Citroen hydraulics - Khamsin, Bora, early Merak, late Indy

Thank you for that Serge,

Paul Frère was one of my inspirations when I began writing in the early 1990's he was very kind and gave me good advice. He was thanks to the prestige of his Le Mans 1960 victory and his great professionalism the leading automotive journalist worldwide in terms of the quality and expertise of his articles and also exposure, published all over Europe, the US and Japan. He was a consultant for many manufacturers and wrote quite a a few books. His driving ability remained sharp until the end, he tried an Audi Le Mans sports prototype well into his 80's at Paul Ricard. One anecdote about him I like is when an early Dodge Viper soft top blew off at top speed during an article test drive. After having to walk two kilometers back on the autostrada to pick it up he related the story to the Dodge media department folks in attendance. When they told him the top was not meant to be used for such high speeds he said well in Europe we do and you did not do your homework properly. Verbal spanking! At Le Mans 24 hours race week in the 1990's every time he entered the press room three hundred journalists from all over the world would look up from their desks with great respect.

Good translation except I would replace race with run: "I would have attempted a run in both directions"

When he drove the just born Bora Group 4 for a few laps of the Modena Aerautodromo those in charge got excited by his feedback and had him try out a few things during many more laps, eager to benefit from his experience.

In the summer of 2007 I interviewed him at length on the phone for two books, I was in an office in Geneva and he was in the south of France not far from his Monaco residence. He had been very surprised at the Citroen Maserati pairing but was very, very impressed by the Bora and Khamsin. It is he, by pure luck who, after years when I had sought the truth abut that mysterious Unicorn, the Citroen SM V8 one off, that he made me fall off my chair when he said completely out of the blue that Giulio Alfieri had shown him the car with the engine installed in it.

He was 90, one of the best interviews I ever did, a great Gentleman with so much knowledge and understanding....six months later he passed on. That was possibly his last interview. He has a corner at Spa named after him, RIP Monsieur.

 

I agree with his assessment particularly the top speed of 161 mph as it's what I saw in Nevada on my friends Bora which had the longer gears, my own was rev limited to 140 mph. That was at about 4000 ft elevation so maybe in the winter in death valley it might push a little more.

 

I'm not familiar with a rev limiter... was this OEM or something installed aftermarket? ... any idea how it works?
- Art

 

Oh yes and it's a very effective too. It's called preservation of one's bank account should you blow the engine by exceeding the recommended limit. The number of times I've exceeded 140 mph by very much is zero. My Bora has the short set of gears which I prefer for acceleration purposes. I don't like the car at speeds over that anyway. The one thing I disagree with Paul Frère on. It likes to dance around.

 

Yes.
It was an undesirable factory option, commonly referred to as US spec

 

Oh come on now ... not all US cars got shorter gears. It was a factory option for anyone that wanted it. On twisty roads hilly I find it advantageous.

 

This demonstrates poor "Thread Topic Discipline" but...

LOL! "It's called preservation of one's bank account should you blow the engine" ... ."commonly referred to as US spec"...

How does one determine one's gearset as long or short? The only available data I have are my redline speeds: 55+mph in 1st, 80mph in 2nd..
I've run mine at 140 indicated without much drama of the blown engine or dancing around sort.. In fact I was tired of babying the engine and decided to blow it so I could give it a fresh rebuild.. No dice. Now it sees redline on a regular basis. I guess I am forewarned.
- Art

 

real easy, drive the car at speed. In 5th match increments of rpm speed 2,000, 3,000 etc. to speed traveling. Probably wouldn’t be a bad idea to measure speed with some type of GPS as factory speedos are not know for their accuracy.

Divide the speed traveling by the Rpm at 2,000 divide by 2, 3,000 by 3 etc. multiple that divided number by 5.5 or 6.3 for the brave to find out the top speed of car. In the owners manual will be a corresponding chart for the various gear ratios installed. Match it up.

Note, that the numbers only work with stock size tires. 215/70/15. Numbers will be off with different size tires

 

No, I think you misunderstand. There's nothing wrong with going 140 mph with either the short or long gears. But you will be at redline in the short geared car and I never worried about that. But if you want to see 160 MPH in a short gear car then you will be seriously past the redline for the engine.

 

BEWARE THE DOUBLE FLARE... ?

This may lend credence to the tip I recall hearing in my past, that steel LHM lines should NOT be double flared (or fold flared)... but only SINGLE flared.

Ref Khamsin parts catalog Table 23.

On my Khamsin, the steel HP line (Part 22) from the LHM compressor sprung a leak at the primary accumulator. The leak progressed from zero to a gushing squirt over the course of a 60 mile drive, ending conveniently in a puddle of green on my driveway. The leak occurred at nipple (Part 65). LHM squirted out of the 14mm fitting that clamps the flared end of Part 22 against the nipple. The leak was very persistent:

I disconnected Part 22 at its 14mm hex fitting and inspected it. It was a double-flare, with no obvious cracks or flaws. So the problem was not obvious.The only suspicion is there appears to be very little surface area where the nipple and flared ends mate together, so they need to be aligned very accurately? I tweaked the shape of the steel line so it aligned perfectly with the nipple without any tension at the mating surfaces.

I reassembled it and the leak was reduced, but not stopping.

I removed the nipple Part 65 and an inspection showed no flaws of any kind, and I reinstalled it.

Still leaked.

I cut 1/2" off and re-flared the leaking end of line 22 with a SINGLE flare, reassembled it, and VOILA! ... no leak.

- I've heard that a "single flare" vs "double flare" (or folded flare) is advisable on LHM lines. This may be proof of that.
- I've heard that too much torque on the fitting simply crushes and cracks the flared line end, and doesn't help seal the connection. I didn't torque down excessively.
- The leaking steel line was definitely not original, but it fit the original 14mm fitting, so I don't think I'm at risk continuing using the same line.

Any thoughts?

Cheers,
- Art

 

I think it depends on the type of fitting the pipe is connected. I just sent the two Khamsin brake accumulators to be rebuilt. As you can see in the photo these two LHM pipes have different flares.

Ivan

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Good morning all,

PROBLEM:
I have Khamsin 1180 at my garage for some maintenance. When I drive it, the LHM pressure regulator (tucked below the battery) makes repeated 'Clicking' sounds as I drive. The sounds repeat continuously, perhaps every 20 seconds or even less time interval. I have not ha the main sphere checked, but I don't think it's part of the problem or has any function that makes the 'clicking' sound.

I own Khamsin 1196 and its pressure regulator makes the same sound, at the same interval, except MUCH MUCH louder, in comparison to 1180. I looked closely and both systems are mounted the same. 1180 doesn't have any different mount or sound isolators. I have had 1196's main sphere checked, and it is fine.

My concern is for 1196, the loud one. What is going on that makes the sounds so much louder than 1180? Should I be concerned?

Kindly offer any advice or experience with the LHM pressure regulator on the Khamsin, in relation to this sound, and how it 'Clicks' repeatedly whilst driving.. Why does it do this and how do you decide when to be concerned about its operation?

Grazie,
- Art

 

Art in both cases it means insufficient pressure.

You are a good sleuth, when were all the elements last serviced? Make sure you encompass the entire system in your troubleshooting, people often don't.

 

I concur.
The LHM system or my Indy was refurbished recently (braking spheres) but without replacing the main accumulator that looked functional.
Big mistake!
I had exactly the same symptoms of frequent clicking, because there was no nitrogen left in the accumulator to maintain pressure.
Accumulator replaced, and now it holds!

 

This.

 

What is considered "normal" pump cycle time on a Khamsin running at idle while none of the hydraulic devices are being used?

I am traveling this week but will measure the cycle time on my two K's. Both cars have new main spheres and recently rebuilt brake accumulators.
It would be good to learn what others are experiencing. I suspect the steering rack may be a cause of pressure lost even the the steering is not being used.
The pressure regulator's sound seems louder on a Khamsin than on a Bora, probably due to its location.

Ivan

 

Good question!
ALL new spheres. NO external leaks. Everything functions perfectly!
Cycle time approximately 30 seconds.

 

Are you saying your pump is cut in every 30 seconds and that's normal?
Wow that really is different than a Bora. Steering & clutch?

 

Thanks all,
I was fortunate to have lunch with Dave Burnham and Allan Bentsen yesterday.

If I understood their instructions correctly - there are two Cycle durations, depending on which side of the 'Click' they occur...
(The 'Click' is the regulator saying the main sphere is satisfied with pressure). They were more concerned about a 'silent' Click, than a 'loud' Click.

Cycle 1.) The duration of the pump cycle is the "Rrrrrrrr" noise you hear BEFORE the click. This pressurizes the main sphere and should not be very short.
Cycle 2.) The duration of time AFTER the click, until the pump cycle starts again, is the duration of time the pressure in the system depletes.

Therefore:
If Cycle 1. is short, your primary sphere has run out of nitrogen and it takes just a second for the pump to re-pressurize the diaphragm that is collapsed against the walls of the steel sphere.
If Cycle 2. is short, there is depletion of the pressure elsewhere in the system that demands pressure prematurely from the primary. This can also be a bad main sphere because it's pressure isn't held by the nitrogen/diaphragm, but the steel sphere.

- Kh 1180 experiences very poor power steering assist at low engine rpms, which is bordering on dangerous as you slow down to maneuver into tight spaces, and suddenly you lose steering power.
- Kh 1196 loses no power functions in any engine regimen.

Cycle 1. is easiest to check because it's the main sphere.
Cycle 2. is either the main sphere, or a hunt for problems or leaks in the systems, probably associated with puddles on the ground... or weeping brake calipers, pistons, etc.

(Photo provided for dramatic effect only.. this leak was fixed: Table 23, Part 115 was cracked at the top of the pressure regulator)
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Good stuff on the cycling.

I think your Khamsin needs to be fitted with Depends!

 

Very good information! How many seconds is "not very short"? Same question for the cycle time between clicks.

Ivan

 

Looking at this again it seems to me that the conditions for cycle 1 & 2 are reversed?
I remember a members Bora that had collapsed spheres and you could here his pump running with that "Rrrrrr" non stop because it could never achieve proper pressure. The proper pressure is developed by pressurizing the fluid against the membrane which has a sufficient amount of charge in the nitrogen on the other side of that membrane.

Also you can have a faulty main accumulator and still get sufficient pressure for braking of some sort in those two spheres. I had the white plastic button piece crack in an almost brand new one, faulty, that tore the membrane enough to allow nitrogen to be mixed with the LHM. This was in the middle of Nevada on a long road trip, Area 51 territory and the local Citroen dealer was out of stock ... So I made it back to SF with a fully aerated Crème de menthe milkshake in my LHM tank. Braking was interesting but the nitrogen compressed to nothing when the brake pedal was pressed and the car stopped properly after that.

 

Thanks Bob,
I will review my data from both 1180 and 1196, ask for further clarification and take notes the next time I see Allan. He did a great job describing the how the LHM system behaves. I'm also going to The French Revolution at Lime Rock tomorrow morning and will corner some Citroen people for lively discussion on the matter.

What I want clarity in is:
- How the primary sounds when it's being filled (Cycle 1 "Rrrrrrr")..
- What is happening when the 'Clicks' occur - is that always the primary being satisfied (Cycle 2 "Click")?
- What does it sound like when the regulator shunts pressure to the secondaries and when they are satisfied? (What Cycle is this?)

I have drafted a response, I don't think there are conflicts between Cycle 1, Cycle 2 and what you are saying, but I won't post the final version here until it's been vetted with Dave and Allan. I'm PM you the draft for comment.


.... Here is the data I got ..

Yesterday I drove both 1180 and 1196 back to back paying attention to the LHM regulator cycles, the differences are stark.

1180 - As soon as I got underway in 1180, the Cycle 2 Clicks were the most obvious sound - very short durations between Cycle 2 Clicks, like maximum 10 seconds when cruising a stretch of country road. But any demand placed on LHM pressure triggered a very rapid series of Clicks; any steering input, clutch or braking and the Clicks would start sounding like a very quiet machine gun - the Click intervals were THAT short. Then the Clicks would increase in interval as LHM demand decreased, up to about every 10 seconds maybe 20 seconds or so - which I believe is still short. (What I think is happening is the primary regulator is shunting pressure via the Clicks to the secondaries to satisfy demand, but if the secondaries are collapsed too, then nowhere in the system can pressure be accumulated for long. I will confirm with Allan whether this also means the Secondaries are shot). I got the 'Brake Pressure Warning' light a lot in 1180, but no failure of brakes. Steering and clutch boost failed intermittently at low engine speeds. I was not able to hear any Cycle 1 "Rrrrrrrrr" before any of the Cycle 2 Clicks. No idea why. Maybe the pump is also failing.

1196 - In comparison 1196 was much more 'normal': I never got the low 'Brake Pressure Warning' light. The Cycles 2 Clicks were pronounced, but the intervals were averaging every 20 seconds. Even though the noise is more pronounced than I imagine Alfieri or Citroen would deem acceptable and hence my questioning whether 1196 is performing properly, the system performs well and Dave Burnham says he considers the louder 'Clicks' a sign of health and is walsyas suspicious of quiet 'Clicks'. The Cycle 2 "Rrrrrrrr-Click" intervals were reasonably audible in my 1196, intervals were minimum 20 seconds, and maximum 2mins 30seconds. Very different than 1180.

Cheers,
- Art

NOTE: I took several video files of each car, I'll review them with Dave and Allan for accuracy and comment. Get bak to you after the weekend.

 

I found this bit of information on a Citroen SM from the UK...

..under the heading of 'Pressure Regulator'..

When is it bad?
Regular 'clicking' from the regulator (say less than every 10 seconds stationary and engine at idle) means a possible U/S accumulator sphere, not the regulator at fault. A simple fail test (NOT a pass test) is look in the hole, and if you cannot see the bottom of the diaphragm it is scrap. If your Accumulator sphere dribbles oil when removed it's beyond repair or safe use. Throw it away.

It adds a little more information to the discussion.
- Art

 

Seems like a good place to ask - if I only get 1.5 cycles out of my headlights with the ignition off (but after having been run) on the Merak I should be thinking accumulator replacement time?

Thanks in advance for the coaching.