DKirkpatrick
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Hello — what should I expect for a good top overhaul on this Continental? THANKS (thumb in the breeze... all good...)
top overhaul cost on an O-300D
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Kenny Phillips
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Kenny Phillips
We had ours bored oversize, new pistons/rings/bearings/seals, and it was $12.5K all-in. In 1997. That would be about $20K in today's dollars.
Unless something's bad down below, you still spend most of the money above the crankcase.
Unless something's bad down below, you still spend most of the money above the crankcase.
Tom-D
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I can do a compete overhaul for that. with a good crank, and a good cam kit
Checkout_my_Six
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that's cheap Tom..... 
DKirkpatrick
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So... go w new cylinders? Or overhaul the ones on the engine now... about 2400TT... Last engine I had built my guy said he liked nickel better than chrome.
Coaching appreciated!
dan
Coaching appreciated!
dan
Grum.Man
En-Route
Cylinders $969.00 ea plus shipping
1-1500k labor
500.00 for potential miscellaneous expenses.
1-1500k labor
500.00 for potential miscellaneous expenses.
Grum.Man
En-Route
You can have them chromed and have them dye penetrate tested, seats ground, and new guides if needed for around $400.00 per cylinder at Harrison’s engines using the Nu Chrome process. I’ve had good luck with them in the past. If the plane doesn’t get flown regular Chrome night be the better option as it prevents corrosion.
MIFlyer
Pattern Altitude
Shouldn't the owner also plan for accessory rebuilds (mag/alternator/vacuum) plus hoses (probably replace them all) plus oil cooler flush/rebuild, plus OH motor mounts, plus new plugs and wire harnesses, plus carb OH?
Grum.Man
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No, none of that is required for a top overhaul.
Curious. Why are you looking to replace all your cylinders?
FYI: technically there is no such thing as a "top-end overhaul." Only a complete engine can overhauled. Cylinder work is either a replacement or repair.
MIFlyer
Pattern Altitude
My bad! I missed the "top" in the post. I thought he wanted a full OH
Checkout_my_Six
Touchdown! Greaser!
So....what is required?
Grum.Man
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There is no true “top overhaul” but the expectation from most when one says an engine has had a top overhaul is that it’s had new or rebuilt cylinder kits installed.
Tom-D
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Tom-D
And then they crack..
Tom-D
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not if they are already replaced in the resent past.
Tom-D
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no matter,, it is a repair.
weirdjim
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OF course. Anything thermally stressed will eventually crack. Why would you think that these would crack more than a new cylinder or a cylinder rebuilt in another way? Not arguing, just want to know for my knowledge base.
Jim
Tom-D
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my experience show the 0-300 will crack around the 3000 hour mark.
the new era cylinders are a little better.
exhaust valve to the spark hole is the common place.
and a few will crack around the aluminum head to steel barrel.
Checkout_my_Six
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Mags should get inspected every 500 hrs. I do that at the same time.
Grum.Man
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you are correct, not related to a top overhaul though.
Checkout_my_Six
Touchdown! Greaser!
and lots of other things could and should be done at that time....but, as you pointed out there is no "top overhaul" guidance...it's just what people think it is.
MIFlyer
Pattern Altitude
So, since we're talking top overhaul, can I clarify two points
1. We all understand that this isn't an official procedure, like an major overhaul is, this is someone deciding to replace all the cyclinders at once instead of just one or more.
2. I'm wondering, from the A&Ps here (I see at least 4 on this thread already), how much airworthiness stuff you typically run into in a top overhaul. Is it typical that you get into exhaust work as stuff cracks/etc as you're detaching it? Intake leaks caused by disconnecting the old cyclinders from the intake runners? Baffles shot that are in contact with the cylinder fins" etc. What's normal and fairly expected.
To the original poster, I do question why you're doing all the cyclinders. I know this is a religious matter, but many, including Mike Busch, advise this as a last resort. Did all 6 cyclinders really become unairworthy over the same weekend? It's your plane, but I'd be thoughtful.
Tom-D
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on the same weekend ? not usually, but this a wear process, and found at an inspection.
This is why I want my customer to use a trend. last year was 70/80 cylinder, this year it was a 65/80 cylinder.
MIFlyer
Pattern Altitude
Thanks Tom
Checkout_my_Six
Touchdown! Greaser!
To add to the above, cylinder work tends to be more specific to the engine vs general norms or expectations. Aside from work involving a single cylinder which can be repaired and reinstalled, it's been my experience when it comes to replacing multiple cylinders one should review the entire engine install to ensure there are no hidden issues prior to buying/repairing any cylinders. Have seen a few "topped" engines turn into an expensive repair. Additionally, any engine work is also dependent on the experience level of the person performing the work. I've found it's best go over all possibilities with the mx provider 1st and come up with a plan and written quote up to a certain point or benchmark. This tends to keep both parties on the same page.
Tom-D
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That is why it is best to use new cylinders.
Too many unknowns with used old parts.
what would be the warranty for a A&Ps work?
chemgeek
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Just out of curiosity, why are you replacing ALL of the cylinders? I've always replaced cylinders on condition, not at a fixed time, especially if they are not something like 1800 hours in. And if they are all that worn, I'd be looking at the bottom end, too, and at least considering the potential of a full overhaul. When I pulled the last of the 4 cylinders on my Grumman 10 years ago (it was starting to pump oil), the cam told me it was time to do the whole enchilada. The crank turned out to be worn out of tolerance, too. The only useful part left was the case. Cest la vie. When I did the OH I got a "free" high compression conversion, a nice upgrade for the cost of the STC paperwork.
Tom-D
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I have a case now that the engine was not broken in properly.. the whole cylinders do not need a to be replaced, but the oil control rings do.
the engine has high oil consumption 3 hours per qt. with 300 time since rebuild. the compression is all high 76-78/80.
the engine has high oil consumption 3 hours per qt. with 300 time since rebuild. the compression is all high 76-78/80.
Snowmass
Line Up and Wait
I have done 6 tops and sounds about right except no labor cost for me. I just go with new Superior assemblies. In spite of some scary magazine articles I have never had a problem with my tops doing them myself and I am not an A&P but I am a farm boy which might be even better. Yes, it is quite legal under an A&P. And torque wrenches can safely tighten cylinder base nuts (sorry, you know who).
As to doing other things to the engine at the same time that is a separate matter and is NOT part of a top and in my case not relevant since I am constantly maintaining my engine and accessories.
DKirkpatrick
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The answer to “why all cylinders” is just the time on the engine... think it’s something like 2400 total time w about 1250 on a major overhaul... from a long time ago. I don’t know what I’m doing- hence the post... but it seems like I may get lucky w the bottom and if so, all new cylinders all matching, etc on top, would make a good engine for this airplane.
Snowmass
Line Up and Wait
1250 since a major overhaul is quite low to put on all new cylinders. I would just fix any cylinders individually if required prior to whatever the time to major comes. What I have found on my Conti IO-520 is a leaking exhaust valve around 1700 hours. I seldom had ring leakage. I just remove that cylinder, have an aircraft machine shop fix the valve problem with a good used valve. Removing and replacing a cylinder is NOT a big job in my experience. Most of the work is removing/replacing the manifolds. I once had a GO-300 and replacing cylinders due to ring breakage was routine.
FWIW: No disrespect intended, but these are not the reasons to change all your cylinders. Quite the opposite. Unless you have verifiable discrepancies with your cylinders by your mechanic you may just open a Pandora's box that may not "make a good engine for this airplane." But it's your call.
Tom-D
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when you consider the expense of doing all 6 over doing 1 or 2 it may just make sense to do all of them, specially whey there are 60/80 or lower
parts are not cheap, a new 0-300 piston is now over $300, use guides, valves, springs, pay for honing, cleaning and you are over the $1000.
and then you risk loosing the cylinder when it cracks 200 hours later.
penny smart, pound stupid.
Tom-D
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things to worry about when working on cylinders
do the logs say they were already over sized ? .015" is the limit
who has the tools to do cylinders? the machine that does that job is $50,000. used.
cylinders must have a bushing replace in the rocker are box, price that bushing, plus the hone that sizes it.
Tommy has done a lot of cylinder, the 0-300 price is $969.00 I found I can't compete. You want a custom cylinder plan on $1200.
than they crack.
do the logs say they were already over sized ? .015" is the limit
who has the tools to do cylinders? the machine that does that job is $50,000. used.
cylinders must have a bushing replace in the rocker are box, price that bushing, plus the hone that sizes it.
Tommy has done a lot of cylinder, the 0-300 price is $969.00 I found I can't compete. You want a custom cylinder plan on $1200.
than they crack.
In some cases, yes. But the OP wants to change all the cylinders simply due to time on the engine with zero mentioned cylinder defects. Hence my last reply to him. Or is it your opinion he should change all cylinders based on time alone?
Tom-D
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Where do the you draw the line?
-- 60/80 --
Tom-D
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there was a time the military would change the whole engine at 400 hours