Hi Terry, Interesting post this. A couple of questions:
* Given their prevalent use, have you got numbers on the S2 electronic dizzy for comparison? * You mention problems at low rpm when using the single carb L18 dizzy with sidedrafts, when the total advance has been limited to 30deg to match L18SSS dizzy total advance. What happens when you don't limit the total advance to 30deg, given you mention 36deg tot is usually pretty good with 98RON fuel (just wondering because I havent played with sidedrafts) * What are your recommendations with the 32/36 downdraft weber and vacuum advance - connect it, leave it off, use a manifold vacuum signal, use the carby/throttle signal resulting in vacuum when the throttle is opened and no signal when its closed?? Thanks Andrew > The only place I know of that Nissan used Bosch dizzies was Oz and they > definitely aren't curved to suit twin sidedrafts of any sort out of the > factory - I'd say the problem is something to do with this area. If it wont > rev and the problem wasn't diagnosed on the Dyno runs then I can't say too > much about the competencies of the Dyno operator - I mean other than > recording HP at the wheels, I was told a long time ago that's what the Dyno > was designed for. > > A Hitachi or Mitsubishi twin carby Nissan dizzy is very different inside > than your average Nissan factory downdraft version. Sidedrafts dizzies run > more initial advance, both have stuff all vac advance (which defeats the > arguments somewhat about using vac advance on most Nissan L engines and IMHO > the use of vac advance is most effective with downdraft carbies anyway) and > more mechanical advance but full advance isn't all that different (which is > around 36 degrees on the average L4) > > A factory (Hitachi) L18 single carby dizzy runs 10-12 degrees initial, 10-12 > @ 410mm vac and 12 degrees @ 1900 rpm (24 @ 3800 crankshaft rpm) mechanical > advance (and usually only single spring on breaker plate) which is 34-36 > degrees (crankshaft) at 3800 rpm or WOT which will produce no vac advance > either. > > A twin carby L18SSS dizzy (Hitachi) (Factory Mitsubishi dizzy for the PH44 > are different again and a tad rare today, it hasn't got a vac advance unit > for starters and has a solid breaker plate which runs around 12-16 initial > and 20-22 mechanical @ 3800 rpm, so 32-38 total and I've found that on 98 > octane around 36 total advance is pretty good in most circumstances) - > > back to L18SSS dizzy, initial advance is set to 14 degrees, 16 @ 310mm vac, > and mechanical is 16 @ 3800 crank rpm which incidentally has dual control > springs and split breaker plate - therefore the factory total advance is > only 30 degrees for Hitachi sidedrafts. Problem is if you run a single carby > dizzy with dual sidedrafts at -6 degrees initial i.e. 4 degrees to give 30 > degrees total advance, Twin Hitachi's will spit flames through the xovers or > filters at low rpms, very pretty but not very effective. The effective way > to fix these problems is to recurve the dizzy. > > regards > Terry > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Anthony M. > Reid > Sent: Saturday, 24 May 2003 9:03 PM > To: Ozdat > Subject: RE: L20B Revving problem > > > remeber that i'm in the uk and we never got the 200B here except for > mine which was imported in 1987, the carbs are off a L18T 1979 180B SSS > (810) was thinking of getting the carbs retuned on rolling road > The disy i have is bosch and the number on are > 9 230 064 519 > U-PGFU 4 > 22100-V9600 > 347 > Thats all the number i can see on the casing of the disy > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Maldat > Sent: Saturday, May 24, 2003 6:42 AM > To: Anthony M. Reid > Subject: Re: L20B Revving problem > > > Twin SU's (nissan) were never made for a L20B. > 1979 810SSS is a L18 with twin carbs. (180B) > My L20B is from a 200B 810 the car was badged as SSS,fluffly seats and a > rev > counter is about the only difference.It only had a single carb. > > Whats the dizzy number and I should be able to tell you from what car > and > what year. > > Try lifting your needles about 1mm at a time make sure you do both the > same. > > > > --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/[EMAIL PROTECTED]/ ---------------------------------------------------------------------
