my 8v digi woes

Discussion in '8-valve' started by 8vDUB, May 26, 2010.

  1. 50ftdubdemon Forum Member

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    think hes setting tdc with flywheel tho.. so crank pulley mark shouldnt matter?
     
  2. danster Forum Addict

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    In a perfect world, yes, but as I state previously the crank timing belt pulley has a small keyway to locate it on the crank and these commonly have damage causing the part to not be orientated correctly.
    1 : 2 reduction from the crank to cam, so 1/2 a tooth out at the crank makes 1 tooth out at the cam.
    I got a pile of goosed bottom pulleys off 8v engines in the shed. (about 10) saving them to make into some artwork! :thumbup:
     
  3. 8vDUB Forum Member

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    my thoughts to, and danny, they line up fine
     
  4. 50ftdubdemon Forum Member

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    but if the flywheel is sayin tdc then surely no1 piston is def at tdc. and if hes got cam set with original pulley lined up to head face, then cam overlap has to be correct in relation to crank. in which case isnt position of pulley on crank is irrelavent (unless its slipping about) ?? very possible im being real think here.. just trying to clear it up for my own sake [:$]
     
  5. danster Forum Addict

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    I know it is a bit tricky to get your head around.
    I agree entirely that the piston will be at TDC if the flywheel mark is set correctly.
    However, the drive to the cam via the timing belt is taken off the other end of the crank. If the crank pulley is not quite orientated correctly (rotated a small amount due to damage). It will then throw out the std timing belt marks on the cam pulley against the head, as the belt always has to sit with the teeth meshed on the pulley.
    It should be possible to still set up equal overlap with the vernier pulley though, as this will be able to compensate for any misalignment (if there is any).
    It is misleading to then say that the timing marks are out, or the cam is advanced or retarded based on the verniers measuring increments positions.
     
  6. 8vDUB Forum Member

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    tdc i measured on piston no1 aswell, long screwdriver till it stopped moving them guessed the centre by how far it went before it started dropping, so not properly techniclly but im still sure its right.

    when i put it on the standard pully marks the car was so flat its unreal. and the first picture i put up shows how the cam sat at standard marks, second is equal overlap, 1.5 teeth between the two.

    as it is now, i advanced it half a tooth as it didnt feel to quick, but now im getting this noise, its not masivly faster.

    and its not slipping nowhere...
     
  7. 8vDUB Forum Member

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    also to confirm again. if i put my standard pulley on, i can line the inside dot up with the head, and the flywheel up to the pointer, and now the dampener pulley to the timing cover. and the outside dot with the outer cover.

    cam sits as in picture 1 of cam on page 3. on standard pulley marks.
     
    Last edited: Jun 23, 2010
  8. 50ftdubdemon Forum Member

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    ahhh! so worn crank pulley can throw a standard cam pulley out by half a tooth either way.. as theres only +-1 tooth adjustment (cue sound of penny dropping from great height) :thumbup: like you say really needs cam/ign timing to be completey as it was when leaving factory before theres any chance of sussing whatever underlying prob might be
     
  9. 50ftdubdemon Forum Member

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    so did you get dodgy noise when it was all set standard?
     
  10. 8vDUB Forum Member

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    not as much, the occasional one ping here and there, but it didnt get as hot as normal
     
  11. 8vDUB Forum Member

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    i keep getting told, equal overlap, because its a different cam, because its not standard etc, in all my posts i get told put to equal overlap.

    il try setting it up again on the standard pulley, rest everything and see what happens then
     
  12. danster Forum Addict

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    It is tricky to tell from that pic but it does appear to show the cam advanced a fair bit.
    This could just be down the machining of the keyway in the cam.
    Most cams actually come with a setting point in deg. eg 108deg. This means full inlet valve lift should occur once the crank has rotated 108 deg past TDC.
    It could be the specs on this cam require it to be set at a very specific place. As the head is a mech tappet type, the cam would never have been designed to run on digipants injection.
    It is a TSR 103? Isn't it. That is quite a "lively" profile and may be aggravating idle and setup a little. I would have thought that cam would require a modded ecu to run correctly.
     
  13. 8vDUB Forum Member

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    it is a 103 yes. tsr did actully say via email before that it should go on standard setting till rolling road, but when i put that up i got told' dont listen to them, they dont make the cam, set it to equal overlap.
    this is where the confusion is going. if i can get a difinitive answer to where it should go, and run right, i can set it to that then work around it.

    but all my posts on here at tsr have gone ignored.

    but idle is ok, it runs ok at some points but it causes other things to feel wrong.

    i cant see how the head can cause any probloms but i understand its cut for mfi not efi, but iv been assured its ran fine in another car with no reason to doubt. and as can be seen. its all pretty new inside.

    his car was mint and this only came out for 20v to go in, he ran a standard ecu because he fried the chipped one he got with it, and had no probloms..
     
  14. 8vDUB Forum Member

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    dont really fancy advancing this cam a whole tooth incase it pinks worst thinking about it, if its pinking where it is now...
     
  15. chrismc Forum Junkie

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    A fast road 8v cam, like a stock item, SHOULD give it's best performance at (or very close to) an equal lift on overlap position. All things being equal, the cam should line up nicely using a stock cam pulley...

    As has been said by danster though, it's a fairly wild profile, and, being solid lifter, not normally used with digifant management. As such, idle quality may not be very good, thus it is difficult to accurately set fuelling and timing because the idle is unsteady....
     
  16. 8vDUB Forum Member

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    idle is not a problom at the momnt wherever it sits, since my new coil it idles very well really, the 4 branch makes it sound a little differant though.

    but i can set the idle a co no problom, just cant raise it from the preset one out of set up mode.
    would like to idle at 1000 but i have no probloms with it running at 850.

    il try it on standard settings agian though,
     
  17. 8vDUB Forum Member

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    but as said and shown, its not equal by any means on the standard mark
     
  18. 8vDUB Forum Member

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    iv had some progress guys. i took my pulley off again today as i wanted to make a good solid mark to match the standard pulley mark. well...... i lined them up, put a screwdiver in to line up the keyway, nudge one pulley forward slightly to check the marks, and they were both inline with eachother:o ihad to check a few times, but no lie, they both lined up.

    so id like to make a huge apoligy to everyone helping on the tread for all the confusion,
    and again says thanks for sticking with me.:thumbup:
    and how much of a dick to i feel, dont know why im admiting the problom but il take all the insults on the chin,lol, teach me a lesson[8(]
    [:$][:$][:$]
    ok, so i never had my co meter or timing light at work, and the only time i havnt the rotor arm moved, so i set the arm, on the mark i made for 6* against the notch, should have been close atleast,
    but i got the noise alot worse on the way home,and an oil temperature of 122* [:s]. id say its definitly pinking, but was knocking aswell, so i was very worried sat in traffic on the A4. pulled in and retarded the ignition abit, or so i thought.
    pulled out and the car was flying, atleast more than it was,lol. and no pinking.

    got home, got my gear out, timing was on tdc:o, but the mark was bang on steady.
    so i advanced it up, as i got closer to 6* the mark became more blurry, to the point i could just see it, but its there.

    co meter out, blocked pcv pipe to tb. turned the valve away from the airbox, and raised the dipstick.

    and now my co reading was3.4. and was the lowest it would go. this is after a 3 notch adjustmant on a fairly new afm, so i popped the lid of the afm and put it back 1 notch, and the co went to nearly nothing. so i had to wind the screw what looks like really far in to get to 2%.

    so now, im on standard marks for valve timing, 6* btdc ignition timing, and 2% co. great.

    plugged my pcv hose back on to see what difference it makes. and the co dropped down to .60. pulled my pcv bung out and my 2month old rocker bung has cut in by the cover, im guessing thats leaking. great.

    put everything away to realise the dipstick was still up, so that might not of helped.

    but idle is even lower now, after i finally set it to 1000rpm beforeing revving 3 times and plugging the sensor back on.
    so idle is 750 ish now.
    so my guess is maybe the pipes and bung are leaking, il have to replace them.

    i also realised the reason digi is put into setup mode is to cancel out all the controlling factors to get base:thumbup:

    so after this 30 min break to write this im going to take it for a quick run down the road and see how it feels.

    whilst im here what does everone else do about the icv hoses if they are discontinued??


    again.. i want to apoligise to all contributers.
    and big thanks for the help:thumbup::thumbup:
     
  19. 8vDUB Forum Member

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    lol, sorry, that looks like a s,a :)
     
  20. 50ftdubdemon Forum Member

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    :lol: easy done.. seen far worse by people claiming to be professionals! (who, by the way, rarely own up)

    had same prob with my rocker bung.. v fragile and dont like being disturbed which tends to happen when your doing lots of setups. will obviously throw co reading and idle out tho so should be bit more to come with regards fueling once thats sorted

    so does it look to have equal overlap now? you said timing mark went blurry, you holding a steady 2.25k? wouldnt worry too much mine dances about a bit aswell
     

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