Malpassi filter

[M.J.S]

My 1972 +2 130/5 has a malpassi fuel regulator mounted on the inner wing next to the carbs. I cannot find it in the workshop manual. Were they standard fitment?

Also, are they adjustable to regulate the fuel flow through the filter to the carbs? There is a dome headed nut on the top which I assume must do something, but I see no markings to say what.

I am trying to locate a misfire which feels fuel related. I know from the car's history file it has suffered problems with 'over-fuelling' in the past. I'm wondering what role the malpassi may or may not play in this.

Thanks all.

[gerrym]

MJS, the Malpassi was not original fitment at least according to the Parts Book.

With Dellortos and original mechanical fuel pump, there should be no need for an additional pressure regulator. This is because the mechanical fuel pump naturally matches the fuel supply to the demand, as both roughly correspond to engine revs. A electric pump by comparison is fixed output and depending on type, can generate a lot more pressure that could overcome the needle float-operated valve.

Regards

[ppnelan]

My 1972 +2 130/5 has a malpassi fuel regulator mounted on the inner wing next to the carbs.

My 1972 S130/5 doesn't...

It is definitely a non-standard addition, probably to try to solve a problem caused by something else, e.g. leaky needle valve/dirt in fuel system, sticking/leaking choke, wrong jets, electrical/ignition problem, etc.

Probably best to ditch it - one less thing to go wrong, add lightness, etc...

Post your misfire symptoms and I'm sure you'll get some helpful replies.

Matthew

[CBUEB1771]

With Dellortos and original mechanical fuel pump, there should be no need for an additional pressure regulator.

"Original" is the keyword here. For several years the replacement mechanical pumps have had discharge pressures in the range of 6 to 7 psi, or more than twice what the original AC pumps discharge at. I would check the discharge pressure of the existing pump.

[M.J.S]

Thanks guys. I think i'll bypass it and if it makes no difference then onto ebay the malpassi goes.

I have noticed today looking at some online photos of +2 engine bays that my carb's pipework looks to be connected opposite to other cars.

The pipe from the pump comes up from under the front carb, is connected through the malpassi then goes along the inner wing and comes back on itself into the rear carb and then feeds the front one.

I don't know whether this makes a difference but it doesn't seem right somehow.