That sounds very dangerous. There I times when I would choose to sacrifice an engine to get to a safe location. I hope he's not installing these systems on other people's cars, it might be appropriate for heavy equipment.

Yeah, that's a good point. And that's part of the appeal of these cars, you have so much control over the operation of the car, why start automating processes? It's a good idea on stationary equipment that isn't constantly attended. An alarm is the best option

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1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

He dosent install them he just used it on his own. They're available commercially been used for ages. They install them on fleets or any other type of truck where the operator may care more about the radio station than the flashing buzzing light on the dash. Destroying a owners engine and livelyhood. It dosent lock the steering or the brakes so you will coast to a stop. It would be the same as running out of gas. They do have override buttons as well.

As far as the safety aspect I see your point but with the new electronic engines they do the same thing. Like take for instance cutting your feed pedal in the middle lane of IH35 during rush hour traffic . A 20,000lb truck makes a good road block . lots of people letting you know your #1 !!

No override on these just sit and wait for the engine and transmission to stop fighting and talk nicely to each other! While the drivers yelling a new form of language at them both !!!

Layback40 thanks for the name watch dog I was thinking tattle tale but thats the old black box type systems

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Experience : what you receive 3 seconds after you really needed it !!



86 300SDL 387,000? Motor committed suicide
81 300SD 214,000 "new" 132,000 motor
83 300SD 212,000 parts car
83 300SD 147,000

91 F700 5.9 cummins 5spd eaton 298,000
66 AMC rambler American 2dr auto 108,000
95 Chevy 3/4 ton auto 160,000
03 Toyota 4runner 180,000 wifes

I think I'll just take my chances with the gauge, if I screw up I'll have to write a check.

I've been noodling on this and I have an idea for what may be the simplest mechanical 2 stage system possible.

3 Hobbs switches, all plumbed to the same oil pressure source.
Switch #1 is a NC switch that opens at say 7 psi /.5 Bar. That is the low pressure switch for low RPM & low pressure loss of oil situations.

Switch #2 is a NO switch that closes at 15 psi / 1 Bar. That is the switch that arms the high pressure circuit for higher RPM and higher pressure operation.

Switch #3 is another NC switch that closes at 15 psi / 1 Bar. This is the one that closes and sets off the alarm at higher RPM loss of pressure situations.

The only time you wouldn't be protected was when the oil pressure was between 7 psi and 15 psi - and if you're loosing your oil pressure you're not going to be in that range for long...

If they were adjustable hobbs switches - say 0-30 psi - you could custom tune the ranges to suit you. Only 1 pressure connection and 2 electrical connection to make to install it.

Think this could work Barry?

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1984 300 Coupe TurboDiesel
Silver blue paint over navy blue interior
2nd owner & 2nd engine in an otherwise
99% original unmolested car
~210k miles on the clock

1986 Ford F250 4x4 Supercab
Charcoal & blue two tone paint over burgundy interior
Banks turbo, DRW, ZF-5 & SMF conversion
152k on the clock - actual mileage unknown

Sounds very rational. The only thing needing some thought in my humble opinion. If the oil pressure drops fast it will open the interlock sensor as well. If you have a five pound differential between the sensor used for the interlock and the actual higher pressure sensor. You might only get a beep if the oil pressure fails quickly.

I have to contact a firm or person that is very knowledgeable about pressure switches. It is starting to look like we need a switch that has to operate in the one to two pound area if the boost pressure is to be used.

Unfortunatly in the one pound area looks more probable. By the way almost all the approaches I have considered or others have suggested face one problem or another. Unless electronics are used. The same as the boost pressure one does. Thats if a very low pressure reliable type switch is not practical or obtainable.

I even had to consider if the tubo had some residual inertia that might generate a false alarm. Under load I decided it should not be a factor. As the stream of exhaust gasses stop applying pressure the impeller on the boost or input side sees a load almost instantly.

I suspect a very low pressure sensor can be found hopefully. I base this on the apparent average boost pressure is only five pounds at 60 mph cruising speed. That is about 3000 rpm.

We want the high pressure circuit interlock activated at slightly over 1200 rpm I suspect at this point. I also want to get a pressure profile from the exhaust manifold. It may be an easier managed source to control the interlock.

Do keep the ideals flowing though as the most simple practical and reliable setup is what we want. Several that I had initially invisioned working were not usable when examined either.

Well, I thought about having switch 2 arm the high pressure sensing circuit at say 8 or 10 psi, but the problem with that is that as the pressure comes up from 7 psi (when the high pressure circuit gets energized) to 15 psi (activation pressure for the high RPM sensor circuit) the alarm would probably chirp.

Wonder if it would work to install a coil (or some other component) between the high pressure switch (#3) and the buzzer that would act as an inductive choke and provide a long enough delay to supress that split second signal and keep it from making a chirp?

__________________
1984 300 Coupe TurboDiesel
Silver blue paint over navy blue interior
2nd owner & 2nd engine in an otherwise
99% original unmolested car
~210k miles on the clock

1986 Ford F250 4x4 Supercab
Charcoal & blue two tone paint over burgundy interior
Banks turbo, DRW, ZF-5 & SMF conversion
152k on the clock - actual mileage unknown

I just thought i might share this with yall.
I believe in looking at all areas of the automotive world when looking at different solutions for problems in my cars.
I have seen a product called a oil accumulator that drag racers like to run to prime the oil system before the initial fire up on their multi 10K $ motors.
http://www.summitracing.com/parts/CTR-24-126/
basically when the car is running you open the valve and allow the engine to push pressurized oil into the resevoir. Then you close the valve and shut the motor down whenever you normally would. This stores the oil at full pressure until you need it. When you go to start the car, you turn everything but the starter on, release the valve to prime the full system, then hit the starter and you have full pressure instantly.
This kit also has a function of opening the valve when it sees extreme low pressure in the system itself. This would save the motor and all you would have to do is to put a buzzer/idiot light on the same circuit as the low oil pressure switch which opens the valve.
This would allow you to have a extra shot of oil at the same time you get the indication that something has gone bad giving you time to shut the car down safely.
Andrew

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83 300D "shoulda been a parts car"

In 45 years of driving and over 100 cars I have not yet had a loss of oil pressure that I can remember.

Adding an automatic shutoff would add another group of components to a system which if a leak or failure occurs might cause the loss of oil it seeks to protect us from.

I think I'll just keep it all as built by the factory, thanks!

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Haha, mine shoulda been a parts car too!

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1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition