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914World.com _ 914World Garage _ I think i need a new oil pump or a cooler

Posted by: Aaron Cox Aug 31 2003, 09:14 PM

well. my carb'd 2.0 has about 6500-7000 miles on it since rebuilt last summer. i drive it hard and such, but for the most part it has been good. here's my pproblem- after driving like 45 min - 1hr at like 75 mph, if the car's idle drops below a 1000 rpms at a light, the oil pressure idiot light will flicker and then come hard on- so i heel toe it to stay above 1000 rpms (hot idle carb issue- working on it!!) here is what i think is happening. the stock oil pump sucks. also, i think the oil is getting too hot and thinning out so the pump has a hard time pumping.....

external oil cooler? HD oil pump? what do i do?

btw- fresh oil change- proper level, 20w-50

Posted by: ChrisReale Aug 31 2003, 10:03 PM

How hot is your oil getting? I run 15-50 Mobil 1 and when my oil is at 220, I have about 15lbs of pressure at idle

Posted by: Rob Ways Sep 1 2003, 12:43 AM

I'm having the same problems plus a leak on a 5K engine that I AX fairly hard. I'm at about 5 lbs at 220 degrees. I need a new oil pump asap.

Posted by: sj914 Sep 1 2003, 02:17 AM

I had the same thing happen to me with my first 914. It would be fine at start up and then all of a sudden when the car was warmed up, the oil light would go on, I ended up testing it using a mechanical pressure guage and it would read lower than what was acceptable around I think 15 psi. I decided to pull the engine out and rebuild it. I changed the bearings and had the heads reconditioned. I changed the oil pump to a melling pump and when I finally got it back to together, it still gave me the low oil pressure at idle. I suspect that the oil cooler had some kind of pressure leak. I'm only speculating on the oil cooler because it was the only thing I didn't check or replace, I just cleaned off the exterior before reinstalling it.

Posted by: Jake Raby Sep 1 2003, 08:29 AM

Yes, it sounds like the oil is gettiung too hot, thinning out and dropping pressure.

What oil grade are you using? you may go up one viscosity and see what it does for the temps and pressure drops....

The other issue is the oil pressure relief valve. During many rebuilds the condition of it's bore and the tension of the spring are overlooked. If the preesure relief piston seals poorly, you will have low pressure.

Posted by: sj914 Sep 1 2003, 10:03 AM

I thought those oil relief pistons were mostly for revs. over idle.

Posted by: Aaron Cox Sep 1 2003, 10:04 AM

yeah the relief pistons we couldnt get out (broke a Big f-n screw driver trying) we couldnt get that 1 inch plug off.

im using 20w 50 oil

Posted by: Jake Raby Sep 1 2003, 10:34 AM

So you never removed the oil pressure relief at rebiuld time???? Thats a biggie!

Posted by: Aaron Cox Sep 1 2003, 10:37 AM

nope. the galley plug (1 inch flat blade screwdriver recepticle) must have been glued in there or something. we broke scredrivers, tried a flat chisel and a vice grip.

Posted by: Jake Raby Sep 1 2003, 10:52 AM

Man........use an air hammer to "wake it up" while using a small torch on the outside of the case......

Posted by: Aaron Cox Sep 1 2003, 11:08 AM

yeah, i didnt have access to that advanced technology.....