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mechanical fuel pump

Posted: Tue Aug 05, 2014 8:30 pm
by boydogs
I have already asked about fitting a mechanical pump to my 948 Minor its a 1958 there is a blanking plate on side of engine ready to fit pump, My question is the length of the studs are 3/4 inch. is this enough to fit spacer plate, pump, washer and nuts, or am i to remove studs to replace with longer ones.

Re: mechanical fuel pump

Posted: Tue Aug 05, 2014 8:43 pm
by chesney
You should fit new studs, I think from memory fitting the studs to my '58 they protrude roughly an inch from the block.
Better practice in any case.
Don't forget to use a spacer!!!
Best mod I ever did to my '58 ;)

Re: mechanical fuel pump

Posted: Tue Aug 05, 2014 9:00 pm
by lambrettalad
The spacer is VERY important ,good luck

Re: mechanical fuel pump

Posted: Tue Aug 05, 2014 10:03 pm
by bmcecosse
Different thickness of spacers to adjust the amount of fuel pumped = pressure at the float valve. Use the max thickness that still delivers the amount of fuel you need.

Re: mechanical fuel pump

Posted: Tue Aug 05, 2014 10:15 pm
by chesney
Or, if no spacer at all is fitted, ensures you break the pump the first time the motor turns...

Re: mechanical fuel pump

Posted: Tue Aug 05, 2014 11:44 pm
by bmcecosse
Indeed! :oops:

Re: mechanical fuel pump

Posted: Wed Aug 06, 2014 10:53 am
by philthehill
Strangely on the Sprite I & 2/Midget 2 & 3 (same blocks as the Minor) the spacer is not listed in the spares catalogue only the mechanical fuel pump Pt No: 17H98 and the gasket 2A113.
Does that mean that it is just not listed in the parts list but was fitted or that the spacer was not fitted to the Sprite/Midget as listed above or it is never required so not listed?
The spacer/gasket fitted to the Mini is part No: GUG705603 and the gasket on its own is GUG705779.

Re: mechanical fuel pump

Posted: Wed Aug 06, 2014 11:40 am
by bmcecosse
I think a smaller pump with shorter lever was used originally on A30/35/40 and Spridgets. Now there are 'generic' pumps going the rounds and the stroke is adjusted by thickness of spacer.

Re: mechanical fuel pump

Posted: Wed Aug 06, 2014 2:08 pm
by boydogs
Thanks for all the reply`s, i will fit two new studs and carry on with the modification. good forum.