Twin 38 DGAS Carburettors on essex V6

[rsh]

Can anyone suggest jetting for twin 38 DGAS Carburettors on essex V6 ? Engine is similar spec to the power charts on www.essexengines.com which suggest 142/145 mains 160/160 air which I tried but wasn't happy with. Will get on a rolling road eventually but as local tuners don't carry jets will have to supply a selection. Anyone using the old Car Clinic manifold ?

Edited by rsh on Friday 14th December 08:34

[bluezeeland]

think the sizes mentioned are for a single carb ? Dunno 'bout a double set-up, but am very interested to see what comes up. btw; before going on the rr, wouldn't it be better to have it set, at least roughly ?
Frank

[Geoff38]

just out of curousity , what do the three spherical bearings do on the top of the manifold ??

Cheers
Geoff.

[Slow M]

rsh said:

...as local tuners don't carry jets will have to supply a selection...

Solder and re-drill. It's (relatively) infinitely variable.

When it's dialed in, buy the parts.

Best,
B.

[bluezeeland]

Do Weber do a complete (all sizes) drill set then ?
Sometimes the inadequacy of a 'weekend-mechanic'(like myself) becomes all the more clear........

[TaimarTurbo]

Or cheaper:
http://www.ebay.co.uk/itm/20-Pc-Micro-HSS-Drill-Bi...
And
http://www.ebay.co.uk/itm/4PC-Hollow-Wire-Pin-Dril...

Make sure you measure each drill before using it, they can be in the wrong order.

I have drilled countless jets, airbleeds and restricions on Holley carbs.
Some tips I can give you are:
-Use a slow speed cordless drill and lubricate the drill bit with WD40
-Put the jet in the cordless drill and the drill bit in the pin vise.
If you do it the other way around you will break the drill bit very easily.
-Drill at least one size under, ream to the final size by hand.
-As the entry and exit matters a lot to flow I recommend you flow the jet before drilling.
This is not as difficult as it sounds. All you need is a stopwatch, a large syringe, 30cm of hose and some water.
First pull the plunger out. Attach the hose to the syringe. Put the jet in the other end of the hose. (always use the same length of hose!)
Mark two levels on the syringe, one 1cm-2cm below the top, the other near the bottom.
Now fill with water and measure the time it takes for the water to drop between these two points.
Using this method I've been able to measure jets with an accuracy of 0,5%.

Get at least a 100ml syringe, bigger and smaller bore is better(more accurate).
You want the water to take about 100 seconds to drain out if you want any accuracy.


Fred

ps Just seached on ebay, but can't seem to find a sutable syringe, perhaps you can adapt one of these measuring tubes?
http://www.ebay.co.uk/itm/NEW-MX-ENDURO-OIL-MEASUR...
http://www.ebay.co.uk/itm/Oil-Petrol-Measuring-Tub...

[bluezeeland]

Blimey, think the OP' questions have been answered (or at least leading to the solution)

cheers !

[rsh]

Geoff38 said:

just out of curousity , what do the three spherical bearings do on the top of the manifold ??

Cheers
Geoff.

It's for the balance bar that holds the linkages for the carbs.

[rsh]

Great suggestions guys but don't forget twin carbs = 4 main jets and 4 air correction jets to drill - solder , which is why I really like to hear from someone who has actual experience with this combination first. Real world numbers please ...

http://thumbsnap.com/sc/LiI2TW9d.jpg

Edited by rsh on Tuesday 18th December 08:44

[TaimarTurbo]

FYI 1 4150HP Holley carb has: 4 main jets, 4 High speed air bleeds, 4 Idle air bleeds, 2 or 4 Power valve channel restrictions, 4 Idle feeds restrictions 4 kill bleeds and 12-20 Emulsion bleeds.

I didn't suggest flowing them for nothing. I see no reason why the method I use for Holley's can't also be applied to Webers.

Sorry I can't give you any real world numbers.
But No-one is going to know exactly what jet sizes etc you need, you'll have to find out for yourself.
Even if someone would run the same carbs and manifold, you'll find your combination will require a different jet setup.

Edited by TaimarTurbo on Tuesday 18th December 12:16

[bluezeeland]

TaimarTurbo + 1 (because he's fully right.........)

[rsh]

TaimarTurbo said:

But No-one is going to know exactly what jet sizes etc you need, you'll have to find out for yourself.
Even if someone would run the same carbs and manifold, you'll find your combination will require a different jet setup.

Edited by TaimarTurbo on Tuesday 18th December 12:16

Well duh, state the obvious, of course nobody will know exactly what jet sizes I require, my request is simply to get some numbers and find out which way the jetting sizes went, dual carb compared to single carb. Once I have some data, I can continue my testing ... and I'll be happy to share the results.

[TVR_owner]

rsh said:

Can anyone suggest jetting for twin 38 DGAS Carburettors on essex V6 ? Engine is similar spec to the power charts on www.essexengines.com which suggest 142/145 mains 160/160 air which I tried but wasn't happy with. Will get on a rolling road eventually but as local tuners don't carry jets will have to supply a selection. Anyone using the old Car Clinic manifold ?

Edited by rsh on Friday 14th December 08:34

Rob,
We have the same problem in the UK. We have dyno operators, who are probably the in majority sadly, who will remap your ecu, fit new dump valves etc etc etc.

A person that understands carbs however is becoming difficult more difficlut to source.

If your dyno man does not have a range of jets and drills, he's very probably the wrong man.

[TaimarTurbo]

A quick google search yielded the following.
Note I didn't check any of this, so your guess is as good as mine whether this is correct.
I still don't know what you want with this...

South African Fords:
XR6/30S/granada 3.0:
45 idles
4.0 Aux venturis
55 accelerator pump jets
142 mains
185 airs

XLE cortina:
45 idles
4.0 Aux venturis
55 accelerator pump jets
145 mains
185 airs


Scimitar (running 3L v6 engine):

SE5 40 DFA-1:
180 mains
60 idles
50 accelerator pump
185 airs correction jet
F2 emulsion tube

• stock dfa uses much bigger mains and idles compared to stock 38 dgas

SE5/5a/SE6/6a 38DGAS 3A:
145 mains
45 idles
60 (OD)/ 70(auto) accelerator pump
185 airs correction jet
F50 emulsion tube

Ford capri 3.0:
Main Venturi 27
Aux. Vent. 4.0
Main Jet 145
Emulsion Tube F50
Air Correc. 185
Idle Jet 45
Pump Jet 70
Pump Bleed 30(1)
Needle Valve 250
Float Level * 40/52.5

For 38 DGAS 6C carb, 3.0 litre European spec Capri OEM jetting was......
27mm choke (main venturi, fixed)
4.0 aux. venturi
142 main jets
185 air correctors
F50 emulsion tubes
45 idle (slow running) jet
55 pump jet (no pump bleed info listed)
2.50 needle valve (gas inlet)

TVR_owner said:

If your dyno man does not have a range of jets and drills, he's very probably the wrong man.

Fully agree with that.
If that is indeed the case get yourself a wideband O2 kit and learn to tune it yourself.

[rsh]

TaimarTurbo said:

A quick google search yielded the following.
Note I didn't check any of this, so your guess is as good as mine whether this is correct.
I still don't know what you want with this...

I might not have made it clear but I'm asking about a twin (two) carb configuration, above settings are for standard single (one) carb factory configuration, the settings for which are readily available from your trusty Haynes manual or Google search. When you go from a single to multiple carbs, you need to make some changes, Essex Engines very kindly share their settings, was hoping others would also.

My mission continues, the truth is out there somewhere

[rsh]

Adrian@ said:

Carb settings aside for a moment...one of the things that I now noticed (as I could not see the picture properly until now) is that I would want to be changing the valve spring retainers for the later version, as the older version you are using can fail.
Adrian@

Thanks Adrian, will investigate further.

[thegamekeeper]

I am not convinced the answer is "out there somewhere". The internet is just a load of individuals sitting in their bedrooms typing. Who knows who they are and what they know but you are prepared to take their "opinions" and risk your engine.

Even the OP is vague. What does similar mean? Is your engine 3.4? is it a GA block or a South African ambulance or one of essexengines.com,s trick conversions? Does your cam have 276 degrees duration, .447" lift. Are your inlets 37mm, exhausts 43mm? What is your advance curve on "your" dizzy like?

Sitting in your garage trying things IMHO is pointless. At some point, and it may as well be the first point you need to get it on a Dynamometer and set it up properly in load conditions employing someone who as John said has the gear and also has the idea.

Not even remotely convinced by Adrians lambda sensor and electric drill at this point

[phillpot]

as a little aside this looks interesting.....

Fitted to a Gilbern, and I believe works quite sussessfully ?




ETA any better Thomas?

If not try clicky

Edited by phillpot on Friday 21st December 18:22

[Cerberus90]

Thumbsnap is not working for me at all in this thread, just keep getting '403 forbidden'.

[bluezeeland]

@ phillpot; thats a double intake manifold of an essex with tubing and double Webers DCOE 40', will that fit under an M bonnet ? (very nice, must say !)

at OP; if the guys at Essex engines are doing the inlet, can't they tell you what the settings of the carbs (roughly) are ?