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Jimmy111 Samba Member
Joined: October 05, 2006 Posts: 2643 Location: Wyoming
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Posted: Sun Feb 08, 2009 1:45 pm Post subject: |
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A ACVW motor operating at 6500 RPM, 50PSI and 240F oil temp is capable of sustaining 195HP on the 3 main bearings using a oil that has a cp of 2.9 min. Most 30 coded oils have greater than 2.9 so they will suport more pressure. So unless you are going to exceed 195hp you have no use for a heavier oil.
But most wear occures at or shortly after startup when the oil does not flow well. Especially in colder climates. this is the basis for multigrade oils. They will flow well at cold temps and still give you the load supporting viscosity at high temps. |
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udidwht Samba Member
Joined: March 06, 2005 Posts: 3777 Location: Seattle, WA./ HB, Ca./ Shizuoka, Japan
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Posted: Sun Feb 08, 2009 2:17 pm Post subject: |
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Hence 20W... |
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stcos85 Samba Member
Joined: January 22, 2006 Posts: 40 Location: Melbourne, Aus
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Posted: Sat Feb 14, 2009 6:47 am Post subject: |
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Jimmy111 wrote: |
There is nothing wrong with using a 30mm oil pump in a dual relief motor as long as you are using a remote cooler and the motor is full flowed. The problem occures with the relief valve that sends oil to the oil cooler on the motor. When the oil pressure is too high the relief valve thinks that the oil is still cool and continues to bypass the stock cooler. This is cause of a lot of overheating new motors. I have the drawings that explain this but I dont have time to scan them right now. I will do it on the weekend.
A 30mm oil pump in a single relief case is a really bad Idea. |
Not sure if jimmy111 is still looking at this thread but just read this with interest. I built a 2054cc motor myself, first motor I have ever built, and have no end of oil pressure problems. I have a 30mm oil pump with external filter but no external cooler. Oil pressure seems ok when cold but as it warms up and gets to about 200F while leaving it on tickover it just seems to keep getting hotter rather than cooling. This in turn reduces the oil pressure. Having looked at these diagrams could the 30mm pump be my problems in affecting the control valve. I assume an external cooler from what I have read just hides the real issues.
Would it be wise to try a 26mm pump.
I also have used an older but unused autolinea case which I have read could be porous causing oil pressure problems. I did try to search on here for this subject but didn't find anything. Any comments on either point would help me a great deal |
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Jimmy111 Samba Member
Joined: October 05, 2006 Posts: 2643 Location: Wyoming
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Posted: Sun Feb 15, 2009 10:25 am Post subject: |
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What you describe is exactly the problem with the 30mm pump. Too much pressure and flow for the relief spring. Change to a 26mm pump and you will be fine.
You can also try an oil change and go with a 0w-30 or 5w-30 first and see if that lowers your pressure enough for the relief valve to shut.
About the autolinia cases. It really depends on the casting wether it is porous or not. Some are good and others are not. Most of them that do leak tend to leak on the top of the case near the #1 cylinder.
You shouldnt under most situations need an external oil cooler. But that depends on how well you can tune your motor and how you drive it of course. |
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Jimmy111 Samba Member
Joined: October 05, 2006 Posts: 2643 Location: Wyoming
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Posted: Sun Feb 15, 2009 10:47 am Post subject: |
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I go to Peru a lot and VW's are still a main form of transportation over there. I know many of the good VW mechanics and they use 40w oil in the bugs. The thing is that most people wont take their VW- out of the city because they are almost guarenteed to overheat. My Vw-friends over there cant usndestand how I can take my VW for a 1000 mile trip over the andes or even to the next city 300Km without worry. I kept telling them for years it was the oil that they were using but they never believed me. Finally a few of these people tried 5-w30 and their overheating problems completly went away. Now many of the VW mechanics push 5w30 instead of 40w.
Just a case in poiont for a lower viscosity oil |
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stcos85 Samba Member
Joined: January 22, 2006 Posts: 40 Location: Melbourne, Aus
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Posted: Sun Feb 15, 2009 12:44 pm Post subject: |
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jimmy111,
should take delivery of a 26mm oil pump in the week and will give it a try. lets hope it sorts it out. |
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martyrg Samba Member
Joined: February 29, 2004 Posts: 452 Location: South Lyon, MI. 48178
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Posted: Sun Feb 15, 2009 7:37 pm Post subject: |
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Hey Jimmy111,
I got one of those cases that has the relief valve and control valve seats without a bevel. How do you correct this? What do you use to cut the bevel with? |
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buglover34465 Samba Member
Joined: June 22, 2008 Posts: 65
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Posted: Sat Mar 28, 2009 6:39 pm Post subject: #4 bearing flow balance orifice insert |
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I added the orifice to rebalancee the oil flow to the #4 bearing as I removed the plug for cleaning. |
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piledriver Samba Member
Joined: June 05, 2003 Posts: 184 Location: In my bunker, beside my wall. (Howe, Tx)
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Posted: Mon May 18, 2009 7:45 pm Post subject: |
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The bearing clearance is far smaller than your "restriction".
Think about what actually is the controlling orifice in the circuit... |
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1955ccbug Samba Member
Joined: October 03, 2004 Posts: 730 Location: Olympia wa
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Posted: Fri Jul 03, 2009 9:39 pm Post subject: |
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Jimmy111 wrote: |
There is nothing wrong with using a 30mm oil pump in a dual relief motor as long as you are using a remote cooler and the motor is full flowed. The problem occures with the relief valve that sends oil to the oil cooler on the motor. When the oil pressure is too high the relief valve thinks that the oil is still cool and continues to bypass the stock cooler. This is cause of a lot of overheating new motors. I have the drawings that explain this but I dont have time to scan them right now. I will do it on the weekend.
A 30mm oil pump in a single relief case is a really bad Idea. |
Not sure if anyone still reads this thread but....I was wondering what happens when you use a 30mm pump on a single relief case? |
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Towel Rail Horizontally Opposed
Joined: April 15, 2005 Posts: 4622 Location: SE CR IA US NA PE
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Posted: Sat Jul 04, 2009 12:44 am Post subject: |
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1955ccbug wrote: |
Jimmy111 wrote: |
A 30mm oil pump in a single relief case is a really bad Idea. |
Not sure if anyone still reads this thread but....I was wondering what happens when you use a 30mm pump on a single relief case? |
My understanding is this:
Because the single relief valve has to do both jobs, its spring is lighter than on the later engines, so it will bypass the cooler at a lower pressure. Compound this with a 30mm pump, and you will not only have excessive oil pressure, but the oil will spend so little time flowing *through* the cooler (as opposed to around it), that the oil temp will rise.
- Scott _________________ 1974 Thing -- under the knife
1967 Beetle -- spring/summer/fall driver
1996 Subaru OBW (EJ22, 5-speed, AWD) -- winter car, 3-seasons "don't feel like biking today" car
049 > 070 > 053 > 009
Last edited by Towel Rail on Tue Jul 07, 2009 11:31 am; edited 1 time in total |
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1955ccbug Samba Member
Joined: October 03, 2004 Posts: 730 Location: Olympia wa
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Posted: Mon Jul 06, 2009 9:21 pm Post subject: |
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Thanks Scott. |
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redhot Samba Member
Joined: February 05, 2005 Posts: 447
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Posted: Tue Jul 21, 2009 7:02 am Post subject: |
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I just measured the plug-size of the oil relief passage, and it came out to be 8mm. I cant think that they drilled it in two operaitons, so probably 8mm all the way through.
This is a late 1600case, AS41 as I remember.
So, using this with the 30mm pump should be OK as I understand.
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msalling Samba Member
Joined: February 21, 2007 Posts: 154 Location: Louisville, KY
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Posted: Tue Aug 11, 2009 12:23 pm Post subject: |
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My T4 Vanagon has been running hot. I installed an OT gauge (914 style sump plate sender) and was shocked at the OT! It was 230-250 once warmed up. I verified it with an infrared temp gun at the oil filter mount. After reading this thread(and numerous others) I will try 10W-40 or 10W-30 in place of 20W-50 and see if that cools it off. I ordered a new OP relief spring and plunger just in case. I will check to see if my brakes are dragging but I think my oil has been a culprit. I never drive it hard so I can't imagine I'm putting excessive strain on the engine. I will have the OP gauge installed soon so I'll have more data for comparison. I have roughly 6K on the engine since rebuilding the top end. I hope it is OK. _________________ 1982 Westfalia Vanagon, FI 2.0l |
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TomSimon Samba Member
Joined: January 13, 2004 Posts: 749
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Posted: Tue Aug 11, 2009 9:45 pm Post subject: |
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Wow! Nice pictures and research, bravo!
I came to the conclusion years ago that race engines need a lot of flow over the rod journals to keep them cool. That means a senseble oil viscosity and a lot of rod bearing clearance. Big clearances mean you need a lot of flow, and a big oil pump. Once I started using aftermarket external pressure relief valves (simply a Kinsler pop-off valve set to 80psi in -8 size) life got simple.
Just more grist for the mill... |
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Jimmy111 Samba Member
Joined: October 05, 2006 Posts: 2643 Location: Wyoming
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Posted: Wed Aug 12, 2009 1:07 pm Post subject: |
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This information is mainly for people who have stock or close to stock oiling systems. Of course if you modify your system by enlarging clearances or providing more lifter oiling you will need to supply more oil. |
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volksterii Samba Member
Joined: December 01, 2006 Posts: 425 Location: San Diego CA
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Posted: Mon Aug 31, 2009 9:50 am Post subject: |
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Jimmy111 wrote: |
Here is a photo of the inside of the oil side of the case I took ar RIMCO.
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So looking at this pic, is it safe to say that the side of the pistion in the relief bore when closed also blocks oil from draining out of the lower oil galley? _________________ 71 Westy Hardtop, 1915
2005 Touareg V8 air susp. |
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Jimmy111 Samba Member
Joined: October 05, 2006 Posts: 2643 Location: Wyoming
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Posted: Wed Sep 02, 2009 8:11 am Post subject: |
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Its supposed to. But most of them leak. Some a little and some a lot. |
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Riff Raff Shivering Sambian
Joined: October 25, 2004 Posts: 3096 Location: Alberta
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Posted: Mon Sep 07, 2009 1:53 pm Post subject: |
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Read through this thread twice with interest.
I am running an AutoLinea case in my 61 bus.
2017cc 8.3 CR, mild cam, dual Dells, 30mm oil pump. Full flowed with filter, but no external cooler. I wanted torque- it's a bus and I rarely exceed 4000 RPM although all internals are balanced.
I drive pretty conservatively.
The oil temps run between 100 and 105C and I think that is a little hot.
I am running Quaker State 15W-40 Diesel.
My questions:
Does the AutoLinea case have the smaller oil passages that may cause higher pressures and a bypass of the oil cooler at running temps?
I have an AS 41 Mexican case as well that I am going to build a (mild) 1904 out of. My understanding from this thread is that it has the larger oil passages and is designed for a 30mm pump - correct?
Lastly, I have an older AE block that I am going to build a 1679 out of just to have on the shelf as I have a spare set of MI 88's and heads.
This engine should be run with a 26mm pump - correct? _________________ The greatest obstacle to discovery is not ignorance, but the illusion of knowledge
- Daniel Boorstin |
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68squared Samba Member
Joined: October 11, 2009 Posts: 23 Location: Victorville High Desert IE
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Posted: Tue Oct 27, 2009 2:57 am Post subject: |
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Great read! Has anyone put an external oil filter, cooler and oil pressure regulator in a single relief case? |
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