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Posted

John,

I recall having the same issue with my first E model. Look into Lycoming SI 1172C, we did some work on the oil pressure relief valve and it cured the problem.

Clarence

Clarence, what did you do to the pr valve? Mine is apparently adjusted as far as it will go and the OP dips below 60 psi (bottom of green) at climb/cruise power unless OTemp is below 200F. (AShell 100W) I was told by an engine builder that OP is very sensitive to valve lifter clearance. (If the bore is at the high end of spec and the stem dia is at the low oil pressure is lost.)  

Posted

A new ball is very cheap, I would get 2 and possibly use one to stake the seat.  I would also want to try a second gauge/sensor before digging to deep.

 

Another thought is piston oilers.  They are a spring loaded ball that would be opening and closing during the pressure swings that you are seeing. If I remember correctly they open and close in the 50psi range.  Its a part most never give a thought to, but when we overhauled my engine we found that non of them were opening and closing at their spec pressure.  

Posted

Well I checked the finger screen and the filter and both were clean no metal.  I'm going to do a test hopefully this afternoon to verify if the sender or gauge is the culprit.

 

The three things that keep coming up from different people and mechanics are

1. veritherm

2. oil pressure regulator (some say this is more a Confidential issue than Lycoming)

3. gauge and or sending unit.

Posted

My test flight yesterday yielded nothing both the mechanical and electronic gauges were rock steady no 10 to 20psi fluctuations. :(

 

I'm glad it was steady after 45 minutes of flying but I wanted to find or eliminate something and I achieved neither.

 

I have new springs and balls coming for the oil pressure regulator.

 

I will contact EI to see if they have seen or heard of this before and if it has been the sending unit.

Posted

Clarence, what did you do to the pr valve? Mine is apparently adjusted as far as it will go and the OP dips below 60 psi (bottom of green) at climb/cruise power unless OTemp is below 200F. (AShell 100W) I was told by an engine builder that OP is very sensitive to valve lifter clearance. (If the bore is at the high end of spec and the stem dia is at the low oil pressure is lost.)

Older versions of the pressure relief valve had some form of internal cage. My local engine shop modified it per an SI. There are several variations of springs available as well as internal and externally adjustment bodies. Perhaps you require a stronger spring?

Clarence

Posted

Lycoming offers several different springs for the OP adjuster. If you at max adjustment (in) and still not getting the right pressure you can swap to the next spring to get the range of adjustment back

That is just bypass pressure adjustment, is it not?  

Posted

Blackstone report showed elevated iron. With 1800 hours and just short of 20 yrs. SNEW I decided to go ahead with factory re-built. Since it is under 20 years I get it for overhaul price. Ordered today from Air Power. 6-8 weeks for delivery. Yes I fly almost weekly and have been using Camguard since it came out and Av-Blend before that. I had hoped to get a few more years out of it.

Posted

I went with the Lycoming remain. Normally its more expensive than an overhaul but often they run a deal if you can show its never had a field overhaul they'll give you the remain for the price of the overhaul. Its probably actually the same engine (yes, technically there are very slight differences in specs) but it adds an extra year to the warranty.

 

-Robert

  • 1 month later...
Posted

Re-built IO360A3B6 is on its way from Lycoming. Prop has been dropped off for overhaul. What is best option for governor?  Buy overhauled unit or send mine in for overhaul?  

Posted

I'd send the gov to whomever you trusted to do the prop. BTW: There no need to "overhaul" the prop or gov for part 91. Just have them tear them down, inspect parts. An overhaul may just cost you more. 

 

-Robert

Posted

The prop governor is different for an A3B6 than the A3B6D. Your old governor is a mcCauley C290D5-J/T17 while the A3B6 governor is a DC290D1-/T22.  Yes there are people here and on the MAPA List who say you can "just use the old governor" but this is straight from the factory, because I went through this myself. The gear ratio on the A3B6 is different, thus the governor spins at a different speed for a given crankshaft RPM.  This is why its different.  the flyweights, speeder spring, and a bunch of other internal stuff is different. The old one may fit, and it may appear to be operating just fine, but the pilot control valve nor the flyweights will be in the neutral position during normal operation. When either oil is demamded or needs to be dumped, one of those paths wont flow to spec. It is a different unit and there is NO regulatory approval to install the old governor on the new engine. Just because it bolts up doesnt make it right. 

Anyways, that said.. Part two....

Sending the governor off for an 800$ overhaul is one thing, but the 800$ overhaul is never 800$.  Why? Because governor makers periodically issue updated parts in service letters and bulletins, and since the overhaul shops are repair stations, these parts become mandatory at overhaul. So your 800$ prop governor overhaul becomes a 1400$ job, because it needed new flyweights, new springs, a new valve. The flyweights alone, are 500$.  Thats just one item.  You get the point.   And since they dont know whats inside there or what needs to be changed, by the time you get the call, its already done. Changing to a different model is even worse, more parts need to be changed, plus they charge extra for the conversion in and of itself.  So your Governor ends up being two grand before you even see it coming.

 

To avoid all this I sent mine off to Quality Aircraft Accessories in Tulsa for an "overhaul/exchange" with dissimilar core. They bent me some on the core charge but they good thing is there are no surprises.  It was 1216$ which is still  a lot, but better than 2 grand.

 

Im not trying to steer you to one shop or another, but just ask whats its gonna cost to make the old governor into the new one, or to exchange for the new one, and ask if they guarantee the price will be that, no upcharges.

 

 

 

 

Posted

I used a PCU5000 governor on my F and sold the old core.  I don't remember if they have one for the J model or not.  It's a small compact unit that works very well.

image.jpg

Posted

My original factory engine is the two mag A3B6.  Equipment list says I have C290D5/ T17 governor

And that governor is not approved to bolt onto a A3B6 engine. The pad gear ratios are different.

  • Like 1
Posted

That's how it came from the factory. The type certificate lists four different governors. I don't see that it limits any of them to either engine.

Posted (edited)

What equipment list? The engine doesnt come with a governor.

The parts catalog shows the /T22 governor with the A3B6 engine.Screen_Shot_2015-10-12_at_9.55.56_PM.thu

 

Screen Shot 2015-10-12 at 9.55.41 PM.jpg

Edited by jetdriven
Posted

The parts catalog clearly shows 24-3374 and later having the A3B6 engine and the /T22 governor. Are you sure you have the A3B6 and the /T17 governor?

 

Posted

The the governor is not off the engine yet. I'll check the model no. When it comes off & see if the factory put the wrong page in the POH.  There isn't even a box to check for the T22

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