Timing\ carb query

[MATTT]

Anyone have any ideas on this strange timing problem
It runs better when strobed at approximately 38deg full advance ,15 deg on idle
It should be 30 or 32 Max and 7.5 deg idle
If I set it to that it's rough on tick over and sluggish when pulling away esp at lower revs

1600TP with a unnamed brand new, but already fitted when I bought the van,copy version of a solex 34 pic3 which read some bad reports of

Took off the also new 009 dist and fitted the correct vacuum type one.I with new points ,set slightly wider stock as it had the normall 009 flat spot
It seems to run a little rich would this affect the timing?the carb adjustments seems to work though and I've checked the cold start arm for clearance
I will take it for a drive and see if its pinking I guess as it should do at this setting
The engine was a brand new VAG supplied one,the flywheel has the 3 marks for tdc 7.5 and 10 deg
Regards
Matt

 

[Dave.P]

Did you disconnect and plug the carb end of the vacuum pipe when timing it ?

 

[MATTT]

Yup
Checked the weight advance OK
And sucked the vauum pipe to check the top plate moves freely
The distibuor came off here from a running van that had upgraded to electronic

 

[Trikky2]

Have you got the vac advance connected to the port on the back of the carb or the left?

 

[MATTT]

Did worry about that at first
It's on the left side of the carb the one facing out towards you lower down is blanked off
I did the timing with both disconnected and blanked off as well
I can't remember as it was a while ago if I took the plug outmtomcheck the TDC on the pully mark was correct I think I might have

Next possible plan is to buy a proper solex rebuilt or used carb not a copy one and try i think

 

[Bluesnailman]

How many dimples or marks does your pulley have? if just the one - then that might denote 7.5 deg from tdc. Mine has only one mark, and wasn't sure what it denoted. having determined tdc from the piston position i measured it out and there it was 7.5 deg......

 

[MATTT]

It has 3
Which are I assume tdc 7.5 and 10

 

[Trikky2]

You need to know where TDC is on the pulley first - because the marks varied depending on the engine and dissy. Replacement pulleys came with no marks at all and it was down to the garage to mark them correctly.

Some pulleys were marked with 7.5 BTDC, TDC and 5 ATDC for instance.

On a stock pulley, once you establish TDC, 11.5mm to the right of this mark is 7.5 BTDC

 

[MATTT]

That's the only logical thing I can think of ,the pulley is incorrect
It has a tdc mark at the back edge along with a dimple of the front ,and then 2 further marks both to the right
The 1st mark is tdc as long as its in the correct place
The engine was brand new bought from VAG I don't know if it would have been supplied with a pulley(the pulley does look fairly new too)
I guess I should pullma plug and double check the crank and pulley line up

 

[Trikky2]

Centre of the dimple would normally line up with TDC.

 

[MATTT]

Well after a good run of over 400 miles the exhaust is still sooted so a carb change 1st then a recheck of the timing

 

[Trikky2]

Sorry. What do you mean when you say the exhaust is sooted?

 

[MATTT]

Black inside with soot from running too rich

 

[drew n steph]

Had same issues, found that the notch on rear face of pulley was 5atdc so protractor and mark out from there..

 

[Trikky2]

Had same issues, found that the notch on rear face of pulley was 5atdc so protractor and mark out from there..

That pulley would have been fitted to an engine with the dual vacuum canister. These engines were timed at 5 ATDC at idle with the vac pipes connected.

Many of these were replaced with single vac units timed at 7.5 BTDC because the emissions model twin vac was known to cause flat spots and slightly higher fuel consumption.