Tuesday, April 21, 2015

When starters go to die

We’ve all heard the noise – a horrid metallic grinding as the car’s starter tries to engage a running engine.  What’s it mean when you hear that noise and the motor isn’t running?

It could mean the starter is going bad.  More often, it means there is a damaged spot on the ring gear, the big gear on the motor that the starter engages to turn over the engine.

In extreme cases, the starter can totally destroy itself and the ring gear. 


Sometimes you can make the symptom go away by fitting a new starter.  But the permanent fix is to change the starter and ring gear, which requires removal of the transmission for access.  Here are some examples from a Porsche 911 in our shop today . . .





For comparison, here is an undamaged starter gear . . . check out the difference



John Elder Robison is the general manager of J E Robison Service Company, celebrating 30 years of independent restoration and repair specialists in Springfield, Massachusetts.  John is a longtime technical consultant to the Porsche, Mercedes, BMW, RROC and other car clubs, and he’s owned and restored many fine vehicles.  Find him online at www.robisonservice.com or in the real world at 413-785-1665

Reading this article will make you smarter, especially when it comes to car stuff.  So it's good for you.  But don't take that too far - printing and eating it will probably make you sick.



Thursday, April 16, 2015

Fixing oil leaks on British Motorcars

Rolls-Royce and Bentley motorcars are renowned for their ability to leak oil.  They do so from orifices, joints, and sometimes through seemingly solid metal.  Today I’d like to show you how we address crankshaft oil leaks at the front of the engine. 

A Rolls-Royce V8 being assembled after overhaul at Robison Service (c) JE Robison
The early V8 motors used a loop of rope to seal the hole where the crankshaft emerges from the timing cover.  Behind the rope they had a large washer – an oil slinger – whose job it was to “sling away” most of the oil on the end of the crank, so it didn’t reach the seal.

Rope seals had their origins on steam engines, where they could be wrapped round a shaft and held tight by a large covering washer and nut.  “Tightening the seals” was a regular activity on those old engines.

Inboard power boaters know those rope seals as the gland nuts and packing that seals the propeller shaft where it passes through the hull.  Rope works well there, too, as long as you keep it lubed and tight.

The rope seal doesn’t work so well in a car.  When rope is packed into a groove in the timing cover it seals for a while.  The oil behind it ensures it stays lubricated.  But at some point the rope will wear, and with no way to tighten it up, it will begin to leak.  Collector cars are particularly problematic in this way, because they sit a long time, and the seals dry out.  Then when they are started the dry seals wear quickly until they are wetted by fresh oil. That leakage produces the characteristic drip spots under the front of these motors. 

Traditional Englishmen took those drips in stride, but they prove vexing to many Americans, who are accustomed to leak-free vehicles.  Fix it, they say!  But that’s easier said than done.  When it comes to the free expression of lubricants, British cars are most easily treated with acceptance.  Fixing a front seal leak on a V8 Rolls requires extensive disassembly of the front end, to allow removal of the crank pulley.  Only then – after a couple days of hard work – can you see the seal.  But even now it’s not accessible for change.  No.  The front cover must be removed and once it’s off, you can refit the same piece of nineteenth-century sealing technology, and hope it holds a few more years.

We have a better answer here at Robison Service.  100-some years after the rope seal was invented the idea of using rubber seals came along.  Rubber seals backed by springs are much more durable, and more effective.  State of the art seals that use modern synthetic rubber (pioneered by the Germans in WWII) are even better. They are one of the developments that made the modern leak free car possible.  We can install those seals in your vintage car, and together, one by one, we can stop its ugly drips.

Removing parts to access the front seal - engine removed for ease of service
Here’s a series of photos showing the front of a Rolls-Royce V8, the covers removed, and the new metal and rubber seal.  Through hard work and diligence, we have brought the sealing technology of 1965 to this 1972 Rolls – a feat the original carmakers could never quite accomplish.  It took BMW ownership – and a multi-billion dollar investment – for Rolls-Royce Motors to do this on a production scale.  We can do this on your car for a tiny fraction of what BMW paid.

If you have a leaky old engine, and you want the bleeding stopped on a more permanent basis, this is the way to do it.  Just remember though – this article addresses ONE leak spot.  The typical British motor has over 117 points of potential leakage, all of which must be addressed to eliminate drips.   Many mechanics say that’s simply not possible.  We just say it’s difficult.


But we love challenges, and we are British car fixers through and through.



We remove the front cover, and machine the cover to accept a modern seal, which is pressed into place.  Once done, the seal can be serviced without removal of the front cover.  



Here is the new seal, set in place, prior to refitting the cover.


John Elder Robison is the general manager of J E Robison Service Company, celebrating 30 years of independent Rolls-Royce and Bentley restoration and repair specialists in Springfield, Massachusetts.  John is a longtime technical consultant to the RROC and other car clubs, and he’s owned and restored many fine vehicles.  Find him online at www.robisonservice.com or in the real world at 413-785-1665

Reading this article will make you smarter, especially when it comes to car stuff.  So it's good for you.  But don't take that too far - printing and eating it will probably make you sick.

Friday, April 10, 2015

Suction Throttle Valves and other vintage Rolls-Royce AC troubles

If you have a 1965-1976 Rolls-Royce or Bentley, and you have weak air conditioning the problem may be in your suction throttling valve.  If your air conditioning can’t be adjusted – whether it’s on weak or full blast – the suction throttle valve is likely at fault.  If your AC system won’t make normal pressures, and it’s full with a good compressor, the suction throttle valve or expansion valve are almost certainly stuck.

Both valves are located under the brake reservoir.  The suction throttle valve’s job is to regulate the amount of refrigerant delivered to the expansion valve. By doing so it regulates the capacity of the refrigeration system.

Look for the suction throttle and expansion valves on the left fender well, under the brake reservoir 
All the valves in the Shadow climate control system are operated by servo motors.  This one is no exception.  The servo pulls the valve open, and springs on the body of the valve pull it closed.  You can see those pieces in the photo of the valve, removed from the car.

Suction throttling valve with the operating servo attached, removed from car

Several things go wrong with the suction throttle valves.  All the problems are illustrated in this series of images, of a valve from a 1972 car.

Deformation of the valve body is obvious in this top view of the suction throttle valve
The first problem comes from the heavy springs used to pull the valve back to its resting position.  Over time, the strain from those springs warps the housing and when it warps enough, it jams.  That is a recipe for failure on most of these.  Albers sells a machined aluminum replacement that is less likely to deform in that manner, as shown in the photos.


A new machined housing next to the old suction throttle valve
When the housing warps the piston can't move in the housing.  If this state of affairs is sustained over several years or decades (as is often the case) the valve may be held quite tightly by corrosion.  We soak then in penetrant and knock them free.  The diaphragm on the other side is replaceable.






The next thing that happens is that the valves clog with debris.  The desiccant leaks from the receiver drier and small particles clog the screens on this valve and the expansion valve.  When the screens clog the air conditioner quits working, but not before the compressor has been ruined by trying to pull a vacuum too long (in most cases.)
Sediment from a clogged throttle valve
Clogging is a problem in every vintage Rolls.  In my opinion, the screens don't serve much purpose and you're better off taking them out.  If the screens are in place, the clog and the system fails.  The clogged part has to be found, removed, and cleaned or rebuilt.  Without screens, the valves might eventually clog, but it would take longer and it might never happen.  

Rebuilt Rolls-Royce suction throttling valve with attached servo
Suction throttle valves have not been used in cars for 40 years, and they are unknown to younger technicians.  But they are essential to the good functioning of your car's AC system.

Till next time
John Elder Robison


John Elder Robison is the general manager of J E Robison Service Company, independent Rolls-Royce and Bentley restoration and repair specialists in Springfield, Massachusetts.  John is a longtime technical consultant to the RROC and other car clubs, and he’s owned and restored many fine vehicles.  Find him online at www.robisonservice.com or in the real world at 413-785-1665

Reading this article will make you smarter, especially when it comes to car stuff.  So it's good for you.  But don't take that too far - printing and eating it will probably make you sick.


Friday, February 27, 2015

An Exceptional Final Series Azure


The Bentley Azure was the last of the Crewe-designed and built cars.  They were derived in the 1990s from the Continental coupe, which was in turn spawned from the Turbo R, their most successful design of the modern era.  All of these cars were special, but the final series cars were “more special than others.”  The last cars had engines that were tuned for more power, beefed-up suspension, and huge Alcon racing brakes. The brakes alone would set you back upwards of $40k if purchased from the Bentley parts catalog.  They are what's left of a special performance run built for the Sultan of Brunei, and as vastly as they are his loss is your gain.  They say the Sultan paid millions for each of his prototypes.

The actual final series production cars had a number of little refinements that set them apart from their earlier Turbo and Azure brothers. Taken together, they make these cars really stand out when parked next to a stock Azure. In an exclusive world, these are as exclusive as you get.  Fewer than 25 of these vehicles came to North America.  The rest went to the Europe, Middle East and Asia.

The new (VW-designed) Bentley cars are true mass-produced products. They sell in far greater numbers than any earlier RR/B product, but to many enthusiasts, they lack the handmade feel.  This - in contrast - is the ultimate handmade car.  Every detail on it is unique. The engine is signed by the man who balanced and built it, and the wood is signed by the man who did the final finish.

The interiors were trimmed in special diamond-quilt leather and dark walnut woodwork. The car had unique aerodynamic trim, and air ducts on the hood and fenders. This particular car is dark blue metallic with light grey hides.   

We have had several of them through for service over the years, but this is probably the nicest one we have seen, and it’s likely the nicest example you will find anywhere.  It's been lovingly cared for in a multi-Bentley enthusiast's home.

Every Final Series Azure I’ve seen for sale is described as flawless.  Rather than repeat that same tired claim, I will list what was actually done in the past 12 months in the Robison Service shop.
  • All convertible top hydraulic lines have been replaced, and actuators rebuilt or replaced.  This is a major issue on these cars; it's needed on any car of this age, but seldom done when cars are for sale.
  • Brakes were overhauled, both the calipers and pads, and the hydraulics.  With the Alcon brakes this is an very expensive service that is also oft-delayed.
  • Suspension hydraulics also serviced, with new gas springs and fluid flush
  • Tires are new and correct.
  • Body and trim is undamaged by accidents and free of cosmetic flaws. We did repair two small dings, using the original Glasurit system paint and finish materials.
  • Interior is spotless with new Hilborn carpet mats and seats conditioned with Leatherique.  The wood and leather are as good as you will find in an original car.
  • Major service was completed last year and everything is up to date and working.
  • Relays and wiring are updated.

This car is truly ready to drive or show anywhere.  It is nice enough to place well in any show, right out of the box.  It’s complete with keys, mats, records, etc.  It’s available for inspection in Western Massachusetts and we can ship the car anywhere.

It’s truly one of a kind.  No disrespect intended to any other car, but this car is the only Azure you’re going to find that’s truly “all done.”  I’m pretty amazed its owner wants to sell, but people move on and change cars.  He’s looking for offers in the $120k range for a car that cost almost $400,000 new, and has covered under 10,000 miles in the last 11 years.

Feel free to call me at 413-785-1665 or email robison@robisonservice.com with any questions.


John Elder Robison