MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB GT V8 Factory Originals Technical - SU Carbs on a Rover

I have a set of HIF 6 SU's and the manifold to put them on my Rover V8 convertion.I cut two holes on an otherwise scrap hood and the pots only stick out about 1 inch with my engine placement. I thing I can create somthing that looks good by using two MGC like bulges above the carbs. My qustion is has anyone tried this setup on a Rover and is it on par with the performance of the typical 4-barrel route? I know these were used on many different cars including Morgans so it must be a fairly good setup.
Thanks,
Jim
JCR Royal

Are you using the manifold casting similar to the original B V8's? The pathway is fairly restricted and not particularly smooth but it's certainly usable (I use it myself)...You will get more power with a Weber/Holly 4 barrel for certain but it depends what you're after.

If you tuning is fairly mild I'd stick with the SUs as there's still plenty of scope with them and they're so flexible. If you're after maximum performace then you'll eventually reach a ceiling with the SU's and would be better with the 4 barrel setup.
Stuart Robson

This is not the original SU setup. The manifold has a triangle like structure in the center with the SU's hovering over each valve cover. I believe the original setup places the carbs at an angle back by the heater box were there is a bit more head room. Is this setup any better or worse than the original. I think this will serve the purpose and have the added bonus of being completely different than 99.9% of the cars you see over here.
Thanks for your input.
Jim
JCR Royal

Yes you've got the Landrover/SD1 setup. I'm surprised you've got them that low. There's certainly better gas flow from this than the MG setup but still short of that from the 4 barrel. I'd be interested to see how it looks in the end....

As an aside I'd also like to know how you got the engine *that* low?

Good luck

Stoo
Stuart Robson

It's not that low. Only about 5/8 of an inch lower than the stock position. And I did not get it under the hood. There are two holes right now were the pots of the SU's stick through the top. I fabricated two small tear-drop shaped bubbles that are raised above the hood about an inch. I may use some sort of a cowl induciton type scoop to get rid of some of the heat I haven't decided yet. I have played around with combinations of crossmembers and steering racks and I may have run across something. If you use a RB crossmember and weld CB steering rack supports in the exact same position that they were on the CB crossmember the steering rack runs right between the oil pan and the stock SD1 oil pump cover with a stock filter and no problems with the sway bar. This also allowed me to lower the engine the 5/8 inch I talked about. I'm using RV8 headers because I've heard the block huggers eventually crack, and I don't see how I will get them threaded through the left side with the engine that low.

THE BIG QUESTION? Is all this work worth it??? Is a stock 3.5 going to make this thing more fun to drive?? I have a warmed up '65 1800 that I love BUT it ticks me off at how much effort it is to have fun with. I'm looking for that 600-3500rpm, pull me out of the corners, up hills, passing with little effort power that is not there with the 4 banger. Sure, it can be forced to go fast but I want it to be effortless if that makes sence. I'm not looking to go drag racing, I just want the car to run like it looks. Sorry to babble on but I've spent about every bit of spare time thinking about, or tinkering on this thing so I want to know it's worth it.
Thanks,
Jim
JCR Royal


The stock SU are fine to around 200bhp iv'e seen them on bigger capacity Land Rover engines that make over 220bhp but that must be their limit. They offer very accurate fuel metering and atomisation hence good economy over a four barrel or similar. Rover/Land Rover wouldn't have used them by the zillion otherewise.
If you want a torqey motor and are not bothered with high rpm's then i would stick with the SU's and save a few pennies which can be put towards a good mid-rangy cam, other mods or beer. :)
John Maynard

The John Eales engine in my (works) B GT V8 is on SUs using the standard manifold, and gives 216 bhp @ 5,000 rpm & 264 ft lbs @ 3,000 rpm - very unstressed and easy to drive.

Once when rallying in the Pyrenees I thought we had blown the (R380) gearbox and I drove, and kept on the pace, for two days using only 4th gear. It turned out that the problem ws with the linkage!

NJSS
Nigel Steward

Nigel

....not a 3.5 litre then?
Stuart Robson

This thread was discussed between 17/05/2004 and 20/05/2004

MG MGB GT V8 Factory Originals Technical index

This thread is from the archives. Join the live MG MGB GT V8 Factory Originals Technical BBS now