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blades

Posted: Sat Nov 20, 2010 8:51 am
by scrapper
I am getting 2 different answers, are new blades 18,000 or 30,000? I realize the factory is closed anyway.

What would a new engine cost?

Thx in advance for all insights

Scrap

Re: blades

Posted: Sat Nov 20, 2010 1:29 pm
by N2285U
I think they were about $8k each for outer 404 blades new. You can probably buy used 202s for less than 1/2 of that.

The engine would probably be $18k-$28k to overhaul depending on who does the overhaul, whether or not you get new cylinders, accessories rebuilt, etc.

Re: blades

Posted: Sun Nov 28, 2010 1:40 pm
by scrapper
N2285U & others- reading a mid 60s B@B operators manual, I see the recommended top TEMP forr cylindar heads is just 260 degrees.
Is it possible to most follow that recommendation?

What styles of flying cause greater temps< Overfull load? s, 2 200# passengers? Outside temps?

I see it recommends adding fuelk riskness ta highe elevations and impiues that can help engine temps.

If someone were careful, didn't play games, arley ran temps over 325 could they add 500 hrs to engine life?

TIA
Scrap

Re: blades

Posted: Sun Nov 28, 2010 1:48 pm
by bryancobb
Been a long time but I think it's in Celsius.

Re: blades

Posted: Mon Nov 29, 2010 2:11 pm
by J-nut
Scrap,

Temp is only part of the picture. Enstrom's have been running the 360 Lycomings for years at very high manifold pressure and temps and many of those reach TBO.

Ours are pretty much the same in terms of metallurgy and design except they're lower compression and have an oil cooled exhaust valve. Older ones are narrow deck and newer are the wide deck as well.

I've worked on all kinds of a/c for over 17 years and I'll tell you the best way to get beyond TBO is to fly regularly and keep your oil clean.

Sure if you can keep the CHT's down that helps but cylinders usually get changed due to loss of compression and that is typically a ring issue. It usually comes from inactivity. They sit, they corrode, lose compression, get excessive blowby, contaminate the oil, temps go up, valves get sticky, etc, ect.

My cylinder guy tells me he loves the Lean of Peak guys. They keep him in business :lol: Excessive temps will change the metal but it's typically the rings that get affected and they will soften and collapse but that is mostly related to improper mixture/leaning more so than higher power settings.

Not to say, other problems don't occur but they're not nearly as common as what I've mentioned above.

Price wise, I'll tell you what I have into my engine so far:

Cylinder overhaul with new bigger exhaust valves and new pistons and rings - $4000
NDI/dimensional inspection of internal parts, polishing crank, grinding cam and lifters - $1300
Case inspection, repair and line bore - $750
Bearing kit, gasket kit and misc hardware - anticipate around $1100
Magneto overhaul - $1100
Fuel Servo overhaul - worst case - $800
Flow divider overhaul - $200
Ignition leads - $750
Fuel pump overhaul - anticipate around $750
Mechanical fuel pump - $250
New injectors - anticipate around $320
New Skytech starter - Ebay $250
New lightweight alternator conversion - $750
Additional misc parts - $1500
Assembly - no cost as I will do it myself, otherwise will probably be around $2000-$2500

My cost: around $14,000
My cost with someone else assembling the engine $16,500 so the previous quote is not too far off. Keep in mine though that I'm not including removal and installation either.

Re: blades

Posted: Mon Nov 29, 2010 6:35 pm
by N2285U
J-Nut,

Not to be rude, but your cylinder guy does not know anything about LOP operations if he thinks it hurts the cylinders. Heat is the #1 destroyer of cylinders - period. At 450 degrees your aluminum cylinders have lost over 70% of their strength. When this happens your valves can become "loose" and stay open. This is what burns the valves - not LOP. When a cylinder is run LOP in an airplane the typical CHT will be 300F vs 400F ROP. On top of that maximum internal cylinder pressure is 1100 PSI and well before TDC when ROP and is roughly 700 PSI and at TDC when LOP. Mike Bushce got over 2200 hours on his turbo 310 with no cylinder changes (1600 TBO engine.) That is 12 cylinders run LOP in cruise for 2200 hours. At 100 F ROP your engine is being operated at the worst possible stress range.

Another killer of engines is the full throttle fuel flow being set too low. In a Big Bore Continental you want the minimum fuel flow to be at red line and if it goes past red line that is even better. If it is set too low then you are going to be buying cylinders on a yearly basis. I have been running continentals LOP for 15 years and never have experienced a cylinder failure.

Unfortunately LOP is not practical in helicopters. We are changing power too often to take advantage of the savings provided; however, I will always run my engines at least 200 F ROP if I cannot run LOP. You either want to use much more fuel than is needed or want to use the least amount of fuel to provide full combustion. Anything in the middle is bad for your engine. The red box is bad.

Re: blades

Posted: Mon Nov 29, 2010 11:02 pm
by Brad Bowles
I have been working on piston aircraft for 30 years. Both of my planes and my B2 have carb's. Most carburetor engines can not be run lop due to the enabality of keeping all of the cylinders at correct temps. Fuel injected engines can be run lop but only safely with a correct monitor such as jpi and it normally requires flowed injectors such as gami. Even with that some aircraft still cannot maintain equal temps. Due to other problems with baffle or cowl design. I can't count the number of planes I have known that have gone past tbo with out changing cylinders running rop. 3 cylinder companies and a factory rep at Oshkosh said they see more cylinders that have been damaged trying to run lop with out the proper setup. Then aircraft that run rop. The gami injector guy's that started the lop thing back up will say the same thing. Lop was done in WW2 but only for certain missions and was monitored closely. Lop is safe but only done correct. I also agree that helicopters should never be run lean of peak due to safety issues.
Brad

Re: blades

Posted: Tue Nov 30, 2010 11:15 am
by fixnfly
The outer blades on my brantly (404's) were purchased 3 years ago at a cost of 18,000. The inners & outers i believe cost 30,000. Hope this helps.