8v feels flat & exhaust pop

Discussion in '8-valve' started by jmsheahan, Jun 8, 2010.

  1. jmsheahan CGTI Graphics Designer

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    I recently got my mk2 8v back from the garage after having a cylinder head replaced. I also had a stainless Jetex exhaust installed.

    Basically the car feels a bit flat through the rev range, runs quite hot but most annoyingly judders in 4th and 5th intermittently. In addition the exhaust pops on downshift which is quite embarassing, despite it sounding like a group b rally car:lol:

    Is this a trait of stainless systems or is the timing slightly out or something?
     
  2. Mike_H Forum Addict

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    They've either got the cam timing or the ignition timing wrong, I'd say. It's also possible that they've left a vac line off the FPR or inlet manifold.
     
  3. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    Maybe both. I would say the cam is retarded by 2 teeth or so. Get it sorted and it will have the WORLD full of torque!
     
  4. jmsheahan CGTI Graphics Designer

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    Cheers. Hopefully not the cam timing. It still pulls and idles ok just feels flat. The vacuum lines were replaced so I guess that could be a possibility. Back it goes then, I'm stuck With it until Monday:thumbd:
     
  5. Mike_H Forum Addict

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    Take the top belt cover off and check the position of the cam pulley against the flywheel TDC mark, or even against the one on the bottom pulley (flywheel is more accurate though). It's not difficult. If cam timing is out, then they'll have to re-do the ignition timing when they fix it. You'll have more of a chance of them fixing it if you can demonstrate to the muppets what's wrong - then they won't think they can fob you off with an excuse.
     
  6. jmsheahan CGTI Graphics Designer

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    Cheers Mike, I shall look when it stops raining. To be honest I'd be surprised if they'd have neglected the cam timing - they are usually pretty good in there and the guy who did the work is a mk2 nut.

    Even so, something isn't right. I just hope it's as simple as ignition timing. The car still drives ok, just not hugely quick (no 8v jokes please) and as I say sounds like a bloody group B rally car on downshifts :lol:
     
  7. Mike_H Forum Addict

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    It sounds a lot like cam timing to me. Everyone has an off day, or a day when they're being rushed by the boss.
     
  8. jmsheahan CGTI Graphics Designer

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    Please excuse my ignorance but to sort that will it be a fairly large job i.e require the removal of the belt and everything again?
     
  9. 50ftdubdemon Forum Member

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    could be theyve mistaken 6deg btdc for tdc mark? also whilst youve got tdc lined up on flywheel to check cam timing, take dizzy cap off and check rotor arm points to line on face of dizzy body (and that plug lead at this position goes to no1 cyl)
     
  10. 50ftdubdemon Forum Member

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    pretty sure the bottom pulley/bottom cover/belt can all stay on. once youve got the top cover off have a look and see if you can access the tensioner (sat directly below cam sprocket). if you can then you should be able to slacken off the tensioner, slip the belt off the cam sprocket and turn to correct position.. ie half hr job.

    if intermediate shaft is out of position (rotor arm lining up with mark on dizzy) then you gotta take bottom cover off.. which means removing bottom pulley ie whole job again. alternatively you could just turn dizzy body till it lines up but bit of a bodge!
     
  11. Mike_H Forum Addict

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    Given the dizzy is the wrong way round, they should do really.

    You don't have to take it all off to check it though.
     
  12. jmsheahan CGTI Graphics Designer

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    Right I haven't had a chance to look at the cam timing yet as I'm away from the car but I've just spoken to the garage. They are adamant the cam timing is correct otherwise the car wouldn't run.

    So they they've offered to look at the ignition timing again. This is proving to be a headache - he says there may have been something wrong with the head as I supplied it
     
  13. Mike_H Forum Addict

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    Bull. They're fobbing you off. It would have to be out by several teeth to stop it from running.
     
  14. jmsheahan CGTI Graphics Designer

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    Right, cheers Mike, well it's going back on Friday and then after that time to find a new garage I think :thumbd: I need a mk2 guru in Wiltshire or Cardiff:lol:
     
  15. Mike_H Forum Addict

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    Get your head under the bonnet and have a look. 10 minutes of effort could save you a fortune.
     
  16. jmsheahan CGTI Graphics Designer

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    Cheers for the help. Was indeed the ignition timing. Cam timing was fine. Much better now performance wise although I do still get the odd exhaust pop when hot on downshift - guess that could just be the exhaust.

    My oil temps are still quite high though unfortunately - could this be down to all the new parts in the cylinder head?
     
  17. danster Forum Addict

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    Good that it is fixed.:thumbup:
    Just another bunch of amateurs in that garage then? You really cannot get a much simpler job on any car, as the 8v is so basic and there is plenty of room to work on it.
    A fookin haynes manual must be like rocket science to those spanner monkeys.

    I am actually going to do an 8v timing belt blindfolded to prove a point one of these days.
     
  18. 50ftdubdemon Forum Member

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    what temps you getting? did they fit head as is or recon it? might be probs if they swapped bits over from your old head
     
  19. jmsheahan CGTI Graphics Designer

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    Runs at 106 most of the time but upto 112 odd.

    It's a genuine head professionally refurbished elsewhere by a specialist - not by the garage that fitted the head. Only thing used from old cylinder head was the camshaft.
     
  20. Mike_H Forum Addict

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    No - is that another line of bull from your garage?

    High oil temps would suggest timing or mixture - timing too advanced, or maybe running a bit lean? That temp range is a little bit high, but in this weather, it's going to run a little bit warmer. Is that in motorway driving / back roads, or stuck in a jam? If you want to spend your life being ripped off, take it back to your pet garage. Otherwise, get your head under the bonnet and have a look.

    Is the water temp a bit high too, or just the oil temps? Don't forget to check the coolant looks ok, that the bottom hose is getting hot once the car is up to temperature, etc.
     

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