Oil Temp Issue and possible Carburetor problem

[John Griffin]

I have had on and off again oil temp issues for the last year. After changing the bypass valve on the bottom of sump it appeared to clear up for 26.4 hours. Now, the problem is back.  I sent the cooler and vernatherm out to be cleaned and repaired. They both were ok and the over heating continued. After changing  both of the oil by pass valves and putting on a clear line to visibly see oil flow thru the cooler we now suspect the carb for a couple reasons. First, the low end mixture control makes no difference and when ground running, leaning causes only a minor if any peak before the engine stumbles. Now to the question. I have a core MA-4 SPA w/part #10-3678-32. My mechanic says it is not correct for the engine, which is 10-2356-1. Can the 3678-32 be rebuilt as the 2356-1? May be an ignorant question, but inquiring minds want to know. It would be nice to send out for rebuild and have a spare.

Also any thoughts on the oil temp issue are welcome.

John

[Philipp Prinzing]

Hi John,

if you need a 102356-1 carburetor let me know. I have a spare one, which needs to be overhauled. but i can ship it from germany if you like. Just contact pe via email phil@philipp-prinzing.de

Best regards

phil

[John Griffin]

Continuing the heat issue. Put new carb on engine and it made a difference. It is running richer and you can lean to peak on the ground and in the air. Oil temp stayed below redline but was 95C on a 90F day. AI is suggesting increasing the lip on the lower cowl to create more airflow. Looking at L5 pictures on the internet, I see there are several with the increased lip. My question is, does it make the difference or is it wasted time?

Thanks for any input,

John

[Charles Rooks]

John-

Here is a data point for your consideration.

I have found that the oil temperature of L-5G / O-435-11 will be 90 – 95C depending on the OAT and my RPM. I usually cruise at 2200 (about 78% power).  When I fly in cooler OAT’s, the oil temp will be about 80-85C.  My cowling baffles are the felt strips as per the drawings.

Charles

 

 

[Charles Rooks]

I should clarify for others that I live in Texas and most of the time when I fly, the OAT is 30 – 35C . When I recently flew to Oshkosh, the OAT from Iowa northwards was about 25 – 30C and my oil temp was 80- 85C.  The O-435 really likes the cooler outside temperatures.

 

[John Griffin]

Charles, thanks for the feedback. I believe the carburetor was my main issue. It just took time to narrow the options. My L5 has spent more time in the shop than in the air recently. During the trouble shooting of the heat issue, one of the new chrome cylinders was dripping oil after a test flight and it appeared to have a crack so it was replaced with one of my spares. It ran hot on that test flight so the new carb was installed for the next flight with the new cylinder and it ran 95C. That was a major improvement. After the test flight with new carb the “slobber tube” was dripping oil more than the AI thought it should and he suggested we swap out the 60LB cylinder. That was a good move, there were grooves worn in the cylinder wall allowing blowby. Next flight to break in the second cylinder temp only went to 87C and there was no slobber on return. We are now installing the Airwolf oil filter kit and I hope to have it home this coming week if the hoses show up.  AI still wants to add a larger lip at the bottom of cowl.

John

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