How to deflate C-85 lifters?

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8475
Posts: 76
Joined: Sun May 26, 2019 11:38 am
Name: Dave Sprinkle
Location: SF Bay
Aircraft Type: 140
Occupation-Interests: Engineer
Contact:

How to deflate C-85 lifters?

Post by 8475 »

Back-story for context: My C-85 engine continually drains oil from the carburetor inlet during operation. Blows back on the firewall and down the belly. The rumored cause of this is either: (A) worn inlet valve guides, or (B) running a rocker arm on the inlet valve that does not have the plugged oil drilling. (I'm hoping for (B).)

I purchased a set of plugged rocker arms. Sent them off to Lycon to be overhauled. Now I intend to install them in the hopes that this addresses the oil leak. Continental specs are to check valve clearance with the lifter deflated. Which is the source of my question:

How do I deflate the lifter without removing it from the engine? What's the cheat-code? Thanks in advance!
-dave sprinkle
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6643
Posts: 2564
Joined: Tue May 01, 2018 7:00 am
Name: John C
Location: KLCI, NH
Aircraft Type: 1946 C140/C90
Occupation-Interests: A&P, semi-retired
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Re: How to deflate C-85 lifters?

Post by 6643 »

Turn the engine to where the valve in question is fully open. Go have a beer. Works best with warm engine oil (and cold beer.)
8475
Posts: 76
Joined: Sun May 26, 2019 11:38 am
Name: Dave Sprinkle
Location: SF Bay
Aircraft Type: 140
Occupation-Interests: Engineer
Contact:

Re: How to deflate C-85 lifters?

Post by 8475 »

6643 wrote: Wed May 28, 2025 2:15 pm Turn the engine to where the valve in question is fully open. Go have a beer. Works best with warm engine oil (and cold beer.)
John, great advice! Thank you!
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