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1592 race cam?

Discussion in 'Rootes Racing' started by RootesRooter, Jul 9, 2019.

  1. RootesRooter

    RootesRooter Platinum Level Sponsor

    The fellow I was inquiring for is looking at improving his vintage racer, so he's looking for more than just "road-going."

    There used to be tales of a possibly mythical "Swedish cam" that was extremely radical and put out gobs of power in a 1592, but was still streetable. Anybody else ever hear of it?
  2. sunalp

    sunalp Platinum Level Sponsor

    If I recall correctly, in Chris McGoverns "Alpine, the classic Sunbeam" there is mention of Bernard Unett, a well known rally
    driver that ran a Swedeish square topped cam. It goes on to say that when the car wasn't racing, his wife used it to go
    shopping. According to the book, the cam made "gobs" of power , and extra 10 hp!

    Last edited: Jul 17, 2019
  3. alpine_64

    alpine_64 Donation Time

    Bernd ive read a few theories about the same... And use and drivability should always be forefront of cam selection... A dyno chart is great if you drive on a rolling road :p

    The worked 1600 i have has a very aggressive cam that does little bellow 3200...but its for track use so its tractibility in traffic and from low revs is not really relevant
  4. bernd_st

    bernd_st Bronze Level Sponsor

    Would be interesting to do some comparative Dyno sessions , i.e. cams with different timings vs. cams with increased lifts. I would almost bet that a good 275┬░cam like the 1725cc with increased lift would give the optimum output with street driveability :)
  5. Bill Blue

    Bill Blue Diamond Level Sponsor

  6. spmdr

    spmdr Donation Time

    To revive this old thread, In the past, I have not done a lot of Alpine engine cam testing.

    I have spent more time/effort with reliability. If an engine stays running,

    you don't GET the chance to try other parts, at least by default.

    However, I will tell the story of Steve Sage's SV street car, that I built the engine for.

    My memory is weak but here is what I remember.

    First off, of course, there was a limited learning curve involved, this was a FIRST street only Alpine I had done.

    I had the cam reground just a bit more than stock, SV.

    I followed Smokey Yunick's Power theory on cams, run the cam "straight up" , no advance, no retard.

    The theory holds that IF you GAIN more of what you want by advancing or retarding the cam, you have the WRONG cam grind.

    More about theory later...

    So I put an offset cam key in to remove the built in advance in the cam timing.

    Smoky would be PROUD, I thought....

    The performance of the engine was NOT what I expected!

    The engine would pull GREAT right up to about 4000 rpm!

    At 4000 the power would STOP!

    You could rev it higher but clearly you were adding NO more power!

    Clearly, there was SOMETHING holding the POWER back beyond 4000 rpm.

    It seemed all the world like the exhaust was JUST not flowing enough.

    So I removed the muffler and tested it. It made NO difference.

    At the time, nothing more was done to Sage's Alpine.

    BUT there was the nagging lack of knowledge of what to do to get more power from the Alpine engine.

    I talked to a head guy, he made it clear, the Alpine Exhaust port is NOT a performance port!!

    It is the SINGLE literal bottle neck on performance of the Alpine engine !

    It has TOO sharp of a bend coming off the valve seat.

    So here we get back into theory.

    WHY did removing the cam advance NOT give the upper rpms a bit of a boost, as you would expect,

    with a typical engine?

    With the Alpine, the sad fact is that the exhaust port makes it a NON-typical engine.

    ...at least from a performance point of view.

    Everything you do to the Alpine engine has to take into consideration the weak link of performance.

    It is the poor exhaust port!

    So the problem with Smokey's theory, as far as the Alpine, to put it bluntly, it don't apply.

    The Alpine NEEDS a big Band-aid to FIX the poor exhaust port.

    So the first thing I started doing was grinding cams with more exhaust duration, a dual pattern cam.

    There is a LOT of room out there to find the best Band-aid for the Alpine's weak link.

    (I need to cut this short)

    Last edited: Jan 23, 2020
  7. jdoclogan

    jdoclogan Platinum Level Sponsor

    Dan, you have captured my attention. Do tell more.
  8. alpine_64

    alpine_64 Donation Time

    Not that you dont see this in the series II special tunning manual drawing, but here is a sectioned alpine head...the exuasts runner is a very sharp turn.
    [​IMG] [/IMG]
  9. bernd_st

    bernd_st Bronze Level Sponsor

    Nice sectional pictures Michael. Self explaining regarding the exhaust port. Nevertheless I'm still doubting the statement about no power increase above 4000 rpm. Just look at what Holbay's achieved...
  10. alpine_64

    alpine_64 Donation Time

    Bernd, i think dan is saying that when he removed the advance of the cam there was no more power above 4000 as you were not giving additional exhaust opening... Hence why rootes provide it and why dan is saying to get around the limited exhaust flow he is looking into dual pattern cams to increase exhaust duration and allow the combustion to escape
  11. RootesRooter

    RootesRooter Platinum Level Sponsor

    For those of us who have never sliced our heads into tiny bits: Is (was) this a 1592 or 1725 head? Stock? The lower photo shows an intake port, right? Why is the exhaust valve guide so much shorter?
  12. spmdr

    spmdr Donation Time

    That cut in parts head (iron head, close enough to the Aluminum for reference) point out the Rootes engine evolution.

    The Alpine engine we all love and hate is a revised Hillman 1390 cc, all iron bit/lump.

    Back at 1390 cc, (and 1954) the ports where suitable for the task, if not the technology.

    But the revisions of that engine were just that, revisions.

    If you look at the different versions of the Rootes engine, you can see things on the later engines

    that make no sense, until you look at the early engines.

    The best example I can think of is the "coolant spray" cap in the center of the Aluminum head.

    It is a hold over from the iron head that had the 2 exhaust valves together and needed extra cooling there.

    With the changed valve layout on the aluminum head, 2 intakes in the center, the spray cap was no longer needed.

    But they continued to install them in the aluminum heads.

    To say the Alpines received little performance up grades with the engine revisions is an understatement.

    Rootes knew their limits and even tried to get a better head for the Alpine, but failed.

    That is most likely why a lot of people think the better Alpine engine is the S1-2.

    The ports are better with a smaller engine displacement.

    The 1725 was a revision that didn't really lend it's self toward the High performance world.

    And adding MORE displacement to an Alpine with a limited flow head is counter productive, BUT....

    Easier to do than the REAL fix, a better head, then and now.

    DW steps down from the soap box.
  13. husky drvr

    husky drvr Gold Level Sponsor


    I don't think the remaining section of exhaust valve guide is still in location in the head. Compare the wider, tapered guide location to the intake guide with its narrower, parallel sides. You can also see a definite material change between intake guide and head material that is not present at the exhaust location.

  14. alpine_64

    alpine_64 Donation Time

    The alpine head mod per special tunning manual. Still the very sharp turn and obstruction on the exhaust side per iron head

  15. spmdr

    spmdr Donation Time

    project Alpo

    For those that are skeptical about the theory of the TOO sharp exhaust port turn, I offer another story.

    Project ALPO was the engine transplant in Steve Alcala's S4 Alpine, with an 1986 SVO Mustang drive train.

    The plan was to use ALL of the Mustang parts to have the SAME power with 1000 pounds less weight.

    What could go wrong?

    For those that have installed or seen a 2.3 Ford in an Alpine, you know it's NOT a real good fit.

    It's a bit TOO long.

    And IF you add a Turbo on the side and an Intercooler on the top, it just makes it harder.

    The only way we could see it happening was to do a big mod with the right side steering arm pivot.

    We relocated the pivot to Below the arm to get room for the turbo.

    It required the fab of a bracket on the bottom of the frame box section to mount the pivot bracket.

    We still had a problem with the exit of the turbo.

    We could not use the original cast iron manifold because it ran into the firewall and steering area.

    We ended up making a custom manifold as big of an ID as the original BUT we had to make the turn down much sharper.

    When we finally took it for a drive, it was clear we didn't have the power of the original Mustang.

    We had about Half the boost pressure!

    Of course, the first thought was the muffler was too restrictive.

    We took it off with NO change in performance.

    Then we thought maybe the waste gate was not working properly,

    because it was part of the custom manifold we had to fab.

    We disconnected the waste gate with virtually no change in boost.

    It became clear the sharp bend at the exit of the Turbo was the problem.

    Seeing there was no easy fix, we left it as it was, it still ran quite well!

    Just not as Well as we hoped/expected.

    So the bottom line IS, Exhaust FLOW is Critical!!!

    So what does this have to do with the cam in an Alpine engine?

    The cam is one of the few things to mess with to put a Band-aid on the BAD Exhaust port.

    Take your BEST shot and let US know what you find.
    Last edited: Jan 31, 2020

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