Toyotec's how to refit a 16v EA827 crankshaft drive gear and bolt after removal.

Discussion in '16-valve' started by Toyotec, Jul 12, 2013.

  1. Jon Olds Forum Junkie

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    Another thing (as they say..) There is 'slop' (sorry, technical jargon..) on the bottom pulley to crank interface (I think) meaning it is not 100% aligned every time you tighten the thing on. Never understood why. So dowelling is an aid to getting spot on valve timing also.

    On other engines, two I have worked on fairly recently. Type R Civic: You need to buy a 65 tool to get the bottom pulley off (anyone can loan it from me if local) also the delica/shogun diesel pulley (known issues: another story..) you need a 2M steel bar with pegs etc welded on. Both these two were 'outstandingly tight'
     
  2. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    If the bottom cog is new on a 16v motor @ 8mm wide and the crank nose is in good shape, your delta cam advance/retard is around a max of 0.5 deg CA.
    If the locating tab is worn, as I shown in the report above, then up to +/- 2.5 deg CA on a good crank nose. Cam experiments I have done in the past show when the camshaft is adv/retarded from after 2 deg CA, engine's torque curve is affected on a stock engine. In such a circumstance you have the choice of doweling the cog/crank or to just simply replace with new item.

    The main thing is get that bolt tightened properly!
     
  3. RobT

    RobT Forum Junkie

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    You should calibrate any timing marks with a dial gauge on top of piston anyhow, they can be way out.

    Still dont think dowelling is needed if the thing is put together right. Never done it on any of my engines and they work pretty hard.
     
  4. RobT

    RobT Forum Junkie

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    Be interesting to hear from BrianG on this issue of scinteted metal. I seem to recall Brian thought it was ok to dowel? He does seem to know metals well.....
     
  5. Admin Guest

    I was just thinking something similar. Edit, it's the pulley that is sintered, when I drilled mine it was just like drilling mild steel billet!

    And I think most lapping compounds are made with silicone carbide partials which are very hard 9-9.5 (diamond 10) so they should not discentergrate under the clamping pressures and also dig into the crank and bolt nicely.
     
    Last edited by a moderator: Jul 14, 2013
  6. RobT

    RobT Forum Junkie

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    Last edited: Jul 14, 2013
  7. Jon Olds Forum Junkie

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    smart, but out of my price range...........
     
  8. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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  9. RobT

    RobT Forum Junkie

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    Its the kind of thing cgti should buy and loan to members who only pay shipping costs to borrow it, stump the cost as a deposit, use, return undamaged, job done
     
    Toyotec likes this.
  10. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    You are correct that the bolt does not have to be taken off for a cam belt change, however this bolt can be used and is used (rightly or wrongly) as an engine lock for replacing the flywheel or if the oil seal as to be replaced. Once this occurs and the bolt is not tightened with an independent and robust engine lock your clamping force could end up between the threshold I have stated in my report and micro slip of the cog will begin to occur. The bolt does not loosen, but can stretch over time to reduce clamping and cause the slip. However if the OE procedure is followed, there should be no problem over the life of the engine.
    The OEM will not develop a system or a procedure for production that would cause significant expensive warranty claims, or loss of brand loyalty. So systems what we are discussing are put through many hours of DV testing. I am sure manufacturers like Honda would have also done this on many of their VTEC applications that rev as standard to sometimes 8-9K rpm e.g the K20A, B18C, B16B, H22A Etc. I worked and raced many high revving engines like those, before my watercooled VW experience and found no dowels or roll pins. They did have very tight crank damper bolts though and do have to come off for 40-60k mile cambelt changes. The same for engines from Toyota (3SGE IBEAMS, 4AGE 20v), Mitsubishi (6A11, 6A12) and Nissan(SR16/20 VE).
    Let us be clear I am not against dowelling, just that I have not seen a valid reason for it in any of our applications when most of the problems are caused by inappropriate clamping force and as Rob brought up in this discussion the difficulty to tighten the cog for this final 1/4 turn without give.

    All good this discussion though.
     
    Last edited: Jul 14, 2013
  11. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    You are not leaving the valve grinding paste on the surface though! Just using it to break the glaze of the faces.
     
  12. RobT

    RobT Forum Junkie

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    Opportunity for a new CGTI 'officer'/post? Tool Manager.
     
  13. Admin Guest

    The bolt stretches? How? You measured a bolt that had been fully torqued (and then loosened) it was marginally longer than a new bolt. You agreed it was ok to re-use. Surely it loosens, my ABF bolt was very easy to undo compared to my KR block.

    There have been far to many issues reported with this failure to say it has been caursed by people/garages not tightening the bolt in the correct procedure.

    To me it seems clear that the oem procedure is not adequate, (does the Haynes not state 200nm for this bolt instead of the 90nm 90deg? Someone mentioned it the other day - no Haynes to hand to check ATM).

    I personally feel following the OEM 90nm 90deg is not advisable unless you are doing something to stop the bolt losening with a thread locker or the above mentioned valve grinding compound (but surely a thread locking compound is the safer bet bearing in mind it will have been designed and tested thoroughly by the manufacturer).

    Or I feel the bolt should be torqued up tighter, and if required replace with a higher tensile bolt.
     
    Last edited by a moderator: Jul 14, 2013
  14. Admin Guest

    That was not very clear then, trying to work out if leaving the compound on was a good idea, did not think it was. Hence questioning its hardness etc.
     
  15. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    Tom,

    You have you opinions that do not replace the engineering that goes into developing these components, which I can tell you is very intensive and beyond this forum.
    Apologies if I was not clear on the application of the valve paste as I wrongly assumed those on here would know what I was driving at.

    I did not use any Haynes technicals manuals in this research above, not that I need to but to be clear I have all access to most VW reference material - That is one of my sources. I have Haynes too, but not for this work.

    If you assume VAG gave the wrong information in their authorship of the damper bolt tightening procedure, that I have been using on my fleet of vehicles as have others successfully, then you would need to demonstrate why you think they got this wrong for the one or 3 failures we have seen reported on this forum. I am all for questions to be asked, but please think carefully what I am getting at before attempting to question my research or the input I have had in writing this piece of content.

    I have already stated what the clamping force should be if tightened correctly and what it would be if the procedure is not followed.
    Follow that procedure and some of the links given by Rob for tools and there would be no issue over the working life of the engine.

    All my ABF engines to date never had a problem when tightening procedure was carried out be with a Turbo, FEAD driven supercharger, NASP Plenum/ITB, driven on the circuit or straight line, no issues.
     
  16. Admin Guest

    I'm not convinced I'm afraid and I'm not going to hunt around to forum or Internet to demonstrate the various failures. If people are interested or concerned about their pulley and track work they can search themselves.

    My new bolt goes on next week and it will be torqued up tighter, have thread locker applied or a combination of the two. And if it does loosen over time (or stretch as you think) then the three dowel pins will be there to hold it and the thread locker will stop it falling out lol

    Time will tell with these things and I hope for all who follow the VW procedure it holds up to track work. Simply for me I do not trust it and will not take the risk.
     
  17. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    Hey it is fine to disagree based on your opinion or feelings.
    This does not replace the engineering behind VAG group's procedure for tightening the damper bolt or the fact that dowels are not required with a clamping forces over a certain threshold.

    I should also add in your case you would have to tighten you bolt harder to achieve the same clamping force as you have reduce the bolt face by 50% with the cut outs! Lucky indeed to you have dowels to minimise the time to scatter! Loctite is not in the factory procedure either. So you are introducing your own unique error into an established procedure.

    However to save you trouble I am not interested in failures in this thread unless I can post mortem them and I believe I have covered the main reason for this happening.

    All my engines have been fine on track, circuit and drag racing and on road so for every failure (with unknown root cause) I can bring ten that are fine.

    At this time I will bow out of the discussion so thanks for the input guys :thumbup:
     
    Last edited: Jul 14, 2013
  18. RobT

    RobT Forum Junkie

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    Whats the torque setting with threadlock applied?
     
  19. Admin Guest

    You need to read the technical data sheet, can be found online, I'm out and about and don't have the connection to find it ATM. Just walking back to a vineyard out in the sticks.
     
  20. murph81 Forum Member

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