Hello lads, got some questions about my oldtimer GT with GK engine.

First I want to excuse me for my terrible English, I'm from the Netherlands, and will try my best!

First question, the car is not giving averything at full power. Third, forth and fifth gear, above 4000 rpm, he runs at app. 70%, and some times I can feel the car pull harder. This is since a few days, and I can't get the problem. I know its not running at full power. The old 75hp engine definitely has it, but it just won't come out. I suspect the original carb, but don't know what to look for. I want to learn everything, but I am a rookie with this.

Last question is, I recently bougt two double barrel Solex addhe 40 carbs, and just like the other carb, I really don't know anything about this. I fully stripped them, and ultrasonic cleaned both. They will be glass-blasted later on. What i would like to know is, there are pipes inside the carbs, with the number 32 graved in them. Is this the right size, or what size is usual for my 1300 engine? Also I opened them, and found (I guess) the jets. Its 6 of them, two really small ones, two medium with 210 on it, and two with 55. Who can tell me what these are, and also if this is the right size.

Hope to hear from you guys!!

Thanks so far!

Hallo Robert and welcome to ClubPolo.

You might get to see some of us at Polo Treffen Holland.

Your English is much better than my Dutch (Nederlandse?).

Like you I have a GK engine!

Power loss. Many possible causes not involving carb.

How many kilometers has the engine done?

When was it last serviced?

How good is the engine cylinder compression?

What colour are the spark plug insulators?

Might be the mechanical fuel pump?

Might be oil fouled sparkplugs?

If you have the original Pierburg 2e3 carburettor it might be the second stage pulldown unit's rubber diaphragm has split.

Right, Solex ADDHE C40s just like Wintershall Cup race cars used in 1984.

No idea what jets they used for that.

Might be written in some lucky german's TuV Eintragungsbrief after special individual approval!

Pipes with 32 engraved must be the chokes. A little large without headwork or a high duration high lift cam. I'd suggest 26 for drivability&economy and 31 or 32 for trackday or rally or autobahn.

55 must be idles - ok. Won't need the main jets until 2800+rpm.

(Pierburg on GK has 37.5 while HK needs 47 I think)

Mixture and speed screws can fine adjust for this.

210 will be the air correctors. Yes leaning out at high revs is good.

The small ones will be the main jets and I'd expect something between 112 to 135.

I'd suggest 120. I know zero about Solex emulsion tubes or float height.

What size pump jets do ypu have?

I'd suggest 35? But might need more with 32 chokes.

Solex are much less common than Weber DCOE or Dellorto DHLA so knowledge is rare.

You'll need patience and an AFR gauge attached to a wideband Lambda sensor to set these up right or pay an expert with a rolling road...

At least you can change the jets. That might not be the case for all Solex.

Can you read German?

Interesting but not great news in these two webpages:

http://www.polotreff.de/forum/t/146907

http://forum.polomagazin.de/print.php?thre...675b778c7d5fbe3

Edited 15 February, 201313 yr by dvderlm

I wanted to combine the carbs with a 280/280 camshaft. GK already has higher pressure combustion chambers, so that has to be taken in the jet setup. And I was really in doubt about either bike carbs or double barrel carbs, but liked the double barrel carbs more, as they are more "in style" with the car's age. And I know the bike carbs are much easier to set..

Really don't know what to do about it.. At least I got something to read:)

And maybe it will be bike carbs in the end, but I really wanted to give this a try.. Maybe webers? Because easier to set?

Another two possible power carb related loss causes

Partial secondary idle or main jet blockage in the Pierburg.

The oil breather pipe disintegrates and fine particles build up.

Compressed air and carb cleaner spray might get rid of it.

Also search for 'RAC patrolman trick' om here.

How clean is the air filter inside its box. Salt spray can totally clog up the filter in the air box. The trumpet pipe behind grill sucks it right in... fuel consumption will be bad though.

Tomorrow I will get a new air filter, and open up the carb. Last big maintenance was about 2 weeks ago, and the previous one was at 90000km, 4 years ago. Compression is perfect, spark plugs have just been replaced.. Engine did 100.000km, think that's about 60.000miles??

At the service (maintenence) did they fit GK suitable cold plugs?

Or standard Polo items?

The GK runs very hot due to HCS (hence the huge radiator) so needs Bosch W5DTC or similar to conduct heat away.

If they fitted Bosch 7 heat range it won't spark so well at higher revs.

The W5DTC is no longer available. I used Beru UX56 but they are also hard to find.

Bosch have combined heat range with their SuperPlus products. Can't think of any multi electrode cold plugs, so you'll probably need to move to NGK or Champion -

Maybe 7.8 or 9 heat range - yes the numbers go the opposite way for different manufacturers.

Maybe NGK BUR6ET?

Or Bosch Super4 WR56 (is multi-electrode)

Edited 16 February, 201313 yr by dvderlm

Solex info

http://www.rmcarburetors.net/addhe_rebuilding%20v2.htm

Toyota Corolla 1600cc 2T-G engine (twin cam)

use 55/125/150 and 45 pump jet

so 55/120/200 and 35 to 40 pump jet can't be far off suitable for 1.3

http://www.rmcarburetors.net/Tuning%20Tips.htm

Some more specs including float height. Plus jetting for 1.6 and 2 litre.

http://www.alfabb.com/bb/forums/carburetor...ice-needed.html

Edited 19 February, 201313 yr by dvderlm

Nice mate! Thanks!

Maybe an important add to the pierburg problem, when the engine is cold, until "almost at running temperature", it runs a lot better!

You mean it is running better with choke flap partially closed.

But is not so good when warmed up and fully open - it runs better when mixture enriched

despite the flow restriction of the choke flap.

That suggests an airleak to me.

You haven't answered about the colour of the spark plug insulators, or which type were fitted.

If the insulator nose is white not tan, the engine is running too lean. That's evidence for an airleak too

But the power loss is above 4000rpm.

So it really has to be a 2nd stage problem.

A leak near the 2nd stage butterfly?

Split base moint gasket?

Blocked jets.

2nd stage pulldown unit defective

Accelerator pump diaphragm split.

Are the vacuum hoses in good condition - especially to the Bosch Dignition box behind bulkhead.

If this has a split you have an air leak.

And the Dignition will not retard/advance the spark under load.

Edited 19 February, 201313 yr by dvderlm

Spark plugs are a bit White, and they are Bosch super sparjs?? Heat degree 5??

Take a look at a Pierburg manual.

http://www.ruddies-berlin.de/se2E2e.htm

It is for 2e2 not 2e3 but English.

Or http://www.ruddies.business.t-online.de/se2e3vw.htm

(for 2e3 in German)

There's a troubleshoot table with Complaint Cause and Remedy.

Complaint "Power too small, misfiring at full load" has associated causes

14 Enrichment valve defective,

16 Float defective/Fuel level incorrect,

18 Throttle plates do not open completely,

19 Depression bellow stage II leaks

20 Jet settings not as specified.

(assumes valve timing, ignition, intake, preheating, exhaust, fuel pump pressure, clean filter all in order).

Spark plugs are a bit White, and they are Bosch super sparjs?? Heat degree 5??

Bosch 5 will be fine.

Lack of fuel could be lean, not just too much unmetered air.

Especially at high revs.