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McFarlane Exhaust Valve Reamer??

Storch

Member
Our 10 has the standard IO-540 D4A5. After reading the stuck exhaust valve posts I've decided my problem is likely an exhaust valve beginning to stick.

I have the McFarlane reamers. (I have the kit for the Lycoming engines, there are other reamers, smaller size). I can't determine which one to use, either the .4995pilot-.5005cut or the .494pilot -.499 cut??

Spent several hours looking a the o/h manuals, parts manuals and called ECi and the engine overhaul facility trying to determine the proper size. They said use the one for the half inch valve. Didn't sound very exact considering the difference in sizes between the two McFarlane reamers is minimal.

Don't want to mess up the guide.

Any thoughts?
Thanks.
 
RocketBob recommended using the berry hone for that size and a friend and I use it. It worked well. I assume that the hone will remove more carbon/lead deposits than metal so it is therefore "safer".

The honing went easy, trying not to over do it. A little light oil, drill, pushed in, medium speed rapidly moving from one end to thee other. Five strokes was just about right. Wobble was measured before and after. From minimum to low acceptable wobble. The bore was cleaned with a brakleen soaked plug until clean then oil and installed the valve.
 
RocketBob recommended using the berry hone for that size and a friend and I use it. It worked well. I assume that the hone will remove more carbon/lead deposits than metal so it is therefore "safer".

The honing went easy, trying not to over do it. A little light oil, drill, pushed in, medium speed rapidly moving from one end to thee other. Five strokes was just about right. Wobble was measured before and after. From minimum to low acceptable wobble. The bore was cleaned with a brakleen soaked plug until clean then oil and installed the valve.

This is what I would do. In fact I bought one for the job, but it turned out that I had no build up on the guides at 700 hours.

Larry
 
540 Exhaust guide specifics

Thank you all for your input.

Here is what I finally found in the manual this morning, then performed the reaming. All available free online.

-Lycoming table of limits and torque value recommendations-SSP-1776-3, dated 2017, which replaces SSP-1776.
-Service Table of Limits, Direct Drive Engines-Chart-1.
"T"-applicable to models IO-540 (includes D4A5, among many others).
"T"- O.D. Exhaust Valve Stem (Parallel Valve Heads)-.4932-.4945
"T"-Finished I.D. Exhaust Valve Guide (Parallel Valve Heads)-.4985-.4995
Use the McFarlane-.4985-.4995 reamer.

Performed the job,reinstalled valve. Found minor amount of carbon, don't know if this is the problem.Will finish tomorrow hopefully.

Did not do the intake, one trouble shooting step at a time.

(FYI- Angle Valve Engines are slightly larger-I believe they will require the .4995-.5005 reamer which is included in the McFarlane kit)

Hope this helps.
 
Failed

Well that didn't work.
On the climb out it stumbled for a brief second, the GRT EFIS engine monitor was on 30 second history , #1 EGT went vertically down then recovered higher than the rest, remained higher than the rest for the remainder of the twenty minute flight. Mixture and throttle position did not seem to make any noticeable difference. No other events.

The original flight a couple days ago, when all this began, I had the same occurrence twice in fifteen minutes, at cruise.

History and trouble shooting so far:
IO-540 D4A5
851SMOH
Titan cylinders
Kelley mags- 200hrs since "500" hr inspection.
GAMIs.

Inspected each injector, all clear.
"Flowed" all injector lines, nearly exact amount of fuel coming out after 1 minute flow, about 2 oz.
Compression 72
New spark plugs, resistance checked, gapped and tested-Tempest REM38E
Wiring harness tested, all good.
Exhaust valve reamed, very minor carbon.
Borescoped valve, looked good.

Any thoughts?

Thanks.
 
Well that didn't work.
On the climb out it stumbled for a brief second, the GRT EFIS engine monitor was on 30 second history , #1 EGT went vertically down then recovered higher than the rest, remained higher than the rest for the remainder of the twenty minute flight. Mixture and throttle position did not seem to make any noticeable difference. No other events.

The original flight a couple days ago, when all this began, I had the same occurrence twice in fifteen minutes, at cruise.

History and trouble shooting so far:
IO-540 D4A5
851SMOH
Titan cylinders
Kelley mags- 200hrs since "500" hr inspection.
GAMIs.

Inspected each injector, all clear.
"Flowed" all injector lines, nearly exact amount of fuel coming out after 1 minute flow, about 2 oz.
Compression 72
New spark plugs, resistance checked, gapped and tested-Tempest REM38E
Wiring harness tested, all good.
Exhaust valve reamed, very minor carbon.
Borescoped valve, looked good.

Any thoughts?

Thanks.

Next time this happens, do in flight mag checks. High EGT will occur when firing on one plug. Dropping each mag, individually, will tell you if both plugs are firing in the problematic cylinder and confirm or exclude ignition as the issue.

Larry
 
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To add to what Larry recommends. When you do the mag check do it quickly to capture the issue. If you have a dead plug, when you do the mag check, the bad plug/cylinder will show up as a cold cylinder. EGT will go down to nothing.


I too used to see this stumble periodically. Mostly in climb, but occasionally in level flight. I replaced the fuel pump to no avail. It was a vapor lock issue for me. I had inserted an additional 90 degree fitting at the fuselage side. I replaced all the fuel line between tank and fuel selector with one continuous aluminum line with a straight fitting under the seat. Problem has disappeared. It did not exhibit this problem until I had over 500+ hours on the plane. Also, where is your fuel flow sensor? It should be between the fuel servo and the flow divider, not on the suction side in the tunnel.
 
30 second scale after engine stumble

30 second scale after engine stumble
 

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It looks like that cylinder is suffering from lack of fuel. If it were one plug the EGT would go high. I would open up the flow divider and see if you have some debris, also clean injector restrictor. That cylinder is at -62 degrees LOP. That’s way way lean. Does it always lean that far away from the others? You might also replace your intake gasket, although it seems your issue is too intermittent for that.
 
It looks like that cylinder is suffering from lack of fuel. If it were one plug the EGT would go high. I would open up the flow divider and see if you have some debris, also clean injector restrictor. That cylinder is at -62 degrees LOP. That’s way way lean. Does it always lean that far away from the others? You might also replace your intake gasket, although it seems your issue is too intermittent for that.

Bill, while I agree that #1 may be too lean, (lean stumble) however, in general, I think that the other cylinders are too warm to stay out of the "red box" at 89% power. Perhaps the "gami" spread is too great on that cylinder? Below is quoted from "Advanced Pilot":
Outside the Box

At 65% power, use richer than 100 ROP, or leaner than peak EGT.
At 70%, use richer than 125ºF ROP, or leaner than 25ºF LOP.
At 75%, use richer than 180ºF ROP, or leaner than 40ºF LOP.
At 80%, use richer than 200ºF ROP, or leaner than 60ºF LOP.

Perhaps if debris is not the issue, a swap of injectors to the hottest cylinder would help.....?
 
30 second scale after engine stumble

Looks like an intermittent misfire on the white cyl. Misfired for several cycles, then fired for several more, then misfired for several more, then back to normal. Ignition seems most likely to me, but could also be a fuel issue downstream from the spider. Less likely, but could also be one of the valves sticking open that caused the misfires.
 
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Thank you all for the input.

Disregard the 89%,inacurate.
Third set of plugs, all completely tested prior to installation.
Flow divider opened, can't really see much, diaphragm good.
All injectors examined, good.
Flow tested all lines, equal output, about 2oz. of fuel after 1 minute flow.
Electric fuel pump off when stumble occured.
Occurred one time at about 23 X 2400 on climb out, other time at very low setting, about 20 X 2200.
Actually replaced the #1 cylinder lower spark plug ignition wire, after repeated testing, seemed a little intermittent. (It actually felt smoother, thought I had it figured out, then it stumbled).
-62 is after the event.
Normally about -30 to -15 LOP on all cylinders.

If its a fuel issue downstream, why is it manifesting itself only on #1? I have a stock Vans fuel system. No changes since new , 851 hours.

I agree with lr172, sure seems ignition, but before I throw all that $$ at a new harness, would like to know for sure.

??Intake valve??
Getting back on it today.
Guess who's not at Oshkosh in their 10??
 
Have you ruled out an intake leak on that cylinder? Intake tube or clamps on rubber couplings?. Just a thought.
 
I reamed the intake valve yesterday, clean as a whistle.
Intake all good.

Flew it. It did not stumble. But, the EGT on #1 still shows regular drops. They were slight, couldn't feel it. But they are there.

More trouble shooting today. Thinking somewhere in the ignition harness, although it tested good. Maybe magneto, again only about 200 hrs since factory reman.

We'll see.
 
I really don’t think it’s a single ignition wire or plug. If one plug stopped firing, the EGT would rise, not fall. Both plugs would have to misfire to see a fall in EGT like you are seeing. Did you inspect the valve springs? Did you replace the intake gasket?
 
I had a similar problem recently. A stumble means a cylinder is outright not firing, and a single plug momentarily not firing won't do that - the other plug would soldier on, with an imperceptible short dip in power, though the EGT will show it. In my case it was magnetos, way short of the 500 hours I was expecting. On advice that there have been some supply chain issues for magneto parts that contribute to early loss of timing and spark energy, I sent them in, and sure enough, both seriously needed overhaul. With both mags under performing, the occasional misfire of both plugs simultaneously is what manifested in occasional stumbles. Mags overhauled and no more stumbles, and starts much better. In fact, if this is your problem, then one way to tell is if it is harder to start you engine than what you remember from the past.
 
Victory??

I've flown it about five hours since the last stumble. I cannot say I found anything absolute. However, the last thing I did was ream the intake valve, which produced only a very, very small amount of carbon. It slid in and out quite easily prior to reaming.
When I flew it, the EGT was acting quite similar to when it stumbled before but there was no stumble this time???
So I swapped the troubling cylinder egt with the cylinder next to it and it followed it. I dug up a serviceable egt and replaced it. Good even running egt and no stumbles since.
Also I subscribed to Savvy aviation and am gonna run there prescribed testing and send the data to them.

So we'll see.....

Thank you for the suggestions.
 
I really don’t think it’s a single ignition wire or plug. If one plug stopped firing, the EGT would rise, not fall. Both plugs would have to misfire to see a fall in EGT like you are seeing. Did you inspect the valve springs? Did you replace the intake gasket?

Yes on both valve springs and intake gasket.
Thanks.
 
I had a similar problem recently. A stumble means a cylinder is outright not firing, and a single plug momentarily not firing won't do that - the other plug would soldier on, with an imperceptible short dip in power, though the EGT will show it. In my case it was magnetos, way short of the 500 hours I was expecting. On advice that there have been some supply chain issues for magneto parts that contribute to early loss of timing and spark energy, I sent them in, and sure enough, both seriously needed overhaul. With both mags under performing, the occasional misfire of both plugs simultaneously is what manifested in occasional stumbles. Mags overhauled and no more stumbles, and starts much better. In fact, if this is your problem, then one way to tell is if it is harder to start you engine than what you remember from the past.

It always starts like a champ. We have the slick start booster. It never did manifest any morning sickness problems typical of a sticky exhaust valve.

Your comments regarding mags are spot on. I'm gonna start doing my homework on the various electronic ignition options. I have zero personal experience with them.

I spent a couple years deep, deep diving the "LOP" topic (it is the way to the operate for most conditions). Some of the larger radials had variable timing magnetos. Of course they also had a flight engineer to manage them in flight. So that got my interest up regarding the electronic ignition systems.
GPH is not my main concern, reliability is.
Thanks.
 
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