Oil flow question on Type IV, Can the oil pressure relief valve fail to close? |
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Oil flow question on Type IV, Can the oil pressure relief valve fail to close? |
boxsterfan |
Apr 8 2014, 11:44 AM
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#1
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914's are kewl Group: Members Posts: 1,776 Joined: 6-June 03 From: San Ramon, CA Member No.: 791 Region Association: Northern California |
On my 74 2.0L, I still feel that I am experiencing engine oil temps that get too high. For example, in San Ramon, CA yesterday it was in the 70's I believe.
On a short 15 minute drive on the highway, my oil temps got up to just under 220 on a VDO gauge. Yes, these gauges are not perfect, but the only measuring stick I have at the moment. In the past, the things I have done: 1. Adjusted valves 2. Adjusted timing to 27 degrees at 3500 RPM 3. Complete oil change 4. Sprayed some brake cleaner up into the oil cooler from below and blew out with compressed air. 5. Thermostat and flaps operating correctly (new thermostat cable installed last weekend). 6. Plastic flaps are there hanging under the body at the firewall. In the 914 oil flow diagram, there is an oil pressure relief valve that is supposed to close as the engine oil warms up. Do these ever fail? Or sort of fail such that they never get to position "c" in the diagram below? Attached image(s) |
Dave_Darling |
Apr 8 2014, 11:54 AM
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#2
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914 Idiot Group: Members Posts: 14,991 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California |
It can. In fact, it can stick to the point where it dumps oil back into the sump rather than sending it to the bearings, resulting in low oil pressure.
You can remove the bug slot-head screw thing that goes up into the case near the oil filter flange and check the bore and piston for smooth operation. BTW, 220F is not a bad temperature. As long as you're below 240F I think you're fine. --DD |
Mblizzard |
Apr 8 2014, 12:09 PM
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#3
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Advanced Member Group: Members Posts: 3,033 Joined: 28-January 13 From: Knoxville Tn Member No.: 15,438 Region Association: South East States |
I had a similar problem with my 2056. While I did later add an external oil cooler, I was instructed to go back through the basics. Timing was my problem because I had used the 27 mark as TDC and then advanced. (IMG:style_emoticons/default/headbang.gif)
So verify the timing mark you are using it should be the "0" that is visible on the back side of the impeller. Not suggesting you did the same but I swore I had not done it either! Also check your cooling flaps for correct operation and visually confirm that the oil cooler is not blocked. I know you did blow it out but I had a portion of a plastic bag stuck to mine once. A cheap USB camera can do this easily. Check your valve clearances. I know! But I have done them wrong even after setting them correctly numerous times before. Check your plugs to see if you are running lean. Then verify the temperature with an external method. I was able to get my temps back to normal after correcting the timing. Because I anticipate some hot weather driving I added the cooler after fixing the problem. If you just add the cooler you could mask the problem and eventually cause damage. |
worn |
Apr 8 2014, 01:36 PM
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#4
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can't remember Group: Members Posts: 3,164 Joined: 3-June 11 From: Madison, WI Member No.: 13,152 Region Association: Upper MidWest |
On my 74 2.0L, I still feel that I am experiencing engine oil temps that get too high. For example, in San Ramon, CA yesterday it was in the 70's I believe. On a short 15 minute drive on the highway, my oil temps got up to just under 220 on a VDO gauge. Yes, these gauges are not perfect, but the only measuring stick I have at the moment. In the past, the things I have done: 1. Adjusted valves 2. Adjusted timing to 27 degrees at 3500 RPM 3. Complete oil change 4. Sprayed some brake cleaner up into the oil cooler from below and blew out with compressed air. 5. Thermostat and flaps operating correctly (new thermostat cable installed last weekend). 6. Plastic flaps are there hanging under the body at the firewall. In the 914 oil flow diagram, there is an oil pressure relief valve that is supposed to close as the engine oil warms up. Do these ever fail? Or sort of fail such that they never get to position "c" in the diagram below? Yes, they can also leak even if closed. What was the oil pressure like? If that was OK I think you are OK. I would expect if the valve is the problem you should have had low pressure. I ended up resurfacing mine and it improved oil pressure, but had little effect on temp. I run an external cooler on my 2056. Good luck. |
Jake Raby |
Apr 8 2014, 01:39 PM
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#5
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
Most of them fail to close.
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boxsterfan |
Apr 8 2014, 03:29 PM
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#6
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914's are kewl Group: Members Posts: 1,776 Joined: 6-June 03 From: San Ramon, CA Member No.: 791 Region Association: Northern California |
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boxsterfan |
Apr 8 2014, 03:31 PM
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#7
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914's are kewl Group: Members Posts: 1,776 Joined: 6-June 03 From: San Ramon, CA Member No.: 791 Region Association: Northern California |
Yes, they can also leak even if closed. What was the oil pressure like? If that was OK I think you are OK. I would expect if the valve is the problem you should have had low pressure. I ended up resurfacing mine and it improved oil pressure, but had little effect on temp. I run an external cooler on my 2056. Good luck. I don't have an oil pressure gauge, but my idiot light comes on and goes off as "normal" during startup. Idiot light never comes on during operation of the car. Of course, that doesn't mean the oil pressure is correct (or within accepted ranges) during operation. I'm going to have to invest in an oil pressure gauge setup someday.... |
tomeric914 |
Apr 8 2014, 09:37 PM
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#8
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One Lap of America in a 914! Group: Members Posts: 1,259 Joined: 25-May 08 From: Syracuse, NY Member No.: 9,101 Region Association: North East States |
I had it get stuck in my 2270. I believe I rented a ream from Aircooled.net to clean up the bore and I haven't had a problem since.
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boxsterfan |
Apr 8 2014, 09:52 PM
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#9
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914's are kewl Group: Members Posts: 1,776 Joined: 6-June 03 From: San Ramon, CA Member No.: 791 Region Association: Northern California |
I had it get stuck in my 2270. I believe I rented a ream from Aircooled.net to clean up the bore and I haven't had a problem since. I'm definitely going to pull it out this weekend. If that doesn't help lower the temps a bit then I will have to get myself an A/F gauge setup and look and see what I have for mixture going on. When I changed my plugs a couple months back, they looked fine however. |
boxsterfan |
Apr 14 2014, 01:49 PM
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#10
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914's are kewl Group: Members Posts: 1,776 Joined: 6-June 03 From: San Ramon, CA Member No.: 791 Region Association: Northern California |
What's the best tool to remove the oil pressure relief valve plug near the oil filter? Is there such a thing as a flat blade screwdriver that wide?
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Harpo |
Apr 14 2014, 02:54 PM
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#11
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Senior Member Group: Members Posts: 1,304 Joined: 21-August 11 From: Motor City aka Detroit Member No.: 13,469 Region Association: None |
I think they call it a drag link tool. I had mine EDM out to a hex.
http://www.sears.com/stanley-proto-stanley...mp;blockType=G6 |
stugray |
Apr 14 2014, 04:36 PM
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#12
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Advanced Member Group: Members Posts: 3,825 Joined: 17-September 09 From: Longmont, CO Member No.: 10,819 Region Association: None |
QUOTE What's the best tool to remove the oil pressure relief valve plug near the oil filter? Is there such a thing as a flat blade screwdriver that wide? you can "tap" on it with a chisel. Or most flaps carry a socket that looks like a huge flat blade screwdriver |
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