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MG MGB GT V8 Factory Originals Technical - Edlebrock Carb Help

My '64 MGB with a Rover 3.5 L just hit the road on Saturday. Yesterday I logged a quick (very quick) 300 miles in the mountains east of San Diego. Now I really know why you guys are so psyched about these cars! Woo Hoo is an appropriate statement! Anyway my car is equipped with an Edlebrock 1404 right out of the box, and it's running pretty rich. Can someone help me out with the info I need to re-jet the carb properly?

Thanks in advance.

Pete
Pete

I am running a Buick 215 with a stock cam and per recommendations I changed the primary jets and metering rods to

Metering rod - P.N. 1441, 062x652
Jet - P.N. 1421, .080

The engine ran leaner, got slightly better gas mileage but stumbled every time I accelerated. Accelerator pump adjustments only made a small improvement. Ended up going back to the stock metering rods and jets to regain driveability. Haven’t had time to take the metering rods and jets up a notch. Let me know what you end up with.

Jim Miller

Pete,
Take a look at the "Calibration Reference Chart" for a #1404 carb on Edelbrock website. This same info should have come with the carb as purchased.
http://www.edelbrock.com/automotive/index.html
Graham Creswick

I swapped my #1404 needles and jets for:

Part #1443 (.063x.047) - Needles

Part #1422 (.083) and #1425 (.092)- Jets

Bid difference in air quality readings (we have an "Air-Care" program in the Vancouver area). Haven't noticed any hesitation or stumbling.

Now I know why I didn't need any choke with the stock carb prior to swapping jets.

Cheers
Simon
Simon Austin

Pete
I got jets from D & D Fabrications for my 1404 on a Rover 3.5. I don't have the information readily at hand but I just called D & D and described the engine mods and they sent the right jets.
Phil
Phil O

Thanks for the help. I will follow up on the advise and give you all an update with the new jets. I am having a ball, with the car. I am using a lot of gas. Probably due to the carb and the amount and way I am driving.

Pete
Pete

Pete, before you change anything, check the float level. I've seen them WAY out of adjustment while new in the box.
Jeff Schlemmer

Pete, just be gradual leaning it out ... you sure as hell don't wanna give the Rover any excuse to run too lean or it can run brutally hot. Ask me how I know. I think almost all 4bbl carbs tend to run a little rich -- I was never happy with my V8's performance (it was a 4.2 Rover) unless it was set just a frac rich, because when it was set to normal it would always have one or two lean spots that made it stutter a tiny bit, e.g. at cruise. Yes it does swill gas like that but life is short.

It's AMAZING how coarse the different Edelbrock metering rods are from one size to the next. Which is kind of a bummer. One thing I found really helpful is, when you get a set of metering rods, just do a quick MS Excel mockup of the relative richness/leanness they produce. That is, take the area of the jet opening less the area of a given rod at its two positions. I think you'll be shocked by how huge the differences are, and how un-intuitive the different sizes in fact are. One thing to not ignore is the springs, which can have a subtler effect than the rod sizes -- i.e. what level of vacuum makes the rod pop up to the "step-up" section.

A good way to to figure out the best setup is to hook up an O2 sensor in your header and run that to an A/F gauge in the car. Useless unless you're spot on, but at least it will tell you which way you're off.
David

This thread was discussed between 15/03/2005 and 25/03/2005

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