Air filters for Dummies....(me)

[rodbargee]

This I'm sure will probably be blindingly obvious to all you but does a 3.8 air filter ram pipes, and air box fit the 4.2 carbs on a S2? I presume as the "collector assembly" fits the S2 it might :?

[Heuer]

The air intake box is interchangeable (design is slightly different - the three ribs on the top) between all cars with SU's. The carb trumpet box on the 3.8 will not have the hole for the breather elbow (used for oil fume recirculation) as this engine vents the fumes to the road. The 4.2 uses vacuum from the carbs to draw oil vapour out of the cylinder head. Not a big problem as you could either drill a holes in the trumpet box and attach a breather elbow or vent to the road.

[rodbargee]

The air intake box is interchangeable (design is slightly different - the three ribs on the top) between all cars with SU's. The carb trumpet box on the 3.8 will not have the hole for the breather elbow (used for oil fume recirculation) as this engine vents the fumes to the road. The 4.2 uses vacuum from the carbs to draw oil vapour out of the cylinder head. Not a big problem as you could either drill a holes in the trumpet box and attach a breather elbow or vent to the road.

Thanks for that....interestingly the trumpet box does have the elbow so may not be from a 3.8....still, good for me :D

[daverawle]

The air intake box is interchangeable (design is slightly different - the three ribs on the top) between all cars with SU's. The carb trumpet box on the 3.8 will not have the hole for the breather elbow (used for oil fume recirculation) as this engine vents the fumes to the road. The 4.2 uses vacuum from the carbs to draw oil vapour out of the cylinder head. Not a big problem as you could either drill a holes in the trumpet box and attach a breather elbow or vent to the road.

Thanks for that....interestingly the trumpet box does have the elbow so may not be from a 3.8....still, good for me :D

Interesting; my late S1 3.8 (May '63) has that breather elbow and also the later ribbed plenium box, although that's a breakable bit so it may well have been changed.

Dave

[rodbargee]

The air intake box is interchangeable (design is slightly different - the three ribs on the top) between all cars with SU's. The carb trumpet box on the 3.8 will not have the hole for the breather elbow (used for oil fume recirculation) as this engine vents the fumes to the road. The 4.2 uses vacuum from the carbs to draw oil vapour out of the cylinder head. Not a big problem as you could either drill a holes in the trumpet box and attach a breather elbow or vent to the road.

Thanks for that....interestingly the trumpet box does have the elbow so may not be from a 3.8....still, good for me :D

Interesting; my late S1 3.8 (May '63) has that breather elbow and also the later ribbed plenium box, although that's a breakable bit so it may well have been changed.

Dave

Yes this too has the ribbed plenum chamber......supposedly off a 3.8, still you wont find me complaining :)

[Heuer]

Sorry, I should have been clearer in my original reply. The early 3.8's did not have the coupled engine breather, later ones did. The coupled breather arrangement (cylinder head housing, pipework and modified trumpet box) came at about the same time they dumped the outside bonnet locks (Oct '61?), the change of design to the air box (ribbed covers for strength) sometime later.

[rodbargee]

I think I'm with you on this....were saying that the later 3.8's did have the breather elbow pipe and associated head pipework......the ribbed plenum chamber was later, and all (this is the crunch)are suitable for my 4.2 S2 He says hopefully. Even if its not completely correct in all detail it will make it run better than the all or nothing SU's arrangement at the moment ( no common air filter load, and dodgy KN filters on only two!! carbs):D

[Heuer]

Check the carb needles. The standard needles for use with the stock filter assembly should be UM. If K&N, ITG or open trumpets are used the needles should be UO or custom ones. Could be the reason you are having problems. The needles have the code stamped on the shank but you will need to take them off the piston to see it. Otherwise, as you say, the trumpet box and air box are the same from Oct 61' cars onwards including the S2.

Incidentally what are you using for the filter? ITG make a 'drum' free flow filter that attaches to the air box - SNG sell them and it looks almost stock but without the silver can.. Check what needles are required though - probably UO.

[rodbargee]

Just sorted out the purchase of the trumpets (as discussed) :D and the air box with ribs and bracket (all off ebay) the last thing is the filter assembly the sng one looks favorite at the moment, the one original one on ebay went to someone with slightly quicker reactions! Haven't looked at the jets yet but since driving it home I decided not to bother touching it till I got the right parts. Only two of the carbs had any filter at all !! so I guess the jet's won't be right in any case! Thanks for the information!
:D

[rodbargee]

Having got the filter assembly and bits together :D where is the screen wash pump supposed to go? (was in the well for the air canister!!)

[Heuer]

If t is a RHD car then it should be on top of the washer bottle next to the heater box. Picture to follow tomorrow if you need one.

[rodbargee]

As you might be able to see from the pic the washer bottle just has a screw top! is this where a OE electric pump should be? (just in front of the brake and clutch resevoirs and to the right of the su without a filter)
Cheers
Adam

[Heuer]

Adam

Forgot yours is a later car than mine. On the S1.5 and S2 they put the expansion tank next to the heater box and moved the washer bottle to the other side, nestling between the brake reservoirs and the rearmost SU. The washer pump should be part of the washer bottle cap. e.g. http://tinyurl.com/5d3mnk

[daverawle]

Adam,

The OE pumps are quite weak so if yours isn't working well it can be replaced with a cheap modern one. This is how I did mine:
http://tinyurl.com/6luk54

Dave

[rodbargee]

Cheers all, I think a pump with a bit of push is in order.......lets face it there's plenty more pressing things to get right!!
Adam

[rodbargee]

Adam,

The OE pumps are quite weak so if yours isn't working well it can be replaced with a cheap modern one. This is how I did mine:
http://tinyurl.com/6luk54

Dave

Very impressive Dave, I have just had a walk round the Alladin's cave that is the Hutson Motor company in Bradford, mouth watering and cheque book quaking, now, How to rob a bank?!
Adam

[rodbargee]

Well all the air bits are bolted together complete with new gaskets etc the only thing I'm not sure about now is the rubber ring that sits on top of the air filter canaster and presumeably slides across the top of the assembly as the engine rocks. Is this all there is? It seems a little too loose a fit on the air box, perhaps there's something else missing? perhaps another rubber ring which would fit tight on the air box and squeeze into the bigger rubber ring? but the engine runs better already :D :D

[Heuer]

Adam

There is only one large rubber seal. It presses on to the air box and locates onto the filter canister via a groove in the rubber. So in effect it is sealed but allows movement of the engine/airbox against the fixed filter housing. Check the rubber grommet and you should see the groove so one side of it can be lipped onto the fiter using a small screwdriver. Sounds as if you just have it butting up rather than properly located. Let me know if you need a photo.