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Header tube Dent repair

Discussion in 'Rootes Racing' started by spmdr, Jan 4, 2022.

  1. spmdr

    spmdr Donation Time

    I picked up an old Bill Atalla header that had the front tube dented in for alternator clearance.

    I wanted to save it, but how?

    Replacing the tube is the typical process.

    I have occasionally thought of making a hydraulically powered device to take the dents out of Tiger headers,

    but, as with a lot of things, never got a Round-to-it.

    With this Alpine header, anything I would have made would be too big to fit where the dent was.

    This tube was dented down to about 5/8" thick!

    I thought about filling the header with water or oil.

    But putting enough pressure into the header to bend the tube would likely be uncontrollable.

    How about air pressure and then heat up the bent spot?

    I checked the web and found others had done it.

    I picked up an expanding freeze plug to seal up the end of the header.

    And a metal plate with a chunk of inter-tube rubber to seal off the head flange.

    I tapped the plate for a quick connect air fitting.

    I pressurized the header to 100 psi and fired up the Ox y-actelene torch.

    It worked like a charm.

    Last edited: Jan 4, 2022
    Shannon Boal likes this.
  2. puff4

    puff4 Diamond Level Sponsor

    I’ve used sand in the past for such things. Fill the pipe with sand… pound it tight… heat the desired area to cherry red, then pound the sand again… the pipe will slowly press out again. But your solution seems to have worked nicely.
  3. alpine_64

    alpine_64 Donation Time

    F me.. They really beat the leading runner flat... Any performance advantage would have been gone the way it was clenched.....
  4. DanR

    DanR Diamond Level Sponsor

    I had come into possession of that header from an unknown source in that condition. If you know me I don't throw "anything" relating to a Sunbeam away:)

    Dan did the impossible in repairing the header and I am very proud to have been a "Keeper" in this process...
  5. 65sunbeam

    65sunbeam SAOCA Membership Director Diamond Level Sponsor

    Brilliant work to save a good part!
  6. Aladin Sane

    Aladin Sane Gold Level Sponsor

    The headers on my 302 were massaged a bit by the previous owner. Since that pic, I have had them ceramic coated. I think I can live with a drop in performance. 20210227_142140.jpg
  7. jdoclogan

    jdoclogan Platinum Level Sponsor

    Dan, you have incorporated the Burt Munro problem solving ingenuity from one of my favorite movies, The World's Fastest Indian.
    Intense inventiveness! Do you now plan on using it with an alternator vs generator install? I used the Atalla header on my Promotional HLM and had to do a milder dent alteration for fitment purposes. Another advantage to my prototype header using 1 1/4" OD pipe.
    bernd_st likes this.
  8. spmdr

    spmdr Donation Time

    I was a bit surprised how much the tube was Beat!

    I assumed that custom header would have had extra clearance there.

    Both of the Alpines that would be fitted with that header currently have the early original Tri-Y headers,

    so I assume this header will go right on with no mods.

    But down the road, moving the charging device away from the original location is not off the table.

    Also, one reason to play with this header is to see how it can be improved,

    IF it needs it.

    And I suspect THAT question has been answered by the bashed in tube.

    One thing I did do, is play the header like pan flute.

    And as I suspected, the center 2 tubes are shorter than the out side tubes.

    I'm liking Jerry's header, with the fixture flexibility to change tube sizes and lengths.

    And don't get me started on stepped tube sizes...

    BTW, I just saw old Burt and new Burt (AH), AGAIN, about a week ago on the DVD!
    I had an uncle similar to Munro and I have his '51 Triumph to prove it.
    Last edited: Jan 4, 2022
  9. spmdr

    spmdr Donation Time

    There is a rumor that a program, maybe "Engine Masters", did a test to see how much bashed header tubes effect power.

    I have not seen it.
  10. Barry

    Barry Platinum Level Sponsor

    Not a rumor. The show "Engine Masters" is available on Motortrend on Demand (https://www.motortrendondemand.com/) which is a subscription streaming service.

    Season 1 Episode 4 was titled "Exhaust Header Bash! Testing Power Loss From Dents". The short version is that beating the crap out of long-tube headers on a 400 cubic inch SBC making about 550 HP hardly changed the power or torque numbers.
    husky drvr likes this.
  11. Alpine 1789

    Alpine 1789 SAOCA President Diamond Level Sponsor

    Just one word of warning on the Bill Atalla headers: Be prepared for a lot of extra work if you plan on using a gear reduction starter. I used the adjustable one from British Starters and was told that it would not fit with the header. I took that as a challenge and eventually found a way to make it work (as I recall, I had to fabricate a custom bolt to finish the job) but it took quite a while and lots of fiddling and cursing.
  12. spmdr

    spmdr Donation Time

    The more I hear, the more it looks like these headers are not the prime time answer.

    They appear to be an design example to improve on.
  13. alpine_64

    alpine_64 Donation Time

    Bill made it for his project SIV racer.. They were designed for that car.. Then a batch made as the jigs were there.... So more = lower unit price. Thats my recollection
  14. Bill Blue

    Bill Blue Platinum Level Sponsor

    As I recall, one of the improvements that Bill made to these headers was to increase the diameter of the primary tubes to "improve high end flow". Bigger is better, right?
  15. Barry

    Barry Platinum Level Sponsor

    Bigger primary tubes may be better for a racing engine that is optimized for WOT at high RPM, not so much for a street engine that has to idle in traffic and mostly operates at part throttle and mid-range RPM. Same concept applies to camshafts, carbs, etc.
  16. thomo

    thomo Donation Time

    Many moons ago I was working in New Zealand and there was a guy called Malcolm Clark racing a Rapier in N Z , and I remember him telling me he had done a lot of Dyno work with different types of tube headers and had found nothing better than the factory cast twin outlet manifold , as fitted to the Hillman Gazelle and a lot of other alloy headed rootes cars
  17. jdoclogan

    jdoclogan Platinum Level Sponsor

    Mathematically bigger is not better for the Alpine engine. Possibly if you go to a larger cylinder capacity and make the 2 liter Alpine engine. 1" ID with a 20" length collected by a 4 into 1 configuration is the optimum for the best scavenging. https://forum.sunbeamalpine.org/index.php?threads/physics-math-and-an-alpine-4-into-1-header.28990/ I will see about getting a mandrel bend construction soon for the prototype I fabricated.
  18. spmdr

    spmdr Donation Time

    I agree with Jerry.

    With the even firing of the Alpine engine,

    a 4 into 1 exhaust with equal tubes has peak scavenging better than the original Tri-Y.

    Tr-Y exhaust do better with uneven firing engines/applications.

    My goal is the simple old "more power" one:

    (BUT, to go beyond where a lot of the past Alpiners have been.)

    Make as much Torque as possible AND (this is key) MAINTAIN it as the RPMs go up.

    And part of that goal includes a higher flowing/lower restriction exhaust.
    Last edited: Jan 8, 2022
  19. jdoclogan

    jdoclogan Platinum Level Sponsor

    Through discussions with Dan (spmdr) I needed to better understand the cam relationship to intake and exhaust flow. Thus, I sought out more understandings about center lobe angle. The article link I'm about to share "overlaps" (get it?) with the cam threads. The article I found ties in with this discussion (Dan's torque goal) as well. The article is from an April, 2001 Motor Trend article by David Vizard (yes, the same Vizard who designed the Alpine head modification) https://www.motortrend.com/how-to/cam-lobe-centerline-angle-tech/ It is a great read for those that enjoy to be immersed in technical discussions.
    Shannon Boal likes this.
  20. Shannon Boal

    Shannon Boal Platinum Level Sponsor

    As for firing order of an inline four cylinder, I have only seen one firing order. 1-3-4-2...... I heard that an odd English Ford existed, but have never seen one

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