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Backfire on start up.

Posted: 27 Dec 2011, 19:42
by pugwash
As the heading says, turns over ,backfires once then runs ok, could the timing ne out ? 2L a/c

Re: Backfire on start up.

Posted: 27 Dec 2011, 20:34
by sarran1955
Hello,

I'm sorry , but my crystal ball is in for repolishing at the moment.... :roll:

Perhaps you could give some engine details, or other clues.... :wink:

How many grilles on the front... :!: :!:

Do you fill it with diesel or petrol.... :?: :?:

Stuff like that...
Its a VW thing


Cordialement,




:ok

Re: Backfire on start up.

Posted: 27 Dec 2011, 20:39
by dugcati
yes most likely timing - if too far advanced

Re: Backfire on start up.

Posted: 27 Dec 2011, 20:50
by sarran1955
Hello again,

No seriously,

For example, does it turn over well b4 starting.... :?: :?:

Have you changed anything recently...... :wink:

Have you been tinkering with a 10mm spanner....

Stuff like that...


:rofl :rofl :rofl

Cordialement,

:ok

Re: Backfire on start up.

Posted: 27 Dec 2011, 23:46
by pugwash
sarran1955 wrote:Hello again,

No seriously,

For example, does it turn over well b4 starting.... :?: :?:

Have you changed anything recently...... :wink:

Have you been tinkering with a 10mm spanner....

Stuff like that...


:rofl :rofl :rofl

Cordialement,
:ok

Lol :ok correct, its A 2L Aircooled 82, recently had trouble with Dizzy, and had to put a 009 and elect ign in for the time being :shock: I think its timing, any guidance on what I should set it at woiuld help, it only bangs once on the turnover, then runs ok, its set at 5 BTDC at the momentr

Re: Backfire on start up.

Posted: 28 Dec 2011, 08:34
by CovKid
Those 2 litres don't run well on 009s fella (no stock v-dub does accurately). The problem you've got is that without the vacuum advance/retard, the dizzy won't meet the needs of the engine at all throttle openings and you can't therefore set a timing point that works perfectly. From memory of the 009 you aim to get 29 degrees at max throttle opening and live with whatever you get at idle. Its a rotten compromise and thats all it is, a compromise. The right dizzy is miles better in terms of performance/economy/safe running.

I should add that many dizzy units on these now have wear/play but a good lathe man could rebuild an old one for you. This is rather early in the day for me to muse your problem so excuse me if I'm not as sharp as I might otherwise be but the carbs themselves are somewhat complex and lots can go wrong there too. are both carbs working in unison? Shut off valve working correctly on L/H one?

Re: Backfire on start up.

Posted: 28 Dec 2011, 09:50
by pugwash
CovKid wrote:Those 2 litres don't run well on 009s fella (no stock v-dub does accurately). The problem you've got is that without the vacuum advance/retard, the dizzy won't meet the needs of the engine at all throttle openings and you can't therefore set a timing point that works perfectly. From memory of the 009 you aim to get 29 degrees at max throttle opening and live with whatever you get at idle. Its a rotten compromise and thats all it is, a compromise. The right dizzy is miles better in terms of performance/economy/safe running.

I should add that many dizzy units on these now have wear/play but a good lathe man could rebuild an old one for you. This is rather early in the day for me to muse your problem so excuse me if I'm not as sharp as I might otherwise be but the carbs themselves are somewhat complex and lots can go wrong there too. are both carbs working in unison? Shut off valve working correctly on L/H one?

Carbs are working fine,been checked and all working ok.

Re: Backfire on start up.

Posted: 28 Dec 2011, 10:25
by jason k
is that you chris?

my mate has a known good cu dizzy in bridgend.

if you want his details drop me a PM :ok

Re: Backfire on start up.

Posted: 28 Dec 2011, 11:33
by dugcati
CovKid wrote:Those 2 litres don't run well on 009s fella (no stock v-dub does accurately). The problem you've got is that without the vacuum advance/retard, the dizzy won't meet the needs of the engine at all throttle openings and you can't therefore set a timing point that works perfectly. From memory of the 009 you aim to get 29 degrees at max throttle opening and live with whatever you get at idle. Its a rotten compromise and thats all it is, a compromise. The right dizzy is miles better in terms of performance/economy/safe running.

I should add that many dizzy units on these now have wear/play but a good lathe man could rebuild an old one for you.



well put that man take 10 points!

Re: Backfire on start up.

Posted: 28 Dec 2011, 14:59
by pugwash
jason k wrote:is that you chris?

my mate has a known good cu dizzy in bridgend.

if you want his details drop me a PM :ok

Yes Jason, its me :trunk :trunk PM you later :ok

Re: Backfire on start up.

Posted: 28 Dec 2011, 19:57
by sarran1955
Hello,

Right its very simple:

009 dizzie ------to-------bin ------in a ====== straight line. :wink:

Cheapo solution, get van dizzie off e bay, or even buy new chinese knock off SVDA for about 70 €, fit a coil with 1.5 ohm resistance, ( ie anything NOT electronic ignition)

The chinese knock off SVDA ( CKOSVDA for short) :rofl :rofl :rofl :rofl even comes with points and condenser :roll: fitted.

Set your timing to 8 degrees BTDC, you will need a strobe light and a tippex.

Set your dwell angle to 45 degrees, or about 16 thou gap.

Set your ( I hope) standard solex pict carbs, for the idle mixture to be at 4 % co.

You will now have a reasonably smooth motor, with no drive through flat spot.

Mangled carbs and airleaks excepted of course.. :roll: :roll:

Cordialement,

:ok

Run on 4 star.