carb / VX engines

[Skufy]

Apart from the supercharger, what are the main diffs. between a VX engine and a normal carb engine?

Same for gearbox, what changes were made to cope with the extra power?

I presume mountings are all identical.

[Wallace]

Oh gosh - speaking from memory . . .

1. The head. Larger inlet valves, sodium cooled exhaust ones

2. different cams, different dizzie

3. different pistons (lower CR)

4. suposedly different crank (although no difference on the engine I pulled to bits)

5. different water pump and oil pump (I think !)

6. The box - compaired to a monte one - different back axle ratio, different shift linkage, bronze splashed selector forks.



And probably a whole lot more - but I think these are the major ones . . .

[Pope1]

In addition, here are a few more that I've come up with:

Different carb with lots of plumbing and electric fuel pump from 2000 i.e
Different air filter and housing
Different radiator
Larger clutch
Special uprated head gasket (ESSENTIAL)
Oil cooler (not sure if this is standard on the other models)
Modified exhaust ??

As far as I am aware, the mounts are the same. I know you asked about the engine and gearbox but I just thought I'd add that the VX cars are also supposed to have stiffer springs.

[A1.6HPE]

Hello Skufy,
The fuel supply circuit has a cut off solenoid valve which (I believe) cuts the petrol supply if the petrol temperature gets too high.
The ignition system is different on some cars, having a M-M Digiplex mapped ecu (not chippable!).
The speedometer has the green zone identified for highest torque and I think has more mph on it.
Of course the bonnet has the "bulge" to clear the carburettor but I am not sure if that is a styling thing or if it is really neccessary.
Strangely the Coupes have Recaro front seats (HPE does not).

[Pope1]

Leo,

Yes I think the bulge in the bonnet is necessary - my under bonnet felt wore out there from rubbing on the top of the carb intake!

The fuel solenoid was part of the original plumbing but my car seems to run quite happily without it for what that's worth :) .

Are you sure that Digiplex was fitted to the VX models as standard? Mine doesn't have it nor did the spare car I bought for parts many moons ago. Wasn't aware that was an option :o .

[A1.6HPE]

Hello Chris,
I have a feeling that someone once told me that they had a "flat" bonnet on their VX as they had not been able to get a proper one. I guess that it must have been a close fit - probably with no liner fitted.
I once had a 2000ie which had Digiplex ignition and have seen others but you have got me doubting that I have seen a VX with Digiplex.
I think that Lancia fitted Digiplex to the last cars, but VX production ended before the ie cars so maybe the VXs never got it.

Leo

[Pope1]

I think only the i.e models were so blessed but I'm sure someone will shout soon enough if I'm wrong.

[chrisc]

Bonnet bulge is not essential, if you have the foam stuff removed. My silver hpe vx has the wrong bonnet on it at the moment and it fits fine.

[Pope1]

Cheers Chris. That's well worth knowing. I've got some new underbonnet material to install after the engine goes back in and I was wondering whether it was going to be too thick. Obviously not. :)

[Skufy]

Thanks for all the info, if this little project comes off I'll probably have a few other questions.

Basically if I understand correctly, a VX head will fit on a normal 2.0 and a beta 1.3 or 1.6 gearbox could be bolted onto a vx engine to take advantage of final drive ratios.

The engine in question is not in a beta , it could end up in one though.

As i think of it, have twin weber or dellortos ever been tried with a blower?

[Maigret]

I believe the motor had nitriding done which will not be visible, so the crank will appear the same but the surface will be much harder. I believe the cams also.

The main and BE bearings are same dimensions but higher spec than STD engine. Also used in FIAT turbo engines. I have used FIAT turbo parts when VX not available.

There is not much point in having multiple carbs attached to a blower as it all goes through the blower before being distributed to the intakes. Being positive displacement blower some efficiency is gained by putting a smaller carb than non-supercharged.

[Wallace]

All 2 litre engines had nitrided cranks. I think the cams are the same material as standard - but different duration. Yes, a VX head will go onto a standard engine - according to Guy Crofts book, it will give a little more top end for a slight loss in torque lower down - what you'd expect with larger inlet valves. If you running na, then the cams would need to be changed.

The boxes are all the same - and will swap.

Guy Croft does a manifold to fit a single 40 onto - you can't fit twins- and there would be no need to as the blower provides the extra breathing ability ! With a change of cams, a bit of overdrive to the blower, it's about 180 bhp tops. The standard inlet manifold won't let you go any higher than this.

[Skufy]

With a change of cams, a bit of overdrive to the blower, it's about 180 bhp

I could live with that, it's only a little less than my V6 alfa!