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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21474 Location: Oklahoma City
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Posted: Sat Sep 04, 2021 7:32 am Post subject: Re: Oil Pressure issue |
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oprn wrote: |
Lots of times we would have a customer ask for a "calibrated test gauge" to do pressure testing on new process piping and vessels but not want to spend the $800 to $1100 or so to get a proper one. We would take 6 or 8 of your class 1A gauges, run them up with a deadweight tester and pick the best one. Then we would check it on the way up and on the way back down at 10 points in the range and record the results on a calibration form along with the serial number and last government approved inspection date of the deadweight tester used and send it with the gauge. The Boilers Branch accepted that in lieu of a proper test gauge.
raygreenwood wrote: |
Also the tolerance is of "reading"....so as you mention..... plenty accurate. a + 0.5% of an 8 psi reading is 0.04 psi. If your gauge is getting to be off (and temperature can mess with it) ....thats a span of 0.08 psi. Just not important. If you are reading lower than 8 psi at idle.....these gauges are accurate enough to tell you that its too low Ray |
I would like to point something out here that I believe you and many others are not clear on. In your example above you are calculating accuracy as "% of reading". This is incorrect unless you have a gauge that maxes out at 8psi. Gauges are generally listed as a "% of full scale" not "% of reading". Therefore a 100 psi gauge with an accuracy listed of 0.5% "OF FULL SCALE" could read 1/2 psi off anywhere on that scale from bottom to top and be in spec.
Instruments with an accuracy listed as "% of reading" are in a whole different accuracy class and much much higher price range. That is "Test Gauge" accuracy.
There, now you know and no one will fool you!
Getting off topic here, sorry! |
I know the difference. I am perfectly clear on gauge classifications.
All but the gauge I listed as class 1A with no certification.....are % of reading.....and NOT percent of scale. Again.....its not just "test class" or "process" or "industrial".....its which rating system the gauges are classified within.
The nomenclature listing "full scale" on these gauges......means that the entire scale is included in the accuracy rating and not just "middle" of scale.
Test class gauges are expensive.....but not even close to what they were a decade ago.
Ray |
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craigman Samba Member
Joined: March 28, 2004 Posts: 2397 Location: redding
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Posted: Sun Sep 05, 2021 11:29 am Post subject: Re: Oil Pressure issue |
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never understood this 10psi per 1K rpm "rule".. To me that is way too low. I prefer more than that. At 6K rpm I wanna see 80psi. Look at newer cars that go 200K plus miles. They all have high oil pressures.
I always blueprint my oil pumps, use sealant instead of a gasket, and always shim my oil control valve shut. I don't want any pressure loss.
Never had an oil related problem yet. |
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Mberglo Samba Member
Joined: January 13, 2020 Posts: 381 Location: Huntsville, AL
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Posted: Sun Sep 05, 2021 11:34 am Post subject: Re: Oil Pressure issue |
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craigman wrote: |
never understood this 10psi per 1K rpm "rule".. To me that is way too low. I prefer more than that. At 6K rpm I wanna see 80psi. Look at newer cars that go 200K plus miles. They all have high oil pressures.
I always blueprint my oil pumps, use sealant instead of a gasket, and always shim my oil control valve shut. I don't want any pressure loss.
Never had an oil related problem yet. |
How do you shim the control valve shut? |
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craigman Samba Member
Joined: March 28, 2004 Posts: 2397 Location: redding
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Posted: Sun Sep 05, 2021 11:49 am Post subject: Re: Oil Pressure issue |
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Mberglo wrote: |
craigman wrote: |
never understood this 10psi per 1K rpm "rule".. To me that is way too low. I prefer more than that. At 6K rpm I wanna see 80psi. Look at newer cars that go 200K plus miles. They all have high oil pressures.
I always blueprint my oil pumps, use sealant instead of a gasket, and always shim my oil control valve shut. I don't want any pressure loss.
Never had an oil related problem yet. |
How do you shim the control valve shut? |
just stack a couple of washers between the spring and screw cap. Basically it just increases the spring pressure so much it won't open. |
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Mberglo Samba Member
Joined: January 13, 2020 Posts: 381 Location: Huntsville, AL
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Posted: Sun Sep 05, 2021 2:02 pm Post subject: Re: Oil Pressure issue |
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Changed oil to 15w40 and verified control valve is not stuck. No improvement, but raised idle to get light to go out. Reviewed engine paperwork, and appears he just reused the pump. I may buy a “blueprinted” pump from Samba classifieds |
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Cusser Samba Member
Joined: October 02, 2006 Posts: 31268 Location: Hot Arizona
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Posted: Sun Sep 05, 2021 3:26 pm Post subject: Re: Oil Pressure issue |
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craigman wrote: |
never understood this 10psi per 1K rpm "rule".. To me that is way too low. |
For me, just what I've observed with my VDO gauge with my 1835cc engine for 4 decades.... _________________ 1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297 |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Mon Sep 06, 2021 10:24 am Post subject: Re: Oil Pressure issue |
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Finally got your measurement. Too late I see.
_________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Mon Sep 06, 2021 10:31 am Post subject: Re: Oil Pressure issue |
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craigman wrote: |
never understood this 10psi per 1K rpm "rule".. To me that is way too low. |
You and 10,000 other guys that don't understand that oil protects engines by film strength not hydraulic pressure. _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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Mberglo Samba Member
Joined: January 13, 2020 Posts: 381 Location: Huntsville, AL
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Posted: Mon Sep 06, 2021 4:12 pm Post subject: Re: Oil Pressure issue |
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oprn wrote: |
Finally got your measurement. Too late I see.
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I appreciate you measuring that. I didn’t realize how easy it would be for the valve to fall out. I measured it and got 0.626 diameter, so it should be ok. |
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RWK Samba Member
Joined: June 24, 2009 Posts: 1337 Location: S.W. MI
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Posted: Mon Sep 06, 2021 4:31 pm Post subject: Re: Oil Pressure issue |
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.626, a bit small.. _________________ 73 Type 181
63 Type 113
63 Type 261- 428 071
62 Type 241-378 025 178 530 |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Mon Sep 06, 2021 7:49 pm Post subject: Re: Oil Pressure issue |
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I wonder if he reused the bearings too... _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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Mberglo Samba Member
Joined: January 13, 2020 Posts: 381 Location: Huntsville, AL
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Posted: Tue Sep 07, 2021 7:38 am Post subject: Re: Oil Pressure issue |
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Build sheet shows other typical rebuild parts such as bearings. I haven't spoken to him. Maybe he inspected it, cleaned it up and reused it. In any case, I think I'll order a new one and swap it out. I'm out of town for a couple of weeks, but will do this when I get home. Thanks for the help. |
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Mberglo Samba Member
Joined: January 13, 2020 Posts: 381 Location: Huntsville, AL
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Posted: Mon Sep 27, 2021 6:05 am Post subject: Re: Oil Pressure issue |
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I installed a mechanical oil pressure gauge and verified that I get the same readings as my electrical VDO. 0psi at hot idle is not what you want to see.
I ordered a new Schadek 26mm oil pump and removal tool. When I pulled the old oil pump out, I was surprised to find it was 21mm! That gave me hope that I might just be on to something.
With the new 26mm pump, Bus now has 40psi at cold idle, 30psi at 220degrees down the highway, and 10psi at a hot idle. Much better.
It makes me wonder what size pump came on this bus originally. Stud length indicates it may have come with the 21mm pump. Bus is a 71 for reminders, and I have reason to believe the case is original. |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Mon Sep 27, 2021 4:17 pm Post subject: Re: Oil Pressure issue |
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Yes that would be the stock size oil pump. _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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modok Samba Member
Joined: October 30, 2009 Posts: 26740 Location: Colorado Springs
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Posted: Mon Sep 27, 2021 5:22 pm Post subject: Re: Oil Pressure issue |
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I'm not sure about they "year" model year vs production date, body vs engine....ect
but I assume...that the 21mm oil pump matched the single relief oil system.
I don't think a dual relief oiling system ever had a 21mm pump
there was a 24mm pump also |
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txoval Samba Member
Joined: January 23, 2004 Posts: 3540 Location: The Woodlands, TX
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Posted: Mon Sep 27, 2021 6:03 pm Post subject: Re: Oil Pressure issue |
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Since it’s running good I’d leave it alone, but in the future you can DFL coat the gears |
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Slow 1200 Samba Member
Joined: July 02, 2004 Posts: 2103
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Posted: Tue Sep 28, 2021 2:09 am Post subject: Re: Oil Pressure issue |
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70 and early 71 engines had 21mm pumps with dual relief cases, then they went to 26mm pumps (and dished cam gears) |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Tue Sep 28, 2021 3:54 am Post subject: Re: Oil Pressure issue |
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Yes I was going from memory. My ‘71 SB had the flat cam gear and a 21mm oil pump. _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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Cusser Samba Member
Joined: October 02, 2006 Posts: 31268 Location: Hot Arizona
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Posted: Tue Sep 28, 2021 9:40 am Post subject: Re: Oil Pressure issue |
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oprn wrote: |
Yes I was going from memory. My ‘71 SB had the flat cam gear and a 21mm oil pump. |
My 1971 Convertible also had a flat cam gear, surprised me when I disassembled it in 2016. Good thing I'd waited to confirm before I ordered my
Maxi2 oil pump/filter. _________________ 1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297 |
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Ohio Tom Samba Member
Joined: February 09, 2006 Posts: 1657 Location: Marshallville Ohio
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Posted: Tue Sep 28, 2021 10:39 am Post subject: Re: Oil Pressure issue |
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Stock oil relief spring should attempt to regulate at around 45psi.
If your cold oil pressure is lower than that, you most defiantly have an issue.
I bet the valve is stuck open.
Happens once in a while.
The plunger gets jamed up.
Remove plug and spring, plunger should fall out.
If it doesn't, fire up the motor for a few seconds. It should blow it out (with whatever debris was jamming it up).
Re-assemble and clean up your mess. |
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