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Thread: RS Aizawa ITB 1.6 - valve stem seals - improvements while in the head ?

  1. #16
    Ninja Messiah kung fu jesus's Avatar
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    RS Aizawa ITB 1.6 - valve stem seals - improvements while in the head ?

    Probably the biggest needs for doing valvetrain stuff is a spring compressor, a clean work surface, abundant lighting, and organizers, cups, or trays to keep components together.

    The first time I did a head reassembly was at a kitchen table. It surprised me how smoothly everything fit together.

  2. #17
    3,000 rpm - starting to feel the power atlex's Avatar
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    272 9mm Lift I/E cams from Toda arrive this coming new week.

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    HarryB (11-08-2021),kung fu jesus (11-07-2021)

  4. #18
    Ninja Messiah kung fu jesus's Avatar
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    Should be rowdy but still streetable. What engine management are you using? Plans for indexing?

  5. #19
    3,000 rpm - starting to feel the power atlex's Avatar
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    Quote Originally Posted by kung fu jesus View Post
    Should be rowdy but still streetable. What engine management are you using? Plans for indexing?
    Currently: ME221
    Link G4X is waiting here in the box, though :-)

    Indexing is on the cards. I've got the Maruha adjustable gears.

    There's also a Finnish chap who published a goldmine of research on this subject... with the same spec cams.

    https://mymazdamx-5.blogspot.com/201...specs-and.html

  6. #20
    3,000 rpm - starting to feel the power atlex's Avatar
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    HarryB (11-09-2021)

  8. #21
    3,000 rpm - starting to feel the power atlex's Avatar
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    They're in and spinning freely

    Wouldn't want to run much more lift on this head without relieving the exit and entry path around the bucket orifices.

    I've measured the gap without any shims in yet so I know what to order.

    Those boring numbers are over @ http://www.mighty5s.com/thread/964/a...b-built-thread

    The good news is that the gaps (minus the 0.2 or 0.25 mm lash spec) are all OVER 1mm so I can easily order the lash caps without worrying about grinding them down.

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    HarryB (11-14-2021)

  10. #22
    3,000 rpm - starting to feel the power atlex's Avatar
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    Just wanted to say that dealing with Cat Cams directly in Europe is a pleasure.

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    HarryB (11-19-2021)

  12. #23
    3,000 rpm - starting to feel the power atlex's Avatar
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    I've been doing the lash adjustment and I've two 'direct' specs to work with:

    Toda's spec from the cam spec sheet:
    IN: 0.20mm
    EX: 0.25mm

    Mazda's NB2 Solid spec per
    IN: 0.21±0.03 mm
    EX: 0.31±0.03 mm

    ( https://trull.org/~alex/pubmirror/ww...e_overhaul.pdf )

    As such I've got the intake valves to 0.19 or 0.20mm - and I'm really happy with that.

    I'm now redoing up the exhaust valve setup since one was a bit tighter than it ought to be. 0.24mm on one valve - the rest were 0.26. To address the 0.24mm I'll end up taking it closer to the range of the Mazda spec. And I'll treat the Toda 0.25mm as the safe minimum. But for exhaust this seems sensible.

    Lash Caps - Tip of the Valve Stem or Tip of the Bucket Post ? Well now...

    Supermiata and/or Bill@MiataRoadster suggested the best way to go with the MMD buckets was with 6mm supertech lash caps upside down, the post of the bucket being 5.57mm but I ordered lashcaps from Cat Cams, which only have a 2.5mm skirt and it turns out that with the NB keepers in for the supertech TI retainers, there's legitimately enough clearance to install the lash caps 'normally' on the valve tip. 3.1mm of clearance between tip and top of the keepers with 2.5mm of skirt on the lash caps. Seems the better way to do it. Also no more lash cap randomly pulling out with the bucket, or weird greased lash cap installs.

    I'll get to the intake cam, invert the caps, .. measure clearance all over again, and then retime her ,etc.

    My only real opponents are wind, rain and time. Mostly wind though.

    On a side note..

    In my research on valve stems and temperature/expansion coefficients and other similar engines I've found loads of different specs. here are some interesting ones:

    A 4age spec that was I: 0.15-0.25mm E 0.20mm-0.30mm - but the valves of the 4age are a bit shorter than the B6 or BP.
    zz2 have very similar valve lengths to the B6/BP (5mm difference max) and I: 0.08-0.18mm and E: 0.22-0.32mm specified.

    Effectively, the shorter the valve stem the tighter the clearance can be, but it mostly matters for the exhaust side.

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    kung fu jesus (12-07-2021)

  14. #24
    3,000 rpm - starting to feel the power atlex's Avatar
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    It runs!

    https://www.instagram.com/p/CXMBSu7AVGP/

    Let the fuel pump run to cycle out the old fuel from the lines.

    Plugged the laptop in to get a log.

    This was one of the quickest startups I ever had with the car.

    No Smoking. Not noisy. Rich Cold Startup as usual.

    At the end I let it idle without any throttle for one minute and it was happy to sit at 1100 with 14 AFR.

    I've ordered some new cam belt covers and idlers to address an issue with the front (the belt seems to be coming too far forward and the old covers look rough)

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  16. #25
    3,000 rpm - starting to feel the power atlex's Avatar
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    News on this.

    The VE table tuning is now in its 8th iteration.

    I've been to 7800 RPM now in the map. It's pulling golden. The 7K+ region is less mushy with the solid lifters in. Even with a load of ign adv removed it's fun up there.

    Now to circle back to the original smoking problem. Evidently, it wasn't valve seals but rather piston rings. But as of today's tuning and thrashing session I may have actually cured it. I can't quite believe I have. But my car just stopped smoking out the rear as of the last 10 pulls of the run. It's been using less and less oil each day I've run it.

    Multi-day Method documented here: https://mighty5s.com/thread/3918/smo...le-stuck-rings

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    HarryB (12-21-2021)

  18. #26
    6,000 rpm - mere mortals would shift HarryB's Avatar
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    You might have actually cured it. I have experienced instances when this has been cured by hard running an engine in a small motorbike; piston rings need pressure to properly seat.

  19. #27
    3,000 rpm - starting to feel the power atlex's Avatar
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    Quote Originally Posted by HarryB View Post
    You might have actually cured it. I have experienced instances when this has been cured by hard running an engine in a small motorbike; piston rings need pressure to properly seat.
    I'm about to get it back from the body shop and I'm re-visiting this now.

    looking at a more aggressive process, after doing some research and thinking. wishful thinking ? perhaps. I'm ready to try some things.

    Get the cylinders to the point of the start of the compression stroke - so we can build pressure in the cylinder.

    take a mixture of acetone and toluene/xylene (both are in gasoline as octane boosters, and they are in universal disolvent/synthetic paint thinners)

    first let it soak a bit, then force the mixture past the rings using pressure. [ a modified compression tester hose and attach that to a pressure source (er... tyre pressure pump!) ]

    keep forcing fresh mixture past the rings so that whatever varnish/deposits are really and ideally liquified and ready to be ejected...

    put in fresh thicker oil (5w50? 10w50?) with a small % of kerosene and naptha .. effectively, MMO or redex. - thicker oil to maintain a sensible weight and lubrication.

    go out and drive it, quite hard. at one point in december/november I nearly thought I had it sussed as it wasn't smoking at all on over run coming down from 8k, but it didn't last heh. and then the sheep got me.

    I think I'll need to extend the hard driving part. Maybe take it somewhere fun. I've got plenty of hills to do that with.

    p.s. yes, I know I'll need to be careful with these chemicals. my health and all that new paint lol.

  20. #28
    6,000 rpm - mere mortals would shift HarryB's Avatar
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    And the bottom end bearings too; they need proper lubrication.

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    atlex (08-31-2022)

  22. #29
    3,000 rpm - starting to feel the power atlex's Avatar
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    ^ Thanks for the reminder Harry

    I'm planning on not rotating the engine significantly while I do this, as I don't want any of this mix coming through the oil pump.

    I'll get the chamber to the compression phase and then put it in 5th / handbrake up.

    I'll finish each cylinder with a teaspoon of real oil to bore before letting the engine turn.

  23. #30
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    RS Aizawa ITB 1.6 - valve stem seals - improvements while in the head ?

    Have you scoped the bores?

    Also are you running a catch can? I have used cans to monitor blowby. Sometimes the PVC system just doesn’t work like it should and can offer paths to diagnosis.

    Driving in heavy vacuum can help free the rings after your treatment.

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