Heavy deposits in cylinder heads

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Patrick C

Registered User

• Mar 20, 2021

• #1

I have Found what I believe to be heavy deposits in the cylinders. O-360-C2A engine @800 hours on my 59 A model. Engine has Spaulding on the tappets and we are proceeding with over haul.



Engine seemed to be running strong up to last flight when plugs filled with crud.


Are we running to rich?, too lean?, or is this a normal condition.

 

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D

DENNY

SPONSOR

• Mar 20, 2021

• #2

What are you running for fuel? Are you leaning and how?
DENNY

 

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Patrick C

Registered User

• Mar 20, 2021

• #3

100 LL. Leaning as much as possible keeping CHT below 400. Towing banners 35mph high power settings mostly 2000 msl. I have pulled cylinders from other aircraft doing the same mission and not seen deposits like this. This engine was not run much in the 10 years prior to my purchase.

 

Idleclamp

FRIEND

Waukesha, WI

• Mar 21, 2021

• #4

The inactivity is probably the culprit of the spalling on the tappets. I also found that in my engine that was not very active previous to my purchase. FWIW, my pistons looked very similar to yours in the picture, but I’m not sure what caused that.


Sent from my iPhone using SuperCub.Org

 

Idleclamp

FRIEND

Waukesha, WI

• Mar 21, 2021

• #5

Sent from my iPhone using SuperCub.Org mobile app

 

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Idleclamp

FRIEND

Waukesha, WI

• Mar 21, 2021

• #6

Sent from my iPhone using SuperCub.Org mobile app

 

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BC12D-4-85

SPONSOR

Fairbanks, AK.

• Mar 21, 2021

• #7

Show pics of piston skirt and cylinder above and below piston ring travel. Bet there's some surface scoring of both. Can you feel it with fingernail? If so it's hard for rings to get a good seal against the cylinder. Just a guess however. I had one engine do that.

Gary

 

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Patrick C

Registered User

• Mar 21, 2021

• #8

I will post more pics tomorrow. I am in agreement that inactivity is an engine killer. We regularly get well past TBO running our engines hard and often.

 

BC12D-4-85

SPONSOR

Fairbanks, AK.

• Mar 21, 2021

• #9

The reason I mentioned scoring was my cam and lifters sloughed enough hard metal to score the pistons and cylinder wall. The oil consumption increased as did carbon on the plugs and piston surface.

Gary

 

G44

MEMBER

SW Michigan

• Mar 21, 2021

• #10

Patrick C said:

This engine was not run much in the 10 years prior to my purchase.

Click to expand...

There is a good possibility of the cause of your problem.

 

180TigerCub

SPONSOR

Penn Yan, NY

• Mar 22, 2021

• #11

Pistons and combustion chambers look normal. If they sit for a while, the carbon and combustion byproducts become crystalline and look ugly but largely do not affect operation.
The lifters are corroded. Looks like they were rotating which is good. The cam lobe is probably as bad.
Sitting too long, long oil change intervals or exposed to salt air. Hopefully not all of the above.