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delliott101
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Joined: February 22, 2008
Posts: 1304
Location: Boise ID
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 Posted: Sun Apr 22, 2012 5:25 pm Post subject: Yet Another Oil Pressure Thread --- 1970 Bug |
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Some months ago I posted about my oil light coming on at idle. I rebuilt my 1600SP and it is now a 1641SP. PLEASE don't ask "did you do it right?" or "Did you put in the correct oil pump" or anything like that. YES everything was done correctly and checked by a friend who works at a local VW shop. The case was align bored by another local shop run by a couple of old VW trained mechanics and they have been doing this since I was a wee baby in swaddling cloth.
I installed a later oil cooler, later doghouse, later fan with the rebuild. Yes, done correctly, and yes, the cooler was cleaned and blown out.
My engine has about 3000 miles on it and has been running great. No problems. But, we are now in suddenly Summer weather... like in the mid 90 degree range...
Today I drove it for a 20 mile one way trip and about 10 miles in, at idle, the oil light came on. When I drive the light shuts off at speed, but when I put in the clutch to downshift, it comes on for a second, then shuts off when I get into gear.
So when I got where I was going (a cleaning job) I let the car sit in the shade with the decklid open. After 2 hours, I was ready to leave and checked timing and also took out the rain gutter contraption off the decklid to see if I could get better cooling. I had the same problem with the light on the way home.
I am running HD-40 oil, so I know the weight is heavy enough and not thinning out. The engine RUNS fine and I don't hear any weird sounds. When I rebuilt the engine, I cleaned everything inside the case immaculately. I am tempted to take the decklid off and see what happens when I drive it, as I am wondering if it is a cooling issue, but other people don't seem to have that problem around here... So I am open to suggestions as to what it could be.
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Transplanted Jersey Boy living in Idaho by way of Northern California!
We don't own old VWs, we just take care of them for the next driver |
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drs1023
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Joined: October 20, 2011
Posts: 1107
Location: Georgia, USA
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| Posted: Sun Apr 22, 2012 5:39 pm Post subject: |
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| Could be a bad oil pressure sending unit. If you have a gauge, connect it for testing. If not, either replace the sending unit (cheap) or a gauge (still not too bad). |
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delliott101
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Joined: February 22, 2008
Posts: 1304
Location: Boise ID
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| Posted: Sun Apr 22, 2012 5:45 pm Post subject: |
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Nice idea, but it is brand new.... when I rebuilt the engine I used new parts for what I could and what needed to be replaced. The only thing "outside" the engine I didn't replace were the oil pressure relief valves... but I cleaned them thoroughly, as well as cleaned where they fit into and our visual inspection showed them in good shape... but I can replace them easily.
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Transplanted Jersey Boy living in Idaho by way of Northern California!
We don't own old VWs, we just take care of them for the next driver |
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mph2
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Joined: April 21, 2012
Posts: 28
Location: Strawberry Plains, TN
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| Posted: Sun Apr 22, 2012 6:36 pm Post subject: |
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| Just because it's new doesn't mean it's not bad. I have had bad oil senders before. The best way is a gauge they rarely lie |
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johnnypan
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Joined: October 24, 2007
Posts: 5464
Location: sackamenna
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| Posted: Sun Apr 22, 2012 7:32 pm Post subject: |
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Shadek makes a 30mm 'super' oil pump,it flows at a higher volume than a stock pump.It should cure your light issue..if it does you may have an issue with the linebore/bearing measurement..if they slightly overbored your case...say .022 instead of .020 for instance then oil under pressure leaks between the case and the back of the bearing.
Question...did the shop doing the linebore use a "portalign" tool? or do they have a drill press jig?one should be wary of machining cases in that fashion
heres Rimco doing a case...on a lathe..
http://www.youtube.com/watch?v=d-oMfB-pYbg |
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goober
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Joined: May 03, 2003
Posts: 200
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| Posted: Sun Apr 22, 2012 7:41 pm Post subject: |
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| Did you replace the oil pump plate? If not, did you clean up any grooves in the old plate caused by the gears? Is you oil pump/plate gasket less than .005" thick? |
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gevmage
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Joined: February 12, 2008
Posts: 1004
Location: Kentucky
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| Posted: Sun Apr 22, 2012 8:46 pm Post subject: |
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It's easy enough to measure. You can measure the oil pressure with a gauge. The spec is:
30-weight oil
oil at 70 degrees C
check oil pressure at 2500 rpm
new engine: 42 psi
wear limit: 28 psi
Harbor Freight sells an oil pressure gauge kit for something like $50.
Before I rebuilt my top end, my oil light flickered (edit: when engine warm); the results of the above test were 18 psi. I bought a new oil pump, blueprinted it, then installed it with the top end. After, the test showed about 40 psi, and the oil light hasn't flickered since.
Craig Steffen
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Craig Steffen
proud owner of a 1972 Superbeetle
Rebuilt brakes, engine top end, 34PICT-4; now runs like a top at 75mph
Last edited by gevmage on Mon Apr 23, 2012 5:21 am; edited 1 time in total |
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Zimmdub
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Joined: February 08, 2012
Posts: 4
Location: Lancaster, Pa
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| Posted: Mon Apr 23, 2012 3:21 am Post subject: |
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| If my oil light comes on when downshifting or stopping or taking off from stop, I know its time to add a quart. |
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Zimmdub
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Joined: February 08, 2012
Posts: 4
Location: Lancaster, Pa
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| Posted: Mon Apr 23, 2012 3:22 am Post subject: |
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| If my oil light comes on when downshifting or stopping or taking off from stop, I know its time to add a quart. |
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delliott101
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Joined: February 22, 2008
Posts: 1304
Location: Boise ID
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| Posted: Mon Apr 23, 2012 6:49 am Post subject: |
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I Installed a brand new pump on the rebuild and the oil level is where it should be. I was not having this problem before yesterday. I am also going to check with the shop here in town and get some suggestions, too...
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We don't own old VWs, we just take care of them for the next driver |
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gevmage
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Joined: February 12, 2008
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Location: Kentucky
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| Posted: Mon Apr 23, 2012 7:04 am Post subject: |
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| delliott101 wrote: | | I Installed a brand new pump on the rebuild |
What was the gear/body height difference of the oil pump? Did you use an old or new pump cover?
| Quote: | | I was not having this problem before yesterday. I am also going to check with the shop here in town and get some suggestions, too... |
It might be that your oil pump is a below spec, and almost on the edge tripping the pressure sensor when the oil's hot. So when you get the engine a bit hotter than usual, it started flickering. You'll know if you measure the oil pressure with the standard conditions.
Craig Steffen
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Craig Steffen
proud owner of a 1972 Superbeetle
Rebuilt brakes, engine top end, 34PICT-4; now runs like a top at 75mph |
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delliott101
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Joined: February 22, 2008
Posts: 1304
Location: Boise ID
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| Posted: Mon Apr 23, 2012 7:12 am Post subject: |
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| gevmage wrote: | | delliott101 wrote: | | I Installed a brand new pump on the rebuild |
What was the gear/body height difference of the oil pump? Did you use an old or new pump cover?
| Quote: | | I was not having this problem before yesterday. I am also going to check with the shop here in town and get some suggestions, too... |
It might be that your oil pump is a below spec, and almost on the edge tripping the pressure sensor when the oil's hot. So when you get the engine a bit hotter than usual, it started flickering. You'll know if you measure the oil pressure with the standard conditions.
Craig Steffen |
Will do... thanks
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Transplanted Jersey Boy living in Idaho by way of Northern California!
We don't own old VWs, we just take care of them for the next driver |
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gevmage
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Location: Kentucky
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| Posted: Mon Apr 23, 2012 7:15 am Post subject: |
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| delliott101 wrote: | | Nice idea, but it is brand new.... |
I believe you were referring to the oil pressure sensor here.
It's not very likely, but it's always possible that the new oil pressure sensor you installed was faulty.
It's also quite possible that the transition pressure of the new sensor is different (higher) than the old one. They're really only designed to warn you of ZERO pressure; the threshold isn't precise. It's supposed to turn the light on starting anywhere from 2 to 6 psi. Do you have the old sensor that you could swap in to try?
Craig Steffen
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Craig Steffen
proud owner of a 1972 Superbeetle
Rebuilt brakes, engine top end, 34PICT-4; now runs like a top at 75mph |
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delliott101
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Joined: February 22, 2008
Posts: 1304
Location: Boise ID
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| Posted: Mon Apr 23, 2012 7:31 am Post subject: |
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| gevmage wrote: | | delliott101 wrote: | | Nice idea, but it is brand new.... |
I believe you were referring to the oil pressure sensor here.
It's not very likely, but it's always possible that the new oil pressure sensor you installed was faulty.
It's also quite possible that the transition pressure of the new sensor is different (higher) than the old one. They're really only designed to warn you of ZERO pressure; the threshold isn't precise. It's supposed to turn the light on starting anywhere from 2 to 6 psi. Do you have the old sensor that you could swap in to try?
Craig Steffen |
No... I changed the sensor when I got the car because it was doing the same thing before the rebuild. The reason I did the rebuild was because of this same oil light problem. When I got into the engine, it was very worn.
I do have the sensor on my wife's engine that I can try, though... we are going to start working on her vert in a couple of months... so she is not needing it...
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Transplanted Jersey Boy living in Idaho by way of Northern California!
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delliott101
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Joined: February 22, 2008
Posts: 1304
Location: Boise ID
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| Posted: Tue Apr 24, 2012 8:50 am Post subject: |
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I swapped the sensor switch... no more light at idle...
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