What Lycoming Engine Do I Have... Standard/ Wide Flange??

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HomeBuilt101

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My engine logbook and a stamp on the crankcase says the engine is a "L-10748-48" and I was told that it came out of a Super Viking so I look at the Viking POH and it says that Lycoming engine offered is a IO-540-K1A5, K1B5, K1E5 and it says "300 HP engine with max continuous HP turbocharged of 250 HP" so that sounds good but I look at the Parts Catalog specific to that engine and it does not show a turbocharger.

So how would I know what derivative engine I have (K1A5, K1B5, K1E5)?

I have reached out to Lycoming and they say that they cannot identify the engine by the "L-10748-48" because it was too old and their computer does not go back that far.

I look at a bunch of different parts catalogs and the valve covers look different however my engine looks like the engine in the third picture (lower left) in the attached PDF (looks like the K1A5).

So why the two different valve cover designs on the same IO-540?

I see that there is a "Standard Cylinder Flange Crankcase Model" and I look at the Parts Catalog and the picture shows an engine with round-ish looking valve covers with six bolts so I think this must be the cylinder heads that are associated with the "Standard Cylinder" (top left in the attached photo of the cover page of the parts catalog) but then I look at a different Lycoming Parts Catalog for a "Wide Cylinder Flange Model" and that engine has valve covers that look very similar to the "Standard"

Then I look at another catalog and I see a much different looking valve cover that is oblong shaped and has 7 bolts but the catalog still calls it a "Standard Cylinder Flange Crankcase Model"

So I figured that I would reach out to the experienced people on this forum and ask if you can PLEASE explain a little bit about the history and reasons as to why there is a major change in the design and what my engine is called...

THANKS for your advice!!!
 

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Deuelly

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There are two types of valve trains on the common Lycoming engines. Parallel valve(upper two pictures in your attachment), and angle valve(bottom two pictures). The two types of cylinder flanges are commonly referred to as narrow deck(standard) and wide deck. Looking at your serial number I'd guess you have a narrow deck(no letter after the -48). Narrow deck cylinder hold down screws would be internal wrenching(think Allen wrench). Wide deck hold down screws would be external wrenching. Types of accessories would determine the exact model you have.

Brandon
 

wsimpso1

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My source says wide deck Lycoming engines have serial numbers ending in an A, or if wide deck and with roller tappets, E. The easy distinguisher is if the cylinder flange nuts look like normal hex nets, you have a wide-flange, and if they are internally hex nuts, for Allen wrenches, you have a narrow deck.
 

HomeBuilt101

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Good information...THANKS.

OK it looks like I have a "angled valve narrow (standard) deck engine since my cylinders are held on with the internal hex head.

So what was the reason for the change? It seems that they had the original design and then went with a wide deck...because it is stronger or newer is better?

Same question about the parallel valve verses the angled valve...looking at Lycoming's website at first glance would the angle valve cylinder have bigger bore and/or valves or better intake/exhaust port design/flow?

Looking at Lycoming's website at first look it appears that the IO-360 has the parallel valve and the I)-390 has the angle valve so it looks like the angle was to accommodate the bigger bore...however...the IO-540 has the parallel valve and mine is an angle jopbber...They also have and IO-580 with the angle valve cover...with chrome valve covers so that is pretty cool...

I presume that the crankcase halves are different with the -A serial numbers having a wider hole for the cylinder to bolt on to and/or the cylinder has a larger flange so as to accept the nut and washer.

Also curious as to if the crank/rods/accessory case/ governor would be the same components...
 

wsimpso1

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You have so many questions. Dave Prizio's "Powering Your Plane" would be a good book to buy.

Angled valves can be (and are) bigger allowing better breathing and more power from same displacement and rpm.

Story is the bottom ends are the same.

O-360 is opposed 360 cubic inch, carburated, and if 100 Low Lead fueled, usually 180 hp at 2700 rpm.

Wide deck has same bores and strokes and valve gear as older narrow deck. I do not know the reason for the change. They are generally considered equals and parts are available for them.

IO-360 is fuel injected opposed 360 cubic inch, might be 180 hp and parallel valves, or it might be angled valve and 200 hp at 2700 rpm.

Take either engine with four cylinders, add two more cylinders and now you have 540's. Either type could be carburated or fuel injected, parallel valve or angle valve.

No matter type, understand that Lycoming cylinders will generally go two builds. An entire engine that has been rebuilt once and well up in hours on the second run is unlikely to give third run of 2000 hours without major work and money... and so how many builds is a big determinant of value.

Billski
 

TFF

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There was no change in design. They were concurrent. One was a light weight light duty engine and the heavy duty heavier engine. Lycoming stuff is parts bin so a manufacturer could mix and match to a certain extent; I believe the Lycoming engine types is more than 500. Lots are just data tag differences.
 

Toobuilder

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There are angle valve IO-360/540's and parallel valve IO-360/540's. Angle valves breathe better and almost always feature tuned induction, cold air sumps. (Though some Robinson helicopter models are parallel valve engines with the tuned induction).
 

HomeBuilt101

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Good information thanks...

>Dave Prizio's "Powering Your Plane"

You just added a book to my Christmas list. On one of the three days of winter we get here in Arizona I will snuggle up by the fire with a cup of coffee and read this book and thank Billski...
 

Dan Thomas

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The engine's data tag should have the model stamped right on it. Never seen one with just a part number.
 
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