Anatomy of a historic 8V race engine

Discussion in '8-valve' started by TonyB, Jan 7, 2023.

  1. TonyB Paid Member Paid Member

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    For those that are interested, here is a record and exploration of an 8v race engine, plus some further development to adapt it to a new role.....seemed like an interesting, focused subject.

    Been a while since I've done much 8v work, but whilst I'm happily developing the 16v race engine elsewhere with some good results I'm keen to get back on with the 8v development. They are such good engines and give so much more than they should when you look at the spec on paper.....when developed properly!

    So, on to this thread; for clarity much of the history and spec I discuss is subjective as I purchased the engine sight unseen, except for a few pics of it insitu in a packed workshop in an unused state and some research I've done plus my own knowledge gained over many years building and racing them..

    The advert said ‘buy the twin 45 DCOE’s and pay an extra £300 and get what might or might not be a race engine’. Always interested in things like that. From the few pics on show it was clear that it had a set of twin 45’s with a genuine weber linkage kit. So looking good there, plus a decent heat shield and matching manifold. Also on show an adjustable vernier, maybe an early Schrick one, a light weight flywheel and with its six springs on show, a Sachs/Helix clutch plate.

    What was more interesting was that under the current black paint on the block you could see patches of an earlier blue paint finish. Now this wasn’t the common TSR blue, which would be less interesting, but the darker blue that was reminiscent of a shade used by the late Mike Callaghan. This would indicate it could be a far harder edged engine than a TSR one.

    After some more digging it turned out that the engine belonged to a long term CGTI member and racer who I had known through the forum over the years and who had recently passed away. |His family were selling off some of his VW parts hoard, and this was part of the initial batch of parts to be sold.

    All of this added up to an engine that was likely to have been a decent spec at some point, but its current spec and condition was unknown. As it was on the other side of the country I didn’t have the time or inclination to travel 500 odd miles to have a look and I have quite a few race engines in stock it was not an essential buy. However it all added up to a potential good buy, so a deal was done to get it shipped.

    It duly turned up nicely packaged and protected, and then the fun part began………finding out what I actually had!!

    IMG_20220505_174218_resized_20221231_062402621.jpg IMG_20220505_174510_resized_20221231_062401365.jpg IMG_20220507_163152_resized_20221231_062401069.jpg IMG_20220507_163214_resized_20221231_062400720.jpg

    So there you are.

    The eagle eyed amongst you will have also noticed the lockwire and the rather neat works style engine mount, amongst other things.

    If there is any interest I'll carry on and put up some more info on what was inside and future developments and use for this engine.
     
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  2. Tristan

    Tristan Paid Member Paid Member

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    "If there is any interest I'll carry on "

    Oh Tony.... do you really need to ask?
     
  3. RoccoMatt New Member

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    Very interested to see inside this thing. I'm quite a fan of the 8v too and keen to get back on one I've got stashed in the garage. I picked up a block ages ago with (from memory it's been that long) kolbenschmidt 82.5mm pistons in it for all of £100. I plan to have some cheap fun with a crossflow head and some bike carbs
     
  4. TonyB Paid Member Paid Member

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    Ok, so here are a few pics of the basics with the cam cover and the sump off to have a nose.

    IMG_20221228_170032_resized_20221231_061707332.jpg

    So clearly not std! Early 5 bearing head, big cam, as I recall its about 12.5mm lift and looks to be between 285 and 300 degree duration, not measure it yet. Some decent clearance machined in the head, quite tidy job and proper solid lifters with lash caps under. Probably most important its very clean in there and little wear evident. Head gasket is a fibre job and the head bolts are std. The fibre gasket works, but I'd use a steel ABF one myself and the std head bolts are not a problem, even the works Audi STW used shortened std head bolts so not an issue, but if the motor is going to be stripped a lot then some studs and nuts might be useful.

    IMG_20221230_162504_resized_20230108_034731474.jpg
    IMG_20220515_174327_resized_20230108_042431006.jpg

    So the bottom end. Looks very pretty and again clean and tidy. Lots of ARP....mains and big ends which is handy. Std rods, look to have been balanced and the crank of course lightened and balanced. Not really a great fan of knife edging etc. as I don't see the point as the benefits are limited and moving weight about without doing a lot of clacs is probably not that smart, as well as taking the hardened surface of the crank off is again not a great help, works cars never bother so probably not a good idea on balance....but it is what it is and looks trick :-). Looking down to the bores I could see the pistons were 82.5 but std cast Mahle or similar OE and measured the stoke at 92.8, so a 2.0ltr engine in a DX block. Bearing surfaces were unworn and the big end bearings had some wear marks but nothing much....will swap them out anyway and put some ACL or King ones in for peace of mind....looks std sized but need to check.

    IMG_20221230_162106_resized_20221231_015222296.jpg IMG_20221230_162151_resized_20221231_015221387.jpg

    One interesting note is that the rods have a number of tuners marks on them, dots on the sides and base plus numerals......which confusingly as all differ, so the rod might have a 4 marked on it and 3 dots, or some such confusing notation! Just need to take a note of which marks relate to the current configuration and hope they are correct!! Also came with a windage tray and baffled sump as you would expect, windage tray has been taken off here of course.

    IMG_20221230_162441_resized_20221231_015220069.jpg
     
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  5. Tristan

    Tristan Paid Member Paid Member

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    Goes to show the strength of mk2 era internals.
     
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  6. TonyB Paid Member Paid Member

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    Yes, but I think the engine was probably a Slick 50 engine originally, and again probably an 1800. I suspect the 2.0ltr conversion (so pistons and crank) was a more recent rebuild and development. The head and possibly cam are likely from the original build, as there are a number of tuners marks and some have been scratched out and over written. I believe its last intended use was as a Hotrod motor....but more on that later.
     
  7. RoccoMatt New Member

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    Some lovely insight here and it's nice to see some proper engine archeology! Thank for sharing and nice to see such a lovely thing in such good condition (not jealous at all...).

    With the rods I'd wager they've been swapped around to make up sensibly weight matched pairs with the pistons in its various builds. I'm assuming all the rod numbers at least match the caps?

    With regard to your comments about knife edging - I'm a little confused here. Only the bearing and seal surfaces on a crank are hardened otherwise it tends to fail pretty spectacularly due to the bending and torsional vibration seen in use. Knife edging is a funnily divisive topic. If material is being removed from the counterweights to balance the rotating assembly in a high performance engine, it's usually beneficial (in terms of windage and effective oil shedding). It quite often just comes down to cost.

    Looking forward to any updates as and when on this to brighten a wet January.
     
    Last edited: Jan 9, 2023
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  8. drunkenalan Paid Member Paid Member

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    why do i never see boxes of goodies for sale..

    nice find there Tony keep the updates coming
     
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  9. Laim New Member

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    Very interesting, keep it coming
     
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  10. Hot Water Forum Member

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    Look forward to more updates Tony!
     
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  11. Jon Olds Forum Junkie

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    Dual marked rods (4 and 3) may mean its run a big end at some point in its life, and the rod was replaced ?
    Nice work sharing, thanks
    Jon
     
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  12. Andy Mestengo New Member

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    hello
    1.какая мощность?
    2.крутящий момент?
    3.коэффициент видео?
    4. обороты?
     
  13. TonyB Paid Member Paid Member

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    Yes, could well be.....at least seems caps and rods are matched. Juts need to remember to make a note of where they are now on the assumption there is some science behind their current positions.

    I'm no expert but I understand if you machine or polish a surface on a forged crank or rod you then need to stress relieve it by shot peening or some such process for reliability and to keep things straight and true. I agree less is more generally, but looking at proper race cranks they are never that light, mass seems to be quite important, no doubt to counterbalance the other rotating components. As very little weight has been removed from the other rotating components it seems to me there must now be more imbalance.....but like I say I'm no expert, just the way I see it.

    Maybe a discussion for a seperate thread, very interesting for sure.....probably in one in the system somewhere.

    I have plenty more pics and info, time and concentration is the issue lol.
     
  14. TonyB Paid Member Paid Member

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    All the rods seem to have the same combination of various marks and teh marks match on each rod, so just look like different turners/shops marking the rods differently. Hence I imagine the 2.0ltr crank was the last change and the same rods from the 1.8ltr were re used and balanced to suit.

    Just wondering if I add my marks for future reference or if that just adds to the confusion.......sort of feel obliged to now for its on going history lol.
     
  15. TonyB Paid Member Paid Member

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    1. No idea yet, with the big venturi 45 DCOE's I'd imagine 170/180 ish bhp if its all the parts are matched properly and with the right bolt on bits and setup, but its an unknown at present
    2. Again no idea mid 150's lbs/ft?
    3. same, should be around 12:1 I'd think, need to measure that.
    4. it should make power 7>7.5k I'd think, but they are safe with ARP to well over 8k, I've run std rods with ARP to over 9k with no ill effects on 159mm long rods.
     
  16. TonyB Paid Member Paid Member

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    So a bit more info about past history etc.

    IMG_20221230_162757_resized_20221231_015121382.jpg

    Some tuners marks. RPM? the numbers maybe a job number or date, not sure, but I'd think the last marks.

    IMG_20221230_162654_resized_20221231_015122821.jpg

    Previous tuners detail removed, unsure why.....looks like it could have been a date. TSR used to mark their heads like this, so could be a later Dave Crisell head? The marks below look similar to other heads of his I have.....but why change the previous mark to solid, from what? This head would have always been solid lifters not hydro, maybe to denote the change from shim on bucket to a lash cap under? If so this is probably a replacement head, or different one to the original, as a race engine would not normally run the std shim over bucket arrangement as they can scoop the shims out with big cams.....but back in the day maybe that was more normal?

    IMG_20221230_162638_resized_20230113_010828962.jpg

    Block marks unclear, but its a DX mark, the numbers are unclear. Also the darker blue original pain can be seen under the more recent black....its darker than it appears here.

    IMG_20221230_162747_resized_20221231_015122090.jpg

    Put some paint on the block to build/check it to keep it all clean. I don't use heat resistant, and yes it comes off eventually but its there to stop dirt getting in during the rebuild more than anything.....just happen to have a few tins of the TSR typoe blue on the shelf, so why not.

    IMG_20230102_115425_resized_20230113_012337053.jpg

    And finally, as suspected the Sachs race clutch. Better than expected actually, as a virtually new 4 puck paddle clutch and pressure plate with a tidy lightweight flywheel. These sachs/Helix clutches as are good as it gets for the 020 boxes, either in full organic or metallic paddle such as this. The organic clutches are sweeter to use and have a nice 'slip' to them to use the clutch out of hairpins etc, but for real abuse the paddle clutches have a stronger clamping force, but are a bit more snatchy to use and need more care it pootling about. Ok when you give it 8k and drop the clutch, but less fun for more sedate driving.

    IMG_20220507_163143_resized_20221231_062401748.jpg

    More to come when I get a chance.
     
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  17. Andy Mestengo New Member

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    Привет.Мне кажется.если раскрутить двигатель до 8000 об/мин и резко бросить сцепление,то скорее всего коробка развалится(будет сильный удар).но так как диск сцепления задемпфирован то может и выдержит, но сомнительно. Диск выглядит как кастомный.
    Посмотрите на ход коленчатого вала и форму поршней и на то, как они выпирают из блока, а также на форму каналов и камеры сгорания.
    А что за коробка передач была с этим двигателем? И какие передаточные числа?
     
  18. Andy Mestengo New Member

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    why can't I view photos in full screen?
     
  19. TonyB Paid Member Paid Member

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    Hello. It seems to me that if you spin the engine up to 8000 rpm and abruptly drop the clutch, then most likely the box will fall apart (there will be a strong blow). But since the clutch disc is damped, it can and will withstand, but it is doubtful. The disk looks like a custom one.
    Look at the stroke of the crankshaft and the shape of the pistons and how they protrude from the block, as well as the shape of the channels and the combustion chamber.
    What kind of gearbox was with this engine? And what are the gear ratios?


    No, the wheels spin even with sticky slicks as the cars are light, boxes are fine even with solid disc clutches they are fine if you dump the clutch at 8k, but 5 or 6k will be enough. If using an 020 box you must bolt the final drive after removing the standard rivets or that will fail.
    You drop the clutch and you control the wheelspin on the throttle till it all catches up with itself (with a LSD of course), with proper motorsport ratios you have a very long first so that works well and gets some heat in the tyres. If using a std box [gear ratios] with a low diff I used to use second off the line as first becomes too low other wise.
    The disc is a Sachs Motorsport items, std motorsport spec.
    The pistons protrude above the block to get the squish correct, you set this based on what type of gasket you use. The block is decked [machined] to suit the pistons and get this gap correct.
    The piston and chamber pics are to come.
    No idea what box was used, many available though.
     
  20. Andy Mestengo New Member

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    There is an interesting and inexpensive option. Manual transmission with a sports range from the car (VAZ Lada 2108).through the transition plate.7 row​

    main pair 3,5-5,3
    1- 2,92 38/13

    2- 2,05 39/19

    3- 1,56 28/18

    4- 1,31 28/29

    5- 1,13 35/31

    6- 0,94 32/34
    [​IMG]
     
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