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Woodland Hills, CA
Join Date: Dec 2008
Location: Southern, CA
Posts: 634
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Engine Build Noise Help
I just completed an upper end rebuild on 2.0 Aluminum case motor and it has a fairly deep ticking noise. I used 2.2 E Mahle PCs and 2.2 heads. I'm running Dougherty's DC-30 Mod-S profile Cams. Stock Webers.
I fired the motor for the first time last weekend and noted that the motor was quite noisy for the first 3 or 4 minutes during the 20 minute 3000 rpm break-in. When the motor reached 200 degrees the noise appeared to go away. I wrote it off to a dry motor taking a while to get the oil fully circulating. Over the next couple of days I buttoned up a few things on the car to take it in its' maiden cruise. I then started it...to take it out on a cruise and this same noise appeared. It sounded like extremely lose valves but maybe a little deeper. I then took the car out and the noise again appeared to go away after driving for 20 minutes or so. I stopped the car for 15 or 20 minutes and admired the car (sorry  ) When I restarted the car again, the same multiple ticking noise, just not as loud. I thought maybe an exhaust leak? Maybe piston slap? Still unsure what was going on, I took the car back home.Today I took the car out again as I had an alignment appointment. Same thing...all over again. To me it's not right. I stopped at a very reputable Porsche shop on the way back and he thinks that the valves are nicking the pistons at the fly cut edge. he believes the pockets are deep enough. He believes it maybe too much cam lift. Any more expert opinions before I pull the motor down again?  
Last edited by gsjohnson; 08-19-2013 at 06:32 PM.. |
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08-19-2013, 06:25 PM
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Registered
Join Date: Jul 2004
Location: Texas
Posts: 180
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GS, I recently pulled apart a 69E that someone else did with S cams and pistons It had a light knock on one bank that diminished when warm. It had very little deck clearance and the cams were set at 3.5 All of the exhaust valves were touching the pistons,but none were bent.
After setting correct deck and proper cam timing,all is good. warren |
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08-19-2013, 07:15 PM
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Registered
Join Date: Jul 2008
Location: Spokane WA
Posts: 585
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Did you check valve to piston clearance during assembly? You can set the no. 1 piston to TDC then run the valve adjustment to zero clearance. The thread pitch on the valve lash adjustment screw is 1mm so one complete turn equals 1mm valve travel. Screw the adjuster two revolutions in then turn the engine through two complete revolutions (gently by hand) and if you encounter any resistance STOP. If there is no valve to piston interference then your problem lies elsewhere. If the valves hit the pistons then you know what you have to do next...
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08-20-2013, 12:02 AM
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911 2.2 T targa
Join Date: Jun 2012
Location: Netherlands
Posts: 89
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Does it sounds like this ? Then it could be a cylinder
 . See my thread on this issue: Ticking noise after rebuild 70's 911T
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08-20-2013, 12:21 AM
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Woodland Hills, CA
Join Date: Dec 2008
Location: Southern, CA
Posts: 634
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I did not check the piston to valve clearance. Several people had told me that there shouldn't be a problem with this combo. Looking back, I should have checked it as others are now saying that there could be valve/piston interference and/or deck height issues. I relied on some others. For sure my mistake. At this point, it looks like the motor is going to have to come apart...
I was looking for confirmation that this is probably what's happening... Heinz I had read your thread previously, and although the noise is similar, the symptoms are different. My noise goes away as the motor warms up whereas your motor gets louder as it warms up |
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08-20-2013, 06:49 AM
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