Oil Pressure Switch on a Formula Ford

[4redno]

I'm in the process of restoring a Lotus 69 Formula Ford and have a question about oil pressure switches.

If I buy a fixed 20 psi switch, I'm concerned the light will go on frequently in slow corners which would be a distraction. However, if I buy an adjustable switch and set it at say, 17 psi, I'm wondering if I risk doing more damage to my car should I even have a serious oil pressure issue.

Can some of you vintage ford guys chime in on your experience with oil pressure lights/switches?

Thanks...Keith

[Roland V. Johnson]

If it comes on in the corners, you are in the wrong gear. When you are in the proper rev range, you should have more than 30#'s.

[Brian]

considering my engine, built by a respected shop and lasting just fine thank you, has 5 psi of oil pressure coming off the track at about 2000 rpm, your light will be on a lot as you drive back to the pits. 20 PSI on the track is a fair setting, and as stated keep your revs up over 5000 anyway. I have 35 psi hot, I had to buy a new OP gauge since the one in the car was a 160 psi range (why?) and 35 PSI was awful close to zero on the gauge...

If there is one thing I hate about FFords, it's oil pressure...

Brian

[Roger Eade]

As has been stated, don't be to concerned about the oil light coming on around a corner, if it does, build a new engine,its f****d, also you only need a switch at about 10- 15 psi, in a motor in good tune 40 psi is max HOT at revs, also do not confuse pressure with flow, they are quite different.
Roger

[4redno]

If the switch is set at 10-15 psi, is that too low to shut off the engine in time ro prevent a grenade should a problem present itself?

[Charles Warner]

A switch set at 10-15 psi is fine. It WILL be on as you drive around the pits after a race. Under those conditions 5 psi is probably what you will see (as has been mentioned earlier) and is quite OK. There is no guarantee that the illumination of a light set at any pressure threshhold will save your motor. It MIGHT give you enough warning, depending on the problem and how fast your reactions are.

[Dick R.]

One use of a low oil pressure switch/light is to remind you that the ignition switch is on when the engine is not running and the master switch is on. Helps save the battery, points, coil, etc. Especially if your battery charging setup requires the master switch to be "on".

Dick

[DanW]

If the switch is set at 10-15 psi, is that too low to shut off the engine in time ro prevent a grenade should a problem present itself?

FWIW I am but a grasshopper with this, so consider the source.
I had wondered about this myself at one time.

1. If the oil pressure dips or switch fails, engine cuts out at corner exit while you are flat to the floor with a pack of other cars, is it likely you will spin on drop throttle oversteer?

2. If you downshift for a slow corner and allow the engine to drop to idle before blipping the throttle for changing down, the engine quits?

3. Race over. Entering the paddock at 5mph with a line of cars behind you, engine stumbles or you have to clutch in and out; the oil pressure switch opens, you get a punt in the gearbox by the guy behind you.

The bearings need the presence and flow of oil. They do not need a lot of pressure, just oil flow to provide lubrication and carry away the heat generated by shear. I have been advised by my engine builder to replace my 6-8psi pressure switch every year because of the Kent vibration and pressure pulsation from the oil pump. Considering all the above, I am not sure I want to use one in the primary wire to the coil.

Regards,
Dan Wise

[4redno]

Dan, the oil pressure switch doesn't cut the motor, it just ignites a warning light. You can still drive around (assuming your engine is still functioning) with the switch on.

...Keith

[DanW]

Keith,

Thanks. I misunderstood your original post. As the "Church Lady", Gilda Radner often said "Never mind."

Regards,
Dan

[4redno]

Actually Dan, Emily Litella was the character played by Gilda Radner who was known for her catchphrase “Nevermind”. The Church Lady was played by Dana Carvey and was best known for the catchphrase “Well, isn't that special?”

You are 0/2 but we have some lovely parting gifts for you.

Doh!

Keith

[DanW]

Thanks Keith, my memory was the second thing to go and I don't remember what the first thing was...

Meanwhile, back at the original thread...

I used to autocross a stock Kent engined car. Hard right hand sweepers would often cause all the oil to travel up the side of the pan and the oil pump pickup would go dry. Nothing like seeing the oil pressure gauge at 0 for a few seconds with your foot to the floor. It happened more than once, until I started running an extra quart in the sump for autocross. Two years later, when I pulled the motor for a rebuild, the bearings and crank showed normal wear for 70K miles, but no damage.

[msflynn03]

I believe that it was the "Roseanne Rosanadana" character of Gilda Radner that used the Never Mind phrase.

[4redno]

Sorry MSFlynn03, you didn't make it into the bonus round either.

I checked with "Richard Feder of Fort Lee, New Jersey" and he confirmed that Roseanne Roseannadanna's catchphrase was "Well it just goes to show you, it's always something".

Thanks for playing.

Cheers!...Keith

[bob darcey]

Wasn't it, "If it's not one thing it's another"??

"It just goes to show ya...it's always something! If it's not one thing, it's another!"

http://youtube.com/watch?v=qd_syuD-N_k&feature=related

Emily Litela IS the "Never Mind" lady (this one is Gilda at her best):

http://www.youtube.com/watch?v=afi2xeM5ZSI&NR=1