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Sun Jan 02, 2011 6:00 pm

a little history into my story is probably needed to help diagnose my issue. i bought a decent running 66 standard with a engine from a 74 that has 1600cc dp, solex and 009 boush. i did a top end rebuild with new stock heads, pistons, rings, pushrods etc. i then bought a weber progressive 32/36 dfev and installed that. i installed everything and got it running. i set valves, timing,points, rejet the carb with Primary idle, 45 secondary 60, mains 125/190, air jets 160/180 it will idle and start just fine. i can slowly give it gas and raise the rpms with no stumbling or flat spots. but when i go wot the car will die/jerk/or backfire through the carb. i dont know what is causing this is my first carbed car anyhelp would be great. is it possible my accelerater jet could be to large and causing this it says 55 on my jet just wondering if this could be something. thanks for reading

Sun Jan 02, 2011 6:11 pm

You should have got Kadrons but this may help you:

http://www.thesamba.com/vw/forum/viewtopic.php?t=386388&highlight=progressive

Sun Jan 02, 2011 6:15 pm

Have you done a spark plug reading?

Sun Jan 02, 2011 6:16 pm

How cold is it?

Sun Jan 02, 2011 6:22 pm

Gotta get more heat to the intake.

Sun Jan 02, 2011 7:17 pm

its around 42 degrees here. i have the preheaters hooked up but one of the preheater risers from the exhaust is clogged i drilled out the other side to help me get more he btat i broke a drill bit off in the other side and cant get it out so i am probably going to get a new exhaust. i think preheat may be some of the issue but not all. i took a heat gun and heated up the intake under the carb and it helped some but it still back fired throug the carb a couple of times during wop. is there anything else it could be. im already trying to fix the preheat issue but i feel it may be something more than that.

Sun Jan 02, 2011 7:21 pm

i havent done spark plug readings yet but i did install all new ignition componets plugs,wires,point,condenser,rotor,cap. i will check them tommorow to put a check in the box but i fell like it is an a/f issue.

Sun Jan 02, 2011 7:35 pm

It may be partly due to general coldness.
Your primary jets sound s little small, you could try a bit bigger maybe to see if it helps.
The way you descibe it sounds lean at full throttle.

You may be aware of this already but just in case:
One thing to keep in mind is this is a mechanical secondary. So I guess what you are supposed to do is not open the secondary at lower rpms.
Since you have a small engine it might not want FULL throttle till well past 3500 rpm or so.

If it had a vac secondary you would be able to floor it right off idle, but the manual secondary requires a careful foot.

The darn thing has so many drawbacks I don't know why anyone likes them, but some people like them, perhaps you will turn out to be one of THEM? hahaha

Sun Jan 02, 2011 8:00 pm

we have a street header that is modified to work PROPERLY for centermount carbs. The non-stock headers that are available are improperly engineered for adequate preheat.

Sun Jan 02, 2011 8:46 pm

which exhaust system are you refering to john?

Sun Jan 02, 2011 9:00 pm

im guessing its the basic street header on the site i may give it a try john

Sun Jan 02, 2011 9:02 pm

yes, the one with the Deluxe Preheat.

It is VERY effective. We'll have some temp #s to show how well it works. The beauty of good preheat is it makes your A/F richer without making the jets bigger, maximizing efficiency.

12vvr6 wrote: im guessing its the basic street header on the site i may give it a try john

Sun Jan 02, 2011 10:35 pm

Preheat not enough for sure, and the 009 distributor does not work well with that carb. When you order the exhaust get an SVDA distributor from AC.net at the same time. Your fighting two problems and will need both parts to correct the issue.

Sun Jan 02, 2011 10:50 pm

Agreed and agreed but no one mentioned the accel squirt yet. Look down the carb....with a mechanics mirror.....and see if you have any squirt at all when you crack the throttle fairly rapidly. No squirt? That is the place to start. Your symptoms sound like that. Junk in the squirt nozzle, bad pump diaphragm, etc.....
If you get a good healthy squirt then the other 2 things are your issue.

RC

Sun Jan 02, 2011 10:53 pm

RockCrusher wrote: Agreed and agreed but no one mentioned the accel squirt yet. Look down the carb....with a mechanics mirror.....and see if you have any squirt at all when you crack the throttle fairly rapidly. No squirt? That is the place to start. Your symptoms sound like that. Junk in the squirt nozzle, bad pump diaphragm, etc.....
If you get a good healthy squirt then the other 2 things are your issue.

RC

X2 Start with the little stuff, and work your wy up from there.