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Firewall Forward at 1450 Hours

Ironflight

VAF Moderator / Line Boy
Mentor
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I mentioned on another thread that I am essentially doing a ?Top Overhaul? on the Valkyrie right now due to significantly increased oil consumption and dropping compression. Of course, having everything opened up and removed is a great time for an in-depth inspection, so here are a few things that I have found:

1) The baffles are quite remarkable ? no cracks at all! These were built from the ?old? non-pre-punched kit (which came with a mimeographed set of hieroglyphics for instructions) and required a lot of fabrication. My previous experience with baffles on used spam cans had me expecting cracks and wear early in their life, so I am extremely impressed with their performance. I think the key, like with all assemblies, is to keep the pre-load on parts low or zero ? if the fasteners are used to pull parts together, then the assemblies will constantly try to pull themselves apart.

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2) Those long aluminum tube spacers that you use to keep the flanges on the oil cooler apart? The ones with the long steel bolts going through them? Yeah?.aluminum and steel ? they tend to corrode together. I think I?d look for some 4130 in the same size and make them that way next time.

3) Speaking of oil coolers ? mine is dead. Or I should say, the flanges are dead ? cracked at the mounting bolts. They weren?t cracked (that I could tell) at the last annual. I talked to Pacific Coolers, and they said that the cost of repair would be the same as buying a new one (about $260) ? but they did have some used, zero-timed Niagara?s for sale for $200 outright! I have a new one on the way.

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4) The little carb heat box that attaches to the exhaust had really worn itself to death. I have a spare, but seriously ? it really doesn?t add much heat to the carb. I think if I really was depending on carb heat, I?d use a real heat muff next time.

5) Hoses, exhaust, air box ? all in great shape after 6.5 years of flight.

6) I took the opportunity to remove the primer system completely. I had disconnected it last year when I saw a crack in the connecting line from the solenoid (even with a triple coil, it had cracked). In the five years it was active, I used it exactly once ? to test it during phase one. With an accelerator pump in the carb, I find it?s just an added complication, and this was an easy time to take it out and re-do Adel clamps to be more efficient.

New cylinders should be here in a couple of days, but I have some traveling to do, so it might be a couple weeks before it?s finished up. I?m just glad that this came to a head AFTER the Rv-3 was flying?. 

Paul
 
What did compressions drop to?

The cowl hinges appear to show little to no wear in the pix, is that representative of actual wear?
 
Any chance of some pictures of the wear on your pistons and rings you described in the other post? Exhaust valves too if possible. This could be educational...
Regards,
Erich
 
What did compressions drop to?

The cowl hinges appear to show little to no wear in the pix, is that representative of actual wear?


Compressions dropped below 60/80. I am a believer in the "button it up, fly it, and try again" theory on low compressions - but you can't get stuck in an endless "DO"-loop - sooner or later, you have to admit that there's a problem. In this case, all the air was going into the crankcase, so I knew it was rings. I was just going to hone and re-ring, but after some significant study and consultation about the ECI nickel cylinders, that just didn't seem like a great option with this many hours on the jugs.

Yes, the cowl hinges are original - they can last a long time of you build them without any preload.

Any chance of some pictures of the wear on your pistons and rings you described in the other post? Exhaust valves too if possible. This could be educational...

I've tried to take some, but with the camera I have, all I get are reflections that don't really show anything. If I get anything that is educational, I certainly will share it.

Paul
 
cooler

Here is what I do with the cooler:
4130 spacers machined to a length that allows a very slight push fit between the flanges. AN 970 washers with the edges trimmed to clear the cooler and installed between the flange and spacer tube would be desirable, obviously adjust the length of the spacer to allow for the washers.
AN 970 washers at both ends of the bolts.
Use all four outer attachment holes.
If the cooler flanges are slotted, as most are, adjust the location of the cooler so all bolts are in the middle of the slotted hole.
 
Here is what I do with the cooler:
4130 spacers machined to a length that allows a very slight push fit between the flanges. AN 970 washers with the edges trimmed to clear the cooler and installed between the flange and spacer tube would be desirable, obviously adjust the length of the spacer to allow for the washers.
AN 970 washers at both ends of the bolts.
Use all four outer attachment holes.
If the cooler flanges are slotted, as most are, adjust the location of the cooler so all bolts are in the middle of the slotted hole.

That's pretty much what I had, except that I had normal sized washers. The cracks basically started right at the holes, so (like you) I am going to use larger washers, with a straight edge ground to make them fit, like you did. That should increase the bearing surface a bit. Making 4130 spacers this morning as well....
 
That's pretty much what I had, except that I had normal sized washers. The cracks basically started right at the holes, so (like you) I am going to use larger washers, with a straight edge ground to make them fit, like you did. That should increase the bearing surface a bit. Making 4130 spacers this morning as well....

I did the same. So far, so good, 460+ hours. I think the large area washers and the support on the flange are the key.
I also sandwiched one layer of baffling material between the cooler and the baffle. I was told that this isolates the cooler thermally from the baffle and can help to reduce oil temps. There is also a theory that it reduces vibration into the flanges vs them being hard fixed to the baffle.
Something else to consider and it is really easy to do. I don't know if it works but I don't see any down side either.
 
That's pretty much what I had, except that I had normal sized washers. The cracks basically started right at the holes, so (like you) I am going to use larger washers, with a straight edge ground to make them fit, like you did. That should increase the bearing surface a bit. Making 4130 spacers this morning as well....

Paul,

Consider adding a 1/8 or so stiffener inside the flanges like the Grumman design.

tiger-oil-cooler.jpg


It's probably easier than hacking washers and should be better support.
 
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Paul
I hear you talking about parts that have failed others that look like new, and yet all I can focus on are those zip ties. I can't believe that after 6.5 years your engine hasn't fallen off!:D Sorry..sometimes I can be a SD.
 
My next door neighbor has an RV6 with a 180 lyc. New engine, newly installed about 7 months ago. With less than 120 hrs, here's pics of the inside of 2 of his new ECI cyclinders where the nickel came off and trashed the engine. ECI has had them back for a while and so far he's just getting a runaround.

n3kxt0.jpg


2z7n3mf.jpg
 
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Paul,

Consider adding a 1/8 or so stiffener inside the flanges like the Grumman design.

tiger-oil-cooler.jpg


It's probably easier than hacking washers and should be better support.

I used 3/4" angle. Probably overkill but you are right, it was really easy.
 
I used 3/4" angle. Probably overkill but you are right, it was really easy.

The drawing doesn't really show it, but the stiffeners are 1/8 alum., so they do have some "meat" in them...:)

The other thing not shown is that the outer flange bolts via nutplates into a 4130 angle where the aft and side baffles are joined, so the stiffener is actually sandwiching the soft flange between two fairly robust members.
 
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Paul
I hear you talking about parts that have failed others that look like new, and yet all I can focus on are those zip ties. I can't believe that after 6.5 years your engine hasn't fallen off!:D Sorry..sometimes I can be a SD.

I know - shocking, isn't it.... ;)
 
My next door neighbor has an RV6 with a 180 lyc. New engine, newly installed about 7 months ago. With less than 120 hrs, here's pics of the inside of 2 of his new ECI cyclinders where the nickel came off and trashed the engine. ECI has had them back for a while and so far he's just getting a runaround.


Man, thats nasty looking. What symptoms did he experience when this happened? Loss of compression and burning oil I assume?
Why the heck hasnt ECI forked over some new cylinders on warranty? Not sure what the delay/debate would be about. Hope he stays on them.

erich
 
More than one way to skin a cat

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3) Speaking of oil coolers ? mine is dead. Or I should say, the flanges are dead ? cracked at the mounting bolts. They weren?t cracked (that I could tell) at the last annual. I talked to Pacific Coolers, and they said that the cost of repair would be the same as buying a new one (about $260) ? but they did have some used, zero-timed Niagara?s for sale for $200 outright! I have a new one on the way.
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Paul

Paul,
Two ideas. If you are married to the baffle mount oil cooler, forget fancy alloys, the solution is called NEVERSEIZE. I see that problem all the time in my day job. Try removing the bolts which secure a motor mount to a 10+ year old alloy engine. Same thing happens. I always coat the shank of those bolts with NeverSeize and it prevents the galvanic corrosion.

Second idea. Do away with the vibration and heat that are transferred into a baffle mounted oil cooler. Keep the cooler in the same general vicinity, but mount it [with Adel clamps] to the engine mount. See photos of Gary's setup below.

GarySOilcooleronenginemounttopview.jpg


GarySOilcooleronenginemounttopview2.jpg


GarySOilcooleronenginemountmountingcloseup.jpg


Hope these photos give you some ideas to ponder. I tried to find a thread about doing this, but could not find it. I KNOW it exists, but the search engine failed me this time. I hope these two ideas help.

Charlie
 
Man, thats nasty looking. What symptoms did he experience when this happened? Loss of compression and burning oil I assume?
Why the heck hasnt ECI forked over some new cylinders on warranty? Not sure what the delay/debate would be about. Hope he stays on them.

erich

It was burning oil and when he pulled on the prop it was obviously not doing well on compression (20 and 40 on those 2 cycls). Case is apart now. Pistons sidewalls are scuffed as is cam, crank and bearings. Looking ugly. Feel bad because he flew 400+ hours the prior 2 years on a 4 cyl Subaru with no real problems (other than dirt slow). We talked him into a "real" engine...oops.
 
Paul,

I see the reason why your compression dropped!

You have Zip-ties on your engine mount!:D

Don't you know that Zip-ties on engine mounts have caused entire wings to fall from aircraft!?

Sorry... couldn't help myself:rolleyes:

Next time I'll just go to the primer thread for my fun...

Sorry about the FWF OH,

Scott
 
Paul
I hear you talking about parts that have failed others that look like new, and yet all I can focus on are those zip ties. I can't believe that after 6.5 years your engine hasn't fallen off!:D Sorry..sometimes I can be a SD.

Ahhhhh! I wasn't the first!:(

Dang~
 
I'm a big proponent of getting the oil cooler off the baffle, but not with a round flange and a hose to the firewall. Mount the cooler to the engine mount with clamps and build a small plenum with baffle material around the edge to transition the air to the cooler. Nothing to shake, break, repair, strengthen, etc.

In fact, I've been thinking of making an installation kit to do just this for years now. Not applicable to the RV-8, but a picture is worth a thousand words.
Engine185.jpg
Engine186.jpg
Engine189.jpg


Please note that the mounting hardware is temporary. I used tubes and long bolts during the final installation to go through both flanges of the oil cooler.
 
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Oh, you mean....

Paul
I hear you talking about parts that have failed others that look like new, and yet all I can focus on are those zip ties. I can't believe that after 6.5 years your engine hasn't fallen off!:D Sorry..sometimes I can be a SD.

Like This? :D

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So does this make you feel better? A guy?s gotta? do SOMETHING while waiting on parts to arrive! ;)

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You have to remember that an Adel clamp is nothing more than a clamping band that has been padded with a rubber (or synthetic rubber) strip used to mount things to a tube. Whether the clamp is metal or a tie-wrap makes little difference, so long as there is no way that movement can cause any grit to wear at things. BTW, I inspected the whole mount, and nowhere that I had a tie-wrap did it do any more than dull the finish of the powder coat. But while everything was accessible, I used some spare baffle seal and rubber tape to make it prettier?.

Paul
 
BTW, I inspected the whole mount, and nowhere that I had a tie-wrap did it do any more than dull the finish of the powder coat. But while everything was accessible, I used some spare baffle seal and rubber tape to make it prettier….
Not too get too picky here, particularly b/c I really am a skeptic about the whole zip tie wearing through engine mounts thing... but a little protection for the braided oil line where you have it zip tied might not hurt. I used some of the left over NAPA oil breather tubing that Van's provides to protect my braided lines from zip tie abrasion, but the baffle fabric you used around the mount should work good too.
 
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Not too get too picky here, particularly b/c I really am a skeptic about the whole zip tie wearing through engine mounts thing... but a little protection for the braided oil line where you have it zip tied might not hurt. I used some of the left over NAPA oil breather tubing that Van's provides to protect my braided lines from zip tie abrasion, but the baffle fabric you used around the mount should work good too.

Yeah, you're being too picky... :D:D:D;)
 
Paul, what are zip ties? Do they use those on the shuttle, is that how you got them? I'm more concerned with the paper towel in the braided hose... ;)

Serious question now: Should I make sure I do not have or buy I should say, nickle or other plated cylinders? I am considering buying from American in Tulsa so I can build it along with the mechanic. All guidance is appreciated!! I mean I AM WORKING on the TOOLBOX right now...

http://www.vansaircraft.com/cgi-bin/catalog.cgi?&browse=misc&product=toolbox
 
Well that's a nice looking toolbox Bob - oh wait, it's the factory demonstrator, so it should be! ;)

The only thing I'll tell anyone about cylinder choices is that for everyone that has a bad experience with a certain brand/process, some other guy will have a good one. There are so many variables that go into the choices, and every manufacturer has had their own ups and downs - someone is going to catch a normally good product in a down quality cycle, just as sure as someone will catch it in an up cycle.

I don't consider 1500 hours "bad" on a set of jugs - wish I'd had better oil consumption along the way...but hey. I know a couple of guys that did!

Now go build your toolbox - you've got plenty of time to watch the swings in the engine market.
 
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Paul, between this post and one on another thread regarding you flying around LOP for all those hours!, what can you says about running LOP now that you finally got an up close look at the inside of the jugs and pistons?

I have been running LOP, but with only 110 hours and not opening up the engine to take a look I can't comment and am very curious.

Thanks!
 
6) I took the opportunity to remove the primer system completely.
Paul-Do you have any pics that show how your primer was connected to the gascolator? I saw in one of your pictures in this thread where it was but couldn't get a good look. I currently have the Van's standard instructions copper line b/w the gascolator and solenoid but don't really like it because that line is pressurized, even when the primer is not operating.
 
Paul, between this post and one on another thread regarding you flying around LOP for all those hours!, what can you says about running LOP now that you finally got an up close look at the inside of the jugs and pistons?

I have been running LOP, but with only 110 hours and not opening up the engine to take a look I can't comment and am very curious.

Thanks!

No issues that I can see related to LOP operations - but I think if there were going to be problems, I'd have seen them long before now. Valves look good (all my compression leakage were down into the crankcase), and LOP is cooler than peak, so CHT's have always been low. The things I have seen in the cylinders seem related to the debonding of the ring surface coating that has been mentioned by some already. That seems to have been an ECI problem that was known about, but I had never heard of.

Paul-Do you have any pics that show how your primer was connected to the gascolator? I saw in one of your pictures in this thread where it was but couldn't get a good look. I currently have the Van's standard instructions copper line b/w the gascolator and solenoid but don't really like it because that line is pressurized, even when the primer is not operating.

I'd have to dig into my archives for photos, but it was very standard - the solenoid was mounted on top of the gascolator, and the coiled copper tubing went from there to the engine - the coiled copper was never pressurized unless the solenoid was activated. My copper tube cracked at the solder joint where it joined the engine manifold - that was over a year ago, and I have just had it disconnected and capped.

Paul
 
the solenoid was mounted on top of the gascolator, and the coiled copper tubing went from there to the engine - the coiled copper was never pressurized unless the solenoid was activated. My copper tube cracked at the solder joint where it joined the engine manifold - that was over a year ago, and I have just had it disconnected and capped.
l
Was the solenoid attached to the gascolator only with an aluminum fitting then, or was the solenoid also secured some other way? Sorry for so many questions, just looking for other options for mine. I live where it can get cold, so I need to leave my primer system in.
 
Was the solenoid attached to the gascolator only with an aluminum fitting then, or was the solenoid also secured some other way? Sorry for so many questions, just looking for other options for mine. I live where it can get cold, so I need to leave my primer system in.

Mounted with a steel nipple on the gascolator
 
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