At 11:48 PM 12/2/01 -0500, MGALUVR@aol.com wrote:
>.... 62 MKII MGA roadster. .... I have some gas that drips from the bottom
>of both carburetors after I shut the car off .... I put a pair of SU's on
>this engine that were left over from the previous engine (1622 CC).
Those would be SU H4 carburetors, which are prone to leakage around the
main fuel jet packing gland on the bottom. The leak can generally be cured
with the installation of a gasket set, which includes the cork jet seals.
>I assume these that are currently in use are the 1 1/2 inch variety. I
>know there are also 1 3/4 inch SU's out there also. Were these larger
>carbs standard on the larger 1800 cc "B" engine ?
Nope. All SU carbs used on MGA and MGB B-Series pushrod engines used
1-1/2" carbs.
'55-'62 MGA had dual H4's, 1-1/2 inch
The MGA Twin Cam engine had dual SU H6 carbs, 1-3/4 inch.
'62-'67 MGB had dual HS4's, 1-1/2 inch
'72-'74 MGB had dual HIF4's, 1-1/2 inch
'75-'80 MGB had a single-Zenith Stromberg 1-3/4 inch carburetor.
>.... Would a pair of 1 3/4 inch SU's give me any appreciable performance
>boost?
For competitive racing where the engine spends a lot of time running above
5000 rpm, yes. For a "civil" street machine, probably not. My MGA
currently has a 1600 engine with MGB "18" head and a slightly warn street
cam. It will do well over 100 mph with the stock 1-1/2 inch SU H4 carbs,
and it wins lots of autocross events. So not quite sure of your idea of
"appreciable".
>.... What cars were the larger SU's normally used on? ....
MGA Twin Cam, MGB GT V8, some TR's and Morgans with large 4-cylinder
engines, and a whole bunch of six cylinder British sports cars. Lots of
others to numerous to list. Check into a good SU carburetor service manual
for all such details.
Barney Gaylord
1958 MGA with an attitude
http://www.ntsource.com/~barneymg
///
/// mgs@autox.team.net mailing list
/// or try http://www.team.net/cgi-bin/majorcool
///
|