If Rebuilding an Engine - Are Porting, Polishing, and Balancing a Viable Option?
Hello All,
I am trying to get some feedback regarding Airplane Engine Rebuilds vs Car Engines. As I remember, an Eon or two ago, Porting, Polishing, Balancing, Blueprinting, and matching / aligning the ports during an Engine Rebuild were viable means of easy / free horsepower. Yet, I seldom see any reference to this regarding Airplane Engines (possible exception of balancing).
Are there any Airplane Engine "Hot Rodders"? or is the FAA death on such "tinkering" or shade-tree mechanics? Are there any easy ways to do this short of a rebuild?
What are the best and cheapest ways to additional / or at least freeing the horses to a 180 and above engine? I know the Power Flow assists on the smaller and earlier engines.
Does Shaving the Heads enter into it anymore? No, I am not talking about an automotive Moil.
Re: If Rebuilding an Engine - Are Porting, Polishing, and Balancing a Viable Option?
I have heard about a few rebuilders doing this sort of work, but can't say exactly what they do. One company in CA that specializes in this is Lycon.
[www.lycon.com]
Re: If Rebuilding an Engine - Are Porting, Polishing, and Balancing a Viable Option?
Martin,
I don't think the porting and polishing is common on aircraft engines. It might be done but not recorded. The re-porting and polishing would change the original certified configuration and would require an STC.
I know that there would be improvements to Lycoming performance....also have had discussions with a Lycoming engineer reguarding allowable material to remove from intake & exhaust ports.....there isn't extra to remove. In this case, on the intake, probably would want to add material to provide a better bend radius for the flow to turn prior to entering the valves.
There are tons of improvements ideas in this area.....unfortunately I don't think any of them are permissable with the certified versions.
If you are able to go uncertified, you may want to check Superier.
Re: If Rebuilding an Engine - Are Porting, Polishing, and Balancing a Viable Option?
Why would porting and polishing be considered the same as "reconfiguring"?
One would only "de-burr" and smooth the ports or "allign" the heads with the exhaust.
Wouldn't this assist in flow ie remove constriction and obstructions?
Again, there maybe a reason to have a rough intake or exhaust.. but if that were the case, why wouldn't race car mechanics spend so much time and effort "cleaning this area" for flow and effeciency?
Adding material? I guess that would depend on the head, but THAT probably would be an obvious issue.
Re: If Rebuilding an Engine - Are Porting, Polishing, and Balancing a Viable Option?
We "Clean" up your cylinders via removing casting flaws and radising the bends. We do not remove material as you may be familiar with in the auto industry as the material is needed for cooling. We flow your cylinders and match flow to the best and provide a computer print out showing flow at various valve lifts. Performance varies but normally see a 10-15% increase in flow and more even fuel flow numbers all for the modest price of $175.00 per cylinder.
Might add that we have over 30 years experience in the high performance engine business building championship sprint car and drag motors and have been match flowing aircraft cylinders for the past three.
Re: If Rebuilding an Engine - Are Porting, Polishing, and Balancing a Viable Option?
I have been fully porting air craft cylinders for over a decade. The people I do work for would never tell anyone that they did it due to liability and ignorance. I must state categorically that this type of modification should NEVER be done by the inexperienced, the week end warrior or anyone not well versed in induction system design and tuning. The structural integrity of the cylinder is of paramount importance and should NEVER be sacrificed in any way for the sake of increased air flow. Simply hogging out an intake or exhaust port is a recipe for disaster!
Mr. Fehrman is a professional engine builder and knows what he is doing. I too am a professional in the field of cylinder head and induction system design so please, take it from two people who know, if in doubt don't attempt this. Refer the work to a professional.
Now, with that being said and all the horror out of the way let's discuss the enormous amount of power and fuel efficiency to be had from such modifications. My fathers Bonanza has an IO470 with fully ported cylinders and a mild increase in camshaft It cruises at 215mph and burns less fuel than when it was in stock trim. Oh, yea, it also spins a three blade prop. Its one fast climbing bad ass little aircraft all because the induction system efficiency has been increased.
Referring your cylinders to a professional with the ability to increase there air flow efficiency will pay HUGE[i][/i] dividends.
Re: If Rebuilding an Engine - Are Porting, Polishing, and Balancing a Viable Option?
Darin, Your comments are impressive about huge dividends after a rework...what HP increase would you expect to receive from a 161 HP 0-320-D3G Lycoming?
I may be interested in your services. Also do you need the entire engine assembly or this this cylinder work and/or camshaft modification?
Re: If Rebuilding an Engine - Are Porting, Polishing, and Balancing a Viable Option?
Keep in mind though, that cruise speed only increases with the cube root of the horsepower ratio -- it takes a LOT more horsepower to go significantly faster. On the other hand, rate of climb increases directly with the excess horsepower -- a little improvement goes a long way.
JimC
Re: If Rebuilding an Engine - Are Porting, Polishing, and Balancing a Viable Option?
There is a good article about this very subject in this month's Aviation Consumer. They pointed out that corrosion and lack of use are the primary killers of aircraft engines these days, and that custom performance work such as this didn't really change that. Although they accepted the premise that this type of work can result in an increase in power, they called into question the cost/benefit equation, suggesting that you might be better off spending the extra money elsewhere. It's an interesting read.
