[bucholzi]

Ok, this is just because I'm getting fed up with fabrication on my 89 F250 supercab which is being restored, and hence trying to cut down on the to-do-list: Those heat-shields under the bed (over the muffler) and under the cab, are off course rusted completely away; how important are they and are they worth replacing?

Thanks,
Simen

 

[F350farmboy]

I would at least replace/fabricate the one to cover the fuel tank.
Where were the other ones supposed to be?

 

[F350farmboy]

I found one at LMC, the only heat shield they had, and they're asking $280!!!!!! It would definatly pay to fab your own up (if you're going to replace it).

 

[bucholzi]

The heatshield for the midship tank is intact, it's those two mounted on the cross sills under the bed over the muffler (279 and 179 dollars at LMC, which is more than they are asking for two new doors..)and one under the cab (not in LMC-cataloge).

Considering people mock up new exhaust and reroute, make dual pipes, stacks and so on, and obviously doesn't have any big heat issues afterwards, then it's a question if it is worth the work.. Unless these IDI's generate especially much heat?


Maybe I should just get a smaller, straight pipe muffler to get better clearance ;-)

 

[F350farmboy]

Ive seen plenty of stacks on these 'ol IDI's and I didnt see any heat shields. I like the idea of removing the muffler. I would like to warn you before you do.......These engines are pretty loud w/ no muffler.

I would at least buy a glasspack muffler because 1). I like the sound 2). they're cheap ($20-30) and 3). they're way smaller in diameter than an oval-shaped muffler.

Im just saying.....

 

[arthurgoboom]

IMO the muffler creates a restriction, which slows the exhaust gas down (takes energy away) and converts that kinetic energy into heat, so if you had a straight through muffler or a straight pipe it would be less of an issue to have a heat shield. I presume the under-bed heat shield is there to protect the paint on the bed and any cargo from catching on fire, so if your paint and cargo are expendable, don't even worry about it. Otherwise, use your hand or infrared temp gun to see how hot the floor of the bed gets.

 

[bucholzi]

[ QUOTE ]
I presume the under-bed heat shield is there to protect the paint on the bed and any cargo from catching on fire, so if your paint and cargo are expendable, don't even worry about it.

[/ QUOTE ]

I would say that cargo catching fire would be an issue.. /ubbthreads/images/graemlins/wink.gif

On the rusted out shields there were quite a bit of old tectyl which didn't seem to have taken any damage from heat (it was just as dry and cracked as everywhere else on the truck..). How does tectyl tolerate heat compared to paint (using oil-based), i.e. if the tectyl survives paint should to?

 

[xtremefreerider]

I wouldn't worry about it too much. I ran stacks through my bed as close to the rails and bed box as possible with no issues to the paint or anything else. I did have problems when cargo came in direct contact with the pipes but that is to be expected....

I suggest removal of the muffler (or get something more free flowing) and don't worry about heat shields with the exception of near the fuel tank.

 

[NorCalPR]

Kinda off topic, but kinda not:

My exhaust tip has this restrictor on it. It looks like two plates with a bunch of holes in it, about 3/16" in diameter. Should I cut these suckers off?

 

[Greg77]

I'm running into the same problem you are. I've got two boxes that just need to be painted and put on. Every box I've seen they are rusted of. I'm going to take and either cut some out with the plasma or have them sheared. Ford had them kind of fancy but if you just take the old one and have the square part sheared that shoiuld be good enough. I have access to stainless drop so that's what I'm going to use. The factory ones were only like 16 guage so if you can find a machine shop and have him shear some it should only cost you $50.00 or so. LMC has a lot of products but they are the most over priced place in the world to buy pickup parts from.

 

[NorCalPR]

Note that I do HVAC Mechanical construction. We have a shear that has a ability to cut 16gauge mild steel 72" long. We also have a 20 foot brake with the same capability. We also have a roller..

I can probably make you the pieces and ship them to you.

 

[Greg77]

I need to find the pieces we took off and saved for patterns. They aren't very big about maybe 12" wide and 14 to maybe 16" long. They just fasten to the underside of the box channels with sheet metal screws. Ford had some bends in one of them but if you just screw on a flat piece where the old one was that will be better than 90% of the ford diesels on the road.

 

[arthurgoboom]

I somehow scored a box with intact heat shields with the fancy bends you mention, but I agree there's no need for the bends. Cut a flat sheet and go to town. They don't have to be thick either, all they have to do is reflect the radiant heat. I would say the galvanized stuff you use for HVAC ducting would be great.

 

[NorCalPR]

No problem. I can put bends in about 5 seconds to any metal. 0-180 degrees.

I have plenty of Galvanized metal. I think we have some extra galv 16 gauge.

 

[NorCalPR]

[ QUOTE ]
Kinda off topic, but kinda not:

My exhaust tip has this restrictor on it. It looks like two plates with a bunch of holes in it, about 3/16" in diameter. Should I cut these suckers off?

[/ QUOTE ]

Just cut it out. There were 4 in a row, about a inch spaced apart. Really makes a difference in the truck, not to mention sounds a bit better. I bet it did wonders for my EGT's.

 

[icanfixall]

The end pipe "plates" are there as a spark arrester. They are supposed to break up the soot sparks that may blow out the tail pipe.

 

[NorCalPR]

Owell, they're gone now. I figure they arent there on other diesels o r aftermarket exhausts, so screw it!