I have recently been reading car stuff on web sites.......not good :) anyway I was reading about backpressure valve opening times etc and some stuff about timing advance etc.
ANYWAY - the question is could retarded timing provide more torque (for hill climbs) than advanced timing ? I currently have my dizzy completely advanced. Jeff -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Terry Rudd Sent: Monday, April 19, 2004 9:49 PM To: [EMAIL PROTECTED] Subject: Re: Dizzy If you condense all of the replies on this subject then the details on why a solid breaker plate was used with the competition L engines with Mukini or Weber carbies (as in those without inbuilt vac unit metering) become more evident. Basically, a standard dizzy is fitted with a vac unit and in order for it to do its job the breaker plates are in two pieces one of which is attached directly to the vac unit, and also they usually have dual return springs fitted to the solid plate. This standard vac advance/retard system allowed dwell variance which relates directly to points gap variance and this is a bad thing especially in a competition engine. Dwell variance is also caused by a worn dizzy, as in loabs and shaft bearings etc. Dwell is the number of degrees that the distributor shaft rotates with the points closed (and therefore charging the primary coil) and when the points open the coil fires. Points gap is directly related to engine timing ie if an engine is timed with the correct points gap and then the gap is made smaller, the timing will be less and the dwell will be higher and the opposite also applies - Ppl who use a dwell meter (recommended) instead of feeler gauges to set the points gap will have seen this. The correct dwell angle is far more advantageous than the correct points gap, and setting the points gap get more inaccurate if the points are used. As Errol alluded to the timing spikes at certain rpms (usually high rpm) was why the solid or welded breaker plate was use in racing with carbies that didn't come equiped with a vac unit metering device, the downside is the engine can be a bit cranky on cruise below 2500 - 3000 but the performance gains are really noticeable from 3600 - 4000+ rpm to as high as your game to go which is were most L series engines are running most of the time. regards Terry Topic: Dizzy ======= Date: Sat, 17 Apr 2004 08:07:14 +1000 From: "Errol Smith" <[EMAIL PROTECTED]> ---------------------------------------- The main reason for welding or replacing the breaker plate with a solid item is to help stop timing scatter. With the standard diaphragm plate the timing can move 4-6 degrees at high engine speeds. Disadvantage of making the breaker plate solid is the lack of cruise advance from vacuum. Cheers Feral Errol Get Serious! http://www.datrats.com.au/ -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of James Fitness Sent: Friday, April 16, 2004 11:13 PM To: [EMAIL PROTECTED] Subject: Re: Dizzy My old turbo 240z had the plates welded up... static timing - best thing for a Big boost carby turbo... (probably good with fuel only efi too?) mark krawczuk wrote: >dont they either stretch the adv springs or elongate the adv spring holes >in the plate? >i think they usually recurve the dizzy according to what engine setup u >have?? > >mark k > > >----- Original Message ----- >From: "maldat" <[EMAIL PROTECTED]> >To: <[EMAIL PROTECTED]> >Sent: Friday, April 16, 2004 4:03 PM >Subject: Re: Dizzy > > > > >>You dont have or need Vac advance for twin side drafts , hence remove it >>from the dizzy graph it and weld it up. >> >>The timming does not change , I think they call it dwell angle? with >>high/low Rpm. >> >>Malcolm >>----- Original Message ----- >>From: "Jeff Oldham" <[EMAIL PROTECTED]> >>To: <[EMAIL PROTECTED]> >>Sent: Friday, April 16, 2004 5:09 PM >>Subject: RE: Dizzy >> >> >> >> >>>and to add my 2 cents worth WHY is it welded up.....what performance >>> >>> >gains > > >>? >> >> >>>ta Jeff >>> _________________________________________________________________ Personalise your phone with chart ringtones and polyphonics. Go to http://ringtones.com.au/ninemsn/control?page=/ninemsn/main.jsp --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]/ ---------------------------------------------------------------------
