Poor running , servo air leak issue ! HELP needed.

Running rich and fouling the spark plugs really black ,using a lot of fuel and running poorly ! Carbs i thought as did my vw friend, so i contacted a mobile tuning chap who duly popped over to take a look.
Firstly he said he needed to check the timing ,points ,coil and condenser. ( the one thing i did do before he arrived was to put in a new set of bosch wr7cc spark plugs ) any way he struggled to do the timing as the gauge and round thingy with the notch in were not in the correct position i know knowledgable aren't i , so he removed a plug to set TDC and set the timing best he could . Then onto the points , barely opening and burnt ! chucked them out and replaced same with the condenser . Now for the coil , readind 2 on the meter should apparently be 3 ! so this was replaced , we kept firing it up checking progress as we went.
Next was to balance both webber carbs, which was done noting they were quite good to begin with also adjusted mixture, then the throttle was checked which found a problem with the linkages not fully opening so he gave me this job to sort , along with the next issue he found . Carbs ran badly when connected to the servo vacumn pipe , when this pipe was blanked off the carbs performed well , although the brakes suffered on the final test drive as expected to do.
So i have this job to sort also , trouble is i can find no info, part or advice to sort this problem.... SO CAN ANYBODY HELP ?
just to add the bus ran so much smoother after this ( elderly gentleman 73 )had performed his stuff ,he's booked to come back when i've sorted the few issues he has given me to sort plus not just a carb issue !!!
Also is there a way of identifying the cam settings without stripping the engine ?

 

You can take out the oil pump (slacken case bolts just above and below to make it easier, remenber to re torque, remember new gasket and you will probably need a pump puller tool ) and see if you can see markings on the cam gear. Maybe there are markings maybe you will be able to ID it if there are markings.


Check servo hose for splits then probably replace the servo. Or just leave it blocked off and learn to use the brakes without servo.

 

Forget the cam, I expect he was just interested.

With vac hose connected run the engine, crawl under following the hose. You may hear the leak hissing. Improve your chances by using a pipe off cut (garden hose or anything handy) as a stethoscope.

Replace leaky pipe/remake join or whatever.

If you didn't find a leak...

Front of bus side of servo has a breather pipe. Pull it off, engine running put your finger over the breather outlet - if it sucks your servo is faulty.

Depending on what you suspect you can do those tests either order.

 

What engine do you have?

It’s impossible for the cam timing to move, if it’s wrong it’s been wrong since the engine was built. Yes, it can be checked without stripping the engine, as Mike describes, but if the running problem has only just started it’s not the first thing to check, and it may be beyond your comfort zone.

First find the vacuum leak; check the connection at the manifold and the tube and hoses from the manifold to the brake servo. The leak may be within the servo of course.

 

I like my brakes , so servo stays !!! the servo and the brakes work perfectly this chap has only disconnected the pipe to make the carbs perform better , he says that air is leaking from somewhere and has given me the job of rectifying ....hence this thread.

 

Thanks for that i will do this at the weekend and report back.

 

Thank you too , i will check the servo and pipe and report back with pictures. By the way it's a 2.0 but the tuning chap suspects a modified camshaft.

 

ok chaps i've taken some pics of how the chap left the pipe at the carbs ! this enabled the carbs to run better . when i re-connected the pipe i found no air leaks.
I was unsure as to what to pull off the servo to check to see if there was a sucking feeling , so can i be pointed in the right direction please.

 

Last photo, the plastic housing between the operating rod and the bellows has a spur pointing upwards (ref van not photo).
That's the one. The whole plastic housing will spin round, the spur should have a pipe extension to a safe area to avoid damp and dust getting inside the servo. Each time you operate the brakes it sucks some air in here and never blows it out. If it sucks when not operating the brakes the servo has an internal fault.

 

Here's a funny thing. Some servos come fitted with an all but invisible blanking plug in that breather spur, if you don't see and remove it, the servo won't work.

 

Another chap has been in there before. At least three of those hose clamps are too large for the hose and there could be a leak there. And where there are two clamps together at the non-return valve is suspicious - is it supposed to seal a hose that is the wrong size?

When you re-connected the hose did the engine run okay? Has it ever run okay with the servo connected?

Incidentally how are you checking for leaks?

 

I would be tempted to redo the whole lot, with the proper diameter hose and the correct-sized clamps. That is a real mess.

That non-return valve looks a bit odd as well.

 

I think the brake servo breather hose has a hole provided for it in the inside of one of the front wheel arches. So the end is well out of direct dirt and water spray.

 

When connected it ran , but not as well ! It's been running with the servo connected for over 4 yrs ! admittedly i've always known it was never running at it's best ,but i'm limited to changing plugs and points , oil and filters, brake disc's and pads etc etc .The 2 E's are my problem , Engine and Electrics and associates.
I'll be honest only through listening close up laid on my back underneath, i should of applied soapy water.

 

Where is that on my pic's ? please Mike.

 

Is the blue pipe better done in rubber ? and the clips those 3 claw type ? Any recomendation's of suppliers.

 

Soap won't help, it's sucking not blowing.
Use a hose stethoscope to hear properly.

My money is on the servo, the way it's fitted with the unprotected breather (which should be renamed air intake) pointing upwards to catch any crud...there is a clever valve just inside there...have you put your thumb over it yet?

 

Just ordered non return valve and pipe to replace from servo to inlet manifold. And i'll check the servo !...................I'll report back in 7-10 days.

 

Use hose the correct size and suitable for vacuum (SAE J1402A). https://www.wrightsautosupplies.co.uk/product/brake-servo-hose/ https://www.ebay.co.uk/itm/RUBBER-V...IPE-TUBING-BSAU110a-A-SAEJ1402A-/371809379042

There is nothing wrong with the hose clamp type that you have but several of them are the wrong size. The hose diameter that they are suitable for should be stamped into the clamp. The non-return valve looks original but it’s usually under the bus, not in the engine bay.

Listening for leaks is good, use a tube as a stethoscope a zedders says. Disconnect the vacuum hose at the servo, block the end with a bolt and check for leaks, if there are none and the engine runs okay, the leak is in the servo.

 

Or just stick yer finger in that 'ole.