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  #1  
Old 10-10-2007, 11:18 PM
bucaronco bucaronco is offline
 
Join Date: Oct 2007
Location: Florence, AL
Posts: 11
Angry O-320 exhaust port cracks

Hi guys,

I'm new to the forum and still new to RV's really. I bought an RV6 a couple of years ago, and have run into major trouble on the 2nd condition inspection.

Three of four exhaust ports have cracks, and the fourth has significant pitting, which Lycoming tells my A&P, will lead to cracks soon in that one.

Are there any thoughts as to my options here? Can the exhaust ports be welded? If so, will this entail rebuilding the cylinder (pistons/rings)?
Does anyone know of a good source for re-manufactured O-320 cylinders (Lycoming new price is $1,000 each!), or re-built?

Any experiences will be appreciated.

Thx,

Ron
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  #2  
Old 10-11-2007, 12:12 AM
asav8tor asav8tor is offline
 
Join Date: Oct 2006
Location: Seattle, wa
Posts: 679
Default

First, more information needed:

Engine history

TTSN
TTSOH
TT on cylinders
Oil sample history
Oil filter inspection history
Oil suction screen history
EGT and CHT history


Who did the last O/H and what was done and what year?

Yes the cylinders can be reworked, but when welding is required it means the cylinders are well past their prime. Without more info hard to know what to tell you. My guess is you would be best served and least long term cost with 4 new cylinders.

If the last O/H put on reworked cyinders it's possible you will be unable to determine their total time, in this case junk them.

A couple more options:

http://www.factorycylinders.com/lycoming/lycoming.htm

http://www.aeroinstock.com/products/...cat/index.html

Last edited by asav8tor : 10-11-2007 at 12:23 AM.
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  #3  
Old 10-11-2007, 12:22 AM
gmcjetpilot's Avatar
gmcjetpilot gmcjetpilot is offline
 
Join Date: Jan 2005
Posts: 4,283
Default My Opinion

Quote:
Originally Posted by bucaronco View Post
Three of four exhaust ports have cracks, and the fourth has significant pitting, which Lycoming tells my A&P, will lead to cracks soon in that one. Any experiences will be appreciated. Thx, Ron
WOW! Three cracks? Another member just posted he flew his new Lycoming engine like 3200 or 3600 hours and he just replaced it with another new engine and sold his old engine as a core. My point, he got over well 3000 hours with no cracks.

I assume your engine was not new when installed and it also suffered from what many aircraft engines do, Dis-use. Sitting for years will kill them. Flying regularly makes for long life. Cracks are either from operational abuse and misuse or just old age, fatigue. Since it was a used experimental you really don't know whats in the engine.

The right thing to do in my opinion, here it comes, sit down, have a few beers.......trash can all 4 jugs and buy 4 brand new assemblies. Don't cheap out and weld or buy used stuff. New cylinder assemblies are too cheap to pass up. With competition between three manufactures its just the way to go. Bottom line your cylinders are shot. Get NEW jugs from ECI, Superior or Lycoming. They are all good.

Do you fly infrequently (1 or 2 times a week), less than 100 hours/yr, occasionally don't fly for a week or more often? ECI is better for not flying often, Superior if you fly everyday. The ECI jugs are resistant to corrosion and the Superiors allegedly wear better. Lycoming will sell you assemblies and they are the OEM and make good stuff as well. Price wise ECI is the deal I recall. I think the whole deal, cylinder, valves, piston, rings.... are about $900. You could just replace all of the the top end: 4 x $900 = $3,600 (plus labor if you don't farm it out.)

You did not mention hours time (or calendar age) on engine? Buying your plane used, you really don't know the total hours on the cylinders or engine. The real solution may be overhaul the whole deal. Take the engine off and rebuild-it, $12,000? You can buy a brand new engine for about $19,000 from say Mattituck and sell your core for a few grand. With the bum cylinders your core is worth may be $3,000-$4,000, tops, so an all new engine will end up costing $16k or $17k.

You say George WHY rebuild the whole deal? Well you will end up with a super reliable engine, and if you ever sell your plane, an entirely new engine will really add value. You can also opt to upgrade. For example a hollow crank for constant speed prop does not cost a lot more when buying a whole new engine. You can leave it plugged for a fixed prop if you like, but you'll have the option to upgrade to C/S prop later. If your current engine is solid crank you have no choice. its fixed props only. This will add value. People who buy RV's often want the engine to have that option. Also may be that carb is getting old? Rebuilding it is about +$900. If getting a new engine you could upgrade to FI............... Just some ideas.


Sorry that's my opinion. The min is about $4,000 and 4 brand new jug assemblies. You may be able to sell the old cylinders, valves, pistons on ebay to air-boat guys for a few $100, even disclosing the cracks and pits. Cracked cylinders are trash for airplanes for sure.
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Raleigh, NC Area
RV-4, RV-7, ATP, CFII, MEI, 737/757/767

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Last edited by gmcjetpilot : 10-11-2007 at 12:48 AM.
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  #4  
Old 10-14-2007, 10:22 PM
bucaronco bucaronco is offline
 
Join Date: Oct 2007
Location: Florence, AL
Posts: 11
Default bang-for-the-buck ratio

Thanks for both replies...

I agree with the trash-um logic, and will be shopping cylinders this week, and looking forward to getting the RV airborne again with a rejuvenated motor.

Now I'll HAVE to fly more to get my bank-for-the buck ratio back within redline!

Asav8tor, thanks for the sales links...
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RV6 N314L
Florence, AL
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