webers and a non-crossflow

[littlegearl]

ok, basically i'm planning to stick a set of twin-45 webber's on my Cav but it runs a non-crossflow design head

now, i know the parts are out ther to do the change (have it all priced up) but yesterday a mate suggests that you can't weber carburettors unless the head is a crossflow design as i would effectively be havin a 4-into-2 inlet port which he said would be odd...

as i say, the parts are there, i've seen it done but am now confused as i'm sure the Manta i've seen it on wasn't a crossflow

can anyone shed any light on this situation?

just to confuse matters further, at the CCM/Show yesterday i saw a crossflow design 1.8 Manta (carb on offside, exhaust on nearside) whereas my 2.0 runs with the carb/exhaust all on the offside...

[Pigeon]

How many pipes run from the inlet manifold into the head? It's a long time since I've seen a RWD Cav engine but I think there are four. You don't have a "4-into-2 problem". What your mate says is true of engines like the BMC A and B series but not of yours.

Certainly there's no intrinsic reason why you shouldn't put twin Webers on a non-crossflow head. (Though a crossflow head does have advantages; there's probably more room and you don't need to rig a heat shield over the exhaust.)

Course, with an engine compartment the size of yours you could easily stick a V8 in it...

[littlegearl]

yeah, i'm almost certain four pipes run off the inlet manifold

he has a Midget (A-series) and my bro/another mate both have an MGB (B-series) so he was comparing my engine to theirs where if they want twin weber's they need a crossflow head - my bro runs twin SU's for this very reason...

after a quick poke around in my engine bay with a torch (after reading the thread about inlet manifolds) my inlet/exhaust manifolds appear to be joined, this suggests i'm gonna have to make sure this isn't going to be a problem when i get my new inlet manifold for the carbs... though i'm sure they've already thought of this as it is based on my engine!!!

have often wondered what size an engine i could fit in my bay, i've seen both a Monza GSE straight-six and a Rover V8 but i'll be as a happy as a pig in the proverbial with my new carbs (finally realising my new cylinder head too...)

edited to add: cheers for the help!!!

>> Edited by littlegearl on Sunday 9th November 22:17

[joospeed]

I think your friend is a little confused, the carbs don't know what engine they're bolted to, crossflow or non-crossflow it makes no odds, however by the time you've accurately set up the webers on the rollers you might find you've spent as much as a cheap aftermarket engine management system and would have much worse fuel consumption (webers have quite large atomisation droplets) and still no contro over the ignition timing. In this day and age there's no reason to think about carbs unless it's specified in a race series rules or similar. Weber parts can be expensive..

[Pigeon]

Carbs have the advantages of reliability and simplicity. A set of Webers would be far easier to fit than an engine management system and much less likely to go wrong. One of the advantages of the Mk 1 Cavalier is its simple electrical system. Keep it that way.

I might experiment with bolt-on management systems on my own vehicle, as I am a techy type and would be happy to redesign/rebuild bits of the system to avoid possible problems, or just to get the thing to work the way I wanted it to. I wouldn't advise anyone else to do it unless there was some constraint that ruled out other solutions.

[littlegearl]

joospeed said:

Weber parts can be expensive..

i like that quote.

weber parts are very expensive, indecently so... but i wouldn't think of upping my fuel/air mixture any other way... you have to remember this is for a car built in 1978...

also, if i was going down the easiest route for more power - junk the Vauxhall 2.0 8v ohc for a 2.0 16v XE out of a GSi Cav mk 3 - i'd still rip off the fuel injection system and replace it with a nice large set of carbs (possibly 48s rather than my proposed 45s)

[grahambell]

Bit late with this, but running twin DCOEs on a non-crossflow engine is no problem. Popular mod on hot Anglias and Mk1 Cortinas back in the 1960s and Chrysler UK even fitted them as standard on some of their hot Hunter and Sunbeam models, which also had a non-crossflow engine.

Also had a mate many years back who used to rally a Manta, which of course is essentially the same as your Cav. That also had a tuned 8 valve 2-litre, but fitted with twin downdraft Webers.

[duffgun]

I know this is very late but as you are now probably aware that you cant bolt twin Webber sidedrafts straight onto the cav RWD as the brake servo will fowl the seconded carb, you will probably have to get a special spacer to fit it on the engine or move the brake servo

[Buffalo]

Yeah - thanks for the heads up. I think he had this pointed out to him at some point though. I can't remember what model brake servo he was supposed to use though...?

I think he's heading towards an XE now... kids ey?

[stesrg]

Forget the webbers and go for delortos these are a little better to keep in tune and if you look on ebay should pick up some at a relatvely good price.
Iused twin 45s on my alfa powered alpine a payed £300.00 for a pair and set them up myself the injection system worked out a lot expensive.