FJ40 Mark/Downey Header (8 Viewers)

[Fe3]

I need one for my PIG. I have the original Downey header. Will the new exhaust bolt up?

We have taken the original Downey header and made significant improvements.

One improvement that we are quite proud of is the articulated joint to connect the header to the exhaust. This allows 13 degrees of freedom in any direction! This improvement makes for a much better installation experience vs the old-school flange.

 

[Fe3]

I need one for my PIG. I have the original Downey header. Will the new exhaust bolt up?

Here are some pictures to help tell the story:

From here: FJ40 Mark/Downey Header - https://forum.ih8mud.com/threads/fj40-mark-downey-header.1267016/page-7#post-14706817

 

[Fe3]

I need one for my PIG. I have the original Downey header. Will the new exhaust bolt up?

@gonzopancho

 

[gonzopancho]

@gonzopancho

Bolt up? No. The OG Downey had a 3-bolt flange and we went to a more sophisticated joint.

That said, it’s straight-forward to weld the new tailpiece to your existing exhaust.

 

[PabloCruise]

I guess I ment the whole enchilada for a pig?

Oh man, a stainless Pig exhaust would be very nice indeed.

I wonder if @gonzopancho could do a mock-up on his 2F Pig?

 

[Ry24000]

Maybe @gonzopancho could do a mock up on my Pig.

 

[Fe3]

Maybe @gonzopancho could do a mock up on my Pig.

Where are you (and your Pig) located?

 

[Ry24000]

Where are you (and your Pig) located?

PNW. Carson, WA

 

[gonzopancho]

Oh man, a stainless Pig exhaust would be very nice indeed.

I wonder if @gonzopancho could do a mock-up on his 2F Pig?

Gonzo assumes that Pablo is referring to the 1978. Gonzo has another pig in the works:

• 79 body (green/white)
• 74 frame
• Built/locked 60 axles w/discs & 3.73 gears
• Mosley 4.4L 2F, H55F, split case w/ 3:1 lo-range

and has thought many times about attempting his own stainless exhaust, just not as fancy as on the 78. Gonzo needs to learn TIG first, though, and he’s still re-learning MIG.

At the end of the day, the real problem is that the market for 55 exhaust systems is much, much smaller than 40s or even 60s, and shipping would be a chore.

 

[Advrider639]

I am at the installation portion of my header replacement , just pulled mine out of the box. These have a very visible bow across the flange. This doesn’t seem right to me. The four inner tubes are not inline with the outer two.

Thoughts?

 

[charliemeyer007]

Who made that? Looks like warping from the welding to me. What is that gap 1/8"+. Have you ask the manufacturer. It may be fine after a few heat cycles with retorque every time. Snug it up hot, then again when its cold. Can't see the difference in outer and inner tubes.

 

[Advrider639]

These are Trimeki.

Full disclosure I have sent them an email, but considering it’s Sunday I don’t expect a response until tomorrow. Really was planning on knocking this out today. Was wanting to see if anyone on here had similar thoughts.


It’s either with in spec or I’m sure they’ll make it right.

 

[pb4ugo]

These are Trimeki.

Full disclosure I have sent them an email, but considering it’s Sunday I don’t expect a response until tomorrow. Really was planning on knocking this out today. Was wanting to see if anyone on here had similar thoughts.


It’s either with in spec or I’m sure they’ll make it right.

I'm sure they'll appreciate you putting the cart b4 the horse.

 

[Advrider639]

That’s an interesting take…

I am simply asking if this is normal or not. Seems off to me, but I’m not the expert. Would like to press on with my installation.

 

[Grayscale]

It is not untypical to see warping that results from welding. It is welded-construction, not cast, so it barely matters, as it will likely yield to flat upon torquing the nuts on the studs. Local warping could be more problematic, like if the curve is welded in place by the header pipes - use a shorter straight-edge to see it. What is more important is equal thicknesses of flanges, header and intake manifold. Measure both with a micrometer or calipers. An exhaust leak at the head is dangerous, so depending on how it is warped, you might change your approach to gasket material, and gasket-maker vs no glue. One header flange that I had was thicker than the intake, so sealant on the intake manifold is going to be essential, Remflex gasket, using a custom stepped-washer, etc., it kinda depends on the geometry that you are trying to correct.

Without any further research, I'd trust the header and assemble. I like anti-seize and a torque wrench, thread file or equivalent for prepping the head studs.

 

[Ol Yeller]

A nice long gentle curve will flatten right out once bolted up, as mentioned a tight localized warp in the flange would be the real concern.

 

[Advrider639]

Confirmed with mfg today that these are in spec. Very nice outfit. Installation will resume tomorrow.

As advertised, these do include a remflex gasket and the flange thickness matches the intake manifold. No need for half moon washers.

Yes I know I am missing a stud - waiting on tap to clean up threads.

 

[charliemeyer007]

Awesome. I did my header in 3, like 10, then 20, then 28? or what ever the spec's said. Then I heated them up good and retorqued them in pattern at 100% after the cooled I checked them again or was that backwards to the plan, after a few cycles I checked them again - they didn't move. Oh and I used high temp anti seize and stainless steel nuts. I used 2 man-a-fre header gaskets applied wet with my custom made step washers and extended studs. That set up has been on 2 different engines at least 3 times total and has never leaked. I did plane the header on a big piece of glass with sand paper once.

 

[Downey]

When Downey Off Road Mfg. built Headers 1,000 years ago the Header flanges were always warped when pulled out of the welding fixture. The good news is the flanges straightened out while still tightening the nuts with finger pressure, soooooo wrench pressure certainly finished the straightening job in a flash.

 

[zerotreedelta]

Is there a recommended torque on the slip joint bolt? I didn't want to overdo it, but I'm getting a pretty solid exhaust leak there despite the ball settling cleanly.

(I'm more familiar with a traditional v-band setup, and not quite sure how that setup is supposed to "seal".)

Edit: removed, rotated the clamp a bit and retorqued...same deal, leaks through the clamp joint, definitely not sealing for some reason. I can't really see how that band draws things together with the rounded shape - a v-band "wedges" the two halves together in comparison, whereas this style does not. Seems like it'll need hi-temp RTV or something like that, but not ideal and seems...odd. Curious if I'm just missing something.