Quote:
Originally Posted by blue62
Swapping valves from one engine to another is not a good practice.
Just as swapping valves from one position to another in the same engine is not a good practice.
Your RAKT's show that one bank is running lean and the other is running rich.
So I would check very carefully for an exhaust leak before the O2 sensor and also at the O2 sensor bung weld. A pinhole exhaust leak can cause your issue.
when you do the vacuum test make sure the engine is fully warmed up.
An easy place to TEE in is where the vacuum line from the fuel pressure regulator is connected to the intake. Near the throttle body.
Put one leg of the TEE directly into the intake, one leg of the TEE into the vacuum gauge, one leg into the line to the fuel pressure regulator.
Just let the engine idle. DO NOT rev the engine. Let it idle for 2-3 minutes while you watch the gauge. record the readings. BUT the MOST IMPORTANT thing is what the needle does.
Record any action from the needle. Does it tick??? does it vibrate does it move in any way no matter how slight over a 2-3 minute period with the engine at idle???
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Yeah, I know swapping valves is not ideal. Like I said though. They were lapped and tested working... I guess that may not mean working in all states per your previous point. I took this as a 'no-no, by the book', but lots of people do with no ill effect. Porsche says the part numbers are the same and the fitment was spot on to the valve guides. Finish on valve guides and valves looked perfect at install. FYI I only swapped exhaust valves. Intake valves all looked great and have never showed signs of problems (leakdown check with both manifolds off and no air ever came form the intake valves, but a lot of air came out the exhaust).
The RKAT values are within 1 point of each other. Isn't that good enough for a beautifully running motor? I'll double check for an exhaust leak this weekend though. Last time I put my smoke tester on the exhaust and saw nothing before the o2 sensors. I figure 1 point could just be from o2 sensor variation, thus why I've got extra o2 sensors on order too. (But I've swapped the o2 sensors from side to side too)
The exhaust was full of coolant at one point before the head swap. Literally I put a heat gun on the muffler then smoke and coolant smell came out the tailpipe. I was worried that all this burning coolant may have had an ill-effect on the o2 sensors or the SAI system or even the cat.
The vacuum gauge is on order... will get to play with it next week. Thanks so much for the help. I'll update once I've done the vacuum testing and looked for exhaust leak.