"Bubble Block" Build...

Discussion in '8-valve' started by wfarrell, Feb 22, 2012.

  1. wfarrell Forum Member

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    Hello all,

    Thought i should finally share a few pictures from my Golf/Audi 3A "Bubble Block" engine build. I'll be adding more posts over the next week or so (please bear with me - not an IT blogging whizz-kid ;)

    Cheers, Will
     
    Last edited: Feb 22, 2012
  2. wfarrell Forum Member

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    the block arrives....

    The idea of building the engine started about four years ago after I purchased a Passat estate from a certain Mr Tim Stiles (as in the original TSR -- now happily retired in central France). The Passat was somewhat knackered, but it did have a very nice TSR "big valve" 2.1 8V engine, with a 2E bottom "tall block" end (with Diesel crank etc).

    After breaking the Passat for parts, i set about planning an engine for a future mk2 project. Having always loved Supersprint 4:2:1 exhaust systems -- the desire to fit a Supersprint exhaust manifold meant a "short block" was required (to enable the manifold to fit the mk2 body). Rather than bore out a PB block, the decision was made to search for an Audi 3A block. This would provide a 2.0 litre bottom end in a short block package. Plus the 3A has piston oil squirters - good for cooling, which is niceā€¦

    After much hunting on ebay/forums/scrapyards, a very tired 3A bottom end was located and purchased. Thankfully the critical surfaces (bearings, sealing, cylinders) were all in fair or serviceable condition. The project was now on !!

    Here's the raw "bubble" block with it's original 82.5mm bore sitting on a rather untidy workbench:

    [​IMG]

    [​IMG]
     
    Last edited: Feb 22, 2012
  3. wfarrell Forum Member

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    Off to the machine shop...

    The next job was to take the bore out to 83.5mm (to fit an Autotech/JE piston kit purchased the prior week), and skim the block top face to ensure good gasket sealing.

    The machining work was carried out by an excellent local firm called Benchsound (managed by a gentleman called Ray - great bloke :-)

    Benchsound in Stanford-le-Hope:

    [​IMG]

    After a couple of days the block was ready for collection and back on the workbench with 83.5mm bores, a perfect skimmed top top face (-7 thou), and thoroughly cleaned thanks to being submerged in Benchsound's hot cleaner tank. Nice!

    [​IMG]

    [​IMG]

    The keen-eyed will spot the machinist managed to skim the gasket dowels too ! I sourced a pair of new dowels from the local VAG dealer for later fitment (to ensure perfect gasket alignment with the bigger bores).

    All ready for painting :-)
     
  4. wfarrell Forum Member

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    Paint - Carplan Blue

    The block now deserved a suitable paint. Due to the cylinder head link with old-school TSR, the colour choice was to be the familiar Carplan blue:

    [​IMG]


    The block outer surfaces were degreased with thinners, and two coats of the enamel paint were applied to the relevant surfaces....

    [​IMG]

    [​IMG]


    Looking pretty :-)
     
  5. wfarrell Forum Member

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    Engine Stand

    Onto the next stage. A new Clarke engine stand was purchased from Machine Mart. My house was in a state of extreme DIY at the time, so with winter looming the decision was made to build the engine in the house, rather than a freezing cold garage.

    Rather than mount the engine "end-on" to the stand, I wanted to mount the engine "side-on" to enable the fitment of the clutch assembly etc whilst on the stand. My good friend and gifted engineer Rob Russell (who runs www.bornagaincars.com in his spare time), offered to construct a jig that would enable side-on mounting. Pics below:

    [​IMG]

    [​IMG]


    So now with the block all machined and painted, the next stage was to refresh the cylinder head and valvetrain. Stay tuned for the next post - cheers :-)

    Will
     
    Last edited: Feb 22, 2012
  6. mr hillclimber Club GTI Supporter and Sponsor

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    Looking good...:thumbup:

    No doubt you hav'nt but don't forget the pistons may need a similar amount taken off them to allow for the block skim..depending how far the squish band protrudes.
     
  7. Haze Paid Member Paid Member

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    Looking nice done this myself :)
     
  8. Lee21 New Member

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    Hi,
    I have just bought a bubble block that I am going to drop into my wifes mk1 GTI cabriolet. I will be putting a slightly re-worked GTI engineering 8V head with 276deg cam which was part of the GTI engineering 1900RE upgrade. My question is regarding the dizzy are you using the 3A or the original from your engine and modifying the gearing? if you are using the original what are you doing about the the timing advance are you installing a knock sensor Also what are you doing regarding the blocking the old audi breather inlets on the block. I have seen on various forums that a kit was available to do this with a freeze plug and a plate. Any advice from anyone would be gatefully received. cheers
     
  9. Haze Paid Member Paid Member

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    original dizzy with 3A gear, blanking plate from tsr
     
  10. rubjonny

    rubjonny Administrator Staff Member Admin

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    the extra plate and freeze plug is to block off the breather on the front, I dont recommend you do that instead plumb it into the breather on the head. the 2.0 blocks can breathe a bit heavy, this is why vw fitted the extra block breather. plus its cheaper as you dont need to buy the block off kit ;)
     
  11. TSR 2.1 Forum Member

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    My TSR unit has this block off plate fitted, from TSR. I may well see about running it as you suggest. As I have a few spare units kicking about.
     
  12. rubjonny

    rubjonny Administrator Staff Member Admin

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    if its not breathing heavily then no worries, but some do :)
     
  13. rubjonny

    rubjonny Administrator Staff Member Admin

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    thinking about it maybe its only a problem on later injection system, as the 2.0 block has a PCV valve in the rocker cover breather, the block breather bypasses the valve to breathe direct into the inlet. on the k-jet engines there is no valve so you may not require the block breather?
     
  14. TSR 2.1 Forum Member

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    Ah yes my one is a later 'J' reg one. But I might just give it a shot to see if it helps
     
  15. rubjonny

    rubjonny Administrator Staff Member Admin

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    if its running ok at the moment then i wouldn't worry about it chap, its just a case of if you're building another one i wouldn't bother with the block off plate as its extra expense :)
     
  16. wfarrell Forum Member

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    Guys - after a long long wait, here's a pictorial update of my Bubble Block engine build and install, hope you enjoy the pics

    Cheers, Will

    1. Steel crank sourced from Germany -- taken from a Passat the journals were in perfect condition
    [​IMG]

    2. Schrick 268 cam -- deliberately mild profile to fatten up the mid-range and hopefully give a nice responsive drive and stable idle etc
    [​IMG]

    3. Set of standard con-rods from PB lump -- ARP bolts fitted, rods were subsequently lightened and balanced together with the cranks, pulleys etc
    [​IMG]

    4. JE 83.5mm pistons -- it was really difficult to source pistons for the 3A block (has oil squirters) - thankfully Autotech Tuning from San Francisco offer this excellent kit with ring pack, pins, etc
    [​IMG]

    5. Here's the nucleus of the whole project - a TSR Pack C big valve digi head purchased direct from Tim himself in central France (came with a free Passat GT wagon attached!!)
    [​IMG]

    6. and now fitted with new Ferrera valve set supplied by TSR, together with Schrick valve springs and Ti retainers supplied by Bar-Tek
    [​IMG]

    7. Botton end build in progress with crank, rods, pistons, intermediate shaft, blanking plates, Schrick sump and G60/PG oil pump all in place
    [​IMG]

    8. a quick peek down the bore - pistons should give a 10.5 CR when flush with deck (pistons stand just a couple of thou proud of the deck at TDC)
    [​IMG]

    9. MLS head gasket fitted - opted for a 83.5mm ABA item; machine shop had dome a great job on the rebore - perfect alignment to bore circumference
    [​IMG]

    10. And now with the head in place - ARP under-cut studs torqued to spec (very nice fastener to install)
    [​IMG]

    11. Almost complete on the stand with mk3 ancillaries fitted ...now where is that gearbox?
    [​IMG]

    12. 020 8V gearbox overhauld/refurbed with new bearing, synchs, seals etc plus a Quaife diff which should enhance both traction and handling
    [​IMG]

    13. Engine and 'box together at last !
    [​IMG]

    14. So after five years (!) my mk2 finally has an engine back under it's bonnet (also refurbed the subframes, new mounts, brake lines, servo etc etc)
    [​IMG]

    15. and finally for now, Supersprint 4:2:1 manifold being fitted (had it "Zirco-coated" and aramid wrapped -- just to be sure of manageable temperature around the steering boot)
    [​IMG]
     
    Last edited: Aug 18, 2013
  17. Brookster

    Brookster Paid Member Paid Member

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    Cast Steel Crank you mean ?? ;)

    Forged Crank Standard 92.8mm stroke
    [​IMG]

    Cast Crank Standard 95.5mm stroke i think ?
    [​IMG]

    Billet Steel Eurospec Race Crank 92.8mm stroke
    [​IMG]
     
    Last edited: Aug 18, 2013
  18. wfarrell Forum Member

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