KR head: race cams : pocketing std pistons : some useful info, maybe....

Discussion in '16-valve' started by Jon Olds, Nov 16, 2014.

  1. jamez Forum Member

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    EERRRRRR when building your motor dry as it where i reckon the hyd. lifters have surely somewhat leaked down and reduced there height, presuming you have not converted to run solid lifters.......this would account for not having clearance issues without having the pockets machined, you did after all only try 2 valves...0.5mm can make a huge difference when the motor starts and the lifters pump up (if they have leaked) i suppose to confirm you could rotate the head with valves , cams and lifters and measure actual valve lift from the valve face, if the cams inlet is 11.2mm and the valve moves 10.5.. there is 0.7mm slop that will be taken up on a running motor, this would increase the valve lift during running and render the plasticne "control for interferebce" test on a static engine useless

    Maching the guides and moding the seals sounds dodgy as if it fails and drinks oil your back to stage 1 with a knackerd head
    I would be inclined to measure all of your hyd, lifters and use a measure from the largest or thickest on for calculation purposes, or use a bucket and shims from an 8v dx .
     
  2. Sirguydo

    Sirguydo Fastest milkman in the West Paid Member

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    Just to add a little to the mix been doing a bit more investigation into my engine woes :(
    Can't find my vernier calipers at work so no measuring ATM but my race prepped kr engine is as follows :thumbup:
    Also had some direction off Chris which confirms the following :thumbup:
    Bored 1.8 Kr block ( bore measurements when I find calipers )
    Diesel crank
    Decked and pocketed Pistons of unknown VAG origin currently hope to find out more as could do with another at the very least[8(]
    Will post a couple of pictures of my damaged worked on piston :cry::thumbup:
    [​IMG]
    [​IMG]

    John could you please post some pictures of how you do your measuring as it'll help me understand things better :thumbup:
    My dyslexia makes understanding written explanation difficult but seeing something makes it easy for me :thumbup:
    But understand if you don't want to share to much race prep information ;)
     
    Last edited: Nov 29, 2014
  3. Jon Olds Forum Junkie

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    My lifters are solid not hydraulic.
    Not sure how to upload photos, as I know a photo is worth a thousand words.
    Piston looks like an ABF, distance above top ring looks near standard
    This thread is to share experience and hopefully benefit from the combined wisdom of the members.
    I use a decent quality digital vernier for most of my measuring, which measurement(s) are you interested in?
    Jon
     
  4. Sirguydo

    Sirguydo Fastest milkman in the West Paid Member

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    Photos ? Do you have a smart phone ?
    What do you use to post ? Laptop or tablet ?

    I like to share too as I'm never going to compete and the old trick bits I've acquired are no big secrete nowadays lol

    You seen my modified hubs ?
     
    Last edited: Nov 29, 2014
  5. jamez Forum Member

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    sirguydo the black deposit on the piston is that only baked onto the piston or is damage to the piston, it looks like baked on and burned oil due to excessive hot spot
    as the pockets look small could they be abf with the elevated section milled off? do abf and kr have the same diameter?
    My block some years ago when i was building it up.

    [​IMG]

    [​IMG]

    [​IMG]
     
    Last edited: Nov 29, 2014
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  6. Jon Olds Forum Junkie

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    ABF/9A 82.5 and KR 81mm bore
    Laptop is steam driven thing (Win 7) that currently will not run youtube or open attachments. Haven't a clue why?
    Jon
     
  7. Jon Olds Forum Junkie

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    On reflection modifying the guide top and shortening the stem seals is a bit OTT. Have managed to selectively build the head by measuring everything and choosing parts as sets (length wise), so achieving (hopefully) the most clearance when the cams go in.
    On going...
    Jon
     
  8. Jon Olds Forum Junkie

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    Holy thread revival.
    Added some further input here for a race 8V head I am building now
    The same type of VS39 springs, this time the inner spring platforms are made by me of brass (nicer to work with)
    Interesting points to note;
    The exh guides have a step on them to prevent them being driven too far in, on assembly.
    Meaning the ford lower platforms won't fit. (ID too small, can't be modified easily)
    So Austin Healey lower spring shims used instead. 0.595" ID and 32.5mm OD, probably at least 2 per valve
    The new brass inner spring platform needs boring to match the OD of the guide exh step . (14mm)
    Std 2 piece stem seal still fits. Bit tight, but it fits
    Pictures show the inlet valve end resukt. ford lower platform, as they fit the inlet valve guides (parallel sides)
    So a bit of a mix and match
    Up std upper caps modded to fit the imperial outer springs. (tough as old boots, about 1mm off the cap ID)
    If any of this makes sense to anyone..
    Jon
    Think it should all be ok.
    Now where's that GS6 cam...
    ford springs into vw 1.JPG ford springs into vw 2.JPG ford springs into vw 3.JPG ford springs into vw 4.JPG ford springs into vw 5.JPG
     
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  9. boroko

    boroko Paid Member Paid Member

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    I am thankful that this is out there, complete with pictures intact.
     
  10. Jon Olds Forum Junkie

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    Good site to share experience. Also useful for me to refer back to, as I have a shocking memory, LOL...
    Jon
     
  11. boroko

    boroko Paid Member Paid Member

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    Sometimes my memory is like that of a fruit fly, so I have to make notes to myself to have any hope of keeping it, so I understand. I'm in the US, and it seems that is so much more info from your side of the pond. 30 years ago I circle tracked a (real) Beetle. Now that everyone is grown, I'm playing again. I stage rally a mk2 Golf with an ABA, and collecting shiny parts to build one into a clone ABF. I have a KR sitting in the shop, but a ABF would be fun. FB is useless and has no persistence, and finding people doing good in depth engine work is becoming rare. More-so on an older platform. I love what I can learn here. Please keep it up. It is oh so pleasing to shame latest and greatest platforms with a 35+ year old car....
    bo
     
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