Lancia Volumex cam and carb

[cotters]

Hi there

I wonder if anybody can help me, I have two Vx HPE cars and whilst one is about half way through the proverbial rebuild the other is my daily drive.
What I am after is some infomation about the recommended cam and carb for these engines to increase their power. I have been told that the inlet cam from a 2000 HPIEis the one to get, I have a Thema 2000ie engine in bits and was wondering if this was the same cam?

As for the carb I seen to spend a lot of time fiddling with it, and it seems to go out of tune easily. What is the best replacement for it or is there a way to get the standard unit to work well?

Also whilst I'm thinking of it I have been told that a change of blower pulley works well, what does this involve and does it do any good? The engine that I am thinking of modifing was rebuilt by a local engine reconditioner about two years ago and runs on Mobil 1 oil.

Thanks for your help,

Alan

[Fingers]

Hi there, I've pretty much done all the mods to my VX that you state. I've got a 45 DCOE on a Guy Croft manifold, the smaller supercharger pulley, and a different inlet cam. I went for a Guy Croft cam, his 3A, as I couldn't find an IE cam and he was having a deal at the time. It goes really well. Pulls strongly, and revs out nicely with plenty of power. What do you want to know about it? Where abouts are you? I'm in CHCH, so if you're ever around this way let me know.

[cotters]

Thanks for that Fingers,

I don't supose you know how many teeth the smaller pulley has do you? I have seen in several places that the supercharger needs to be speeded up by 7% but I can't find any other info.....

I am interested in the Thema cam mainly because I have one sitting around and I am thinking that the two engines ( the HPIE and the Thema ) are basically the same - so maybe the profiles are the same. Did you change both cams or just the inlet?

Nice to know that some one else in NZ is using these cars still, I am up near Auckland but if I get down your way I will let you know.

Thanks again for you reply

Alan

[Mantua66]

Hello all
Out of interest the standard blower pulley has - if i remember rightly - twenty three teeth, gives you a ratio of about 1.3:1.
I have used an eighteen tooth pulley - gives about 1.6:1.
This was with a standard carb and the difference was staggering, although i had to retard the ignition somewhat.
I used the car for about nine months and it never gave me any trouble (paid ‚£150.00 for it)
I tried the Beta ie inlet camshaft and was very disapointed - engine generated a lot more heat than anything else and the torque was pushed further up the rev band, with no difference to the top end rev limit - only achieved 6000 maximum.
To be fair i don't know if this was anything to do with the original carb (probably) may work a lot better with a single 45 conversion.
Anyway "all good things come to an end" as they say, the car was stolen.
My next attempt involved my everyday VX, this time i built an engine from the ground up and smoothed out the coolant galleries + other things to help cope with the extra heat from the increased blower speed.
Incidently my rear blower bearings run in oil now, thanks to a home made oil tank, much better than grease.
Replaced all three pulleys with HTD items, crank having a Beta IE pulley machined to take the new pulley wheel - because i want to run a Microplex from a Croma turbo ie.
I made one fatal ERROR, i was talked into using Croma turbo pistons by a friend, so i do not quite get the power i was hoping for, but the car is very reliable, runs normal temperatures and i am currently using a Digiplex mapped ignition system.
Even with the low C:R it's better than a standard VX, NO worse on petrol and when i do a piston swap, should show the sort of performance i was hoping for.
The carb is also going, i have modified the inlet manifold to take fuel injection, have this running on a test bench and first impressions are encouraging but DIY has put this on hold.
Anyway that's enough waffle from me.
A damned fine forum Mr Croft.

[Guy Croft]

Hi Yalcin

good post, well done.

Your problem of not getting much better performance with the higher lift (9.9mm) from the normally aspirated inlet cam will be because the std small Vx carb with its tiny chokes and inlet (outboard) manifold is very restrictive - won't flow enough air and also the standard system exhaust system with its high back pressure is blocking the exhaust - & similarly - inlet flow.

I have had 180bhp with a 40 dcnf Weber fitted on the Vx on the standard inlet manifold and exhaust but over that, because supercharged engines are very sensitive to back pressure, you almost certainly have to get rid of the standad mufflers and run big bore straight thru low loss silencers. For ultimate power I recommend a 36" 4-1 header too.

How much a 40dcnf will give with the right ex system I don't know, there will always be a significant flow loss compared with a sidedraft carb bolted right to the blower intake. Doing that also gets rid of the fuel puddling that plagues the standard setup.

GC

[Fingers]

yes the pulley is one tooth less than standard. I thought it was 21 but as mentioned above the standar may me 23, I'll check when I get home tonight. I did the pulley first and it made a noticealbe difference to the torque. I'm running standard exhaust manifold with two straight through resonators only, and it's not loud at all. I've only done the inlet cam, the fuel consumtion with both done would be huge, as it is it uses more fuel around town than my 4l Cherokee, but on the open road it's not much worse than standard.

[Mantua66]

Thanks for the encouragement Mr Croft.
So it seems the standard "wheezy" carb was the cause.
Twenty-six mm chokes Mmmm.
Plus the joys of "flooding" when the engine is switched off due to the carb heating up, amazing to think no insulator was fitted to combat this.
I had a the standard iron maifold and factory exhaust on the car that was stolen but the performance difference before and after the pulley change was shocking.
Better still, no difference in fuel cosumption in or out of town.
I kid you not! it was in the Capri 2.8i and Peugeot 205 gti (2.0 not 1.6) bracket - i know i raced against both - Capri man had to do a double take because my pile of rust had obliterated him so convincingly from the traffic lights. Went back to Essex with his tail between his legs.
The new car has an Ansa four branch which i know is for a normally aspirated 1.6 Beta.
Pipes are too narrow and not of even length as Mr Croft has suggested, wonder how much torque this restricts?
"Fingers" if i may ask, what is the max revs you are getting with the GC3a camshaft?
Also what do you mean by resonators? My mouth is watering as i type, improved flow and its not loud? perfect.
My plan of action is,
1. loose the small Webber, don't fancy the DCNF much, would need to cut the bonnet to get a decent flow of cold air to it.
2. The 36" 4:1 big bore header sounds like a real worth while investement.
3. Get rid of those awful low compression Croma turbo pistons, why-o-why did i fit those? They must be well below 7.5:1.
Thank's for all the advice so far, much appreciated.
Like the preview facility, you can see all your dodgy spelling before you post!
Will also get the camera out and send in some photos of the oil tank and htd pulleys if anyone is interested.

[Fingers]

The new pulley has 21 teeth, counted last night.

A resonator, the americans call them a glass pack, that probably doesn't help much. It's just a muffler that's about 2-3 times the diameter of the pipe, but flows straight through with no obstruction and has a few small louvre type holes on the inside open to the gas flow and I believe they're stuffed with fibreglass (hence the glass pack name). As for max revs, the nice thing is that you don't have to 'wring its neck' to get great power out of it, but it revs quite freely to 6500, I'm a little reluctant to take it over this although I have read that it will happily. But I have taken it over 7000 with no trouble.

[Mantua66]

Thanks for the information.
My memory plays tricks! I stand corrected, standard pulley has twenty-two teeth.
Nice to know you can push the engine beyond 6000rpm, want to have an engine that has a simillar rev range as the carb or injection engine.
I don't mind "wringing the neck" of my engine, TC's were built for it.
Big bore pipe with high flow silencers here i come.
Thank's again to all for the advice

[cotters]

Thanks for the information about the supercharger drive gear, as I type my friendly bearing supply shop is in the process of getting one made up for me!
As for the carb from experience I can only nod my head in agreement. What were Lancia thinking of?
A few years ago I got some information about this thing, I found out that (I think) the Talbot Simita -or was it Samba had the same carb with bigger chokes in it. I did the scrap yard trip and found one, and gave it a try. It did work better that the standard one but not by much, and it dripped into the inlet like the standard unit and went out of tune just as fast....
In the end I went back to the original unit, intending to try and work out some form of fuel injection, but that has yet to happen:(
I would be interested to know about the fuel injection that 'Mantua66' has planned. That sounds like the sort of thing that I would be after, I was also thinking of the Bosch ie system from the Thema / Delta TC cars but I don¢ž¢t know if they are able to be tweaked for a different engine, does anyone have any idea if this would work?

Thanks for the help guys.

[Mantua66]

Now if i have not messed up the file attachment.
This is my project at the moment.
complete management system is from an early Croma turbo ie.
Thats injection system and Microplex ingnition. Will fit a phase sensor and coil pack to eliminate distributor with the annoying oil leak later.
Modified the "ring" main/injector rail to be tight in the only space available.
Inlet manifold cut and flange welded, then blasted so it looks more like an original part.
This all has to fit under the bonnet, with no outward appearance of any modifications.
Will go for xylan coating (thanks GC) on the blower later, Beta 2000 inlet cam and probably aftermarket fuel injection to do away with the flow meter.
So far engine fires up on the button, not bad for a VX lump that has not run for about six years. Try getting a Vx to start after a winter lay-up.
I don't for one moment expect the unit to run perfectly, but has shown a lot of promise.
In the UK i remember the Crysler/Talbot Alpine, later Solara had the same carb as the VX, funny how all these "proper", practical cars all disapeared.