Oil pressure at idle
05-20-2005, 08:07 PM
#1
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Oil pressure at idle
Checked the archives but nothing specific about this.
Replaced the driver side exhaust lifters due to one being louder than the rest. All was well and then I got a new chip which made the idle speed 800 rpm instead of ~950 rpm with the old chip. After the car warmed up fully at idle with the ower idle speed (didn't connect these at first), one lifter was louder than the rest again.
I figured I installed them wrong or something, so out they came again (fun). Now with them replaced again, the noise is back (only on one). This got me thinking, hmmm... maybe it's idle speed related (duh). With idle above 950rpm no noise (other than the clickity clackity that appears normal using the passenger side as a reference).
So this leads to oil pressure at idle concerns. When fully warm past the 194F mark, the oil pressure is a tad under 2 bar at 800 rpm (previously it was about 2.25bar at 950rpm). When revved to 2500 rpm it is at 5 bar but not pegged. Any cause for concern? Thanks.
Replaced the driver side exhaust lifters due to one being louder than the rest. All was well and then I got a new chip which made the idle speed 800 rpm instead of ~950 rpm with the old chip. After the car warmed up fully at idle with the ower idle speed (didn't connect these at first), one lifter was louder than the rest again.
I figured I installed them wrong or something, so out they came again (fun). Now with them replaced again, the noise is back (only on one). This got me thinking, hmmm... maybe it's idle speed related (duh). With idle above 950rpm no noise (other than the clickity clackity that appears normal using the passenger side as a reference).
So this leads to oil pressure at idle concerns. When fully warm past the 194F mark, the oil pressure is a tad under 2 bar at 800 rpm (previously it was about 2.25bar at 950rpm). When revved to 2500 rpm it is at 5 bar but not pegged. Any cause for concern? Thanks.
05-20-2005, 09:22 PM
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Originally Posted by Steve Weiner-Rennsport Systems
Ken:
What oil brand and viscosity are you using?
How many miles on the car?
What oil brand and viscosity are you using?
How many miles on the car?
05-20-2005, 11:36 PM
#6
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Noisy lifters are caused by either a failed seal on the lifter body or foreign material inside the lifter passages from infrequent oil changes.
It IS cause for concern and should be replaced ASAP.
It IS cause for concern and should be replaced ASAP.
05-21-2005, 01:45 AM
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Originally Posted by Steve Weiner-Rennsport Systems
Noisy lifters are caused by either a failed seal on the lifter body or foreign material inside the lifter passages from infrequent oil changes.
It IS cause for concern and should be replaced ASAP.
It IS cause for concern and should be replaced ASAP.
That's the point, I have replaced all three driver side exhaust lifters twice now with the same end result (ie one noisy lifter at idle). The sound it not coming from the intake lifters and goes away with a few hundred rpm increase in idle speed. I agree that one lifter should not be noisier than the rest. Where is the oild feed for the lifters (somewhere around the rocker arm shaft bolts, I'm guessing). Maybe there is some crud stuck in the passage way.
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05-21-2005, 02:02 AM
#8
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I know I sound like a broken record BUT if you don't know what size lifter Porsche installed at the factory then how do you know what size lifter to replace it with? (this is not directed at you Ken but to everyone in general) 0.5mm can be the difference between throw you in the backseat acceleration and just moving "fast."
05-21-2005, 02:07 AM
#9
Race Car
I had/have the same thing. The rear most cyl (closest to the muffler) seems to be louder and its not intake. I did mine a few times as well (burned up Steve W's phone line during the job...Thanks buddy 
). Even the originals, the louder was the rear most and it took rev'ing up at 2000 rpm for a few minutes to get the noise to go away initially. I get the feeling it may be the furthest point and under the least pressure. Believe me I cleaned everything before it went back together and it still has the faintest of noise more than the others. Hell it could be a valve not properly seating, cut wrong....who knows, but with 100K on the clock I'm running with it and time will tell.
). Even the originals, the louder was the rear most and it took rev'ing up at 2000 rpm for a few minutes to get the noise to go away initially. I get the feeling it may be the furthest point and under the least pressure. Believe me I cleaned everything before it went back together and it still has the faintest of noise more than the others. Hell it could be a valve not properly seating, cut wrong....who knows, but with 100K on the clock I'm running with it and time will tell.
05-21-2005, 12:04 PM
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Originally Posted by JasonAndreas
I know I sound like a broken record BUT if you don't know what size lifter Porsche installed at the factory then how do you know what size lifter to replace it with? (this is not directed at you Ken but to everyone in general) 0.5mm can be the difference between throw you in the backseat acceleration and just moving "fast."
