I have flown the HAPI engine for many years and found it to be very reliable. My problems have been with modifications. Interesting to know that I am only getting 50 horsepower. That makes the KR II design even more special. One thing I have always wondered about...when the engine is warm, it is very hard to turn over...cold, it turns over easily with compression on each cylinder. Hot, it is very stiff, and my poor starter won't crank it. It has been this way as long as I can remember. Why?
On Oct 18, 2018 11:24 AM, "svd via KRnet" <krnet@list.krnet.org> wrote: > > > On Oct 18, 2018, at 9:00 AM, krnet-requ...@list.krnet.org wrote: > > > > Message: 1 > > Date: Wed, 17 Oct 2018 16:47:43 +0000 > > From: Great Western Airsports <f...@greatwesternairsports.com <mailto: > f...@greatwesternairsports.com>> > > To: "krnet@list.krnet.org <mailto:krnet@list.krnet.org>" < > krnet@list.krnet.org <mailto:krnet@list.krnet.org>> > > Subject: KR> HAPI 1835 Questions > > Message-ID: > > <894D2EEDDB99FD48A33353F6FB0162BBD07E15F9@exch3-mbx05.email3.local > <mailto:894D2EEDDB99FD48A33353F6FB0162BBD07E15F9@exch3-mbx05.email3.local > >> > > Content-Type: text/plain; charset="us-ascii" > > > > Hi all, > > > > I'm pretty new to the group and hope there will be someone who can > answer my questions. I've a KR2 with 1835 HAPI which I've not opened up > yet hence some of the questions I'm asking. > > > > 1. Engine is low hours and quite tight - what max static RPM should I be > expecting with a 52 x 48 prop? > > > > The engine should make ~50hp max (HAPI spec says 60hp max at 3200rpm). > To get it you want something close to 2900- 3000rpm static. On take off > you’ll get ~200-400 rpm more. You match prop to the engine - not the other > way around. If you get only 2700 rpm static (and there is nothing wrong - > common problem in with your 52 x 48, you need a different or re-pitched > prop. > > > > 2. Was this engine built with hydraulic lifters? > > > > Actually - maybe. HAPI did go for hydraulic lifters to counter the need > to adjust every 5 hours (only a bit of an exaggeration). I think their > Magnum engines had hydraulic lifters. Turned out that was a problematic > approach and best practice (like Revmaster) is back to solid lifters - and > sufficient head cooling to reduce thermal deformation (that may have been > the root cause of frequent valve adjustment requirement and a bevy of other > problems). > > > 3. Was this engine built with a standard cam and standard 1:1 ratio > rockers? > > > > 4. What is the max EGT figure? > > > > 5. Any recommendations for mild tune upgrades that'll maintain > reliability for the 1835 HAPI? > > > > Perhaps the most important mod is the removal of the 4th bearing flow > restrictor. > http://www.greatplainsas.com/service1.html <http://www.greatplainsas.com/ > service1.html> > > Some say the Hoover Mods are key to reliability: > http://vwengineconversion.com/index.php?id=menu-conversion-hoover-t2 < > http://vwengineconversion.com/index.php?id=menu-conversion-hoover-t2> > > I don’t know, but this manual is very informative: > http://vwengineconversion.com/data/content/menu-conversions/ > hoover/VW%20aircraft%20engine%20building-hoover.pdf < > http://vwengineconversion.com/data/content/menu-conversions/hoover/VW% > 20aircraft%20engine%20building-hoover.pdf> > > You can also find a lot if information in the Yahoo KR group’s VW files: > https://groups.yahoo.com/neo/groups/KRaircraft/files/VW%20Engines/ < > https://groups.yahoo.com/neo/groups/KRaircraft/files/VW%20Engines/> > > And you can check out these two VW Yahoo groups for interesting threads > and advice: > https://groups.yahoo.com/neo/groups/VW_Conversions/info < > https://groups.yahoo.com/neo/groups/VW_Conversions/info> > https://groups.yahoo.com/neo/groups/KRaircraft/info < > https://groups.yahoo.com/neo/groups/KRaircraft/info> > > This site used to have a tonne of information, but seems to be under > construction now: > http://vwengineconversion.com <http://vwengineconversion.com/> > > > > Interestingly, the Sonex builders probably have the most recent experience > with VW’s and their forum reflects that and their problematic experiences > with the AeroVee: > http://www.sonexbuilders.net/viewforum.php?f=7 < > http://www.sonexbuilders.net/viewforum.php?f=7> > > > The take home is something like this: Get rid of the 4th bearing flow > restrictor and then keep the engine cool (pay a lot of attention to > baffling and maybe make the revmaster oil cooler mod). You could consider > the 30mm oil pump mod too. > > However, if you start mod’ing the engine to make more power, you’ll have > to start making some major changes. Higher power will probably necessitate > moving to Revmaster or ForceOne 4th bearing and crank. > > > Cheers, > Owen > > > > > > Many thanks in advance. > > > > Brad Wagenhauser > > _______________________________________________ > Search the KRnet Archives at https://www.mail-archive.com/ > krnet@list.krnet.org/. > Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options. > To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org > _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. 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