 on: February 06, 2019, 04:47:43 PM »
It does look stock... maybe they had a junction in case a dual tank switch was factory installed?

Thermo sleeve to the rescue! BD is the man!
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction

Offline Papawoodi

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Re: Fuel lines next to exhaust pipe. How close is too close
« Reply #6 on: February 07, 2019, 06:30:06 AM »
Thanks for all the feedback... I have a 2000 Silverado donor truck for the motor and transmission to be put in my prolonged C10 extended cab project. So yesterday evening I looked underneath and saw heat shields there. Took one off made some cuts and bends to fabricated something to help block the heat. Will see how this helps and use a laser temperature gun from a friend to see how hot things are getting. I assume in the long run I will end up buying that thermo sleeve as BD mentioned.

1985 C10 Silverado single cab SWB 350/700r4
1986 C10 Scottsdale Extended Cab project

Offline 75gmck25

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Re: Fuel lines next to exhaust pipe. How close is too close
« Reply #7 on: February 07, 2019, 07:07:59 AM »
My '75 had a dealer-installed aux tank, and everything seems to indicate that the factory setup was designed to make it easier to add on a 2nd tank at the dealer.  There were rubber hose connections for the connections to the original main tank, and there were pop-apart junctions in the wiring for the sending unit. 

When you look at the aux tank setup, the sending unit and tank switch wiring scheme seems really odd, until you realize that it was designed to make it easier to add that 2nd tank.  For example, in my '75 the sending unit wire runs down the passenger side (main) and the dual tank switch wiring runs down the driver (aux) side and then across the fuel line brace and over to the solenoid.

Bruce

Offline JohnnyPopper

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Re: Fuel lines next to exhaust pipe. How close is too close
« Reply #8 on: February 07, 2019, 04:39:41 PM »
Nice work, you're good to go!
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction

Offline Papawoodi

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Re: Fuel lines next to exhaust pipe. How close is too close
« Reply #9 on: February 08, 2019, 08:17:29 AM »
I have a parts 87 truck and it seems to have the rubber hoses as well. My only thinking now should I replace them with some braided heat resistant ones... The originals are old but not all cracked up or anything...
Will check the temperature this weekend with that laser temp reader.
Had my little boy under the truck with me yesterday giving me opionons and all was going well till he got some dirt in his eye...
1985 C10 Silverado single cab SWB 350/700r4
1986 C10 Scottsdale Extended Cab project

Offline JohnnyPopper

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Re: Fuel lines next to exhaust pipe. How close is too close
« Reply #10 on: February 08, 2019, 01:25:09 PM »
It happens...

When my son was 16 we re-did a '55 Chevy Short Bed, Second Series for his High School Ride.

Some of the best times...

1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction

Offline Papawoodi

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Re: Fuel lines next to exhaust pipe. How close is too close
« Reply #11 on: February 11, 2019, 06:24:38 AM »
Ok I used that laser temp reader this weekend... The Exhaust was 150 DegF and up. The heat shield was around 115 DegF and the fuel lines were around 85-92 DegF. Seems this varied when idled vs checking it after driving at idle. Plus, I checked it on the rubber lines and the hard lines and where the same pretty much. Outside air  temp was 70 DegF that day.
I guess numbers seem ok on the lines, plus I could always wrap the rubber lines if needed.
1985 C10 Silverado single cab SWB 350/700r4
1986 C10 Scottsdale Extended Cab project