Car Has No Compression On #4, ...can I take the valve cover off without draining oil? |
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Car Has No Compression On #4, ...can I take the valve cover off without draining oil? |
7TPorsh |
Jun 30 2016, 12:30 PM
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#1
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7T Porsh Group: Members Posts: 2,691 Joined: 27-March 06 From: Glendale Ca Member No.: 5,782 Region Association: Southern California |
A problem has recenly developed and I can't figure it out. The car starts up easy and on the first crank. I let it warm up a few minutes and drive....It drives fine as it's warming up.
Then after about 15 or 20 minutes the engine starts developing a shudder. Idles fine but and can run ok under low load but under some load the #4 cylinder starts popping and firing up through the carb. feels like it's running 3 cylinders and wasting gas. It's been suggested I do a compression test but I'm thinking if the engine runs great cold and while warmin up; the compression should be ok. Is there a case where comprression is ok when cold but low when hot? Can't figure out why car runs great when starts f'n up. 1.7 with dual weber 40 IDFs |
Dave_Darling |
Jul 8 2016, 02:49 PM
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#2
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914 Idiot Group: Members Posts: 15,048 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California |
Look at the valve tips when each cylinder is on TDC. If one of the valves on #3 is sitting with the tip closer to the head, it's a dropped valve seat.
With zero compression, the problem is almost certainly serious enough that to fix it you will need to drop the engine and remove the head. At a minimum. --DD |
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