Twin Webers - need cert?

ian86, Oct 11, 4:35am
I'm doing up an old Cortina with the 1500 motor in it. It will need to be re - registered with the old black plates, it will be standard but was thinking of putting a set of 40mm side draughts on and a slightly warmer cam.
Just wondering if the Webers would require a cert in todays world ?.
bantam3, Oct 11, 4:37am
No, if engine mods don't increase the power by more than 25%. But don't quote me on that:)
ian86, Oct 11, 4:39am
That was quick :) , thanks for that.
tony9, Oct 11, 4:40am
It is 20% now.

Minor modifications to OE engine  the modifications result in not more than 20% more power than the OE engine,
which may include the fitting of:
 extractor or free-flow exhaust manifolds, big bore exhaust systems; or
 changed intake manifolds; or
 changed or multiple carburettors; or
 modified fuel injection systems; or
 changed ignition systems; or
 alternative cold air box induction systems.
Note: LVV certification is always required for the fitting of a supercharger or turbocharger as a
modification, or the upgrading of a supercharger, turbo or wastegate, or the re-chipping of
electronic engine control units on turbo vehicles.
sr2, Oct 11, 5:03am
I’m a great fan of 1500 pre cross-flow Fords but Twin 40 DCOE's on a std motor could be a bit of a recipe for an over-carbureted disaster. The single 28/36 DCD from a 1500 GT would give far better results particularly if you used the 1500GT Cam (be aware that even with the single carb the 1500GT ran larger valves).

To successfully run twin DCOE's on a pre crossflow you would need to be looking at a balanced motor, extensive head work, an aggressive cam and a modified distributor with no vacuum advance.

Sounds like a great project, love those old ‘tinas!
201, Oct 11, 6:07am
Very good advice from sr2 as it will only drink lots of petrol and not really perform as good as it could. The 28/36 down draught will work way better until you extensively modify the rest of the engine.
cheers.
lookoutas, Oct 11, 7:38am
I once had flash looking triple Stombergs on the Mk3 engine in my Mk1. It went like stink, but needed about 3000 revs to get it moving, and a heap more on an uphill start, with a lot of clutch slipping. (useless handbrake)
Got so pissed-off with it while at Trade-school in Auckland, I drove home to Taumarunui on the first weekend (wasn't in the plans) and chucked the single twin choke down-draft Weber back on. Getting an instant squirt down the gurgler solved all those problems.
Never took it off again, and someone else persevered with the flashies.

Guess that's beating the same drum as sr2 & 201.
framtech, Oct 11, 8:44am
40's will be ok but you will need to fit smaller choke tubes and jet and tune to suit airflow, only real issue is warming up before running as there is a risk of fire as the side d's spit and carry on until the engine is warm, fuel can build up in airbox , You need to keep you foot in it if they catch and suck the flame into the engine,, had it happen many times years ago with the rallycar.
sr2, Oct 11, 9:26am
Mmmm, possibly on a 2 liter Pinto but on a bog standard pre-crossflow 1500?

Do agree with on the fire risk however, my nephew lost a mint Escort Van when the DCOE's on the modified 2 liter crossflow his father and I had fitted coughed back and burnt it to the ground.

IMOP despite the toss factor it's a sod of a carb setup to live with in a street car.

That aside I also need to confess to having recently purchased a triple DCOE and manifold setup for my latest project- but that's another story!
snoopy221, Oct 11, 9:40am
Reading this simply RECOMMEND-FROM EXPERIENCE
remove and blow out ya accellerator pump jets REGULARILY
sr2, Oct 11, 9:46am
How the 'eff are ya snoops me old mate?
Only a few weeks till Targa time, looks like we'll be down your way.
barrylarry, Oct 11, 11:59am
just put the weber and lumpy cam with the standard air cleaner. no one will know. they run like dogs anyway
mrfxit, Oct 11, 6:12pm
Yep just had this early this year with a 1600cc Avenger.
Lumpy cam/modded head/ twin sidedraft Dolorto 40's & extractors.

Was a right royal pig at anything under 3000rpm
Even with 1 Dolorto & stock cam it was a pig.
the-lada-dude, Oct 11, 7:06pm
I think they'll be absolutely ok, I can give you a good starting point on sizing the bits in the carbs. although the best bet is to contact ( Murray at Weber Specs )

The advantage with this set up is the development potential if you start tinkering with the engine. The main venturi choke size is critical to the performance of your carbs . i'd start at around 27 mm maybe as high as 29. . make sure you run the ' O ' ring mounting plate and stud springs . spending time matching all the intake flanges and gaskets is worth at least 5% power increase . and a 3 > 5 angle intake valve seat job another 5 +
ian86, Oct 11, 8:36pm
Thanks for all the feedback, I do understand # 5,6,7 what you are saying.
It seems to be a common upgrade on these so thought it would be a pretty sorted setup?, it is the eye appeal factor of the twin sidedraughts that I like, but certainly I want something that works and is not a problematic.

It is a GT engine and I do have the original carb set up, so once the engine is rebuilt I may be better to stick with that?. the only thing I don't have is the original GT air cleaner, just a ramflo, and the originals are as they say, like rocking horse shit, I guess in the day they where the first things to go .
mrfxit, Oct 11, 9:05pm
Upsizing carbs on those engines is best with down draft webbers

Any of the 28/36- 32/36 - 32/32 - 38/38 will do the job easily but the 28/36 will be hard to find these days.
Variations of the bigger 2 models are available brand new
the-lada-dude, Oct 11, 11:53pm
CRAP . go get some advice from Murray at Weber Specs . cost nuttin

if you're tempted to re-cam for the street stick to around 50* overlap 108 > 110 * LCA . if you shake the the dice., the #'s fall out to around 25-65 / 65-25 . so this is split timing straight up . leaves you the option of about 4* advance / retard . your intake valve size means around 0.360 " lift and as you're not above 6200 rpm. . you might be able to find a cam with aggressive acceleration flanks that gets to that lift pronto. possibly stronger valve springs ?
elect70, Oct 12, 2:55am
How would they know how much youve increased the power by > yet to see a testing station with a dyno . . Up it 40% & just ell them its only 20% or detune it if they require test for rego & re tune it afterwards .
richardmayes, Dec 27, 5:58am
Thanks Sir!

How would a WoF issuing garage, ever know your modifications produce less than 20% increase over OEM though?

I have a pipe dream project that involves getting my old PI Triumph back on the road with electronic injectors, ford falcon coil pack, various bits & bobs from the jap import tuning industry, and a Link ECU to make it all happen. a TR5 cam would in theory give it just under 20% more go than the 2.5PI cam.