TheSamba.com :: View topic - Bit size to dril pic-34 to 130

Sun Aug 10, 2008 8:04 pm

What bit size do I use to drill a pic-34 127.5 main jet out to 130 with.
Dose this sound right?
1.3208mm .052" bit #55
I ordered one but it wont be here for a while--want to drill the one I have in the meantime.

One other thing
Is the pilot jet supposed to pass air from the outside of the carb?
Another words should you be able to blow air through it like a main jet but just a lot less?

Sun Aug 10, 2008 9:42 pm

Steve
you should really use a reamer to open a jet, using a drill will leave swirl marks in the jet that can actually make a jet flow less. I would think you could find a jet at VW shop for about the same price you will pay for a good USA made #drill, I just bought a couple different sizes at a local VW shop and I think I only paid $2.00 each.

Earthquake

Sun Aug 10, 2008 10:22 pm

Use a 1.30mm drill bit to drill a 1.30mm hole.

The pilot jet gets its air from one of the two bushings you can see down the throat on the side. One is for the "auxiliary" jet, and one is for the pilot jet.

Sun Aug 10, 2008 11:09 pm

"I would think you could find a jet at VW shop for about the same price"

Believe it or not no such thing in Madison WI--250 thousand people.
Take me about a week to get via Internet order.

But good point I guess when I think about it I don't want to ruin the 127.5 I have if it work well after drilling it for a 130 so I'll just wait. I just built a new motor and I think the single hose vacuumed advance Bosh distributor I have is not working and the only extra one I have is 009. My carb is a pic-34 and I just soldered the throttle plate hole up tonight and need a bigger main also.

May be my problem all along:
Here is my distributor I guess it is a mismatch with my 5 degree ATDC pulley I used.
I don't really know were I got this distributor but it says 7.5deg BTDC @ 800-950rpm on a site I looked at ? I assume the the pic-34 wil work well with this distributor?

Distributor: VW 043-905-205, Bosch 0231 170 034
Beetle 1974 * 1600 Federal Manual Trans
Points: 01 011
Condensor: 02 074
Rotor: 04 033
Dust Cover: 039-905-241, Bosch 1230 500 139 > 1230 500 147
Cap: 03 010
Distributor Cap Clip: 034-905-265, Bosch 1231 251 033
Parts Kit (Shims, Washers & Hardware): 059-998-211, Bosch 1237 010 007
Coil: 00 015 (Blue Coil: 00 012)
Vacuum Can: 07 059
Ignition Wires: 09 001
Spark Plug: W8AC
Timing Set At:: 7.5deg BTDC @ 800-950rpm w/strobe and w/single vacuum hose disconnected and plugged
Advance/Retard Range: Vacuum: 8-12deg Adv; Centrifugal: 7-12deg @ 1600rpm, 20-25deg @ 3800rpm
NOTE: Volkswagen (with Bosch's help) now makes this distributor in Mexico and is available brand new and ready to install. Please click this link:Beetle (Puebla, Mexico) With Points Distributor to view the specs

Mon Aug 11, 2008 4:52 am

Steve, it should work fine. I don't like to totally fill the hole up. I like to close it and re-drill it to about 2mm. If there is significant plate wear, I like to close it more or all the way though.

If a guy is using a DVDA and setting the timing to 5ATDC (I usually set it to about TDC with these myself, todays fuels are different), then there is no real reason to close up the plate. With the SVDA or 009s timed closer to 7-10 BTDC, sometimes you have to close the plate down to get minimum idle and still engage the volume screw, whose function is more important that folks seem to think.

I've worked extensively with getting the 34-3 to work right with SVDA and 009 style distributors, and maintaining the critical features of the carb in the range it was designed to run it is part of the key. Jetting is too. The main jet is less of the issue than the idle jet most of the time.

Tue Aug 12, 2008 1:04 am

Hope my distributor is an 0231 170 034 and not a C or D variant. I don't see any letters stamped on the thing, so this must make it an SVDA?

"The main jet is less of the issue than the idle jet most of the time."
So what idle jet with throttle plate hole closed up do you use.

"still engage the volume screw"
I don't know what your talking about here?

Tue Aug 12, 2008 5:25 am

Usually about a 60-65 idle jet works out for good AFRs for me.

The volume screw is that big screw. Engaged means still open.. lotta times with fast timing , these have to be turned down all the way to get the idle speed down, which is a problem.

Thu Aug 14, 2008 11:57 pm

Ordered new Jets will let you know how it runs when they arrive and are installed.

Will try plate soldered closed, (what I did), first then drill out hole to 2mm like you suggest.

Thanks again