DIY Explorer 302 Headers

[allmyEXes]

The '80's E-series RH manifold might work. It's possible if a mirror image LH was made would it fit? How about something off of some kind of a Australian Ford?
Ebay van manifolds

 

[Josh P]

Flip them and route it like a 292 y block

 

[Josh P]

I was looking at manifolds for the M2 and some forced induction. The marine manifolds might work. There is lots of options where the exit tube is facing, it also bolts on so you could easily make your own to attach to the log manifold

 

[allmyEXes]

Tomorrow I will look around her for a pair of the to see what the Explorer fit issue is.
289-302 early Mustang exhaust manifolds pr

 

[97Sandbox]

To anyone with TMH/OBX: can you describe or better yet share a picture of how close the driver's side collector is to the block and how close the passenger side collector is to the motor mount bolts?

I started some mock up tonight and those areas had less room than I thought.

 

[97Sandbox]

After looking at some more pictures (thanks @410Fortune and others), I think the passenger side collector is past the motor mount on TMH/OBX. I'd still love to know how close the primaries get to the bolts though. Leave them too low and the primaries will rub on the bolt ends. Bring them up too high and the primaries will block the spark plugs.

On the driver's side, I'm guessing the collector tilts away from the block relative to the flange. It kind of looks like it in these pictures, but looking at the space alongside the engine bay, i think it's going to have to tilt as much as possible to use the factory downpipe.

 

[Turdle]

If this helps at all,
That driver side motor mount bolt gets loosened , then the engine lifted on that side, to tuck the torquemonster in between the motor mount, shock tower and valve cover lip. Not kidding.

Edit. Should have typed stud. You loosen the motor mount stud nut. The one you can get 1/16 of a turn , then flip open end, repeat.

 

[97Sandbox]

If this helps at all,
That driver side motor mount bolt gets loosened , then the engine lifted on that side, to tuck the torquemonster in between the motor mount, shock tower and valve cover lip. Not kidding.

Edit. Should have typed stud. You loosen the motor mount stud nut. The one you can get 1/16 of a turn , then flip open end, repeat.

Yuck! Maybe I need to do a little less looking at TMH design and a lot more playing around in the engine bay. I do not want to make headers that require undoing engine mounts.

 

[97Sandbox]

Jigs assembled

 

[97Sandbox]

After a full afternoon, I have collectors.

This is not for the faint of heart. Without having seen a set in person, I can confirm TMH are worth every penny haha

 

[410Fortune]

I love it! Wooden jigs perfect

 

[allmyEXes]

3 dimensional for sure.
It turns out that the 65-68 Mustang manifolds would point at, blow right onto the firewall.

 

[97Sandbox]

The driver's side collector is in such a tough spot almost directly below the cylinder 8 spark plug and exhaust port. It's going to take more creativity than I anticipated to make a good flowing design with serviceability in mind.

 

[CDW6212R]

Ditto all of that. I thought through those issues several times each time I gazed at the mess down in there, on each side. I decided early that the collectors had to move, they really should be moved back a bit. They were placed where they are for new car production, not for ongoing servicing by owners or mechanics. There is more room below and behind the stock collectors.

But you have to decide if you are building something for yourself, or for others, or mass production. I don't care about resell value or to make money, or sell the idea etc. I'm after a better part for my vehicle, and moving the connections is better for me and performance. Thus too, I want V-band clamps and no ball collector joints.

 

[97Sandbox]

I'd like to move the collectors downstream and use v-band connections too, but I'm out of time for scope creep. In order to try to get these done and my Mounty running before winter comes (I have no shop/garage, all this work is done outside) the rest of the exhaust must stay stock.

I figure if I can make a stock replacement style header (like what TMH is) I can get most of the benefits of headers in less time than TMH would take. Hopefully I learn a lot and will figure out a game plan for a full custom exhaust in the future.

 

[97Sandbox]

Does anyone know if the EGR fitting location/tube length matters? I'm thinking it'd be easier to just trim down and weld on the double-male adapter than to buy material and a tap to make a bung.

After more playing around with tubing last night, I've come to the conclusion that there's no way to make the Cylinder 8 primary work without a tight bend at the head and some pie-cutting at the collector. Looks like TMH and OBX did it that way. I just can't find any way to route the tubing that won't force another primary to have to make a similarly sharp bend or block the cylinder 8 spark plug.

 

[CDW6212R]

The EGR pipe can be almost any length, the air leak built in near the vacuum hose ports are the important section. Save that part from any EGR pipe, and make the end connections any way that works best for you.

That pipe routing, the #8 port, that's again about the collector. If you moved it any amount to improve that area, how hard would it be to modify the down pipe to match? That would be legal but yes make it unique to your truck, no future parts would swap as bolt on's.

 

[97Sandbox]

That pipe routing, the #8 port, that's again about the collector. If you moved it any amount to improve that area, how hard would it be to modify the down pipe to match? That would be legal but yes make it unique to your truck, no future parts would swap as bolt on's.

Yes, the stock "collector" exit flange location is what makes this challenging. It's horizontal and level with the frame rail which I'm sure was helpful for mass-production line assembly, but it's too close to the cylinder 8 exhaust port and spark plug for optimal primary routing.

I think you'd have to cut the downpipe back quite a ways to get the header/downpipe joint into an accessible place like alongside the transmission. At that point, you'd be making a long tube header and I think you'd need a two-piece design like Jamie proposed, otherwise, you'd never be able to snake the header in with the engine and trans installed -- the frame is just so close.

While that could all be fabbed, it overlooks something: upstream O2 sensor. As I understand, you want the O2 sensor as close to the hottest exhaust gas possible, but after the collector so it "sees" the whole cylinder bank. Suddenly we're back to wanting a shorty header and dealing with the tight spot between the block and frame.

If Bob from TMH ever sees this, I'm sure he'll just be thinking "I figured all this out 20 years ago and there's just no better way to do it!" hahaha. While I still want to believe there are improvements to be made, I'm not seeing any ways around the bigger tradeoffs Bob made in his design.

 

[CDW6212R]

The OEM collector is a major problem in that location, the size is just 2.25" piping, but the ball collector design is huge. If you'll scrap that, and weld a V-band flange down a few inches from the old collector joint, it should install past the frame easily versus the OEM connection. The O2 sensor is located close to the lowest point of that down pipe, near the bottom center of the trans. That's way past the collector, not an issue related to the header. I've read that the V-band flange with clamp on it is about 3/4" larger in diameter than the base pipe. Without the clamp the flange is about 1/2" larger.

 

[97Sandbox]

The ball collector isn't bigger than four 1-5/8" pipes squeezed together though.

You're probably right there's more room than I think to move the O2 sensor. I cannot overstate how tight it is between the block and frame though. Especially in an AWD/4x4 configuration, it'll be a challenge to reach up and position a v-band clamp, let alone get access to it from the side to tighten it down.