Volumex supercharger overhaul - strip

Supercharging, turbocharging, charge cooling
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Guy Croft
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Volumex supercharger overhaul - strip

Post by Guy Croft »

Step by step sequence, detailing the progressive strip of the Lancia/Fiat 'Volumex supercharger, the 'Roots' type blower used on the Lancia Beta Vx and Fiat Argenta/Spider Vx.

If you ever buy a Vx - send the blower to me for overhaul, don't try and do it yourself, this is definitely one area that requires my specialist experience. I know 'how and why' and I won't keep you waiting for weeks. These things are 26+ years old and if you say 'it sounds OK' - you might just end up with a junk blower.

I am going to have a major gripe now!
Watch out Lancia Fiat owners! There have been no replacement OE parts - gears, rotors, casings - available for these units almost since they were ever first introduced in the early 70's. Surprised? Well, they were built at Abarth and not many - I reckon just enough for the production run of cars and possibly no more than that. I have NEVER seen a new one for sale.

These blowers are super-popular for racing on vintage cars like MGs because they look just like a prewar blower. Ho ho. Unfortunately mostly they get run on amateurish crank-nose driven methanol powered instalations that lead to the total destruction the blower (and often the engine too), so they are getting very rare.
If they ever bothered to call me first I could at least tell them how to array the inlet setup and blower drive even if I don't know the first thing about methanol.
Attachments
rear seal (there are 2 of them) vulcanised (hard) and well-past its 'sell by date'
rear seal (there are 2 of them) vulcanised (hard) and well-past its 'sell by date'
Vx blower strip 42.jpg (12.52 KiB) Viewed 29612 times
using the right tool for this job is the only way to get the rear bearings out, slide hammer with expanding head, SKF.
using the right tool for this job is the only way to get the rear bearings out, slide hammer with expanding head, SKF.
Vx blower strip 41.jpg (23.88 KiB) Viewed 29609 times
heavy build up of carbon in the bearing housing betwen seal and bearing, enough of this and the rear bearings are going to seize, plus blower vents might block, allowing petrol in to the bearings.
heavy build up of carbon in the bearing housing betwen seal and bearing, enough of this and the rear bearings are going to seize, plus blower vents might block, allowing petrol in to the bearings.
Vx blower strip 40.jpg (25.27 KiB) Viewed 29607 times
rear bearing housing removed from main casing and bearing puller. The grease-packed rear bearings are a 'throwaway' item on any serious overhaul.
rear bearing housing removed from main casing and bearing puller. The grease-packed rear bearings are a 'throwaway' item on any serious overhaul.
Vx blower strip 39.jpg (22.73 KiB) Viewed 29609 times
With the rear bearing bolts removed and gears off, the shafts can be slid (or gently knocked) out  of the front bearings, carrying the front seal collar with them.
With the rear bearing bolts removed and gears off, the shafts can be slid (or gently knocked) out of the front bearings, carrying the front seal collar with them.
Vx blower strip 38.JPG (8.54 KiB) Viewed 29597 times
View from inner face of front gearcase, looking out, you can see the seal - just like a crankcase seal that holds the EP oil in the gearcase.
View from inner face of front gearcase, looking out, you can see the seal - just like a crankcase seal that holds the EP oil in the gearcase.
Vx blower strip 37.JPG (9.55 KiB) Viewed 29593 times
The front seal can be pushed you with a drift either way, there is no locating face.
The front seal can be pushed you with a drift either way, there is no locating face.
Vx blower strip 36.JPG (13.16 KiB) Viewed 29591 times
remove the main casing vent pipes carefully - they are easily snapped
remove the main casing vent pipes carefully - they are easily snapped
Vx blower strip 35.JPG (5.87 KiB) Viewed 29584 times
Front gearcase with seals and bearings removed, the small holes allow petrol vapor to vent from the main casing without contaminating the seal region and EP oil that lubricates the precious gears.
Front gearcase with seals and bearings removed, the small holes allow petrol vapor to vent from the main casing without contaminating the seal region and EP oil that lubricates the precious gears.
Vx blower strip 33.JPG (14.35 KiB) Viewed 29580 times
Carbon contamination from years of use, from backfires, reverse flow of exhaust gas, builds up behind the gearcase seals and damages them, leading to high oil consumption. The oil level must be checked every 800 miles and more often on an old engine.
Carbon contamination from years of use, from backfires, reverse flow of exhaust gas, builds up behind the gearcase seals and damages them, leading to high oil consumption. The oil level must be checked every 800 miles and more often on an old engine.
Vx blower strip 32.JPG (11.47 KiB) Viewed 29583 times
This is an inner sleeve from one of the 4 point bearings, keep them in order and with the bearings if re-using, but if the bearings fall apart during dismantling - junk them without a second thought, or irreparable gear damage is sure to follow..
This is an inner sleeve from one of the 4 point bearings, keep them in order and with the bearings if re-using, but if the bearings fall apart during dismantling - junk them without a second thought, or irreparable gear damage is sure to follow..
Vx blower strip 31.JPG (6.63 KiB) Viewed 29569 times
With the front bearings pressed out the 2 seals can be prised out, taking care not to damage the alloy housing.
With the front bearings pressed out the 2 seals can be prised out, taking care not to damage the alloy housing.
Vx blower strip 26.JPG (14.11 KiB) Viewed 29569 times
Press the front bearings out from this side, if they fell to bits when you removed the rotors, put them back together for this op. A socket works fine as a mandrel, they are not a very tight fit.
Press the front bearings out from this side, if they fell to bits when you removed the rotors, put them back together for this op. A socket works fine as a mandrel, they are not a very tight fit.
Vx blower strip 24.JPG (18.96 KiB) Viewed 29566 times
Front gearcase, one bearing removed; the bearings are a 4 point contact type and very durable, save if they feel good and don't fall apart on dissassembly - a sure sign the cage is worn.
Front gearcase, one bearing removed; the bearings are a 4 point contact type and very durable, save if they feel good and don't fall apart on dissassembly - a sure sign the cage is worn.
Vx blower strip 23.JPG (19.36 KiB) Viewed 29560 times
The only gaskets used are shown here, gearcase cover, main casing front and rear, rear bearing housing. Don't waste time making new ones, OE quality Silicon RTV will do the job just as well - if not better.
The only gaskets used are shown here, gearcase cover, main casing front and rear, rear bearing housing. Don't waste time making new ones, OE quality Silicon RTV will do the job just as well - if not better.
Vx blower strip 22.JPG (10.13 KiB) Viewed 29552 times
Rotors removed, the seal collars are grooved to create a 'labyrinth' seal to reduce the pressure acting on the seal. These collars MUST be removed from the shafts for clean & polish, they are NOT part of the rotor.
Rotors removed, the seal collars are grooved to create a 'labyrinth' seal to reduce the pressure acting on the seal. These collars MUST be removed from the shafts for clean & polish, they are NOT part of the rotor.
Vx blower strip 21.JPG (15.58 KiB) Viewed 29551 times
With the rear bearing housing removed, the front gearcase with rotors still in it (left of shot) can removed. It usually takes 'nudge' with a light hammer and suitable drift and takes the old gasket with it.
With the rear bearing housing removed, the front gearcase with rotors still in it (left of shot) can removed. It usually takes 'nudge' with a light hammer and suitable drift and takes the old gasket with it.
Vx blower strip 20.JPG (18.71 KiB) Viewed 29549 times
rear bearing housing removed, not that the rotors are still in place in the front gearcase.
rear bearing housing removed, not that the rotors are still in place in the front gearcase.
Vx blower strip 18.JPG (17.95 KiB) Viewed 29541 times
Lock the rotors with a piece of wood and undo the bolts that secure the rear bearings, keep the bolts and washers.
Lock the rotors with a piece of wood and undo the bolts that secure the rear bearings, keep the bolts and washers.
Vx blower strip 14.JPG (18.41 KiB) Viewed 29538 times
Behind the gears is the front bearing retaining plate, here we can see the outer sleeve of one of the 4 point bearings, don't lose or get it mixed up at this stage.
Behind the gears is the front bearing retaining plate, here we can see the outer sleeve of one of the 4 point bearings, don't lose or get it mixed up at this stage.
Vx blower strip 17.JPG (14.28 KiB) Viewed 29538 times
I am always amazed how people do things DIY, but the 2 gear retaining nuts - you MUST use a 'nut gun' (heavy duty air impact wrench) for removing these, or you are going to damage something. Don't lose the 2 special washers.
I am always amazed how people do things DIY, but the 2 gear retaining nuts - you MUST use a 'nut gun' (heavy duty air impact wrench) for removing these, or you are going to damage something. Don't lose the 2 special washers.
Vx blower strip 16.JPG (14.37 KiB) Viewed 29534 times
Rear bearing cover removed, full of carbonised and contaminated grease, as I'd expect on 30 year old blower. Save the gasket if you can, discard the grease..
Rear bearing cover removed, full of carbonised and contaminated grease, as I'd expect on 30 year old blower. Save the gasket if you can, discard the grease..
Vx blower strip 13.JPG (17.77 KiB) Viewed 29531 times
With the gearcase front cover removed, the two gears are exposed, they are identical. This pair? Ran the unit out of oil...all scrap, quickly.
With the gearcase front cover removed, the two gears are exposed, they are identical. This pair? Ran the unit out of oil...all scrap, quickly.
VXgearsdamaged.JPG (14.12 KiB) Viewed 29531 times
Once unbolted the front cover gearcase needs a bit of persuasion to remove because the reinforced gasket holds it to the gearcase.
Once unbolted the front cover gearcase needs a bit of persuasion to remove because the reinforced gasket holds it to the gearcase.
Vx blower strip 09.JPG (13.54 KiB) Viewed 29528 times
Front cover loosened, let the filthy, sulphated and carbonised old EP90 gear oil drain off..
Front cover loosened, let the filthy, sulphated and carbonised old EP90 gear oil drain off..
Vx blower strip 07.JPG (16.49 KiB) Viewed 29519 times
Drive pulley removed. The back of the pulley runs in the front cover seal.
Drive pulley removed. The back of the pulley runs in the front cover seal.
Vx blower strip 06.JPG (15.34 KiB) Viewed 29518 times
Nut, special washer (for some reason missing in this shot, see rebuild series, later) tapered collar and drive pulley.
Nut, special washer (for some reason missing in this shot, see rebuild series, later) tapered collar and drive pulley.
Vx blower strip 05.JPG (15.93 KiB) Viewed 29518 times
Support the blower via the pulley and give a sharp strike on the shaft with a dead-blow hammer. Fit the pulley nut before striking or you may damage the shaft threads.
Support the blower via the pulley and give a sharp strike on the shaft with a dead-blow hammer. Fit the pulley nut before striking or you may damage the shaft threads.
Vx blower strip 04.JPG (16.72 KiB) Viewed 29507 times
You either need an OE tool for restraining the drive pulley + very big vice + big T bar, or just a high torque 'nut gun' to get the front nut off.
You either need an OE tool for restraining the drive pulley + very big vice + big T bar, or just a high torque 'nut gun' to get the front nut off.
Vx blower strip 03.JPG (13.56 KiB) Viewed 29496 times
Typical dirty old Vx unit ready to strip, remove the oil reservoir and keep safe, the unit is useless without it.
Typical dirty old Vx unit ready to strip, remove the oil reservoir and keep safe, the unit is useless without it.
Vx blower strip 02.JPG (15.88 KiB) Viewed 29508 times
This is a GC built Vx race unit, the belt driven blower on right of engine produces about 6psi boost on the 2 liter TC
This is a GC built Vx race unit, the belt driven blower on right of engine produces about 6psi boost on the 2 liter TC
Vx unit .JPG (20.58 KiB) Viewed 30634 times
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