TheSamba.com :: View topic - EMPI reproduction 30PICT-1 Carburetor - An in-depth review

Sat Jul 05, 2008 10:45 am

keifernet wrote: ALL-IN wrote: I know I'm way late on this topic, and I'd like to show my appreciation for the information on this forum...

Quick question on the topic of Carbs, currently running a 12OOCC 40HP 6V engine in my 62 bug, I received a consult from a mechanic who suggested I get a new carb instead of trying to rebuit my current one (not sure why), anyway, I've been trying to reasearch a replacement for the current Solex 28 PICT-1. Any suggestions and or website links???

Thanks.

They can be rebushed and rebuild with great success...

I've been known to do a few :D

http://www.thesamba.com/vw/forum/viewtopic.php?t=71746

:shock: Wow :shock: ... after reading all the Keith praise... I don't see how I can't ask you for assitance with a rebuild... I'll e-mail you later, off the forum, for details. Thanks!

And thanks to everyone for the added info.

Tue Jul 08, 2008 4:00 am

Great work. Does anyone have official technical data, curves etc. about vacuum values of mm hg at specific rpm's for different carb. or vacuum advance units?

Tue Jul 08, 2008 12:18 pm

I used mmHg because my first gauge I used for tests, that small one, the lowest mark on it was the metric one too, and was finer calibrated on that scale, so I chose metric. Also, the Bentley manuals, they have specs listed, sometimes in both SAE and metric, but I think the older ones are only in metic. Plus then I got that ultra accurate gauge that was in mm Hg.

Anyway, like I said, took to the factory repair manuals for official specs. And also, look on the OldVolksHome's page full of distributor information - however, they are given in inches of Hg so you'd have to convert.

http://www.oldvolkshome.com/ignition.htm

Tue Jul 08, 2008 12:26 pm

thank you, I got it now :)

Tue Jul 08, 2008 4:33 pm

glutamodo wrote: The 28PICT-1 is better though, it's got the bigger choke that can later be upgraded to 12V and the better choke pulloff diaphram setup. Of course, you can just put that carb's top on an earlier body. I ran one that way for well over 10 years.

Bah, 12V! I'm going for the ultra stock engine look, and my car is still proudly 6V, so that's not a concern here. As for the better choke pulloff, well, the 28 PCIs didn't have one at all, so the 28 PICT's pulloff piston can't be so bad, right?

I don't actually know, because I haven't managed to find a nice 28 PICT yet, but as soon as I get my hands on one, I'll be swapping out the 30 PICT-1 in my 1385. I guess we'll see how it works.

Tue Jul 08, 2008 5:49 pm

It should work OK. I ran a 28PICT (with the later top, as mine was 12V) for years, I think I ran with a 120 main and 145y air correction.

That pulloff piston, if they are not all worn out they work OK. I have a few carb tops of the early type if you should need one.

Mon Sep 08, 2008 1:50 pm

This was a great read, very informative. Thank you.

I have a 1600DP, owned it for 17 yrs. The last 8yrs it has been sitting waiting for a donor bug to push around. Now have a 69 bug which the motor now resides. I am having issues with the carb. It is a Solex 28Pict-1 with a 12V electric choke. (FYI- the electric choke has never been connected electrically)
I purchased and installed a rebuild kit. Since then I have been trying to get it just right.
1-Under braking or coasting down hill, the engine will die.
2-When on the throttle, there is hesitation, not alot, and only in 1st and 2nd gear.
Obviously I need more adjustments.

Any advice would be greatly appreciated.

Mon Sep 08, 2008 2:44 pm

I take it this is with an adapter to fit a 1600DP and that it ran OK before you took it apart.

Sounds to me like you need to richen up the idle mixture a little bit. It might not need much, just to turn the brass spring-loaded mixture screw on the side of the carb out a quarter to half a turn.

Flat spots on acceleration, make sure the accelerator pump is spraying good and aimed somewhere between the leading edge of the throttle butterfly and the middle.

How tight are your throttle shaft bushings?

-Andy

Mon Sep 08, 2008 8:18 pm

Yes, it has an adaptor plate and it ran beautifully before.

I have and will adjust the "brass spring-loaded mixture screw" on the side of the carb. You say to "richen up the idle mixture" I need to back the screw out? More air?

I did hear and see inside the carb (while idling), instead of a spray of gasoline, it sounded and looked more like "sputtering" or "splattering" of gasoline.

I don't know what is considered to be "loose" or "too loose" on throttle shaft bushings, however I am certain that they are not tight.

By the way, since reading your report about "idler cam limiter pin", I didn't realize there was a pin missing to keep that cam from "flipping over" which it has done several times while driving down the road(frightening!).

Thank you.

Eric

Tue Sep 09, 2008 2:55 am

Loose throttle shaft - Well if it ran OK before then if they are loose then they may not be too bad. It just lets air into the idle mixture through leakage and that affects the idle setting.

Sputtering of the accel pump. Should be a solid stream. You may have dirt in that discharge arm. You might have to pull it out and blow it out with compressed air, then place it back in, re-aim it, then tap it down carefully to reseat it.

69GaBug wrote: I have and will adjust the "brass spring-loaded mixture screw" on the side of the carb. You say to "richen up the idle mixture" I need to back the screw out? More air?

That's not an air bypass screw, it's a volume screw. (the air bypass screw, or idle speed screw, on a 28PICT-1 is the screw on the throttle arm) It lets more of the idle mixture running through the pilot (idle) jet go though the small hole at the bottom of the carb. Since the throttle plate is nearly closed at idle, this, in effect, lets more fuel into the works, richening the mixture. And this also impacts the running of the engine well above idle speed as well.

Here's a page from an old owner's manual that describes the idle speed setting. Just don't go 550 RPM like it says to. More like 850-900.

Tue Sep 09, 2008 10:34 am

Great info!
That is exactly the information I needed.

The next question that comes to mind is how to determine the engine is idling at 850-900 rpms. Do I need a tachometer?

Eric

Tue Sep 09, 2008 5:37 pm

Yes, it's difficult to get an idle of 550. I usually follow what I read elsewhere which is to adjust the idle just high enough so the generator light goes out.

On a side note, I found that if you check your idle jet and set it to whatever it was originally, you really can get the idle pretty low. On my '63, it had a 55 idle jet (should have had a 45) but some idiot had drilled it out even larger. I had a collection of spares and found that most of them had been drilled or had simply worn larger so it was impossible to tune it per the owner's manual. Something to check if you have exhausted other options when tuning things.

Tue Sep 09, 2008 7:25 pm

Well you have it on an dual port engine, and 550 is going to be nearly impossible. How to tell if it's 900 or so, well I could do it by ear, from experience and get it pretty close. But how to describe it, that's kind of hard.