Another Type 4 1800 AP Engine Project (going 1911cc now 1971cc now 1992cc finally 2056cc)

Discussion in 'Restorations' started by Deefer66, Sep 5, 2019.

  1. Cylinders

    Also made a start on fitting rings..

    href="http://thelatebay.com/index.php?threads/piston-ring-gap.85638/">Piston Ring Gap<


    Before realising perhaps I should check cylinders first...

    So looking at Bentley..

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    Measure new pistons (Ebay bargain!) At 95.95 as on the tin..

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    Found clearances to be a bit snug so spent a day carefully honing cylinders and measuring... and honing....and measuring etc.., to get as close to 0.05mm clearance all round as possible..

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    So now st least they slide nicely with an oil ring in place to go through deck height procedure.....

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    Last edited: Jan 10, 2020
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  2. Deck Height


    As I'm early in the build and to get stuff ordered I set up block with my crank in place with bearings (both ends) and put on a con rod and piston ( with the bottom oil rings only on to make t easier to move but still hold piston in the right place) and a cylinder.

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    Clamped on homemade deck tool.. an aluminium plate with holes to mat h cylinder rim and steel tube spacers to be able to bolt it down hung head studs. I set up dial guage and set to top dead centre for that cylinder..

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    I measured step off edge of cylinder down to piston at top bottom and both sides.. both sides above gideon pin probably most important as in line with pin but wanted to make sure there wasn't much rocking going on.

    I got about 1mm which would be good but would make my compression ratio too high so..

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    ..will probably add a .25 shim and open up chambers to get compression ratio down and keep deck height quite low. VW say up to 1,5mm is ok

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    Last edited: Jan 25, 2020
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  3. 0.05mm clearance should be fine, the 1990 VW Technical Bulletin increased the piston/cylinder clearance from 0.03mm ± 0.008mm to 0.045mm ± 0.005mm.
     
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  4. That sounds good to me.:thumbsup:
     
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  5. Combustion Chamber Measuring

    So after finding stock 2 ltr pistons with their deeper dishes 10 -15cc combined with 1800 heads and their bigger combustion chambers (because 1800 pistons have shallower dishes, 5cc, I guess...) I sourced some ebay 96mm AA pistons advertised as 7cc valve pockets and got the cylinders opened up in the machine shop.

    1800 heads usually have chambers about 56 to 58 cc so having the deck cleaned in the shop to take 0.5 to .75 to take them back to a good dealing surface should have knocked about 6cc off the chamber. However, when measured when they came back they were at 48cc and CR would be bit high for the Webcam 73/86 I chose.

    So I've been opening out chamber and remeasuring with the cut out perspex and syringe. But I have found weighing the syringe on the 0.1g scale a bit more accurate than reading the marks on the syringe.

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    Adjusted them all to get an evenaccross the board

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    Last edited: Jul 4, 2020
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  6. Now just to re-clean everything finish off those pistons rings and put it together....

    Oh and build the heads up and bring the rockers a bit to fit swivel feet

    .. and refurbish the carbs ...

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  7. Cylinder to Head Clearance

    Other jobs I forgot that got done. ...

    Taking 0.75mm out of the head made the shoulder of the cylinder hit the head before the base for part of it by a tenth or two (mm that is...)

    Took a good old fashioned metal file to the cylinder

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    and a finger file/sander to the head

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    Should get some air to flow through the gap now

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    Last edited: Jan 10, 2020
  8. Connecting Rods

    Added the Tech Note oil splash groove with a 3mm chainsaw file...

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    And weighed and adjusted con rods

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    Last edited: Jan 8, 2020
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  9. Crank Distributor Drive Gear

    And stripped the old drive gear off the 1800 crank

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    Don't forget the snap ring before you start pulling... or you snap your puller... doh!

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    Cook the rings on a skillet

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    That's the distributor drive cog on there the cam drive takes a bit longer to cook but get it good and hot and it slides right on... wear welding gloves get everything ready and clean and woodruff ket in and flat

    And replace in the order they came off keeping dots on the outside


    And make sure the snap ring sits in its groove properly

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    Last edited: Jan 7, 2020
  10. Re cleaned

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    Re bagged bits

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    Bit snug for space down the end of the garage..

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  11. How did you check the main bearings with plastigage other than the split bearing? Thanks
     
  12. Can only plastiguage the split main the rest were the big ends.. could try with a bore micrometer inside the shells and measure the crank if you really want to

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  13. But only once the bearings are in the crankcase and torqued up.
     
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  14. Thank you. That’s what I figured. The red plastigage threw me off. Nice tidy build by the way. I am in the midst of an 1800 rebuild/refresh...my third attempt. The engine was running well but a long list of should haves and taking care of small issues before they become big ones. I’m spending a lot more time measuring and getting the details right.

    Thank you for sharing your build progress. The
     
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  15. Cam Bearings Install

    Better do some more updating...

    Decided to give double thrust bearings a go..so got a set of Waterboxer can bearings and a stock type 4 set to mix and match...

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    Just needs a little filing of the case to take the additional tang but really easy to fit after that.

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    Fitted cam and torqued up case, cam stiff.. couple of taps .. belts... with a drift to each end spins lovely but no real float so a couple of wipes of both ends of both pieces on an oiled 400 grit and all good at 0.05mm

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    Was a bit less..about 0.03mm in a torqued up case.

    Fitted main bearings after marking in the case to make installing crank easier...

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    Test installed crank and cam torqued up case tested for binding... all good.



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    Last edited: Jan 7, 2020
  16. A far better job than knocking a tang into the plain bearing with a blunt instrument - no matter how careful you are a thin wall bearing shell will be damaged, and so will the crankcase. And every day is a school day, I didn’t know a wasserboxer cam thrust bearing is the same size as a Type 4.
     
    Last edited: Jan 6, 2020
  17. The wasserbox set has one pair that is narrower ...Otherwise it'd be ideal so still need to buy both sets!

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  18. Oil Pump

    During disassembly noted some wear on the rivets of the cam..


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    Didn’t look in to too much at the time as was going to machine the gears and fit a bolted on new cam.

    Should have noticed that pump gear spindle popping out though!

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    Couldn’t even turn cam more than the gap between two bolts when I was looking to see if cam bolt fouled on pump, sorry about blurred pic.

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    So couldn’t find Loctite so “glued” with permatex and peened over the ends , peened a lot more since to mushroom over the ends to hold in might even drill in ad fit a grub screw yet.

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    Checked gear backlash at 0.14mm


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    Bentley says..


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    Fitted new oil ring seal (there’s two in a gasket set .. it’s the thin one) with red rubber grease on the ring and some heavier grease/lube on gears to help priming..

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    Bagged it up clean and ready to go in later..
     
    Last edited: Jan 7, 2020
  19. Crank Install

    Got all the crank bags back out of the box..

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    I mixed up some clean engine oil and some assembly lube and some Red Line break-in oil additive to lube up the bearings and fill the oil galleries in the crank


    Torqued up big end bolts.. (aka connecting rod nuts..)

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    Checked side play..

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    was ok .. forgot to write down!

    Dropped the whole lot in the case, the premarked bearing shells makes this easier.. also double check the bearings oil holes match up with case holes.. think @MorkC68 had an issue with a set that were drilled wrong..!


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    Put case together with big 6 through bolts and checked for rotation

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    Last edited: Jan 7, 2020
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  20. Cam Install


    If you bought a new cam chances are its bolt on and you'll need to machine the face of the cam gear to stop the bolts hitting the back of the oil pump..

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    The five holes are not exactly even so should only fit one way when you bolt it on... but with dot at the top of cogs the furtherst away lobe should be pointing straight down ..

    Hopefully, the dots on the crank cam gears are pointing the right way and you can rotate the cam so they're at about 2 to 3 o clock, align the dots (sorry next two photos up side down.. )

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    and roll the cam down keeping the gears meshed until the cam sits in the bearings,

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    At this point i give everything a tap to seat it in to make sure... Spin it round both ways cam shouldn't lift out, cam backlash should be no more than a small click when you rock the gears..

    bolt the case together torque up the big six through bolts...again...

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    make sure everything still spins...

    and it did...:chewie:

    ...I know the case is a bit dirty still on the outside...:oops:

    EDIT:

    Realised I didn't say about choice of cam...

    After much debate I went with the split duration 73/86 cam from Webcam.

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    Why..? Stock Type 4 ones I could find here were hydraulic lifter grind, and for not much more from the states you could get one with a bit more lift and duration but keep it bus friendly. Scat options were a bit long in duration for me to get a reasonable dynamic compression ratio on this size of engine, probably better suited to next step up in displacement.

    Webcam don't do a sheet for the split one so i made my own

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    With some matching lifters ..

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    Last edited: Jan 22, 2020
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