Updraft carbys

[VH-FTS]

I'm having a debate with a few lads over beers about what an updraft carby system is. Some claim it is to allow the mixing of warm air to prevent carby icing. Another claims it prevents an engine fire due to over priming.

Google and text books won't provide me with an answer. Are there any pruners who wish to share some wisdom?

Thanks

FTS

[PyroTek]

Older engines used updraft carburetors, where the air enters from below the carburetor and exits through the top. This had the advantage of never "flooding" the engine (http://en.wikipedia.org/wiki/Flooded_engine), as any liquid fuel droplets would fall out of the carburetor instead of into the intake manifold (http://en.wikipedia.org/wiki/Intake_manifold); it also lent itself to use of an oil (http://en.wikipedia.org/wiki/Motor_oil) bath air cleaner (http://en.wikipedia.org/wiki/Air_cleaner), where a pool of oil below a mesh element below the carburetor is sucked up into the mesh and the air is drawn through the oil covered mesh; this was an effective system in a time when paper air filters (http://en.wikipedia.org/wiki/Air_filter) did not exist.

Your googling is substandard :ok:
http://en.wikipedia.org/wiki/Carburetor

that is what you wanted right?

[tinpis]

http://www.vintageandclassicreproductions.com/CARB-U2.jpg

from 1920 Chrysler

Rover used em up until 1959

[VH-FTS]

Brilliant guys, didn't even think of Wikipedia! :ok:

[18-Wheeler]

I think you'll also find that one of the main reasons aero piston engines (the flat ones) use updraught carbies is because of aerodynamic reasons - They need to keep the top of the engine as flat as possible so all the manifolding and so on has to go underneath.

[PyroTek]

Brilliant guys, didn't even think of Wikipedia!

funny that, i just searched: "updraft carburetor" on google, the wikipedia article was the first result... :cool:

[VH-FTS]

No need to be a smart ass...:=

[PyroTek]

Not being a smart-ass, just being from the internet, a veteran even:ok:

[Old Fella]

These type of air cleaners are used on down-draught carburettors as well as up-draught and do not need to be below the carby, but sit on top of the carby. The statement that engines fitted with up-draught carbys "never flood the engine" is not correct. The raw fuel just lies in the intake air line from the air cleaner and will still be drawn into the cylinder just as with a down-draught carby.

[Capt Wally]

Quite correct 'Old Fella' I agree both counts. Oil bath air filters have been around for both up & down draft carbies for some time. My Holden FC had an oil bath filter & it was fitted to the downdraft stromberg, untill I fitted tiwn carbies, extractors, stage 3 yellow terra head &lowered the old girl, the next stage was to get booked for having an unroadworthy car:bored:.
Enter planes & girls, am paying for that bad mix forever!:bored:
'18W' I would say yr correct there the updraught carby was designed & fitted below the top of an engine (auto & aviation) to contain the overhaul shape/size of the engine to fit inside a streamlined cowl/bonnet.


CW

[Jamair]

Yeah Wally, my first car was a EK Station Sedan with the dual barrel stromberg and an oil-bath air cleaner; spent its early years in SW Qld where bitumen was not common. Replaced the aircleaner with a 'Sports' jobbie, added the stainless steel exhaust.....the mighty 138 grey motor and the 3-speed hydramatic went like a train for the 20-some years we had it. Traded it for $750 on a Datsun 260Z:{

[Old Fella]

CW, both my TEA20 (Grey Fergie) and my 1937 Plymouth have oil bath air cleaners and both have the cleaner located higher than the carby. The Fergie uses an up-draught carby with the air cleaner remotely located with an air trunk to the air inlet on the carby and the Plymouth a down-draught with the air cleaner sitting on top, as was your Holden. Both are easily "flooded" if the applicable starting technique is not used.

[Lasiorhinus]

Pyro, is the internet older than you?

[PyroTek]

Yes.. The internet 'as we know it' - post military stages - came about in 1991 or something, if memory serves me right.
I started on the net in about 1995, yes, i was in year 1, 5 years old.
Our first PC, a gateway with windows 95 on it.
fun stuff :ok:

[Torres]

Like this Old Fella?

http://img.photobucket.com/albums/v315/Woomera/Ferguson%20Tractor/Carby.jpg

Actually, I prefer these:

http://img.photobucket.com/albums/v315/Woomera/Jaguar%20E%20Type/jag9.jpg

:} :}

[Capt Wally]

'Torres' you just bought tears to my eyes with that last piccy. Not seen nor do I want to 3X2" SU's in a long time:bored: That looks like a 3.8 E Type also, might have had 1 3/4" SU's not too sure but the 4.2 had the 3" jobs.
I used to tune mine about every second W/E:bored: But we are now talking side drafts, Webbers the go there:ok:

CW

[sms777]

I do feel sorry for you for the Poms never understanding the KISS(Keep It Simple Stupid) principle. I would have fabricated a single 4 barrel manifold for that Jag, bolt on a 600 vac/sec Holley 4 barrel and go boogie because it would have turned it into a beast. And you could have your weekend off without tuning the damn thing every second.
And if that don't work, put a Chev in it like everyone else do these days :E


You wanna rev it, Chev it! Can't afford, it Ford it!

:D:D:D:D

[Torres]

'66 Series 1 4.2 2+2 (http://www.xkedata.com/cars/detail/?car=1E50182).

They are triple 2 inch SU's. The twin Weber conversion is $4K plus - besides, I like originality and after 42 years, it's still the quickest car in town.

:}

The Ferguson TEA20 restoration back to as new is almost finished.

I can't find out why carbys evolved from up draft, to down draft. However I suspect a major factor may have been bonnet alignment in the days of side valve engines - an updraft carby was below the top of the engine, allowing a lower bonnet. Once valve gear went on top of the head, and carby height reduced, down draft carbys became the norm.

With horizontally opposed aircraft engines, I assume up draft carbys (under the engine) resulted in a flatter cowl and better pilot visibility.

[Capt Wally]

'sms777' all true but yr talking about bastardizing a fast becoming rare car. Sure the Chev conversion would kill the original Jag 3.8/4.2 in a lot of ways but it wouldn't be a Jag after that & you couldn't give it away to an enthusiast:). I recall a pilot here who had a beautiful series two that was stock accept for the Toyota box, he did eventually sell it but was hard to do so after being called a 'butcher'. I did love the feel of those 245 horses tho, all being fed by my lovingly cared for SU's, at great expense of course!:ok:
Edited for 'torres' I wasn't too sure that the early 'clean' rocker covers where also 4.2's:) Why sell it when it's almost finished?
............yeah I know it's a thread drift but how much can ya chat about up draught carby's anyway?:)

CW

..........You wanna rev it, Chev it! Can't afford, it Ford it!, This bit I laughed at:)

[Torres]

Wally, It is not for sale. That reference is when I bought it - which was the cheapest part........ :{ :{

[Capt Wally]

whoooops sorry buddy. On the bread line are we? I used to own a 420G, 4.2, Loved that car. It would sit on the rd @ 100MPH all day, providing you has shares in Mobil Oil!:bored:


CW

[Wormole]

Until very recently I had a 1967 unrestored, but mint Jaguar 420 compact, manual o/d on wires. At 100mph you could actually see the fuel gauge moving. Years ago there was an old deaf guy who made a manifold and sat 8 inch and a 1/4 SU's on a side valve Ford V8 coupe, it ran perfectly, and his favourite trick was to stand a coin on edge on the radiator, and screw the idle back to less than 200rpm without the coin moving.

[Old Fella]

Torres, Yes, my Fergie is as yours. Have had it since 1988 and it has never let me down. Use it for slashing only. My 1989 XJ40 Sovereign, with just 115000 Km is injected and surprisingly good on fuel. Around town, about 13 litres/100 Km. Highway less than 10 litres / 100 Km with excellent handling and ride qualities. I have had the Jag since April 1998, bought it with all documentation and only 52000 Km (One of the last 3.6 litre XJ40's to be Australian delivered 1989). It is original and everything works.

BTW, my 1937 Plymouth is a six cylinder side valve of 201 cubic inch capacity. A selling point, in 1937, was the ability to accelerate away smoothly from as low as 8 MPH in top gear. Driven sensibly it gives about 23 MPG.

[sms777]

Standing a coin on the radiator at 200rpm and not loosing it is impressive as long as you do not expect hairraising performance.

Personally i like my rides to be wild like my women, which is why i chose a cam in my big block 454 Chev about the size of your crank in your Jag. Do not even think about leaning on the guards when it is idling, you might just loose a kidney. At half throttle it will light up the bags non stop for over 300 meters and it will make a u-turn on a fifty cent coin.

Fuel economy?.... forget it! I only drive it on tuesdays when it is 10 cents cheaper:D

[Jabawocky]

sms777

75 posts..........and ya last one is a Gem!:D

There is no replacement for displacement!;)

J

[Peter Fanelli]

Since this thread appears to be heading into pissing match territory I bet none of you has a cock as big as this!

http://i155.photobucket.com/albums/s295/bigt57/Below.gif



























http://i155.photobucket.com/albums/s295/bigt57/largecock.jpg

[Capt Wally]

ahhh yr just jealous 'PF', you obvioulsy haven't got anything to wave yr dick at:E, nice cock tho, big too:ok:
'Wormole' I didn't take my 420G beyond a 100 mph (those days no speed limit on a lot of open rds) 'cause I got confused which guage was the fuel one, you see the tacho & the fuel guage where I think interconnected at very high speed:)
'Old Fella' I reckon the last proper Jag was the series 2 XJ6, after that they went down hil esspecially when Ford took them over.

I know this thread is heading towards being Nazified by the mods but b4 it does what's the point of having a car that goes from zero to God knows what in under a micro second when you can only go as fast as 110k's on most freeways? With a very fast car yr only as fast as it takes for the slower car to reach the next set of traffic lights, in the burbs that's only a matter of a few seconds:) Fast cars do however help keep me in a job.:bored:


CW

[Wormole]

Hair raising performance is of no use to me, I'm bald.
I once drove a real Jaguar XK D type, and I have also had a drive of an ex LeMans Ferrari 250LM either of which would give your big block Chevy a fright.

[Old Fella]

CW, the biggest advantage your Series 2 XJ6 has over my XJ40 is that yours is probably old enough to put on Concessional Rego.

[tinpis]

Wormhole 67? hmmm :hmm: that D-Type didnt live on a farm in the Waikato perchance?

[RadioSaigon]

Standing a coin on the radiator at 200rpm and not loosing it is impressive as long as you do not expect hairraising performance.

hmmm.... isn't there an apocryphal story of RR engineers doing just that during WWII -on a Merlin mounted to a Spitfire???

If there's any truth to it, it would seem the 2 are far from mutually exclusive...

[Wormole]

When I drove the D-Type it lived in Hawkes Bay, but it later went to an eccentric old gentleman on a farm which I thought was nearer to Auckland than the Waikato. As it was the only D-Type resident in N.Z. it has to be the same car.
I understand that the old fellow's estate sent the car to be auctioned in the U.K. where I think it made the best part of a million pounds, It has since been fully restored, and is raced by it's new owner in classic events.

[sms777]

Well....Yes!
If i mounted the Merlin's two stage supercharger on to that sidevalve V8 Ford i am sure it would give the same hair raising performance as my big block Chev and the coin would still stand on top of the radiator.

But that's cheating!
:ok:

[Capt Wally]

yeah yr prob right there 'OF' but there was a time where cars where real cars. Holden haven't made a decent car since the HR days. Ford finished making strong quality cars at the end of the XY series & Chysler, well they never did share the same spot light as the other two in any of their range I reckon. Like I said as for Jaguar they went sth with quality after the XJ series 2, from there on reliability & poor workmanship lead them now to what we see now, just another mass produced ordinary car.
The Japs have it all figured out, mech the best, reliability near perfect, just that they never really could build a car or it's interior that was to remain classic in every sense of the word like an early Jag. Personal opinon of course:ok:
Am surprised this thread is still running, the Mods must be alseep!

CW

[Wormole]

Capt Wally.
Your right about the Japs, but wrong about Jags. The series 2 XJs were probably the worst car Jaguar ever built. They were produced while Jaguar were under the control of British Leyland, the quality was rubbish, and just about anything that could go wrong with a car went wrong with these models. I know. I've owned several of them.
I agree though that they were the last Jaguar with real character, and class.

[Capt Wally]

Oh well 'wormole' we can have our opinions that's why we live in this society, (Mods excluded of course).
I don't believe it was quality that let the earlier jags down they had it everwhere, strong bodies, wood & leather everywhere built like tanks it was reliability via some pretty poor designs that let 'em down. You can have a terrific 'quality' item but with a poor design it's going to give problems regardless of it's quality, this is what the earlier Jags had I believe. I know to some degree this to be true 'cause I cut my teeth on during my apprenticeship on a lot of pommy stuff, mainly BMC & Jaguar,Leyland etc hence I owned a Jag when I 'thought' I knew best!:bored: That was done all the while I watched planes fly over head & thought yep I wanna be rich like them guys !!!:bored:
Anyway with a restored jag it's more about looks than anything else & the Jag beats 'em all in that area, if you want reliability go buy a Jap car !:ok:


CW:)