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. (Most of the stuff here applies to most Type 4 engines ...)

    ((DISCLAIMER: This is a " what I did / am doing" not a "how to" though I am trying to follow best guidance its up to you to make sure you're happy to do it like this if you follow it..)

    It's nearly six years since the excellent

    Morks AP 1800 Engine Build Project

    by @MorkC68 , so thought it was time for another light version

    The Start


    Stanley is a heavy smoker... found a bit of oil in the head when swapping heat exchangers so going for a top end refresh.


    So first guess is valve guides need doing and prob swap out valves while there. Engine out so prob worth renewing crank oil seals....

    While it's out... is it worth the upgrade to a 1911? We've been use to the 2.0ltr in the tintop Bay....
    (additional disclaimer.. there's also a 2.0ltr crank and rods in a box in the garage). Don't want to crazy machining but a nice daily driver is the target.

    Edit Added later to help

    Thought I might as well use the 2 ltr crank I had in a box ...and used pots are not too expensive so jumped to 1971cc (stock 2tr)... then found two different heads were on it, one 1800 and one 2 ltr. But, the 1800 was the bigger 41mm inlet valve so got one to match from the US of A to even things out.., then found 1800 have a bigger combustion chamber in the head and smaller dishes on the pistons so 2 ltr pistons with a big dish wrecks your compression ratio... so sourced some flat pistons to lift it back up but they were 96mm so bored out the barrels to suit that's it now.. 2056 it is..

    Jumps to later parts added here, they might not be in the best order to do things as I did what I could when I could.!

    Let me know if you find anything wrong and I'll try and update as a reference..... .Or even any comment you think might me worth adding.....I'll probably just update the sections anyway when I'm having a quiet lunchtime in the office.... hope it's useful to someone other than me next time!

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    Last edited: Jul 2, 2020
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  2. If you have a 71mm crank and rods fit 96mm B&Ps for 2056cc – you’d be silly not to.;) No machining required.:thumbsup:
    MorkC68 likes this.
  3. Not much in it in the price of the pots and pistons between 1911 and 2056.. just a set of bearings and a bit of time... just when you're in there it's a case of might as well replace the cam and be done!

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  4. Ill be watching this as my guides need sorting, but its just one of those jobs... good luck with it, please post lots of photos as you go!
  5. Blimey, six years ago, that has flown by!

    The motor is still going, leaks a little bit but not to make an impact on topping it up frequently. I think it may be ready for a tune up and valve clearances setting.

    It doesn't like the Castrol GTX Classic oil, it dirties / breaks down the oil far quicker than Miller equivalent weighted, which it barely dirties / discolours.
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  6. I did them on the last one... first time was a pig... overthought it pneumatic hammer ready and everything.. all went wrong burned hands dropped head knocked seats out!... second time easy as.. everything clean, proper hot head cold guides popped straight in even the oversize one.. going to look into guide relining this time see if it's any value!

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  7. Just read it all again.. epic journey!

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  8. Well after a lunchtime research I'm not too much the wiser if the difference in capacities is much variation for a daily driver bus.
    Do the 1911 b&p have any issues regards life - being thinner walls, or heat- need more cooling? Looks the easiest option for a quick refresh, on top of expected head work.... if everything looks ok on stripping

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  9. If you ask our American cousins, they’ll say don’t use 96mm B&Ps (presumably what you mean by 1911) as they’ll distort and the engine will burn oil. My experience so far with 96mm biral cylinders (double cast, iron liner/aluminium fins) is that the engine doesn’t burn oil – and that’s with an 80mm crank so piston speeds are higher than standard.

    But I would never fit new B&Ps and refurbished heads on an old bottom end.
  10. Oh now you're just encouraging a full rebuild

    But if the engines out I suppose it's the sensible thing to do if it's going to be a daily, not after big power just drivability.

    The 2.0 ltr crank looks ok on the whole mucky but it'll clean up..just a bit of light pitting on the journal that the bearing has not been sat on while Sat in the box.

    So either check and go with 1800 crank and aim for 1911 or a regrind (any recomendations?) of 2.0ltr and aim for 2056.

    Currently identified 1800 (021 101 371S) heads which hopefully are 41/34 mm valves.

    Got some DRLA36's to tidy up and a vintage speed superflow ready to bolt on, though wouldn't quite sit on the head right for a test run.. no biggie to sort when heads off.

    Time for a week off and bit of a drive to have more reading and think!.. I'll only have a couple of months to sort it when back and need to get cracking so need a plan...

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  11. Exactly.

    Go with the 71mm (2.0l) crank, the 41x34 heads will work well with 2056cc but don’t use a standard cam. I like the Scat C25 with Lube-a-lobe lifters but Web cams are the best available - and 3 times the price. DRLA36's are slightly small but will be okay and if the VS superflow doesn’t fall apart it will be fine.

    I’d go to Atelier Gonin Moteurs for a crank re-grind but while they’re local to me from Northwichish it’s 783ish miles.
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  12. Well after a week off to drive with Mrs P to Wolfburg and back in the tintop, enjoying the 1100 miles of stock 2.0ltr cruising happily, reading many opinions and playing with spreadsheets....
    It looks less bother to aim for a standard 2lt (1971cc) build what with trying to keep deck height 1.5mm and compression ratios down near 8, which the C25 cam seems to be saying it likes. Will also be closer to the Dell 36's range too.
    All the slightly larger bore kits seem to come with flat top pistons which bump up the CR to near 9 unless you want to spend lots on mix and match kits to get dished or re-work the combustion chamber a lot.
    So probably going for send crank off for a re-grind, new bearings, go with the C25 cam, new lifters, check and re-guide the heads (if no cracks), set of standard 94mm B&P, refurb the dirty Dells and see what Alfa put in them (30 vents I can see), vintage speed exhaust, lick and a spit and off we go.
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  13. A C25 needs more than 8.0:1 static CR; get the deck closer to 1mm. 30 vents should work okay.
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  14. blurb gives 7.5 -8.1 as CR range..guess I'll aim for top end of that. Target is a deck height 1.2 just in case the head a need a light skim..don't want valves poking out too high....
    Using dish and chamber sizes from my CJ build as a guesstimate that'd push static CR up to 8.5.... guess I'll wait till I get the engine dropped and apart to see what the 1800 heads have as a chamber . Seen some pistons in the porche shop with 10mm dishes that might help... not bad price either.

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  15. I’d forgotten you have 1800 heads – they have large combustion chambers and the problem you will probably have with dished pistons is that you can’t get the CR high enough. I know give a range of 7.5 -8.1 for the C25 but I don’t agree. The engine works well with a dynamic CR of around 8.0:1 and you can’t get that with a C25 using a static CR of 8.1:1 because the piston has less time to compress the mixture once the inlet valve closes.

    A standard cam has little or no overlap so the static CR is more or less the same as the dynamic CR but a C25 has the inlet and exhaust valves open at the same time and it needs a higher than standard static CR to end up with the same dynamic CR. Ratio, on the,the two can be substantial.
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  16. Thanks Mr Westy.. a delve into the dark arts of Dynamic CR.. interesting discussion on the dark side I see ;-) . .. you say extra cooling recomended with the c25 too?.. oil filter take off plate?

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    Last edited: Jan 18, 2020
  17. I ran my 2.0l with a C25 and 1800 heads for several years without an external cooler but I had to back off when the oil temps went too high climbing cols, in the UK you’d probably get away without one unless you spend long periods on the motorway.

    I have a 28row cooler with a fan on the 2316cc, sandwich plate with a thermostat and a spacer with the hoses under the pushrod tubes above the lower tins – hope that makes sense. The filter is a Mann W920/14, same dimensions as the standard filter but it has an anti-drain back valve.

    oil cooler adapter.jpg
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  18. .... ok think I've got the whole DCR thing one spreadsheet now.... for a closing angle of 44 ABDC (for a C25) and a rod length is 131mm the only way I can get up to 8 is with flat top pistons and 96 barrels, is this about what you had... obviously all ball park without accurate chamber volume.
  19. Ebat bargain find Alfa carbs from Germany...

    Quick carb dismantle..36 Dells, 30 venturis, .2 emulsions, 52 idles, 180 air and 122 mains.. looks ball park from a few Americans..and tech book figures... bit low on idles from threads over here.
    Might adopt the Alfa manifold as a "velocity stack" / Ramair filter holder, they have tapped inlets for breathers already, might look a bit weird though...
    Propper matching pair too according to tabs, all spindles look great plates all clean insides look nice just grubby on the outside

    I'll come back to clean these later..

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    Last edited: Jan 18, 2020
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