Page 1 of 2 12 LastLast
Results 1 to 30 of 39

Thread: Mercedes-Benz (Ilmor) 500I - Layout Question

  1. #1
    Insider FTHurley's Avatar
    Join Date
    May 2008
    Location
    Boston, MA
    Posts
    11,117

    Mercedes-Benz (Ilmor) 500I - Layout Question

    My Dad and I were chatting the other day, and we were wondering about this engine. I thought some of you fine folks might be able to give us an answer.

    Just what was the deal with this engine? My original understanding was that the rules first said that to have the higher 3.43L displacement and higher boost, the engine needed to be a production block, and have two pushrods and two rocker-actuated valves per cylinder. They then relaxed them with regard to the production part - it just needed to be "production-based." This allowed the Menard version of the Buick, which was supposed to take a fast concept, and help it hold together, because by building a block specifically for racing, it could be built more stoutly.

    The problem this created is that if a company actually want to invest a bazillion dollars, they could create a motor that paid the barest lip service to "production," but that fit the letter of the rule, and get the extra cubes and boost. Nobody thought anyone would ever do this.

    I might be fuzzy on the details, but I think that's the short version of what happened.

    What we can't figure out is what the Benz actually looked like. I've found references to it being a "pushrod" motor, but my Dad thought that it was pushrod in the way that his Alfa GTV6 has "pushrods," as in small ones that go from the overhead cam across a hemi cylinder head to the 90-degree rocker on the other side. This would allow someone to build an OHC racing motor that technically had "pushrods" and "rocker-actuated valves" though it would stretch the rules pretty damn thin.

    Someone else told me that no, the motor was very much a traditional pushrod V8 with a cam in the V, and pushrods up through the block to traditional rockers. The only difference is that Ilmor (with Mercedes dollars) had the resources to build one that could survive the race at those boost levels and revs with no problems.

    So which is it? Or is it another thing altogether? I know there is some serious race engine mojo 'round here, so I figure one of you might help me get my Dad the answer. Thanks.

    Cheers!
    Last edited by FTHurley; 05-01-2009 at 11:38 PM. Reason: Spelling Error

  2. #2
    Registered User
    Join Date
    Mar 2004
    Location
    Fishers, IN
    Posts
    594
    I believe you're correct. From what I recall, the stock block rule change after 1993, no longer required the crank to be located in the same position within the block that the manufacturer located the crank in their production motor. I had been told this was a key component that essentially opened the door to having a purpose built racing engine that received 55 inches of boost and produced some crazy amount of horse power.

    There are a bunch of good technically knowledgable individuals on this board that would know for certain and can explain how Penske took advantage of the rule change. good topic and a nice walk down memory lane 15 years ago this month. Hard to believe its been 15 years.
    Straightup

  3. #3
    Generation 3 EdJVuky's Avatar
    Join Date
    Apr 2001
    Location
    Toledo
    Posts
    3,593
    The cam was very high in the block...at the top of the vee, making the pushrods very short. This lowered the mass of the valvetrain components and the short pushrods were also less likely to flex or bend under load. Better revs than the Buick and better reliability.
    Third Gen Indy Fan

  4. #4
    price checker
    Join Date
    Jun 2001
    Location
    Fort Worth Texas US
    Posts
    11,578
    Quote Originally Posted by irlrules98
    The cam was very high in the block...at the top of the vee, making the pushrods very short. This lowered the mass of the valvetrain components and the short pushrods were also less likely to flex or bend under load. Better revs than the Buick and better reliability.
    I'm having trouble picturing a cam at the "top" of the V. Doesn't seem possible to me. I am not having as much trouble with the "very high in the block" as I am about the "top" of the V.
    Some people will do nearly anything in order to be able to not do anything.

  5. #5
    Insider FTHurley's Avatar
    Join Date
    May 2008
    Location
    Boston, MA
    Posts
    11,117
    Quote Originally Posted by Lucky161
    I'm having trouble picturing a cam at the "top" of the V. Doesn't seem possible to me. I am not having as much trouble with the "very high in the block" as I am about the "top" of the V.
    Was the engine wider that a typical V as a result? I know there was something about them that made the chassis very difficult to drive. I believe the word "pig" was used.

  6. #6
    price checker
    Join Date
    Jun 2001
    Location
    Fort Worth Texas US
    Posts
    11,578
    Quote Originally Posted by Tabernerus
    Was the engine wider that a typical V as a result? I know there was something about them that made the chassis very difficult to drive. I believe the word "pig" was used.
    That may have been part of it, but it still doesn't explain how the cam could be on or even near the top of the V. Just picture a V of any size and try to put a single camshaft at the top of the V.

  7. #7
    Waiting for the next race KenK's Avatar
    Join Date
    Aug 2000
    Location
    225 Miles from Indianapolis Motor Speedway
    Posts
    1,942
    Perhaps this will help?
    "It is a besetting vice of democracies to substitute public opinion for law. This is the usual form in which masses of men exhibit their tyranny." - James Fenimore Cooper

    "One man with courage is a majority." - Thomas Jefferson

  8. #8
    Insider FTHurley's Avatar
    Join Date
    May 2008
    Location
    Boston, MA
    Posts
    11,117
    Quote Originally Posted by KenK
    Perhaps this will help?
    Umm, yeah! Thanks!!!

  9. #9
    Is Bat Boy KevMcNJ's Avatar
    Join Date
    Apr 2002
    Location
    In a flagstand somewhere in the Carolinas
    Posts
    34,045
    where are they now?
    Live like Dave

  10. #10
    Gurney and Fogarty FTW!
    Join Date
    Apr 2003
    Location
    Bloomington, Indiana
    Posts
    2,166
    Quote Originally Posted by Tabernerus
    Was the engine wider that a typical V as a result? I know there was something about them that made the chassis very difficult to drive. I believe the word "pig" was used.
    If I don't miss my guess, the center of gravity on that engine looks much higher than a traditional 2.65L DOHC.

  11. #11
    It's just as likely to be slightly lower. Camshafts aren't light. Overhead camshafts would put the weight higher.

    Quote Originally Posted by FCYTravis
    If I don't miss my guess, the center of gravity on that engine looks much higher than a traditional 2.65L DOHC.

  12. #12
    Registered User
    Join Date
    Oct 2001
    Location
    Dublin, Ohio
    Posts
    3,423
    I would venture that even if the cg was lower the Mercedes def. weighed more seeing it ran a higher boost and a larger displacement. Any extra mass means less ballast where you want the weight located.

  13. #13
    not to hijack, but reading the penske book "in pursuit of perfection" the awesome thing is that they told the entire penske organization at the start of the project and no one leaked it!

  14. #14
    Banned
    Join Date
    Jun 2004
    Location
    Minnesota
    Posts
    2,804
    Quote Originally Posted by AlJRFAN
    I would venture that even if the cg was lower the Mercedes def. weighed more seeing it ran a higher boost and a larger displacement. Any extra mass means less ballast where you want the weight located.
    You lost me on why this means its weight is greater.

  15. #15
    Registered User
    Join Date
    Jul 2004
    Location
    Camelot
    Posts
    1,258
    Actually, this engine, although taller, was lighter weight, as already speculated by rjohnson999.

    The 209 cubic inch, single-camhaft, pushrod Mercedes-Benz 500I turbo V8 is 2.5 inches taller and 20 pounds lighter than the 161 cubic inch, four-cam Ilmor V8. The weight reduction comes because the cam drive system is much simpler in a pushrod engine.
    As far as driveability:
    He [Paul Tracy] says the engine won't be easy to drive at Indianapolis. "It'll be a new experience. Compared to the normal Ilmor, it has a low rev limit and narrow power band. We'll have to be really careful leaving the pits to make sure not to spin the tires too much or overrev the engine."
    Motorsport : ChampCar/CART Misc. News
    No one is completely useless... you can always be a bad example.

    Um, I think when I'm in this idiom, I sometimes get a bit, uh, sort of carried away.

  16. #16
    Registered User
    Join Date
    Oct 2001
    Location
    Dublin, Ohio
    Posts
    3,423
    Interesting, what an awesome engine. I think the best part was that they were probably only running about 80% as hard as they could have, but they had they already had everyone covered and then some.

  17. #17
    . . . . . . . . . 9rows's Avatar
    Join Date
    Mar 2007
    Location
    accounted for
    Posts
    8,281
    Quote Originally Posted by KevMcNJ
    where are they now?
    i have one powering my minivan

    not sure what happened to the rest of them

  18. #18
    Insider FTHurley's Avatar
    Join Date
    May 2008
    Location
    Boston, MA
    Posts
    11,117
    Quote Originally Posted by AlJRFAN
    I would venture that even if the cg was lower the Mercedes def. weighed more seeing it ran a higher boost and a larger displacement. Any extra mass means less ballast where you want the weight located.
    It's funny you mention that. Wasn't one of the quirks about this car that it was breathtakingly fast on the straights, but not as good in the corners? I seem to recall during the race Sam Posey pointing out that they would catch and pass cars going down the front straight, and through turn 1 the passed car would regain some ground, but the Penske was just SO much faster that by the middle of the back straight, it was well clear.

  19. #19
    Insider FTHurley's Avatar
    Join Date
    May 2008
    Location
    Boston, MA
    Posts
    11,117
    Quote Originally Posted by AlJRFAN
    Interesting, what an awesome engine. I think the best part was that they were probably only running about 80% as hard as they could have, but they had they already had everyone covered and then some.
    I kinda wish we could have seen a test lap at Fontana.

  20. #20
    There is no substitute. Spike's Avatar
    Join Date
    Aug 2002
    Location
    Driving the point home
    Posts
    25,220
    Quote Originally Posted by Tabernerus
    My original understanding was that the rules first said that to have the higher 3.43L displacement and higher boost, the engine needed to be a production block, and have two pushrods and two rocker-actuated valves per cylinder. They then relaxed them with regard to the production part - it just needed to be "production-based." This allowed the Menard version of the Buick, which was supposed to take a fast concept, and help it hold together, because by building a block specifically for racing, it could be built more stoutly
    Close. For the longest time the rule on the 209 pushrod motors was that they had to be built off of a stock block production engine. That's what allowed the Buick V6 and, later, Menards Buick V6 as they used production blocks and heads and maintained the overall architecture of the stock engine.

    What changed was when USAC and the speedway dropped the production/stock block part. Roger McCluskey (USAC's director of competition) had a big part in this and the speedway saw it as a way to help the "little guy" as both Lee Brayton and Michael Greenfield (and his father) lobbied for the rules change which allowed them to proceed in developing their own 209 pushrod V8 motors.

    What USAC and the speedway didn't count on was one of the big engine makers (Ilmor, Cosworth) developing such an engine just for Indy.

    Greenfield failed to qualify in both '94 and '95 with his pushrod V8. The Brayton project was bought up by Menard following Penske's success but after USAC and the speedway changed the allowed boost levels, not once but twice, in the off-season the Menard and Ilmor/Mercedes pushrod motors were rendered obsolete.

    Quote Originally Posted by Tabernerus
    Someone else told me that no, the motor was very much a traditional pushrod V8 with a cam in the V, and pushrods up through the block to traditional rockers. The only difference is that Ilmor (with Mercedes dollars) had the resources to build one that could survive the race at those boost levels and revs with no problems.
    As others have pointed out and the brilliant Tony Mathews illustration shows the camshaft was right where you'd expect (and the rules required) it to be. One of the really clever things was the shaft that ran just above the camshaft that carried the roller followers which actuated the pushrods. Very cool engineering.
    "I would really like to go to NASCAR. I really enjoy NASCAR and if I could be there in a couple of years that's where I'd want to be." - Jeff Gordon (after testing a Formula Super Vee)

  21. #21
    Been at Indy since 1956! ZOOOM's Avatar
    Join Date
    Jul 2005
    Location
    Plainfield, Il.
    Posts
    4,720
    Over in the technical thread Lyendyke's engineer, Tim Wardrop said that the engine was so powerfull that it masked the shortcommings of the chassis. The following year Rodger returned with basically the same chassis and the normal Indy engine, and failed to make the race with any of his cars.

    Tim still signs on here with the screen name.... 239, the record speed Arie set at Indy that will NEVER be beaten!

    ZOOOM
    "Doc, just set them fingers sose I can hold the wheel"
    James Hurtubise, June, 1964

  22. #22
    Quote Originally Posted by Tabernerus
    Someone else told me that no, the motor was very much a traditional pushrod V8 with a cam in the V, and pushrods up through the block to traditional rockers. The only difference is that Ilmor (with Mercedes dollars) had the resources to build one that could survive the race at those boost levels and revs with no problems.



    Cheers!

    It was definitely not a traditional pushrod engine, likeable to a Detroit V8.

    The best description for it is that it was a purebred racing block, but compromized in valve technology because of only 2 valves and pushrod operated too in order to use the advantage of addictional cylindercapacity and turbo boost. Those two advantages combined more than compensated the disadvantages of the pushrod technology. Had one of them been taken away the engien would have been closere, if not inferior to a 2.65 Quadcam again. Combined however they did the trick.
    But as the matthews drawing and the books "Prime Movers" and "Quicksilver century" (written by Karl Ludvigsen) may learn you, desgner Illien tried to minimize all the disadvantages of the pushrod concept to the absolute minimum. And ty to get into a position that he could decide which handicaps he had to take instead of being forced to accept whatever handicap a production engine would force him to swallow.
    He thus could avoid a number of handicaps the Buick V6 had due to ists stock heritage....

    The for a v8 unusual Vee angle of 72 degrees is agood example of that. Illien needed that kind of angle and could go for what he needed instead of accepting a 90 degree that a Detroit engine would have forced him to use.

    As for the GC on the engine, it was likely higher then that of the regular Ilmor D.
    The inlet plenum sat a lot higher then on the /D and despite the lack of four camshafts. the more narrow valve angle put the cylinder heads up higher too.
    Not mentioning the camshaft put up as high as possible too...

    Indyote

  23. #23
    Well, I don't know yet what the final result it is gonna be like:

    But it seems there is something coming up about the Penske-Mercedes PC23-500I.

    http://8w.forix.com/penske-mercedes-pc23.html

    Time will tell where this will end up in.


    Indyote

  24. #24
    Quote Originally Posted by Indyote
    Well, I don't know yet what the final result it is gonna be like:

    But it seems there is something coming up about the Penske-Mercedes PC23-500I.

    http://8w.forix.com/penske-mercedes-pc23.html

    Time will tell where this will end up in.


    Indyote


    For those who still have an interest in this engine and the car it was used in,
    better have a look on the site I mentioned above now.

    For the technically orientated readers, chapter 9 in particular might be of some interest. Have a look....
    While Chapter 13, the read about what happened in practice and the difficulties the drivers coped with ....

    Indyote

  25. #25
    . . . . . . . . . 9rows's Avatar
    Join Date
    Mar 2007
    Location
    accounted for
    Posts
    8,281
    Quote Originally Posted by Indyote
    For those who still have an interest in this engine and the car it was used in,
    better have a look on the site I mentioned above now.

    For the technically orientated readers, chapter 9 in particular might be of some interest. Have a look....
    While Chapter 13, the read about what happened in practice and the difficulties the drivers coped with ....

    Indyote
    thanks for the link, good stuff

  26. #26
    That link was great reading. Too bad my local library doesn't have the book he referenced.

  27. #27
    never was wannabe debdrake's Avatar
    Join Date
    Aug 2000
    Location
    too far gone
    Posts
    9,087
    My understanding was that in (I think) '94, Menard was supposed to have had another, more powerful engine which they had tested, but for some reason Menard never brought it to the race (and the following year it was no longer legal).

    Anyone know if that's accurate, and if so, why Menard didn't run the engine in '94?
    I'm from a place called the internet. Nothing disturbs me.

  28. #28
    Quote Originally Posted by debdrake
    My understanding was that in (I think) '94, Menard was supposed to have had another, more powerful engine which they had tested, but for some reason Menard never brought it to the race (and the following year it was no longer legal).

    Anyone know if that's accurate, and if so, why Menard didn't run the engine in '94?

    Not ready yet and/or reliable enough (compared with the V6) seems the most logic answer. But maybe Tim Wardrop knows a bit more on this? (Remembering the great details he told about Team Menard 's manners [or should I say larry Curry's manners ] at the speedway in the thread that brought mi in this forum...


    Indyote

  29. #29
    Quote Originally Posted by debdrake
    My understanding was that in (I think) '94, Menard was supposed to have had another, more powerful engine which they had tested, but for some reason Menard never brought it to the race (and the following year it was no longer legal).

    Anyone know if that's accurate, and if so, why Menard didn't run the engine in '94?

    Found something about it but I think it is fair to mention how I got hold of this.

    The guys of the Penske Site I provided the link also added a chapter with a bit of background about the other 209 Pushrods of 1994, concentrating on the Greenfield. But not much to be told about that one.
    I give the link to that particular page. But what you need to do as well is go to the very bottom of that page. They mention Brayton amn Menard 1994 projects and a link to another page.
    Now that one is not written by them but it tells you more about the menard/brayton Pushrod and why it wasn't used in 1994 yet then i have read anywhere else.

    http://8w.forix.com/penske-mercedes-...reenfield.html

    Again: if you want to know more about the Brayton/menard efforts: go to the bottom of this page and look for the link there.

    Indyote

  30. #30
    never was wannabe debdrake's Avatar
    Join Date
    Aug 2000
    Location
    too far gone
    Posts
    9,087
    Ah, so that's what happened. My understanding had always been that it had been tested in pre-season testing at the speedway, but maybe not.

    BTW, can you point me to the thread you mention regarding Wardrop's take on Curry?

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •