fuel pipe

[bmcecosse]

A filter in the suction line is not a good idea - all the more likely to give your engine a fit of the vapours in hot weather.

[ampwhu]

A filter in the suction line is not a good idea - all the more likely to give your engine a fit of the vapours in hot weather.

eh? i've never known there to be any problems in the past. i usually fit a filter down near the rad drain point, upon entry into the engine bay next to the nearside engine mount. this time i'm going to fit it at the tank end upon leaving the tank. run the fuel line up the chassis, up past the steering box, across the bulkhead above the steering rods along the parcel shelf and down to the pump which is mounted on the nearside inner wing. that should be better than running it under the radiator around the front end. can't see where the fuel line will come into contact with heat providing it's far away from the downpipe.

[bmcecosse]

Suit yourself - but if the pump is struggling to draw up fuel - the additional restriction of a (completely unnecessary) filter could just tip the balance to failure! There already is a filter in the SU pump - why burden it with another ?

[ampwhu]

Suit yourself - but if the pump is struggling to draw up fuel - the additional restriction of a (completely unnecessary) filter could just tip the balance to failure! There already is a filter in the SU pump - why burden it with another ?

there's a filter in the SU pump? i've got the points version of pump. it's never struggled before.

[bmcecosse]

Neither has mine - but others do seem to get problems - and they seem to be worse if a filter is fitted on the inlet side. Yes - the SU filter is in the base - under a hex plug.

[MarkyB]

There already is a filter in the SU pump

True but it's a brass mesh filter, a lot of "silt" makes it's way through it.

A finer filter at the tank exit will have the benefit of the fuel in the tank "pushing" on it.

If ampwhu has done this before without problem, why are you gainsaying him?

Hats off, if you've tried lots of different ways to improve the filtration of the standard system without success, that's useful knowledge.

If you are just adamant that SUs are tolerant of the muck that gets though the mesh filter, or that giving the carb a clean out is a trivial job then you aren't really helping.

[bmcecosse]

I'm simply warning that an extra filter may cause problems on a hot day - with the 'vapours' at the pump. The SU carb is very tolerant of 'silt' - it doesn't have daft wee jets to get blocked. I've never had any problems and I certainly don't waste any time clearing out float bowls! But - each to their own - it's your car - fit all the filters you want!! Just remember when it splutters to a halt........ In fact - on a classic car run at the week-end including the Rest and be Thankful, I stopped to help a lad in an Austin 16 who was having trouble with fuel feed. He was using an SU sucker pump and had a daft big filter on the inlet - and the car was struggling going up hills. We by-passed the filter and so pump straight to carb - and off he went. I followed him back to base. It ran well - 2.2 litre 4 cylinder (AH 100/4 engine) on single downdraught carb - bowled along nicely at 70.

[Kevin]

i usually fit a filter down near the rad drain point, upon entry into the engine bay next to the nearside engine mount. this time i'm going to fit it at the tank end upon leaving the tank. run the fuel line up the chassis, up past the steering box, across the bulkhead above the steering rods along the parcel shelf and down to the pump which is mounted on the nearside inner wing. that should be better than running it under the radiator around the front end. can't see where the fuel line will come into contact with heat providing it's far away from the downpipe.

Thats an unusual route for the fuel pipe to take I assume its been replaced before as there is not enough slack in the original to reach the radiator.
I see from your posting that the current cars pump is mounted on the inner wing I have not seen that done before any chance of a photo as it may be that relocating it to there helps the starvation problem as both the pipe and pump are futher from the manifold, it would also be interesting to see the pipe from there to the carb as well.

[bmcecosse]

Hmm - I don't see any pics, but certainly the fuel pipe is not normally taken on a scenic route round by the radiator! But yes the complete answer to the 'vapours' problems that some have is to either use the low mounted mechanical pump - or mount the electric SU pump low down in the engine compartment. It's more to do with minimising the suction height rather than worrying about exhaust heat. After all - Mini fuel pipe runs up almost alongside the exhaust in a very cramped location - but they never get 'the vapours' ! The fuel tank is of course relatively high mounted - and the pump is low mounted. QED

[ampwhu]

i usually fit a filter down near the rad drain point, upon entry into the engine bay next to the nearside engine mount. this time i'm going to fit it at the tank end upon leaving the tank. run the fuel line up the chassis, up past the steering box, across the bulkhead above the steering rods along the parcel shelf and down to the pump which is mounted on the nearside inner wing. that should be better than running it under the radiator around the front end. can't see where the fuel line will come into contact with heat providing it's far away from the downpipe.

Thats an unusual route for the fuel pipe to take I assume its been replaced before as there is not enough slack in the original to reach the radiator.
I see from your posting that the current cars pump is mounted on the inner wing I have not seen that done before any chance of a photo as it may be that relocating it to there helps the starvation problem as both the pipe and pump are futher from the manifold, it would also be interesting to see the pipe from there to the carb as well.

aha...! maybe a little explanation is in order here.

the cars an A30. i don't own a moggy. i've always owned austins, although i did state that i'd own a moggy in the pick up version, if one crosses my path in the future. i did used to 'part own' a split screen around 20 years ago(VYA 999), but it sadly lost a fight with a volvo one morning!

anyway, seeing as the mechanical components are the same at the front end, i like to ask for advice 'over this side'. moggy owners are quite clued up on matters and i like to source my info from here. so that should sort of explain the fuel line route.

thanks

[bmcecosse]

Ahhhhhhhh - well you probably also have the ghastly downdraught carb with tiny jets that get blocked! So - fit all the filters you like. Now I understand!! Top tip though - fit a Minor manifold and SU carb - and gain ~ 3 bhp which on an A30 is probably about a 25% gain at the wheels!!

[ampwhu]

Ahhhhhhhh - well you probably also have the ghastly downdraught carb with tiny jets that get blocked! So - fit all the filters you like. Now I understand!! Top tip though - fit a Minor manifold and SU carb - and gain ~ 3 bhp which on an A30 is probably about a 25% gain at the wheels!!

1st change on an A series in an A30 or A35 is to change the carb! the 26VME has long been consigned to the scrapheap. i have an SU carb fitted from a minor. i've also got rid of the mechanical pump as well. obviously the 803cc is pretty much useless at the same time, hence the fitting of a bigger engine over the winter.

[bmcecosse]

Keep the mechanical pump - it's ideal!

[ampwhu]

Keep the mechanical pump - it's ideal!

i still have it, it's still on the engine. it happily sucks and blows air as i drive along!

[bmcecosse]

Perfect - it's ideal for pumping fuel.........