Dionk

Stahl Header resurrection

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Greetings all

 

I have a Stahl header that was installed on my project car when I bought it.  It’s been storage until today. 

 

My plan Is to take it to be bead blasted and cera coated.

 

i have concerns and a few questions I’m seeking advice on:

 

1. Seems that a PO welded some smaller width exhaust pipe on to it.  I’d like to have the same width pipe going all the way back to the muffler.

 

I’m guessing this was done so that It could fit into the stock size mid pipe/ muffler that was on the car when I bought it.

 

My question is should I cut this right before the weld so a clean mid pipe can be attached?  Assuming this will need to be a custom size.

 

2.Looking at the holes where the manifold mates to the engine, it seems that there are some areas where the exhuast flow from the head wasn’t aligned with the manifold holes. You can see this from the darker areas in the pictures on two o the holes.  Should I have the header modified hog out that bit that seems to be interrupting the flow?

 

3. Has anything me installed a wide band o2 sensor on a Stahl header? I plan to and I if you have any advice / pictures for the placement of the bung and sensor - would be appreciated. My guess is that this will need to be sorted after I install.

 

So looking for any advice or input on how to handle both of these items.

 

thanks

Dionk

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My Stahl is similar on the ports. Not much you can do. You could try to port it a little, but be careful to not make the pipe too thin.

 

I would cut the resonator thing off just upstream of the weld about 1/4". I put a V-band flange on mine. Got tired of the leaky donut gasket....

 

As for the O2 sensor. I have mine in the collector. Yes, you'll want to mount the header first then figure out where your O2 sensor will fit. I had to move mine again with the 5 speed install as well.

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I would also get the flange surface ground flat, your leakage looks like it comes from the edge of the flanges   These flanges warp a little after the years and the tightening of the manifold nuts cause it to go out a little

They leak a little so guys tighten them up some more and after enough time, they look like this.

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I’m with Stephers on getting the flange milled flat.

 

You can check the alignment of the primaries by laying a one-piece e30 M10 gasket over the flange. Make sure the stud holes in the flange and gasket align, then see how the exhaust holes in the gasket align with the primaries. Stahl headers are generally very well made, so I’d be dismayed if you find that there’s significant misalignment. 

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50 minutes ago, Dionk said:

Has anything me installed a wide band o2 sensor on a Stahl header? I plan to and I if you have any advice / pictures for the placement of the bung and sensor - would be appreciated. My guess is that this will need to be sorted after I install.

 

After the collector, on the single pipe. I did one on the primary muffler just aft of the joint. Horizontally, but make sure that it will not hit the floor when the engine moves from the torque or badly adjusted motor mounts.....at least it's not stainless like the S14 header.

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19 minutes ago, andyleonard said:

This, horizontal toward passenger side. Clears 245 with a Stahl.

IMG_2108.jpg

 

Ideally you do not want to be horizontal. You want at least 15* or so angle up if possible. This is to help let moisture out of the sensor prolonging its life.

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15 minutes ago, roadhog0 said:

 

Ideally you do not want to be horizontal. You want at least 15* or so angle up if possible. This is to help let moisture out of the sensor prolonging its life.

 

Ideally, yes. Not in this application without hitting the floor.

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Mine worked out that the collector was just far enough forward so that I had room to angle the sensor up-

it's visible from the engine compartment. 

 

1. yes, remove the add- on.  If this is for a street car, get some form of resonator, or it will drone.

 

2. that's a small- tube header- you're not giving away much, and if you try opening it up, it's

quite likely that you'll have cracking problems.  Stahls are made to be light and flow well, at the expense 

of durability.  Likewise, they usually have a pretty thin flange, so traditional milling/sanding may thin the flange too much.

They are pretty soft, and will conform- you can test- fit it without a gasket to see if it'll snug down.

 

c. put the bung on the pipe after the header- and make that pipe separate from the header, AND run

a brace to keep the exhaust twist out of the header.  See above re: durability.

V- flanges are what I use, too, but I use the traditional 

stamped retaining flange and donut, because it allows misalignment gracefully.

 

 

t

 

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Thanks all this is the solid advice I was looking for.  I’m considering sending it to jet-hot for ceramic coating. Quote from them was $150 plus shipping.   Anyone use them?

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Mine was $210 for ceramic coating. Looks great but chipped when mounting flange nuts. Go with the Jet Hot.

 

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No offense but rattle can header paint is useless.  It burns off in no time and actually makes the headers look worse.   For cost, I use POR 15 hi heat manifold gray paint, it can brush on and it flows out really nice.    Hard to chip, easy to touch up and will look good for years  It does not burn off.   Did an engine on a 2800CS 5 years ago and coated both manifolds with the POR 15 paint and still looks like new today

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On 2/10/2019 at 5:07 PM, andyleonard said:

 

Ideally, yes. Not in this application without hitting the floor.

I can tell you that without a 15 degree uphill slope, the 02 sensor will soak in condensation and fail very very quickly.   My AEM one lasted maybe 6 months.  The person who put in the bung did it level, and I had to wait to change out the header before it was finally fixed properly. 

 

Also cheap sensors fail quickly.  Get a Bosch and only Bosch.... like in a Bosch box, purchased from a reputable parts supplier who is wearing a Bosch hat, Bosch gloves, Bosch pants and Bosch shoes, being served on a Bosch plate by a person named Bosch, who only knows one word of English  which is.. you guessed it "Bosch".

 

I just picked up 2 from here.  Short of finding the above, these are the best price I could find on real Bosch 02 sensors. 

 

https://www.efisystempro.com/

 

 

 

 

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VHT HEADER paint works ok.  If your prep is good, it actually holds up for a while.

Mine is not, so I respray it occasionally.  Which, every time I do, looks better and better.

 

I have one coated header- it's looked good for 25 years...

 

t

 

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