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jhadler |
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#1
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Long term tinkerer... ![]() ![]() ![]() Group: Members Posts: 1,879 Joined: 7-April 03 From: Lyons, CO Member No.: 529 ![]() |
Hey all,
Starting a new thread here... I'd like to get some advice please. Here's the scoop: New motor. 9:1 2056 w/ceramic coated euro race headers. Stock D-jet and stock ignition. Running on Brad Penn break-in oil. Two shake down drives for break-in (varying rpm and load, staying out of WOT and mostly below 4k rpm), and they both have the same basic symptoms. The oil temps get too high and idle turns to cr*p. Drive one: 75 degree ambient, 40 minutes driving. head temps vary between 250-275, never higher than 300. Oil temps climbed to 230, and once hot won't idle worth a damn. - backed off ignition advance to stock, was running at 30 degrees. Capped vacuum retard hose, seemed to idle better without. (mistake?) Drive two: 85 degree ambient, 25 minutes driving. Head temps vary between 250-300, never higher. Oil temp went to 250. Hot idle just plain sucked. I know I need to get a wideband on there to figure out what the mixture is doing, but if the mixture was going lean, I'd expect to see excessive head temps right? Can the oil temp simply be a tight motor on light oil? It doesn't seem right though. Help? Advice? Suggestions? Last thing I want to do is lunch this motor. -Josh2 |
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Jake Raby |
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#2
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Engine Surgeon ![]() ![]() ![]() ![]() ![]() Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States ![]() |
Retarded timing heat soaks heads and pistons and the charge out the exhaust valve can possibly still be burning while the exhaust valve is open... retarded timing is the #1 cause of most tuning issues that cause engine failures..
People tend to be conservative with timing, thus compromising their engine due to their fear. These engines continually prove to love 28-30* full advance @3500 RPM. For my recommendations on temperatures see the classic thread here on 914 world. SET MECHANICAL TIMING WITHOUT ANY VACUUM HOSES ATTACHED! This timing is all that matters, then reattach the vacuum. Its all in the tune... Thats what I do better than anything. |
jhadler |
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#3
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Long term tinkerer... ![]() ![]() ![]() Group: Members Posts: 1,879 Joined: 7-April 03 From: Lyons, CO Member No.: 529 ![]() |
Retarded timing heat soaks heads and pistons and the charge out the exhaust valve can possibly still be burning while the exhaust valve is open... retarded timing is the #1 cause of most tuning issues that cause engine failures.. That's interesting. Seemingly counter intuitive until you know the mechanism going on. QUOTE These engines continually prove to love 28-30* full advance @3500 RPM. For my recommendations on temperatures see the classic thread here on 914 world. SET MECHANICAL TIMING WITHOUT ANY VACUUM HOSES ATTACHED! This timing is all that matters, then reattach the vacuum. That's what I did. I set the timing to 28 degrees, no vacuum hoses attached, 3500 rpm. So... 30? 32? I understand that running at altitude demands more advance, is that true? -Josh2 |
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