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jmshistoric
Joined: 08 Feb 2022
Posts: 5
Location: Birmingham
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 Posted: Thu Feb 10, 2022 11:31 pm Post subject: Mechanical Oil Pressure Gauge Fitting |
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I'm wanting to fit a mechanical gauge on my race car but I'm struggling to get it all to fit nicely.
Has anyone converted to mechanical gauge before if so how?
I'm finding there isn't enough space between the engine and bulkhead for me to fit a T-Piece to run the warning sender and Oil line off.
I was thinking about running a shot hose from the engine to the T-Piece but it will look quite messy. |
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924RACR
Joined: 29 Jul 2001
Posts: 9064
Location: Royal Oak, MI, USA
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| Posted: Thu Feb 10, 2022 11:33 pm Post subject: |
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I really don't care for mechanical oil pressure gauges, especially on a racecar. Running that hose is a great way to spread a failure point all across the car that can kill your engine; a broken wire will never do that.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype |
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jmshistoric
Joined: 08 Feb 2022
Posts: 5
Location: Birmingham
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| Posted: Fri Feb 11, 2022 12:41 am Post subject: |
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| 924RACR wrote: | | I really don't care for mechanical oil pressure gauges, especially on a racecar. Running that hose is a great way to spread a failure point all across the car that can kill your engine; a broken wire will never do that. |
That's a fair point however from my own personal experience I would rather a mechanical gauge for accuracy and reliability along with a better field of view on the gauge.
I've only ever had 1 failure with a mechanical gauge having used them in over 10 years of racing historic cars and 15+ years of working with historic cars/race cars 90% of which have mechanical gauges. I have however had multiple senders fail and give erroneous readings both too high and low. Which from the other point of view a sender showing a high reading when there may not be has much pressure as you like can be an engine killer.
For reference as some people may find it interesting the mechanical gauge failure I had was on a 1968 Mini Cooper road car with a copper capillary tube to the gauge. Over the years vibrations had hardened the copper and it broke clean off on a cold start with the high oil pressure to the gauge, it immediately went to zero, oil light on and I switched off the engine. There was about a 5-10second window between the gauge not reading and switching the car off, which only produced about a tea spoon of oil that had leaked out.
It takes along time to empty 4 litres of oil out of a 5mm hole even at 60psi, 3 litres per minuet over 50cm of hose to be exact, by which point if you havn't notice you have yourself to blame! It also shows why you should only use proper braided hose, if braided hose can with stand the vibration from running gear and be good enough for the 500+psi of pressure we use when we press the brake pedal it should manage with 60psi of oil pressure and the engine vibrations. |
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Fifty50Plus
Joined: 28 Feb 2008
Posts: 1422
Location: Washington DC area
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| Posted: Fri Feb 11, 2022 3:39 am Post subject: |
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Both points valid but with today's data acquisition systems and software, electronic makes more sense. If you are worried about sender failure, install two. I do at various places in the engine to measure pressure loss.
_________________
1979 924 NA race car H-Prod SCCA
1982 924 NA race car - Sold
1981 924 Turbo sold
1982 924 Turbo sold
1972 911 E race car - traded for Cayenne Diesel
1975 914 1.8 Building for H-Prod SCCA |
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jmshistoric
Joined: 08 Feb 2022
Posts: 5
Location: Birmingham
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| Posted: Fri Feb 11, 2022 8:33 am Post subject: |
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| Fifty50Plus wrote: | | Both points valid but with today's data acquisition systems and software, electronic makes more sense. If you are worried about sender failure, install two. I do at various places in the engine to measure pressure loss. |
Where are you adding in the other senders on your engine? Are there other oil galleries you can pick up on with the NA engine? |
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Fifty50Plus
Joined: 28 Feb 2008
Posts: 1422
Location: Washington DC area
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| Posted: Sat Feb 12, 2022 2:42 am Post subject: |
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Plumbing for remote oil cooler, filter and AccuSump.
_________________
1979 924 NA race car H-Prod SCCA
1982 924 NA race car - Sold
1981 924 Turbo sold
1982 924 Turbo sold
1972 911 E race car - traded for Cayenne Diesel
1975 914 1.8 Building for H-Prod SCCA |
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MikeJinCO
Joined: 08 Jun 2010
Posts: 1245
Location: Maysville, Colorado
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| Posted: Sun Feb 13, 2022 1:15 am Post subject: |
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Earls, Aeroquip and several other AN parts makers have an inexpensive pressure port fitting that goes in line. It has 1/8" NPT threads. I got one to use for my temperature gauge, but to me the temperature sender would restrict the flow
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Mike
'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild) |
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924RACR
Joined: 29 Jul 2001
Posts: 9064
Location: Royal Oak, MI, USA
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| Posted: Sun Feb 13, 2022 10:59 pm Post subject: |
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Yeah, I have those AN fittings, use 'em in my P2 for such fittings. And yes, the temp sensor is too long for that; I took 1/8 NPT Tee fittings, drilled one end to pass the sensor through, plugged the branch, and worked it that way. Not ideal, definitely clunky, but functional.
But aside from sensor problems, yeah, those sensor adapters work beautifully.
Would rather have a better temp sensor, but haven't found a more accurate answer that isn't a thermocouple. Thermocouples are a PITA to plug into my data system, since that one (not an AIM) requires a signal amplifier, unfortunately. The 924 uses an AIM system and it's a piece of cake to plug TC's into it.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype |
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