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ANDYR

using a synchrometer to balance the carbs

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Hi all.

 

With a Sealey VS209 Synchrometer (catchy title) I'd like to balance the carbs but need to 'stick' the thing in the right place so vacuum inlet is the place - correct? image attached Anyone had any experience with this?

 

post-13144-0-86014100-1410635738.jpg

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Yep, that's the one.

I use the Morgan carbtune ll which has columns not dials. The sealey may be easier to read


Лотос - для тех которые знают разницу

ENIGMA for those who are paranoid or download one :)

 

 

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Ive used the CarbTune 4 column one. Pretty easy except getting to one of the little screws as my turbo plenum kinda gets in the way. I would think should be easier on the N/A.

 

Buddsy


 

"Belief is the enemy of knowing" - Crrow777

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Geert...you get more impressive every day!!!


Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

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Geert.  Genius.

 

I shall think of you should I need a saline drip or a blood bypass.

 

I'll let you know how the Sealey goes.  Cheers.

 

 

Andy

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I did a similar thing with just one tube... down the shed wall, a few coils so there's some mass to the fluid, then back up again.  using auto transmssion fluid and a restrictor on the hose, balance the carbs against each other quite easily and only $5, would work as well to balance the throats against each other too if necessary, just one carb at a time.

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Okay.  Good there is some knowledge out there. appreciate it.  I did a set up today and got readings of equal measure (give or take a bit) on cylinder 3 and 4 but 1 and 2 are out.  

 

Adjusting the idle I could hear and feel a difference in the spin of the engine but no change in the readings.  I can 'freeze' the needles on the synchrometer by shutting off the inputs to record what's going on.  Giving the engine a feather or two didn't shift anything and I span the idles both up and down a great deal. The idle mix and main mix emulsions are all full locked down,so what am I missing?

 

post-13144-0-30595800-1411066498.jpg

set up

 

post-13144-0-71139000-1411066513.jpg

dial readings

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I'm not too familiar with the esprit, but I'm fairly sure that you shouldn't have the valve cover breather connected to the back  #4 intake manifold. Only brake servo and vacuum systems should be plumbed into the manifold. A mini air filter on the breather pipe should suffice, or direct it into the carb intake area.

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Same as mine, cam cover breather into airbox (as does the crankcase breather via a thicker, shaped hose).  Not sure where you should direct it without the airbox but definitely not into the intake manifold... where does your crankcase breather go?

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The carbs Must be balanced at the same time as setting the mixture.

ie: set the base mixture to 3 1/2 turns on each carb

Balance the carbs to set the vacuum by :-

fully close all balancing screw ( the screw in the recess next to where the gauge pipe screws in), then adjust the throttle coupling between the carbs if necessary to get the lowest columns of each carb reading within 3mm (or the same pressures on a dial gauge) then adjust the higher of the readings to the lower by opening the balance screws on the relevant pots

Then you can set the mixtures , by moving all 4 screws by the same amount ( the mixture screws not the Balance ones). A colour tune would be useful .

All the time the idle revs need to stay at a constant so as not to affect readings, around 850 I think?

Then recheck the balance and set the mixtures again.

Sorry, just copied from my post on the mot emissions thread and modded it a bit lol

Hope it helps

Edited by Dodgy

Лотос - для тех которые знают разницу

ENIGMA for those who are paranoid or download one :)

 

 

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I have a document on how to balance them if you want a copy PM your email address, but i'm going on holiday tomorrow for a couple of weeks.


Amateurs built the Ark

Professionals built the Titanic

"I haven't ridden in cars pulled by cows before" "Bullocks, Mr.Belcher" "No, I haven't, honestly"

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The crankcase breather and engine breather can just be run down under the car and you can certainly just disconnect it to check if thats whats causing your imbalance. Make sure you plug the manifold if you do.

 

Brian M.

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Hi all.

 

Back from a week away with work. I kept reading the updates whilst away and I have spent my day tinkering with your advice.

 

Replaced crankcase breather fiasco with air filter. Didn't see the forest for the trees here.  The obvious error when looking back on it all.  This had an immediate effect on the running of the engine.

 

I then followed Dodgy's advice and managed to get both carbs balanced and then fiddled for a while to get the best mixture I could.  It's still running a bit rich (smelly) and dark exhaust residue with the odd misfire, but I can easily adjust that I think over the weekend.  Just been for a road test and idle is now about 650! - things settle differently after a while it seems.

 

I shall hook it all up again tomorrow and repeat the procedure to make sure.

 

Attached shots and short video to show progress today.

 

Cheers again.

 

 

IMG_0487.MOV

post-13144-0-03758100-1411744378.jpg

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I have a feeling that the throttle cable should come up from under the carbs...the outer goes to the throttle on the carbs and the inner goes to the bracket on the cam cover. Seems weird, but gives a straight run for the cable...and it's the outer that moves the throttle whilst the inner stays still!!

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Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

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I have a feeling that the throttle cable should come up from under the carbs...the outer goes to the throttle on the carbs and the inner goes to the bracket on the cam cover

Absolutely, the inner cable is attached to the bracket on the cam cover & the outer pushes the throttle open :-)


Cheers,

John W

http://jonwatkins.co.uk

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Forgive me if this is a stupid question but this thread is confusing me even more than I already am with carbs.

 

Where are you plugging these tuners into on the carb?  The balancer I have goes into the trumpets so I am not sure how the ones you guys are on about work.

 

Is it either A or B on the photo below?  I can't find anything on any diagrams to tell me what these screws are.  The photo was taken last year when I rebuilt them and the book never mentioned them at all, so they were not touched.  If anyone can tell me what theses screws do it would be really helpful. Thanks

 

post-5743-0-10862400-1412542021.jpg

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Hi.

 

 

B are the vacuum Tap Blanking Plugs to connect your manometer .     Screws out, manometer connections in.

A are the idle Air Bypass Screws, used to balance .

 

 

This site is really useful for ballancing and first start of dellorto DHLA carburettors : http://theapplebyclan.com/Richard/Tiger%20Super6/Useful%20info/Dellorto/

 

 

Greets Geert

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Nelly...what you have is a flowmeter which measures how much air is flowing into the carburetter choke to which it has been fitted. The other type is a manometer, a pressure/vacuum measuring device, which fits to the carburetter where shown in the above posts and measures manifold depression directly. The "old way" of setting multiple carburetters...that I learned first on myMG TC and then the Alfa GTV...uses a length of rubber tube; one end in the ear and the other held by each choke or carburetter in turn. One listens to the air going in and sets the carburetters to be the same....a flowmeter does exactly this job, but gives a numerical readout rather than relying on the skill of the chap with the ear and rubber pipe!! The "old way" can be just as good... I remember setting up dual Weber carburetters on a Ford Anglia after the owner had spent loads of money on various firms who used assorted measuring devices without getting it right. Once I'd finished with the rubber tube, it would idle with a threepenny bit balanced on the rocker cover....An esoteric art, but eminently satisfactory and worth the time spent practising!!

 

Whatever method you use, the idea is to get every cylinder doing the same amount of work. It is also useful to be able to push back the plug cap connections so that you can short out each cylinder in turn with a screwdriver to earth...once this produces the same rev drop for each cylinder, then you're getting somewhere!!  


Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

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Thank John (as always).  I am really trying to learn all about this but the results I am getting are not filling me with confidence,  I thought I had it sussed last weekend only to find following a 2nd MOT fail that I clearly didn't.

 

I am going by the Des Hammill book, it says nothing in the testing and setting up section about the two sets of screws in my photo as far as I can tell.  It does have a picture of the carbtune II manometer but it also has the flowmeter pictured which I have.  I don't really know if I should be playing with the air screws and what reading I should be getting on my flowmeter.  That said, I thought I had balanced both carbs together two weekends ago as the RH needed winding down slightly to match the LH using the linkage screw.

 

I am starting to think that maybe I have a blockage somewhere, so I may be pulling them apart soon.

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Hi Andy. Difficult to tell from your pictures but it looks as though you have the carbs bolted tightly to the inlet manifold? They should be mounted with Thackeray washers (or the modern rubber equivalents). These allow some flexibility in the mount reducing vibration and so reducing foaming of the fuel. Getting this right will help to get the tune right. Cheers john.

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Synchronising the carbs is one thing....mixture adjustment, although influenced by this, is another. Float level and the idle jets can be critical...the idle jets cover the mixture all the way through from idle to where the main jets come in...the whole of the progression. Check the progression holes in each choke...they are under the brass cap by "B" in your photo...in fact, looking at the photo, you have them removed and you can see the holes. Make sure they are clear....if not, then you will be compensating for this with the mixture setting.

 

 

The idle mixture adjustment screw is the one on the flange that bolts to the manifold...mine are in towers and are very fine threaded. One of them sits under the slats on the Turbo engine cover, and was seized solid...the fine threads can easily do this. This can lead to ruin of the screwdriver adjusting slot, as had happened to mine before I bought it. Being broke at the time, I admit to butchering the tower and the adjuster by cutting it with a hacksaw....this cut a slot in the adjusting needle and unseized the thing in the thread, I could turn it and the seal was maintained so it was rendered functional - if not pretty!! It is these adjusters that affect the mixture....the whole thing is an iterative process, you go round and round the loop adjusting the idle by-pass and the mixture until you have it correct.

 

I would suggest that to set the mixture to the MOT parameters you would need a gas analyser...or a Colourtune, if you can get one to work ( mine won't screw in to the plug threads!) otherwise you are shooting in the dark... For the test, best to go a bit weak....but don't leave it weak afterwards as that risks nasty things happening when you are pressing on a bit.

 

Hope this helps....it's a black art; once you have got it sorted you will be an Adept!!


Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

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Yes it does, I understand the idle screws and have a colourtune so have seen how these affect the engine.  I guess its the bigger picture I am missing, your snapshot of "round the loop" has inidicated its not something you just set once, which is what I thought (and did).

 

Thanks all for your help as always.

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