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> Can our engines develop morning sickness?
andreic
post Oct 16 2018, 09:42 AM
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My 1972 914 1.7L suffers from what I call "morning sickness" -- the first time I start the car on any given day it runs like crap for the first 10-15 minutes. Skipping, won't rev up above 1000 rpm, very low idle, stumbles frequently, sometimes backfires. Also makes some strange noise around 2000 rpm, like a very loud rattle, especially when letting off the throttle.

After 10 minutes all is good, running well for the rest of the day. The compressions, which I have only checked with the engine hot, are uniformly 120-125 PSI.

I come from an aviation background, and aircooled airplane engines are known to have this kind of morning sickness at around 1000-1200 hours since overhaul. The cause is carbon deposits in the valve guides, which make the valves stick when the engine is cold. After warming up, the guides expand from the heat, and the valves do not stick any more. The solution is reaming the guides, which can be done with the cylinders in place (for airplane engines).

Is this something that can happen to our type IV's? Could this explain the problems I am having? What is the cure, short of taking the engine out and sending the heads to a shop?

Thanks all.
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andreic   Can our engines develop morning sickness?   Oct 16 2018, 09:42 AM
JawjaPorsche   Temperature head sensor?   Oct 16 2018, 10:03 AM
Mark Henry   Likely an ignition and/or moisture issue.   Oct 16 2018, 10:13 AM
TheCabinetmaker   Did i miss the induction type?   Oct 16 2018, 01:02 PM
TheCabinetmaker   Hydraulic lifters?   Oct 16 2018, 01:03 PM
Rand   Carbs. Flame me if you want, but that is carb beha...   Oct 16 2018, 01:24 PM
injunmort   theres the answer.   Oct 16 2018, 01:25 PM
andreic   It is a D-Jet system. I have checked several times...   Oct 16 2018, 01:28 PM
914_teener   It is a D-Jet system. I have checked several time...   Oct 16 2018, 03:02 PM
mepstein   It is a D-Jet system. I have checked several tim...   Oct 16 2018, 03:13 PM
Rand   This is getting interesting. Not typical with FI. ...   Oct 16 2018, 01:43 PM
thelogo   :hissyfit: My guess as my car used to do the sam...   Oct 16 2018, 01:44 PM
914_teener   :hissyfit: My guess as my car used to do the sa...   Oct 16 2018, 03:11 PM
Rand   Exhaust leak in my experience is a little popping,...   Oct 16 2018, 01:46 PM
andreic   All vacuum lines were recently replaced, so I doub...   Oct 16 2018, 04:45 PM
Rand   Please don't fall for that. Carbs have as ma...   Oct 16 2018, 01:53 PM
Chi-town   Sounds like you have a vacuum leak. A very small o...   Oct 16 2018, 02:18 PM
76-914   delete, wrong thread   Oct 16 2018, 03:53 PM
Mark Henry   T4 valves don't stick, unless you're runni...   Oct 16 2018, 06:20 PM


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