Saturday, September 15, 2012
The British Invasion car show, 2012
Thanks to Mike Gaetano and all the volunteers for another successful show. 614 cars and counting . . .
Thursday, September 6, 2012
Inspecting Rolls-Royce and Bentley hydraulic systems
One of the more unique features of 1965-1998 Rolls-Royce motorcars is the hydraulic system. The hydraulic system powers the brakes and the rear suspension’s height control. These systems are legendary for their complexity and potential for bank-breaking repair costs. In this essay I'll show you how to check yours out so you can get a sense of what's happening before disaster strikes.
The early version of this system (1965-80) is filled with a derivative of conventional brake fluid (RR363). Newer cars (until the advent of the Silver Seraph series) used Castrol hydraulic system mineral oil, or HSMO. The two fluids are not compatible. Use of the wrong fluid in a car will cause severe system damage. All reservoirs are clearly labeled RR363 or HSMO.
The system contains two hydraulic circuits that operate in parallel for the brakes. One of the systems also powers the rear height control. Hydraulic fluid is stored in reservoirs on the left fender well. Lines carry the fluid to the hydraulic pumps, which are located in the center top of the engine; under the carburetors or the fuel injection. High-pressure pipes carry the hydraulic fluid to the accumulators under the motor. From there excess fluid is returned to the reservoirs. Braided lines carry the high-pressure fluid to the distribution valve assembly located under the driver seat.
A network of steel pipes carries hydraulic fluid to the calipers at each wheel and to the rear suspension and height control. The rear suspension contains height control valves, shocks, and gas springs that sit above the shocks in the trunk area.
All the pumps, valves, and moving parts are subject to failure. Calipers rust or leak. Gas springs and accumulators lose their gas charge. Metal lines rust and rubber hoses deteriorate invisibly. A system this complex can only be fully tested by trained people using special tools in a workshop. However, it’s possible to do a pretty good “quick check” without tools, using the following procedure:
Begin with the vehicle sitting, engine cold. Get in the car and pump the brake pedal 10-15 times. Open the hood and check the level in the hydraulic reservoirs. If the level is low, look for leaks (as evidenced wet spots) Turn the key on but do not start the engine yet. You should see two lights, Brake 1 and Brake 2. Depending on the year of the car these may be in an electronic unit, in a group of lamps, or by themselves in the middle of the dash.
If you do not see the lamps, or if only one is lit, give the brakes 10-20 more pumps. If the light does not come on you can assume that warning circuit is broken. Start the car. Watch how long it takes for the lights to go out. If it takes more than 20 seconds the hydraulic pumps are probably weak.
Run the car 2 more minutes, shut it off, and turn the key back on. Begin pumping the brake and note how many pumps before the Brake 1 and 2 lamps illuminate. Less than 20 pumps indicates the car has weak accumulators.
Start the car again and wait for the lights to go out. Go to the back of the vehicle and bounce each corner. If the car is soft and pushes down a few inches with your weight that’s normal. If it’s rock-hard that is a sign of failed gas springs in the rear suspension.
Sit down on the rear bumper (even better, have two people sit on the bumper) and wait 30 seconds. You should feel the car lift to the original (and visibly correct) ride height. If it does not lift that’s a sign of problems in the height control.
Take the car onto the road. Try braking slowly and quickly. Pay attention to any pulling or diving that may indicate caliper problems or air in the lines. Look for any pulsation or shudder that may indicate warped or damaged rotors. Let the car come to a stop on a gentle slope and release the brake. Make sure the vehicle begins rolling smoothly and the brakes do not drag.
Shut the car off and put it in neutral. Press and release the brakes a few times.
Finally, put the vehicle on a lift and make sure all four wheels spin freely. If any wheels drag that may be a sign of caliper trouble. Next check all the components for leakage. Look at the reservoirs (top left fender well), the pumps (top of the engine), the main valves and accumulators (under side of the engine), the distribution valves (under driver seat), the brake lines and calipers, and the rear suspension components.
Look at the fluid and make sure it looks smooth and uncontaminated. RR363 (used 1965-1980) should be almost clear; HSMO (used 1980-1998) is dark green. There should not be any foam, sediment, or sludge visible. Color should be consistent.
Look at the rubber hoses to see if they are original. If your car is more than 10-15 years old I suggest you replace all rubber hoses as they can swell inside, creating invisible failures. A swollen hose may cause brakes to drag and overheat. Old hoses are also prone to bursting.
Look at the rubber hoses to see if they are original. If your car is more than 10-15 years old I suggest you replace all rubber hoses as they can swell inside, creating invisible failures. A swollen hose may cause brakes to drag and overheat. Old hoses are also prone to bursting.
If your car passes all these tests you can give yourself and the vehicle a pat on the back. If you see potential failures, I suggest you find a specialist and get a more thorough evaluation.
John E Robison
JE Robison Service
RROC Tech Consultant
Wednesday, September 5, 2012
Flanged or Top Hat Liners in Land Rover Engines
The more I see of the 2003-4 Land Rover Discoveries, the more it seems their engines were fatally flawed. Ten years ago, 90% of the engine problems from overheating were due to heads warping or head gaskets failing. 10% were due to what people called "slipped liners."
The same was true for noise complaints. When someone came in with a rap or tick issue the problem was almost always a noisy catalyst or worn rocker shafts - comparatively simple fixes. Only a tiny fraction of noises were from internal motor problems.
Today, with the late Disco motors, those odds have flipped. When a 2003-4 Rover comes in with overheating trouble, the most likely cause is liner or block failure. A noise complaint is more likely to be from excess clearance in the piston-liners (in other words, prematurely worn out.) I've written several essays about how this happens so I won't repeat all that here. The question is . . . what do we do about it?
The solution that has emerged - both here at Robison Service and in the UK - is to rebuild the blocks using flanged liners so the cylinder head seals against the liner, not the block. Then we fit new pistons with proper clearances.
The photo above shows a typical failure. The block cracks at the base of a head bolt bore, between the back of the liner and the water jacket. With the stock liners there is no barrier to prevent combustion gases going round the liner and into the coolant.
The fitment of flanged liners solves that problem by making the liner top the sealing surface. There is no high pressure gas behind the liner, and the cracks are rendered irrelevant.
The photo above shows a flanged liner and a new piston. The o-ring seals the bottom of the liner to prevent coolant dripping into the oil sump in the event of a crack.
This is what a flanged liner looks like installed. As you can see the wide flange covers the entire sealing area of the head gasket.
We can do flanged liners in 4.0, 4.6, and overbore configurations. At this moment (Sept 2012), costs to do a block with flanged liners, new pistons, and all basic machine work in in the $4800 price range. Our American costs are similar to costs from RPI or Turner over in the UK.
We believe this is the only long-term solution to the problems in these late motors, and it provides a substantial upgrade for any older Land Rover V8. However, the liner repair is just the beginning when it comes to engine overhaul . . .
What else do we do when building a motor?
I recommend balancing any engine. Motors like these rely on sophisticated engine electronics to achieve smoothness. That will be considerably improved if the engine is mechanically balanced before assembly.
Front covers and oil pumps have been problematic on these trucks. The pump gears fracture, and eventually the oil pump fails. The result - engine failure from oil starvation. I recommend fitting a new front cover as long as these parts remain available.
Heads are another problem area. We recommend rebuilding the heads. This involved walnut shell blasting to get everything spotless, followed by crack test and a check for warping. Then we fit new guides, redo valves and seats and cut the sealing surfaces perfectly flat. If you're a perfectionist we can also cc the combustion chambers to ensure each cylinder is exactly equal.
This is a rebuilt head. As you can see the sealing surface is cut to a mirror finish. We true these heads to half a thousandth of an inch to minimize the change of gasket failure.
We also rebuild rocker shafts, and swap cams and lifters. Needles to say, every other part is cleaned and inspected before being overhauled, repaired, or replaced. That thinking should also extend to the external accessories like the water pump, injectors, and alternator.
We believe the engines we are building now are substantially smoother and better than what land Rover delivered new.
Till next time
John Robison
J E Robison Service
Springfield, MA USA
(413) 785-1665
The same was true for noise complaints. When someone came in with a rap or tick issue the problem was almost always a noisy catalyst or worn rocker shafts - comparatively simple fixes. Only a tiny fraction of noises were from internal motor problems.
Today, with the late Disco motors, those odds have flipped. When a 2003-4 Rover comes in with overheating trouble, the most likely cause is liner or block failure. A noise complaint is more likely to be from excess clearance in the piston-liners (in other words, prematurely worn out.) I've written several essays about how this happens so I won't repeat all that here. The question is . . . what do we do about it?
The solution that has emerged - both here at Robison Service and in the UK - is to rebuild the blocks using flanged liners so the cylinder head seals against the liner, not the block. Then we fit new pistons with proper clearances.
The photo above shows a typical failure. The block cracks at the base of a head bolt bore, between the back of the liner and the water jacket. With the stock liners there is no barrier to prevent combustion gases going round the liner and into the coolant.
The fitment of flanged liners solves that problem by making the liner top the sealing surface. There is no high pressure gas behind the liner, and the cracks are rendered irrelevant.
The photo above shows a flanged liner and a new piston. The o-ring seals the bottom of the liner to prevent coolant dripping into the oil sump in the event of a crack.
This is what a flanged liner looks like installed. As you can see the wide flange covers the entire sealing area of the head gasket.
We can do flanged liners in 4.0, 4.6, and overbore configurations. At this moment (Sept 2012), costs to do a block with flanged liners, new pistons, and all basic machine work in in the $4800 price range. Our American costs are similar to costs from RPI or Turner over in the UK.
We believe this is the only long-term solution to the problems in these late motors, and it provides a substantial upgrade for any older Land Rover V8. However, the liner repair is just the beginning when it comes to engine overhaul . . .
What else do we do when building a motor?
I recommend balancing any engine. Motors like these rely on sophisticated engine electronics to achieve smoothness. That will be considerably improved if the engine is mechanically balanced before assembly.
Front covers and oil pumps have been problematic on these trucks. The pump gears fracture, and eventually the oil pump fails. The result - engine failure from oil starvation. I recommend fitting a new front cover as long as these parts remain available.
Heads are another problem area. We recommend rebuilding the heads. This involved walnut shell blasting to get everything spotless, followed by crack test and a check for warping. Then we fit new guides, redo valves and seats and cut the sealing surfaces perfectly flat. If you're a perfectionist we can also cc the combustion chambers to ensure each cylinder is exactly equal.
This is a rebuilt head. As you can see the sealing surface is cut to a mirror finish. We true these heads to half a thousandth of an inch to minimize the change of gasket failure.
We also rebuild rocker shafts, and swap cams and lifters. Needles to say, every other part is cleaned and inspected before being overhauled, repaired, or replaced. That thinking should also extend to the external accessories like the water pump, injectors, and alternator.
We believe the engines we are building now are substantially smoother and better than what land Rover delivered new.
Till next time
John Robison
J E Robison Service
Springfield, MA USA
(413) 785-1665
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