PIERBURG Rebuild - pre build advice

Carbs; K-jet; Tanks; Lines; Filler necks, Senders; aftermarket fuel systems; Exhausts and Manifolds;air filters - standard and aftermarket

Moderator:Scirocco Register

Forum rules
Hints, tips and guides for repair and modification - the FAQ section on the main website is worth checking first for information relating to common faults and technical help. Useful posts and guides will be added to the FAQ http://www.sciroccoregister.co.uk/scirocco-faq
h11poc
Posts:75
Joined:Sun May 16, 2021 6:37 pm
fill in the right answer:15
PIERBURG Rebuild - pre build advice

Post by h11poc » Mon May 24, 2021 4:30 pm

Hi all. Next week I wil be removing the pierburg carb and and attempting to rebuild it.

So far i know that the throttle sticks so possible the throttle body or spring. Also the auto choke is hanging off the carb !!

So before i start is there and advice on what I should look for to determine whether rebuild is possible?? I have seen the rebuild kits on the bay but before I spend 40 quid or so I would like to make sure its all worth it.

Any advice on starting points with the Pierburg rebuild most helpful



GT_II
Posts:294
Joined:Fri Feb 24, 2017 12:18 am
fill in the right answer:15
Location:Warwickshire

Re: PIERBURG Rebuild - pre build advice

Post by GT_II » Mon May 24, 2021 7:32 pm

Well worth investing time and money - a great carb if set up properly - pretty much the pinnacle of carburettor design.

There are several threads on this theme worth looking at, this one quite recent:

https://forum.sciroccoregister.co.uk/vi ... =9&t=22215

You'll see links to the official manual and spec sheets - best to follow the manual step by step. I'd hold off on ordering the refurb kit though and wait till you know you definitely need it. My Pierburg only needed a new mounting flange, a new wax stat, a cleanout of the choke cover coolant channel and an adjustment to the fast idle cam. You'll need a decent vacuum gauge to verify components are working and to verify some of the settings.


1992 VW Scirocco GT II 1.8 90PS Brilliant Black 30k
2011 VW Caddy Van C20 Startline 1.6 TDI 102PS 60k
2015 Skoda Yeti SE Outdoor 1.2 TSI DSG 105PS 30k
2013 Fiat 500 Pop 1.2 69PS 35k
2009 VW Fox 1.2 54PS 55k
2009 Smart Fortwo Passion 1.0 mhd 71PS 25k

RussGLAuto
Posts:142
Joined:Sat Jul 14, 2018 11:51 pm
fill in the right answer:15
Location:Spalding

Re: PIERBURG Rebuild - pre build advice

Post by RussGLAuto » Tue May 25, 2021 6:41 am

Rebuild is always possible and worth doing to keep the Pierburg. Trust me, it's a great carb when refurbished correctly. Just make sure no rust in the fuel system. Easiest way to check is your fuel filter. Even the smallest specs in it will tell you, and the culprit in my case was not the tank or filler neck, but the actual hard fuel lines that were almost blocked with rust.

https://sites.google.com/site/pierburgc ... s/about-us

https://sites.google.com/site/pierburgc ... ettor-work

This is what my 2B5 looked like before refurbishment. It needed most ancillaries replacing after sitting in a box in the boot since 2018 having been removed due to "rough running". That said if you want to ditch it in favour of a Webber, you have to ask yourself a question, do you want to go down the road of less power and a manual choke?
You do not have the required permissions to view the files attached to this post.


Daily Driver - 2017 Volvo XC90 T8 Twin Engine - Polestar - Arctic White
Weekend Wagon - 50k 1982 Mk2 Scirocco 1.6 GL Auto - Diamond Silver
Other Half's Wagon - 2008 Mazda 2 1.5 Sport - Cosmos Blue
Daughters Curb Scraper - 2016 Fiat 500 1.2 - White

WreckTangle
Posts:91
Joined:Sat Dec 02, 2017 6:16 pm
fill in the right answer:15

Re: PIERBURG Rebuild - pre build advice

Post by WreckTangle » Wed May 26, 2021 11:38 pm

Rebuilding a Pierburg 2e2 was my lockdown project last year. As said already, it’s worth doing. A lot of owners take what they believe to be the easy route and replace it with a Weber. IMHO this just leads to a different set of knotty problems.

Before you lift a spanner take time to understand fully how it should work. I found the most accessible resource for this was SkyRocket’s videos on YouTube. For example,

https://youtu.be/XTxrLDwexWA

Another really helpful set of resources is available from here. This is about the 2e3 which is sufficiently similar to be nearly all relevant.

https://youtu.be/amnqCUSTnUw

If you can find one available cheaply it is worth buying an identical or similar spare unit. It’s useful for parts, especially if you strip screw heads or have bits missing from yours. On the subject of screws, I found some had rusted slightly. This will depend on the history of yours and how mush oil has spilled over it in service.

You will definitely need a full rebuild kit with all the gaskets and some other service items. Apart from basic tools things I found useful were a cheap hand-held vacuum pump for testing vacuum components, an ultrasonic cleaner, and I found that an electric impact driver with impact bits was the best way to remove rusted screws undamaged. My ultrasonic bath wasn’t large enough to take the largest parts in one go but I did them half-in, half-out turning halfway through. I suppose you could just try carb cleaner if you don’t have access to an ultrasonic bath but the Pierburg has lots of small channels which have a tendency to gum up.

I bought the Haynes Solex & Pierburg manual which is useful but you could get away with just the Pierburg service manual. You want to find a complete, English version online. Such as,

http://vwa1.dadoghouse.com/wp-content/u ... uction.pdf

Many parts are still available both OEM and pattern, secondhand and new. The worst problem you will find is if your 3/4 point unit no longer holds a vacuum. You might strike lucky and find a sound secondhand unit. If you want new, best sit down before you ask the price. See, for example,

https://shop.carservice-kueppers.de/ver ... -129-082-b

Other than watching the videos a few times to get a feel for how it works and what you’ll need to do to strip down and rebuild it my only other piece of advice is to take your time over it and be methodical.



h11poc
Posts:75
Joined:Sun May 16, 2021 6:37 pm
fill in the right answer:15

Re: PIERBURG Rebuild - pre build advice

Post by h11poc » Thu May 27, 2021 9:48 pm

Wow thank you so much for the information. I took it off today and had a quick look at it. I noticed though it won't start unless the pedal is pressed and held and then there is zero idle at all. I'm hoping its not that expensive part you showed me. Also it leaks a bit of fuel from the front .

According to that video the 3/4 point unit does three things of which two seem crucial. I would hope someone on here may have a 2e2 for spares??
I will start the rebuild on saturday but it is worrying me that the throttle seems sticky and that white second butterfly part sometimes jams the throttle open... Ah well.. I got to at least have a try.

thank you for all the information



WreckTangle
Posts:91
Joined:Sat Dec 02, 2017 6:16 pm
fill in the right answer:15

Re: PIERBURG Rebuild - pre build advice

Post by WreckTangle » Thu May 27, 2021 11:16 pm

You might do well to test the 3/4 point unit for vacuum integrity early on because it may take you a while to source a working replacement if you need one. The test procedure is in section 3 of the service manual on that DaDogHouse link. I bought a US Pro 5322 hand vacuum pump kit for under £20 do do that sort of test. It has a vacuum gauge on it sufficient for these tests. You’ll need to engineer a step down from the nylon hoses that come with the pump. I found 1/8” ID unbraided silicone vacuum hose was an excellent friction fit inside it. I used short lengths of vacuum hose with a suitable self-tapping screw in the other end to close vacuum ports for testing. You could just put your finger over the end but that will get boring if you want to see if a device holds vacuum for any length of time.

Be aware that the vacuum ports on the carb are intended to be different bores. Don’t go reaming them out thinking they are blocked.

The little brass reducer in the (plastic) choke pulldown unit it quite important too, but not for the reasons suggested in the video. You will find it impossible to adjust the pulldown unit properly if yours is missing. Check inside the appropriate vacuum tubes. Non-OEM replacement pulldown units tend not to come with them.

You will want to put your waxstat in hot water from the kettle to test and revitalise it.

When you come to adjust your automatic choke unit you will need to put it in the freezer first.

All excellent fun!



h11poc
Posts:75
Joined:Sun May 16, 2021 6:37 pm
fill in the right answer:15

Re: PIERBURG Rebuild - pre build advice

Post by h11poc » Fri May 28, 2021 1:01 am

Wow - I've built many cars and even had the pleasure of setting up the twin carbs on a Volvo p1800s and the QUAD carbs on a Chevrolet corvair.. I will say this , this pierburg seems way more complicated .... But honestly, what you've told me and those videos I'm more than confident I'll know if the carb can be saved.



h11poc
Posts:75
Joined:Sun May 16, 2021 6:37 pm
fill in the right answer:15

Re: PIERBURG Rebuild - pre build advice

Post by h11poc » Fri May 28, 2021 2:01 pm

WOW - the hoses on the was stat are broken so it was rerouted to the starter cover. I guess the was stat is a crucial part?? If it is then does anybody have one?? Literally the plastic hose connection on it are broken so it's beyond repair :-(



GT_II
Posts:294
Joined:Fri Feb 24, 2017 12:18 am
fill in the right answer:15
Location:Warwickshire

Re: PIERBURG Rebuild - pre build advice

Post by GT_II » Fri May 28, 2021 11:06 pm

The function of the wax stat is to control the idle speed during warm-up. If it is not there, you will probably find other settings have been adjusted to compensate, such as the main throttle setting screw, which should never need adjustment, the fast idle cam and possibly the automatic choke.

The later plastic version of the wax stat was discontinued by VW and supersedes to this earlier die-cast version. The hose spigots are 1mm larger diameter but the coolant hoses should still fit:

https://www.volkswagen-classic-parts.de ... -golf.html

or here:

https://www.heritagepartscentre.com/uk/ ... a4QAvD_BwE


1992 VW Scirocco GT II 1.8 90PS Brilliant Black 30k
2011 VW Caddy Van C20 Startline 1.6 TDI 102PS 60k
2015 Skoda Yeti SE Outdoor 1.2 TSI DSG 105PS 30k
2013 Fiat 500 Pop 1.2 69PS 35k
2009 VW Fox 1.2 54PS 55k
2009 Smart Fortwo Passion 1.0 mhd 71PS 25k

WreckTangle
Posts:91
Joined:Sat Dec 02, 2017 6:16 pm
fill in the right answer:15

Re: PIERBURG Rebuild - pre build advice

Post by WreckTangle » Mon May 31, 2021 9:18 am

You also need to determine if you are getting a good flow of coolant through the wax stat circuit. There is an o-ring behind the inlet manifold which can break down and block the coolant channel. Good description of it in the Golf Mk1 Pierburg FAQ. The Scirocco is fundamentally the same setup as the Mk1 Golf.

http://www.golfgtiforum.co.uk/index.php?topic=18871.0



h11poc
Posts:75
Joined:Sun May 16, 2021 6:37 pm
fill in the right answer:15

Re: PIERBURG Rebuild - pre build advice

Post by h11poc » Mon May 31, 2021 7:51 pm

WreckTangle wrote:
Mon May 31, 2021 9:18 am
You also need to determine if you are getting a good flow of coolant through the wax stat circuit. There is an o-ring behind the inlet manifold which can break down and block the coolant channel. Good description of it in the Golf Mk1 Pierburg FAQ. The Scirocco is fundamentally the same setup as the Mk1 Golf.

http://www.golfgtiforum.co.uk/index.php?topic=18871.0
Sadly the wax stat was beyond repair as the coolant lines were snapped off it. I bought the new metal one that GTii put up in the link..
And you were all right, it has been messed around with to compensate for the lack of was stat. Sadly the manual doesn't tell you how many "turns " etc the screws are for standard setting and so on but I will get there. The carb wasn't in such a bad condition so I am hopeful it will be running very shortly.



WreckTangle
Posts:91
Joined:Sat Dec 02, 2017 6:16 pm
fill in the right answer:15

Re: PIERBURG Rebuild - pre build advice

Post by WreckTangle » Mon May 31, 2021 11:00 pm

There are procedures for properly setting most of the things that might have been tinkered with to compensate for the non-functioning wax stat. You need to have set the basics correctly as you reassembled the carb.

You adjust the warm up curve for your new wax stat using special tool 4.07360.02. You’ll be lucky if you can source a genuine one but I was able to make one from a steel plate and a machine screw with very little prior experience of metal work.

The choke plate and the two stages of the pulldown unit can all be adjusted per the instructions in that link.

The throttle stop screw is adjusted with a hot engine by removing the vacuum hose from the throttle actuator (3/4 point unit) and turning the throttle stop screw to get a fast idle of exactly 3000rpm. Then replace the vacuum hose and use the 13mm hex on the back of the 3/4 point unit to tweak the normal idle if you need to. It should be somewhere between 750 and 950 rpm depending on the age of the car.



WreckTangle
Posts:91
Joined:Sat Dec 02, 2017 6:16 pm
fill in the right answer:15

Re: PIERBURG Rebuild - pre build advice

Post by WreckTangle » Mon May 31, 2021 11:05 pm

PS. Before you go to the trouble of reinstalling the carb on the car you might want to obtain and replace the carb flange, VW part number 026129761E, unless you’re absolutely certain it’s relatively new and not leaking. Cracks in the rubber are very hard to spot and will play havoc with engine performance and trying accurately to set up the carb.



h11poc
Posts:75
Joined:Sun May 16, 2021 6:37 pm
fill in the right answer:15

Re: PIERBURG Rebuild - pre build advice

Post by h11poc » Wed Jun 02, 2021 1:11 pm

Hi , thank you. I have no clue what you meant by the wax stat setup. I thought it was just set at factory. However there is a major problem. When I tried to fir the wax stat the lever that holds the throttle pushed the pin of the wax stat in. I have to use an allen key to move the lever so there is no way on earth the wax stat pin will move that lever... Ive attached a photo as I think sure the sprint is installed wrong or something..
The was stat cost me 90 pounds delivered so I dont want to mess it up.



h11poc
Posts:75
Joined:Sun May 16, 2021 6:37 pm
fill in the right answer:15

Re: PIERBURG Rebuild - pre build advice

Post by h11poc » Wed Jun 02, 2021 1:18 pm

Image