MG Performance Forum

Hi ,

After a "steamy" engine ( stud #10 & #11 hand loose) i replaced the studs with ARP's and a new PAYEN AK660.
So far so good .

Waiting for the ARP studs i did some work on reorganizing the cooling and the fuel supply .

My Glass bowl fuel filter i placed half way height ( pump-carb) so that no air could be trapped in the filter. Check.
I removed the paper element and replaced it with the mesh ( as in E-type ) .
So now no air is trapped in the fuel supply and the paper element resistance ( to flow) is gone/far less .

Now everything is into place and the running culture of the engine is horrible.
Appears to be a problem with the needle-seat assy. I checked all electrics and ignition ; no problem there i think.

Suddenly i realized that i mounted a 0.096 needle-seat viton assy ( SU WZX 1096 ) preparing for SC need (?)

Afterwards comparing the 0.07" with the 0.096" i realized that the area of the 0.096" is 88% bigger .
So now the Fuel supply is liquid "stiff" without trapped air and the resistance of the filter is almost gone , i have this feeling that the Float - 0.096" needle combo is not capable of arranging a consequent open-close behavior for the float .

So my question is : does anybody with a SC-HIF44 is running with the 0.07" needle-seat and having good running behavior ?

Should i worry fuel starvation with a 0.07" needle-seat assy in the HIF44 ?

( SU electronic fuelpump is new / SU AZX1331EN .. 5 main displacement is 1950 cc charging with max. 3.7 Psi )

Thanx in advance , Seph