timing?

[the bad samaritan]

My square is really slow at lower rpms, and when i down shift coming around a corner it splutters and backfires a alot until the rpms get up there. is my timing to high? to low? it is a 1641cc with a 009 distributor.

thanks
paul

[Dees 72]

I was told once by a crusty vw wrench that 009's have to be advanced a little bit more than stock to eliminate the sputters. I don't remember the exact, but I'm sure someone else does.

[the bad samaritan]

yeah
i figured it out, it was way to low. now all i need to do is sync and tune my carbs to get all the splutters out.
thanks
paul

[the bad samaritan]

ok now it kinda pops or goes phunk at low rpms when im driving or coasting in gear, like when i downshift could this be mycarbs?

thanks
paul

[the bad samaritan]

i think my idle jets are a little to small after reading the tech articles at aircooled.net.
the carbs are 34 weber icts, on a 1641 cc. any advice is a appreciated. thanks paul

[Aussiebug]

>[email protected] originally said... (1/8/2003 at 6:27PM PST)

>My square is really slow at lower rpms, and when i down shift coming around a corner it splutters and backfires a alot until the rpms get up there. is my timing to high? to low? it is a 1641cc with a 009 distributor.

Paul,

When using a 009 distributor, you MUST time it at between 28 and 32 degrees at 3000+rpm, and let the idle fall where it may.

009 vary (cheap build) and max advance is more important than idle, so that's how it's set. When first installing a 009 you can rough-set it at 7.5BTDC just to get the engine running, then you must reset it at 3000rpm.

Use as much of the 28-32 as you can without the engine detonating/pinging, this will help reduce the 009 flat spot a little.

If it pings at 28 degrees - use a higher octane fuel - NEVER use less than 28 degrees or the engine becomes underadvanced at higher rpom and will rub hotter than it needs to.

Yes - the carby might need larger jets. I'm not familiar with the Webers, but in general, running a 009 means you have to replace the missing vacuum advance with extra fuel, to avoid/reduce that flat spot.

John at aircooled.net is a carburation guru, you can trust what he says on the matter.

Backfiring on the overrun is one sign of lean burning - another indication that you need to look at your carby jetting.

Regards
Rob
Rob and Dave's aircooled VW pages
Repairs and maintenance for the home memchanic
http://www.geocities.com/aussiebug1970/

[truckersmike]

I've just been messing with a new set of Weber ICT's on my 1600dp and I had a lot of sputtering in take off and in the low RPM range too. I drilled out the idle jet from the stock 50 to a 57 which helped. I then drilled it to a 60 and that made a big difference too. My bus is running pretty good with the idle at 60 and the main jet at 120. The 130 mains that came stock were too much for the engine and it ran like crap.

[[email protected]]

Paul, I have a 1641 with an 009 and I had the same problem. The previous advice is correct you want to go around 7 degrees fast at idle and 30-32 degrees at 3000rpm.I timed mine to ear to were it stayed cool and started up quick and it turned out to be 7 degrees btdc. I also have a 110 cam and the 34 pict-3 carb needs to run richer(smallest carb screw out). There's a good site @nateswaterart.com/vw/ were he shows you how to make your 34pict-3 work with a 009 dist. You just have to block a hole and drill out your main jet(I just got the drill bit, it's a #55 bit .0529" you can get it at any hardware store)it's real easy, I'm just finishing up mine.
Good luck.