In this article, the Reverend
Nigel A Skeet
discusses (in some depth) the religious implications of fitting a long
throw crankshaft to an otherwise fairly standard Volkswagen engine.
This is the actual transcript
of a sermon that I was priviliged enough
to attend in Scunthorpe late last year & I'd like to thank him for
letting me reproduce it here.
"Dearly Beloved,
We are gathered here today to discuss the VW (AS) series engine &
ways of improving said motor,
And the Gnostic known as Phil spoke thus;
Having had the pleasure of driving an under-powered (i.e. 1584 cc, 108
Nm @ 2800 rpm & 50 bhp @ 4000 rpm, C.R. = 7·5 : 1, >91
RON petrol) 1973 VW 1600 Type 2, I can understand your desire for
increased engine torque, to improve acceleration and hill climbing
ability. However, do not forget that for a given engine speed (and
associated cooling-fan speed), an increase in torque, results in a
proportionate increase in power. Unless all the additional energy
released, from burning additional fuel, is converted into engine power,
then there will be more waste heat, which has to be dissipated by the
engine's cooling system.
The following checklist, is a summary of the many factors which either
individually or collectively, might lead to engine overheating, poor
performance or poor economy of air-cooled engines. The last European VW
vehicle to be equipped with an air-cooled engine, was manufactured in
1983, so relatively few mechanics (either the DIY owner, independent or
franchised VW garage workshops) fully appreciate the importance of the
cover plates, seals and grommets, to the correct functioning of the
engine cooling system.
Of the air-cooled VWs I have examined, belonging to fellow owners who
purchased them in the later stages of the vehicles' lives, many have
been missing vital components of the cooling system; particularly cover
plates, engine compartment perimeter foam-seal, sparkplug connector
seals, plus other less obvious omissions. On more than a few occasions,
there have been missing, one or more of the large coverplates which
isolate the engine compartment from the vehicle underside, the purpose
of which is to prevent hot reject air from the cooling system, being
recycled back into the inlet of the cooling system.
Any owner of an air-cooled VW, who is uncertain of its service history
and the competence of the attendent mechanics, regarding AIR-COOLED
engines, is strongly advised to consult the appropriate workshop
manuals and conduct a full inventory of all cover plates, hoses, clips,
seals and grommets, to ensure that all are present and correctly fitted.
Air-cooled engines are particularly prone to overheating as a result of
weak fuelair mixtures at full throttle and/or over-advanced
ignition timing. Many engines have been fitted with all-centrifugal
"009" or "050" ignition distributors, which give satisfactory
performance with modified racing engines, but are not well suited to
road going engines, which need additional vacuum advance, to eliminate
acceleration 'flat-spots', at just above idling speed, plus
optimisation of torque and fuel economy, under part-load conditions.
POOR PERFORMANCE & ECONOMY
1. Blocked or restrictive air filter and/or
air-filter housing & trunking.
2. Incorrect carburettor or fuel injection
specification.
3. Incorrect carburettor or fuel injection adjustment
settings.
4. Carburettor and/or inlet manifold icing, during
cold, damp weather.
4. Poorly functioning ignition system (misfiring or
less than optimum spark at sparkplug).
5. Incorrect ignition distributor specifications.
6. Incorrect static ignition timing and/or
centrifugal ignition-timing advance characteristics and/or vacuum
ignition-timing advance characteristics – dependent upon ignition
distributor specification or faults (e.g. sticking centrifugal
mechanism and/or contact breaker base plate and/or leaking vacuum
advance canister) or inlet manifold vacuum.
7. Air leaks in inlet manifold casting (rare cases of
porous casting!), gaskets, connections or hoses – leads to a leaner
fuel-air mixture and change in inlet manifold vacuum.
8. Air leaks in vacuum brake servo canister,
connections or hoses – leads to a leaner fuel-air mixture and change in
inlet manifold vacuum.
9. Holes, Restrictions or obstructions in exhaust
system.
10. Worn, engine cylinder-head valve guides, which
affects inlet manifold vacuum and pressurises the crankcase.
11. Loss of engine compression, owing to incorrectly
adjusted or burnt valves, worn cylinder barrels, pistons and piston
rings.
12. Underinflated tyres.
13. Presence of non-aerodynamic roofrack and/or
luggage and tarpaulin cover.
14. Binding brakes and/or wheel bearings and/or
drive-shaft constant velocity joints.
15. Misalignment of the front and/or rear wheels
(toe-in, toe-out, steering offset ans excessive camber).
16. Incorrect wheel and/or tyre sizes – affects
overall engine gearing (i.e. MPH per 1000 RPM) and may affect steering
offset (dependent upon tyre external diameter, wheel offset and
'kingpin inclination').
17. Mismatching of vehicle weight & aerodynamic
drag, overall engine gearing (i.e. MPH per 1000 RPM) and engine power
& torque characteristics (i.e. maximum power @ RPM and maximum
torque @ RPM).
OVERHEATING
1. Loose or glazed fan belt, resulting in belt
slippage (not applicable to crankshaft-driven cooling fans of VW 411
& 412, 1972~83 VW 17/18/2000 Type 2, 1980~83 VW 1600 Type 2, VW
15/1600 Type 3 and VWPorsche 914/4).
2. Faulty or incorrectly adjusted, cooling-fan,
air-flow control flaps or thermostat bellows.
3. Dirt clogging the cylinder head/barrel cooling
fins and/or oil-cooler matrix.
4. Debris (e.g. cloth rag, leaves, paper, etc.)
lodged inside fan housing or engine coverplates, obstructing air flow
to finned cylinder barrels & cylinder heads and/or oil-cooler
matrix.
5. Dirt and/or oil on internal surfaces of fan
blades, fan housing and coverplates, hence increasing flow resistance
and hence reducing flow rate of cooling air.
6. Restriction or blockage of cooling-system,
air-intake trunking and/or vehicle bodywork grilles.
7. Thick rust deposits on cylinder barrel cooling
fins.
8. Carbonised oil encrustation on the internal
surfaces of the crankcase, cylinder-head valve rocker boxes &
covers.
9. Missing, damaged or incorrectly fitted foam seal,
around edge of engine compartment.
10. Missing or hole-damaged coverplates and/or gaps
between adjacent engine coverplates.
11. Missing alternator sealing ring (circular – VW
Part No. 021 903 203 or elliptical – VW Part No. 022 903 203), or
alternator adjustment-bolt inspection cover, for VW 411 & 412,
1972~79 VW 17/18/2000 Type 2 and VWPorsche 914/4.
12. Missing, partially disconnected or hole-damaged
air hoses from VW 12/13/15/1600 Type 1, 2, 181 & 182 (excluding
1980~83 VW 1600 Type 2) engine fan housing to heating system
connections of exhaust silencer (i.e. muffler) or heat exchanger;
dependent upon type of exhaust system fitted.
13. Missing or improperly fitted clamp from VW
12/13/15/1600 Type 1, 2, 181 & 182 (excluding 1980~83 VW 1600 Type
2) heat exchanger, to heating system connections of exhaust
silencer (i.e. muffler); dependent upon type of exhaust system fitted.
14. Missing or inadequately sealed heat exchanger
covers (covers heat exchanger to engine cooling fan connections), for
VW 411 & 412, 1972~79 VW 17/18/2000 Type 2 and VWPorsche 914/4.
15. Unsealed holes in coverplates (e.g. missing
sparkplug lead seals, duct perimeter seals and grommets).
16. Pre-heater air hose for the standard air filter
is missing or partially disconnected. Where an after-market air filter,
lacking an pre-heat facility, has been fitted, the connection supplying
hot air from the vicinity of the cylinder barrel (VW 1600 Types 1 &
2, with single carburettor or fuel injection – cylinder No. 2; VW
17/18/2000 Type 2 & 4, with twin carburettors – cylinder No.
1; VW 17/18/2000 Type 2 & 4, with fuel injection – cylinder No. 2),
has not been blanked off.
17. Missing sheet-steel air-deflector plates, which
wrap around lower portion of cylinder barrels.
18. Incorrect carburettor or fuel injection
specification.
19. Incorrect carburettor or fuel injection
adjustment settings.
20. Incorrect ignition distributor specification.
21. Incorrect static ignition timing and/or
centrifugal ignition-timing advance characteristics and/or vacuum
ignition-timing advance characteristics – dependent upon ignition
distributor specification or faults (e.g. sticking centrifugal
mechanism and/or contact breaker base plate and/or leaking vacuum
advance canister) or inlet manifold vacuum.
22. Air leaks in inlet manifold casting (rare cases
of porous casting!), gaskets, connections or hoses – leads to a leaner
fuel-air mixture and change in inlet manifold vacuum.
23. Air leaks in vacuum brake servo canister,
connections or hoses – leads to a leaner fuel-air mixture and change in
inlet manifold vacuum.
24. Holes, restrictions or obstructions in exhaust
system.
25. Incorrect fuel octane rating for the engine.
26. Reduced lubrication owing to lack of oil pressure
or restrictions in the oil galleries.
27. Binding brakes and/or wheel bearings and/or
drive-shaft constant velocity joints.
For an air-cooled engine, the oil plays a crucial role, both for
lubrication and cooling, so oil temperature, is an important indicator
of the engine's running condition. To obtain long-term, reliable
operation, it is suggested that once the engine has attained its
'normal' operating temperature, the oil temperature should be
maintained between certain upper and lower limits. Opinion differs as
to what those limits should be, but the maximum 'safe' oil temperature,
for an air-cooled VW engine is generally regarded as being circa
110~120 °C (as measured in the 'sump').
The magnesium alloy crankcases of the VW 12/13/15/1600 Type 1, 2 &
3 engines, become increasingly elastic, as temperature increases (see
Tom Wilson, "How to Rebuild Your Volkswagen Air-Cooled Engine", HP
Books, 1987, p85); quoted as being about 2% and 6% elastic at 105
°C and 115 °C respectively. At the higher temperature, the
crankcase easily distorts as a result of crankshaft whip and other
unbalanced forces. Consequently, 105 °C should probably be regarded
as the upper limit, for dependable longevity of magnesium alloy
crankcases.
Aluminium alloy crankcases, used in what is commonly referred to, as
the VW Type 4 engine (found in the 1972~83 VW 17/18/2000 Type 2, VW 411
& 412 and VW-Porsche 9144, plus some Porsche 912s), are more
tolerant of high temperatures, with respect to elasticity. However, I
have yet to find any upper oil-temperature limits, specified for these
engines. I envisage that any temperature limits, are likely to be
dictated by the properties of the engine oil, rather than those of the
aluminium alloy crankcase.
Ironically, these engines run cooler than the VW 12/13/15/1600 Type 1,
2 & 3 engines, owing to the increased cylinder spacing (see Peter
Noad, "Pacenotes", VW Motoring, August 1997, pp62~64) and uprated
cooling system, facilitating more efficient cooling. The spacing
between the central axes of adjacent cylinders, is 112 mm and
124·5 mm, for the VW 12/13/15/1600 Type 1, 2 & 3 and VW
17/18/2000 Type 2 & 4 engines respectively; allowing greater air
flow between adjacent cylinders of the latter engine. Cooling system
air-flow rates, are quoted as 0·575 m3s-1 @ 4000 RPM and
0·800 m3s-1 @ 4600 RPM, for the VW 1600 Type 2 and VW 17/18/2000
Type 2 & 4 engines respectively.
I and other owners of 1968~79 VW 1600 Type 2s, have found that when
driving at about 55~65 MPH, on British motorways in summer, crankcase
(i.e. sump) oil temperatures, are typically 110~120 °C and one
individual, reported temperatures approaching 140 °C, for his newly
reconditioned engine. 1972~83 VW 17/18/2000 Type 2 engines, are said to
typically exhibit oil temperatures of about 90 °C, under similar
motorway driving conditions. Engine-oil temperatures for both the
1968~79 VW 1600 Type 2s and 1972~83 VW 17/18/2000 Type 2s, plus other
VWs, are likely to be much higher, when the vehicle is subjected to
more severe operating conditions, such as high ambient temperature,
high altitude, climbing a steep gradient, carrying a heavy payload or
towing a trailer.
Increasing the displacement of engines, causes them to run hotter, even
at the same speed, which is particularly noticeable with the VW 1600
Type 1, 2 & 3 engine. It was found (see Peter Noad, Pace Notes, VW
Motoring, August 1997, pp62~63), that increasing the displacement of a
VW Type 1 Beetle engine, from 1500 cc to 1700 cc, resulted in
oil-temperature increases from 100ºC to 107ºC @ 70 MPH &
115ºC to 127ºC @ 80 MPH. Myself and other British VW 1600
Type 2 owners, found that when cruising along the motorway in summer,
at about 55~60 MPH, engine oil temperatures of 110~120ºC are
fairly typical (more than a VW 1600 Type 1 Beetle!), so without cooling
system modifications, your uprated engine, would be likely to run
noticeably hotter than this, which is not good for magnesium alloy
crankcases.
One owner in the Las Vegas area of the USA (summer temperatures
of more than 45ºC), fitted extended air-intake scoops, to
his 1971 VW '1600' Type 2 (called the "Wayback Machine"), with a Bernie
Bergmann 1835 cc engine (69 mm stroke x 92 mm bore). He pronounced that
this modification, significantly reduced engine running temperature,
but did not specify by how much! He also seems to have fitted
supplementary oil cooler with electric fan and manual switch, plus
possibly a thermostatic switch. For further details of the "Wayback
Machine", try Internet website, http://www.scottandmaggie.com.
If significantly increased cooling requirements are to be avoided,
these torque & power increases, would have to be obtained,
principally by an increase in thermodynamic efficiency and volumetric
efficiency (i.e. an increase in compression ratio and improved engine
"breathing" on both the induction and exhaust strokes). Most increases
in engine displacement, by either increases in stroke and/or bore, will
almost invariably result in increased cooling requirements, which is
typically met by increasing the oil-cooling capacity and enhancing the
radiative heat loss properties of the crankcase, cylinder barrels,
cylinder heads and rocker-box covers, as well as ensuring that the
standard cooling system is operating correctly, with no air leakage or
recirculating hot air.
Many of these things are discussed in a book which is still readily
available (see Bill Fisher, "How to Hot Rod Volkswagen Engines", HP
Books Inc., 1970, ISBN 0-91265-603-4), plus a more recent magazine
article (see Bruce Simurda, "Sand Engine Survival", Dune Buggies &
Hot VWs, October 1997, pp80~82), but one recognised oil cooler upgrade,
for the 1971~79 VW 1600 Type 2 engine, with "dog-house" fan housing, is
to extend the oil-cooler "dog-house" by about ¾ inches and
substitute the VW Type 4 oil cooler, which has two additional
oil-cooling channels and associated finning. Many owners (especially in
the warmer States of the USA) also fit a thermostatically controlled
supplementary oil cooler, with electric fan, forward of the rear
jacking points.
If you fitted a longer stroke crankshaft, then the pistons will travel
further up their bores, towards the cylinder heads. Hence, if the
standard 1584 cc engine's 85·5 mm bore cylinder barrels &
pistons are retained, then you would need to use spacers (of thickness
equal to half the increase in stroke) between the crankcase and the
cylinder barrels, to obtain the necessary clearance between the
cylinder head and the piston crown, making it less easy to correctly
align the cover plates, fan housing, exhaust system and
single-carburettor inlet manifold. Where available, it might be better
to use alternative pistons, having a reduced distance between the
gudgeon pin and piston crown.
If one is going to the trouble and expense of non-standard pistons, one
might as well increase the bore slightly and have a matched set of
cylinder barrels & pistons, appropriate to the crankshaft stroke.
According to one book I have read (see A. Graham Bell, "Performance
Tuning in Theory & Practice", Haynes Publishing Group, 1981, ISBN
0-85429-275-6), the most reliable upgraded VW 1600 Type 1, 2 & 3
style engine configurations, for road or rally use, are those of 1849
cc displacement (76 mm stroke & 88 mm bore) or 1904 cc displacement
(74 mm stroke & 90·5 mm bore).
The 1849 cc engine, would probably be the more appropriate for VW Type
2 applications. Coincidently, one could use the 5bolt flywheel
& 76 mm stroke crankshaft, originating from the 1983~92 VW 1900
& 2100 Type 2, water-cooled flatfour engines, to obtain a
particularly robust combination, which would matchup with your VW
Type 2 existing transaxle. I would probably opt for the 1980~83 VW 1600
Type 2 crankcase, with integral full-flow oil filter and standard
cooling system with crankshaft driven fan. I think the 1980~83 VW 1600
Type 2 cover plates align with the 1972~79 VW Type 2 engine bay
perimeter, but I'm not absolutely certain!
Owing to well documented problems of cylinder distortion and
cylinder-head sealing, it is generally advisable to avoid the
thin-walled, big-bore kits, which claim to be a direct substitute,
requiring no crankcase or cylinder head machining. During the 1970s,
the EMPI/Mahle or Kolbenschmidt 88 mm bore kits, were the acknowledged
favourites; preferably with full-skirted (aka round-skirted), rather
than slipper-skirted pistons, for a road-going vehicle.
Using unmodified standard cylinder heads and piston crown to
cylinder-head clearance (aka deck height or squish clearance) of
1·55~1·75 mm, would result in a compression ratio of
about 8·6 : 1, which might be a little bit too high, for a VW
Type 2 engine, using with 95 RON unleaded petrol; especially if the
standard squish clearance is retained. By reducing squish clearance and
increasing the combustion chamber volumes, by removing material to
unshroud the valves, to the edge of the 88 mm bore, one can obtain a
reasonable compression and improved "breathing". Bill Fisher tabulates
flow improvements in excess of 63%, for both inlet and exhaust, at
lifts upto ½ inch. This means that with 1849 cc, a reasonable
pair of twin carburettors, an extractor exhaust system, retension of
the standard camshaft and a compression ratio slightly more than
8·0 : 1, about 100 bhp @ 4000 rpm, is probably attainable.
One 1978 VW 1600 Type 2 Zenith campervan (a rival conversion to the
Westfalia, costing about £1000 more when new; of which only 50
were built) owner, of passing acquaintance (John Wright-Bailey, Tel.
01268 - 491728) who used to be involved in the development of
two-stroke, air-cooled racing engines (or so he told me), had a
self-built "1600" engine, for his campervan, with a claimed compression
ratio of 8·5 : 1 and a squish clearance of circa
0·75~0·80 mm, which he ran on 95 RON unleaded petrol. He
also claimed that it ran cooler and produced more torque & power
than a standard 1600 engine, plus giving 27 mpg petrol consumption.
Engines with reduced squish clearance are less prone to detonation and
tolerate higher compression ratios, owing to increased turbulent mixing
of fuel and air. Bill Fisher recommends circa 1·00~1·25
mm (1·00 mm being an almost universally acknowledged minimum!),
whilst another source (see Tom Wilson, "How to Rebuild Your Volkswagen
Air-cooled Engine", HP Books Inc., 1987, ISBN 0-89586-225-5) advocates
circa 1·40~1·65 mm. My 1911 cc, VW 17/1800 Type 2 & 4
modified, hybrid engine, will have a squish clearance of 1·20
± 0·05 mm.
The Lord said: "I have finally replaced the coil, distributor, cap,
plugs, leads, carburetter, fuel lines, fitted electronic ignition,
clutch cable, brake problems and even now I have a fuel guage which
seems to have lost the plot and it appears to be a tank & sender
based problem."
Did you replace the standard-fitment, Bosch distributor (with both
centrifugal & vacuum advance) with the 009 distributor because the
former was not functioning correctly? Apart from excessive wear in the
distributor shaft and/or bearings (plain phoshor-bronze bushings),
rough or worn distributor cams or corrosion of the internal mechanism,
there is little which can go wrong with the distributor itself! In the
case of shaft or bearing wear, the shaft can be polished and the
distributor housing rebushed. Wear and/or corrosion usually occur,
because of the service-technicians' failure to clean inside the upper
portion of the distributor, plus lubricating at regular intervals, the
cam lobes, distributor shaft, upper & lower base plates and the
centrifugal advance mechanism, which ideally should be done, every 3000
miles. I would be inclined to smear the cam lobes with a thin film of
grease, on a more regular basis!
The upper shaft with the four cam lobes and probably other components,
can be replaced by canabalising other Bosch distributors from the
breaker's yard, including those from water-cooled engines, such as some
VW, Audi, Ford, BMW, Volvo, etc. In the past, I have polished cam
lobes, which for some inexplicable reason, had suddenly become
roughened and were rapidly wearing the contact-breaker, cam-follower.
Wear was so rapid, that during our European touring holiday, I had to
reset the points gap and ignition timing, on a daily basis. After that
episode, I made an additional timing mark on the opposite side of the
crankshaft, fan-belt pulley, so that I could individually check the
ignition timing, of all four cylinders.
Several years ago, I dismantled and reassembled, a hybrid VW 17/2000
Type 2 engine, whose distributor maintenance had seeminly been
neglected for many years and consequently, the centrifugal advance
mechanism had become stiff, through lack of lubrication and
accummulation of dirt, so failed to function correctly. This was
remedied by dismantling, cleaning, reassembly and lubrication. Vacuum
advance mechanisms cease to function correctly, either because of a
ruptured diaphragm inside the vacuum-advance canister, fitment of an
incorrect replacement vacuum-advance canister or sticking
contact-breaker base plates. Contact-breaker base plates can stick,
either through dirt, corrosion or lack of lubrication, but in many
cases as a result of contact breakers, having a toolong a location
post jamming against the lower base plate (see technical tip below).
Many contact breaker points, supplied for fitment to the Bosch ignition
distributor, of air-cooled VW engines, have an excessively long
locating lug, which fouls the fixed base plate, beneath the rotating
base plate, resulting in sluggish operation of the ignition retard
& advance mechanism.
Unhindered rotation of the base plate and hence correct operation of
the ignition retard (if fitted) & advance mechanism, can easily be
restored by shortening the locating lug, using an ordinary, flat-faced
file or a grinding wheel. Although a simple modification, this was
found by the authors, to significantly improve both acceleration and
fuel consumption, which was quoted as being approximately 27 miles per
Imperial gallon, for a 1972 VW 1600 Type 2.
In general, any departure from standard specification, of the engine
itself, plus induction system (i.e. inlet manifold, carburettor &
air filtration) or exhaust system (design and lengths & diameters
of the exhaust manifold pipes and secondary pipe work, plus silencer),
will alter the fueling and ignition advance (static timing, plus
centrifugal & vacuum advance curves) requirements, for the various
engine speed & load conditions. Even just the substitution of an
extractor exhaust manifold & silencer, can have a discernable
effect. Increasing displacement tends to increase the requirement for
ignition advance, whilst increased compession ratio & decreasd
squish clearance tends to reduce it. There are also other factors!
From what I have read, the 009 distributor (VW Part No. 126-905-205,
Bosch Part No. 0231 178 009) is not ideally suited to road-going
vehicles; especially at low engine revs, under part-load conditions,
where additional ignition advance is needed for the "slow-burning"
mixture. It was primarily intended for VW air-cooled industrial
engines, running at a relatively constant high speed.
I regret to report, that I no longer have the standard-fitment, Bosch
distributor (with both centrifugal & vacuum advance), originating
from our former 1973 VW 1600 Type 2, ADSeries engine. I sold it a
few years ago, to a fellow owner on Canvey Island, who also purchased
the dynamo and dynamo-support tower cum oil filler (his had somehow
cracked and was leaking oil). To the best of my recall, a new
distributor of this type, retails for about £140; assuming
they're still available.
Issue 56, Dec. 2001 T2 distributor 231 168
015 asking £20 Tel. 020 8578
8086 (Greater London area)
Issue 54, Aug. 2001 1600 air-cooled engine
bits call Terry
Tel. 01229-770000 day, or 01229-773037 eve (Cumbria)
Issue 48, Aug. 2000 distributors for 1600
asking £5 call
Greville Tel. 01278-733198 (Somerset)
Issue 42, Aug. 1999 distributors 231 167 049 or 231
168 015 asking £5 each call
Bob Tel. 020 8578 8086 (Middlesex)
Issue 41, Jun. 1999 distributors 231 167 049 or 231
168 015 asking £20 each Tel.
01252-329676 (Aldershot)
Issue 21, Feb. 1996 1972 Type 2
distributor call John
Tel. 01223-262360 (Cambridge)
Looking through the Miscellaneous Sales advertisements, in past issues
of Transporter Talk, from October 1995 onward, I came across the above
items, which might still be worth investigating, despite the passage of
time; some parts being slow to sell! If these prove fruitless, try
advertising in the Wanted sections of Transporter Talk, VW Motoring,
Volkswagen Camper & Commercial magazines, plus the various general
sales and VW websites, such as LOOT, type2.com, vwt2oc.com,
rustybay.com, etc; you may be surprised at the response! I think some
of the VW parts suppliers, might also host a sales & wants, website
noticeboard for customers. Several years ago, I obtained my
comparitively scarce, intra-duct ventilation booster fans, by
advertising free of charge, in the Wanted section of VW Motoring.
One article I read sometime ago (see John Connolly, The Distribution of
Power, VW Trends, April 2000, pp28~30) mentioned that the SVDA
distributor (sold by aircooled.net), which features the 009 centrifugal
advance characteristics, plus having vacuum advance. The addition of
vacuum advance, eliminates the flat-spot just above idle, which
commonly arises with an 009 distributor. Compared to the 009
distributor, it also gives a 4 miles per U.S. gallon (i.e. 5 miles per
Imperial gallon), relative-improvement in fuel consumption, with a VW
Type 1 Beetle; corresponding to approximately 15%. Judging from the
blanked oval hole, in the side of the 009 distributor housing, it might
be possible to retro-fit a vacuum advance canister, with the required
advance characteristics, provided one also fitted an appropriate
two-piece, rotating base-plate (I might have one spare, originating
from a VW 411LE distributor), for the contact breaker points.
One book with which I am acquainted (A. Graham Bell, "Modifying New
Generation Engines for Power & Economy", Haynes Publishing Group,
1988), describes the procedure, for tailoring the static, centrifugal
& vacuum ignition advance characteristics, for a modified engine.
The author states that getting the vacuum advance right, is very
important from the aspect of fuel economy and claims to have seen
engines show a 25% reduction in fuel consumption, as a result of using
the appropriate vacuum canister and vacuum source, as outlined in the
chapters on the ignition system and emission controls.
One article regarding the 009 distibutor, which might be worth reading,
is as follows. It was reputedly written by Bob Donalds, of the Boston
Engine Exchange, in Boston, Massachusetts, USA. The USA specification,
VW 1600 Type 2 AESeries engines, are slightly different from the
British & European specification, VW 1600 Type 2, ADSeries
engines; particularly with regard to standard ignition timing settings,
so DO NOT follow the recommendations too literally. There are a few
other air-cooled VW technical articles, on his website
(http://www.bostonengine.com), which you might find worth reading.
When your original distributor fails, or if you just want to get the
latest and greatest, you reach for the fully centrifugal 009
distributor or one of its cousins. When the 009 is used with the
30-PICT-3 or any 34 PICT carburetor, problems begin to happen faster
than you can turn the adjustment screws. Where do you time the new
distributor? Do you use the old timing mark? What does the old
timing mark mean? Why won't my engine idle?
First, most original distributors in the dual port engine (USA
specification) were designed to run with an idle timing of 5 degrees
ATDC (After Top Dead Center). The 009 should be timed at 10 degrees
BTDC (Before Top Dead Center). Setting the 009 at a timing mark
of 5 ATDC would give you an inadequate advance of about 17
degrees total.
Now your engine may idle nicely but you risk melting a piston. The air
cooled Type 1, pre 72 Type 2 (NOTE from Nigel Skeet: there was no
1972~79 VW 1600 Type 2 engine in the USA!), and Type 3 VW engine needs
a total advance of 32 degrees BtdC up at the fan belt where it
lifts off the pulley. When the 009 is set at 10 degrees, this timing
change of advancing by 15 degrees raises the idle so high you need to
lower it by turning the idle speed adjusting almost all the way.
Naturally this shuts down the idle circuit. The engine is now getting
so little fuel; it barely idles. Even if it does idle, it won't
transition to the next carburettor circuit without massive hesitation,
even with a good accelerator pump. Also, the throttle plate if not
closed at warm idle, will create the same effect.
On the dual-port crank pulley, there is a dent on the opposite side of
the original timing mark and slightly to the right. I take the middle
of this dent as 0 degrees. Take the points of an open-end 15 mm wrench
and lay the left side of the wrench in the middle of the dent and the
right side will fall at approximately 10 degrees BTDC. File a new notch
at that spot, I then mark it with red touchup paint.
Nigel Skeet's NOTE: I did something similar when the Minnow Fish
carburettor, was fitted to our 1600, ADSeries engine, but I
measured around the circumference of the crankshaft pulley, in both
directions from the original notch, using a strip of plain white paper
and a pencil. That way, I could check the individual static or dynamic
timing, for all four cylinders (cylinders 1 & 3 by the original
notch, plus cylinders 2 & 4 by the opposite notch. Two further
notches were created to advance the timing further, as required for the
aforementioned carburettor.
The next step to a proper idle is to install a pop rivet in the hole of
the throttle plate.Trust me, it works. This is the brass plate at the
base of the carburetor that opens when you press the gas pedal. Now all
the air the engine draws in at a idle must come through the idle
circuit. You can now back out the idle speed adjusting screw, restoring
the idle by allowing enough air into the carburetor idle circuits
thereby picking up the fuel needed to obtain an idle.
You can now set the timing at 10 degrees BTDC with your 009 distributor
and have the fuel needed for a stable idle and smooth transition to the
high-speed circuits. When rebuilding engines, I lower my compression
ratio to prevent pre-ignition and overheating with a semi-hemi cut in
the combustion chamber. This allows me to run 2 to 4 degrees more
timing without the engine getting too hot.
The carburetor might also need a larger main jet. Does the engine run
out of power just past the idle at 1500 rpm or so and putting the pedal
to floor isn't much help? I find larger, main jets commonly
needed to help with this midrange hesitation and additionally can
increase top end. My best guess for main jet size on a otherwise stock
engine is # 135 the carb comes stock with a # 127.5 unless it's a 71
type 2 then it's a # 125.
Gene Berg Enterprises is a good source for main jets. Changing the main
jet to a larger size can improve gas mileage because less gas pedal is
needed to get up to speed. Rejetting is common when running a non-stock
exhaust. These exhaust lower the back pressure and tend to lean the
motor out. Of course before rejetting, be sure you have reviewed the
basic tune-up, having a proper pre-heater for the carburettor below 50
ºF.
Check your valve adjustment and make sure you have enough compression
for the motor to idle. Any cylinder with under 100 pounds compression
will not fire at an idle. Tuning for performance is done one change at
a time with a fully warmed up engine, and the test drive is the measure
of success.
The original timing set up with the idle settings at 5 degrees BTDC,
was to reduce hydrocarbons for the now standard tail pipe emission
test. Be clear that the 009 distributor will increase tail pipe
hydrocarbons when timed. Depending on the emission laws where you live,
this can make the difference when trying to pass the tail pipe
sniff test.
The following information, including ignition system specifications,
are for USA specification 1971~74 VW 1600 Type 1 & 2 twin-port
engines, with single Solex carburettor and manual transmission, plus
1968 VW 1600 Type 3 twin-port engine, with twin Solex carburettors.
They were excerpted from one portion of the website
(http:\\www.oldvolkshome.com) of the Old Volks Home, in the USA. It is
another website which I think you might find worthy of a visit.
Distributor Parts & Specifications
Now With Type 3 & Type 4 Listings!
Presented to you on this page are the complete listings of Bosch
Replacement Parts for VW Beetles, Buses, Vanagons, Type 3 and Type 4
primarily for the North American Markets. In addition, we have also
listed the Tune-Up Specifications needed for the application listed. As
an added bonus, we have also listed by application the original
Volkswagen Distributor Number, followed by a comma, then the
corresponding Bosch Number that is usually stamped on the distributor
casing.
There is also a "Can Use" listing in each application. A note about
Bosch Product/Part Numbers: I've had a number of emails from those
wondering why I use the Bosch 5 digit rather than the 10 digit part
number. In 1978, in North America, Bosch changed most (but not all) of
it's product numbering system to a 5 digit number and since this site
is promarily geared towards North American listings, I have provided
that product numbering system.
Most parts houses these days use this numbering system in their daily
use, so it's to the benefit of those in the North American area to have
this information. I am in preparation of a page that will be posted on
this site in the near future that will show a complete cross reference
from 5 digit to 10 digit and vise-versa for the benefit of those
outside North America, so stay tuned to this page. If you have
questions, comments or spot an error, email me!.
Thanks to the recent acquiring of Bosch Microfiche Plates, I've been
able to update this page with a number of individual parts for
distributors. As you look through the Index below, you will see
*Updated* next to the link to reflect this. Not all of these items are
available anymore, as obsolescence has creeped through both the
Volkswagen and Bosch supply lines over the years (these fiche plates
are dated from the mid 70s thru the early 90s). I have provided
supersessions wherever it is possible, based on the information viewed
on these plates.
It is interesting to note that some items are still available from VW
whereas not from Bosch and vise-versa. Some people will ask why would I
provide listings on obsolete parts? The intent here is to provide
information to be as complete as possible even if the part is
discontinued. This provides knowledge as to interchangeability of parts
from another unit if possible to get you back on the road. My next big
project related to this page is to prepare an obsolescence/supersession
chart for those who wish to know what's still available either at VW or
on the Aftermarket from Bosch (and just because it's in the VW Dealer
or Bosch Price List doesn't mean it's still available either!).
Acknowledgements
This page was originally created in 1997 with much of the references I
had collected over the past 25+ years of business. In addition
many contributions, comments, suggestions and corrections have been
made by the vast memberships of the Vanagon Mailing List, Vintage Bus
Mailing List, Type 2 Mailing List, VintagVW Mailing List, WetWesties
Mailing List and the web community of VW enthusiasts at large.
To list them all would require a website of it's own, but I must
mention the notables:
Karl Von Salzen, Ron Lussier, Thom Fitzpatrick, Ken Hooper, David
Raistrick, Ken Wilford, Jon Peters, Ron Salmon, Steve Herron, Matt
Roberds, Tom Carrington, Jim Arnott, Ted Finesman, Jim Ellis (aka Rusty
Van Bondo), Mark Dearing, Maurice (The Bosch Man!), Don Haight, Bill
Keating, Bill Voit, Dave Schwarze, Ron Van Ness, Dennis Haynes, Derek
Drew, Karl Bloss, Ric Golen, Steve Dolan, George Lyle, Dworkin, Doktor
Tim, Brian Verbeek, Ronnie Feitelson, VW Howard, Bob Hoover, Eric
(VeeWee111), Bill Bowman, Bob Scott (rest in peace Bob), and last but
not least - my best bud Cliff who footed the bill to restart and keep
the website up and running for a while. To those and many more, a
heartfelt thanks. I get an average of about a dozen emails a day
related to this one page and to those I thank for their response and
support as well.
Cross Reference Feature Available!
OK, so now you have a distributor in your hand and you need to identify
it, right? No sense in reading practically every application listing on
this page, so I have added a companion page. Simply click here to go to
that page. That new page features Volkswagen Distributors in OE Bosch
Number order interchanged to the OE Volkswagen Number, it's subsequent
replacement numbers, followed by the application(s) it was installed
on. As an added feature, each application is crosslinked back onto this
page (at the appropriate application page location) which features the
necessary replacement parts, timing and other specifications. Special
Note: This feature is not yet available for new Type 3 or Type 4
Listings just published - but they will be there shortly - keep
checking back.
Distributor Vacuum Hoses - Where Do They Go?
Probably the most popular FAQ I get in my emails and some posted to the
mailing lists are "Where do the Vacuum Hoses go?" This is mostly for
the "volks" running the Dual Vacuum Distributors, mostly on 71-74 Type
1 Beetle & Ghia, 71 Only Type 2 Bus, so here's a link to click to
an article I wrote for the Type2.com list way back when:
Distributor Vacuum Hoses - Where Do They Go?
Now Let's Continue Below
In the case of superseded distributors, they will appear like this
example:
Distributor: VW 113-905-205M, Bosch 0231 115 078 > 113-905-205T,
0231 167 029
What appears below is the index, by application. Click on the
application shown in the index to go directly to the desired
application location on this page. Distributors without applications or
"Service Replacements" will appear at the bottom of the index by
nickname (such as "009" or "050") or actual VW or Bosch Number
Partial Index - Applications
Beetle Manual Trans 1971 *Updated*
Beetle Manual Trans 72-73 *Updated*
Beetle Manual Trans 1974 Federal *Updated*
Bus & Pickup 1971 *Updated*
Type 3 1967 1600 *NEW!*
Models With "009" Distributor *Updated*
Models With "050" Distributor
Models With VW 315-905-205B, Bosch 0231 137 031 Distributor
VW Models Equipped With "009" Distributor
Distributor: VW 126-905-205, Bosch 0231 178 009
Chrome Version: Bosch 9230 081 094
Can Use: 0231 178 001, 0231 178 003, 0231 129 010, 0231 129 019
Note: The 001 distributor has VW# 126-905-205 stamped above the Bosch
number and is primarily used on industrial engines for constant high
rpm use. The 003 was the successor to the 001. The 009 succeeded both
the 001 or 003 as per Bosch microfiche. The 001 or 003 Looks identical
to the "009". I have a 001 and 003 in my "permanent" distributor
collection (somebody's gotta have a hobby!).
Points: 01 030
Condensor: 02 086
Rotor: 04 033
Dust Cover: 039-905-241, Bosch 1230 500 139 > 1230 500 147
Cap: 03 010
Distributor Cap Clip: 034-905-265, Bosch 1231 251 033
Coil: 6 Volt - 00 016, 12 Volt - 00 012
Timing Set At:: Most applications - 5 to 7.5deg BTDC Static. Full
advance should not exceed 32 degrees at 3000rpm with stroboscopic
timing light.
Here's a couple of links dealing with this subject:
Ken Hooper's Timing The Bosch 009
Ken's Buggy Barn Timing A 009 Distributor
Models Equipped With "050" Distributor
Distributor: Bosch 9230 081 050
Points: 9232 081 044 (Can use 01 030)
Condensor: 9231 081 465 (Can use 02 086)
Rotor: 9231 081 628
Cap: 9 231 081 413
Coil: 6 Volt - 00 016, 12 Volt - 00 012
Here's a bit of Info on the "050" Andy McKinley's
"050" Distributor Reviewed
Type 3 Models Using VW 311-905-205Q, Bosch 0231 137 033
Distributor: VW 311-905-205Q, Bosch 0231 137 033
Models Installed On: This was VW's primary replacement Distributor for
1500/1600 Engines on Type 3 65-67 w/Dual Carburetors.
Points: 01 013
Condensor: 02 069
Rotor: 04 006
Cap: 03 001
Vacuum Can: 07 017
Ignition Wires: 09 003
Spark Plug: W8AC
Timing Set At:: 10deg BTDC Static or @ 800-950rpm w/strobe w/vacuum
hose disconnected and plugged
Got questions, suggestions or comments? email me! "