High oil temp
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- 6643
- Posts: 2326
- Joined: Tue May 01, 2018 7:00 am
- Location: KLCI
- Name: John C
- Aircraft Type: 1946 C140/C90
- Occupation-Interests: A&P, semi-retired
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Re: High oil temp
Actually, I would be a pessimist, but there's no point in it...
John Cooper
www.skyportservices.net
www.skyportservices.net
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- Posts: 319
- Joined: Sat Aug 29, 2020 8:41 pm
- Name: Jody
- Aircraft Type: C-140
- Occupation-Interests: A&P former IA, Retired test pilot
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Re: High oil temp
I tried counting the wraps, I believe there are a few more on the longer spring, maybe not, I didn’t think of a stretched spring, never entered my mind.
I used to build bikes at a race shop years ago, one of the hardest things was to get people to understand that the pre load adjustment on the shocks only changed ride height, it didn’t change spring rate or change the weight that the spring would bottom out at.
So if it’s a stretched spring it shouldn’t have caused pressure loss with increasing temp, it actually shouldn’t have changed spring rate at all?
I’ve only got one flight, tomorrow I’ll fly in the heat of the day again (many of us fly to lunch on Wed) So i’ll look again of course.
I guess it really doesn’t matter why so long as it works, but the drop of 10 psi pressure with 20 deg rise in temp I still can’t explain, has to be the relief valve being partially open due to a weak spring.
Now you have me wanting to measure the pressure it stacks up at, and compare it to a new spring, but the new one is in the airplane
- 6643
- Posts: 2326
- Joined: Tue May 01, 2018 7:00 am
- Location: KLCI
- Name: John C
- Aircraft Type: 1946 C140/C90
- Occupation-Interests: A&P, semi-retired
- Contact:
Re: High oil temp
I think it's the other way around. I expect the problem occurred, and someone tried to fix it by stretching the spring.
John Cooper
www.skyportservices.net
www.skyportservices.net
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- Posts: 319
- Joined: Sat Aug 29, 2020 8:41 pm
- Name: Jody
- Aircraft Type: C-140
- Occupation-Interests: A&P former IA, Retired test pilot
- Contact:
Re: High oil temp
Do these springs lose their heat treat somehow? Think about valve springs, they go through what has to be billions of cycles, get hotter etc. once in a blue moon one breaks, but it’s exceedingly uncommon. Sometimes they lose height and have to be replaced at overhaul, but this spring should leave a very easy life by comparison.
I’ve never done it, but maybe this is a wear part that should be replaced at overhaul?
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- Posts: 319
- Joined: Sat Aug 29, 2020 8:41 pm
- Name: Jody
- Aircraft Type: C-140
- Occupation-Interests: A&P former IA, Retired test pilot
- Contact:
Re: High oil temp
Todays lunch flight, OAT was 94F
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