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TSIO-360 Cam and lifter question


HawkGT

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Yesterday I was watching a Mike Bush video on cam and lifter corrosion.  Most of the video was focused on Contenintal engines discussing how Lycoming lifters have a larger tip which requires splitting the case to replace them where Contenintal engine lifter look more like traditional automotive lifters and can be easily replaced.  He also talked about how Continental permacast cases had a oil galley plug that can be removed to view a few lifters/cam by boroscope, however sandcast cases dont have this feature.

Are the TSIO-360 engines used in M20K Mooney's sand cast or permamold?  Better stated, do these engines offer the oil galley inspection point?

I was talking to an IA yesterday about whether it would be a good idea to replace the lifters on a engine that has sat for an extended duration since it is easy to do on Continentals, based on the above video. He corrected me by saying the lifter can be easily replaced but not the follower which is the point of interference between the cam and lifter.  Im used to the lifter riding against the cam lobe and the pictures I have seen seem to show the same.  Is replacimg lifters an option on a M20K TSIO-360 with potential corrosion issues?  Searched both questions but couldnt find the answer.  Thanks!

 

Jason

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1 hour ago, HawkGT said:

lifter can be easily replaced but not the follower which is the point of interference between the cam and lifter

@philiplane OP (or his mechanic) asserts that replacing lifter does not change mechanical interface with the cam.  How does the thread you provided answer that?  Full disclosure:  I only read about half of the thread you provided.

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Correct. All Continentals have straight body lifters that are easily removed and replaced. All Lycomings (except for the 541 series)use a T shaped lifter that is inserted from the inside when the case is split, and cannot be removed without engine disassembly. Neither brand uses followers. Those are found in some overhead cam car engines.

Edited by philiplane
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2 hours ago, philiplane said:

Correct. All Continentals have straight body lifters that are easily removed and replaced. All Lycomings (except for the 541 series)use a T shaped lifter that is inserted from the inside when the case is split, and cannot be removed without engine disassembly. Neither brand uses followers. Those are found in some overhead cam car engines.

Except for the famed 76 series engines in the 172 and Piper Seminole.

Clarence

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For consistency….

There are two surfaces related to the cam that get damaged either due to corrosion… or, Lack of lubrication…

1) The cam lobe surface….

2) The surface that is riding on the cam lobe, essentially following the surface… is often called the follower (rightly or wrongly)…. The follower is attached by all of the parts to the lifter…

 

3) The follower loses pockets of material that looks like intergranular corrosion…. These sharp pockets don’t lubricate very well with an oil film… pictures resemble the lunar surface….

4) The pocketed surface of the follower becomes a nice cutting tool… and has a tendency to remove the surface of the lobes…

 

Earlier this year somebody posted pics of their IO550s lifters that were nicely poc marked….  There was some supply chain issues regarding replacement parts….

 

 

Something to consider… if the engine hasn’t been run in a long time… many of these surfaces get dry….

Unlubricated parts, can get really hot when started until the oil arrives…

have a plan for pre-oiling, or time to cool, or not over rev the engine, so oil has a chance to get where it needs to go…

 

PP guesses, not a mechanic…

Best regards,

-a-

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the component that transfers lift from the camshaft to the pushrod is either called a tappet, or a lifter. Flat tappets are used in adjustable valve trains. They are solid bodies with (usually, but there are exceptions like flathead Fords) no  valve lash adjustment. The valve clearance adjustment is done at the rocker arm. In aircraft engines, we have hydraulic lash adjustment, which is an insert inside the tappet body. It controls the valve lash automatically and it is self-adjusting. You can actually remove the hydraulic part from the tappet body. I think the OP's mechanic was confusing the ability to remove the lifter portion (hydraulic unit) from the tappet body, without removing the entire assembly. You can remove the guts of a Lycoming lifter without removing the tappet body from the case, if you really wanted to. You might do that on the rare occasion that the lifter has collapsed and will no longer adjust the lash, so long as the tappet body is still OK where it rides on the camshaft. But on the Continental, the whole lifter comes right out once you have removed the rocker arm, push rod, and push rod shroud from the engine. Which is a good thing, since there is an epidemic of faulty lifters on later model Continental engines. They've forgotten how to harden the faces, and maybe are using poor steel which corrodes easily.

a cam follower is usually a roller device used in overhead camshaft auto engines that do not use pushrods. They usually have needle bearing equipped rollers on the cam end, and a bridge or arm that transfers the lift to the valve. Interesting fact- the roller lifters in the newer Lycoming engines are called roller lifters, or roller tappets, not cam followers, because there is still a pushrod on the other end. 

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I’ve done a couple of these  at the shop now. Really, if you’re going to own one of these things long-term or you going to look at buying one, pulling all the lifters and looking at all of them is really the smart thing to do here. Last one was a 600 hours since overhaul and 12 years ago, and eight of the 12 lifters had minor but distinct pitting and rust. luckily the cam was OK. 

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@jetdriven That was the point I was trying to verify with the IA when he started talking about not being able to remove the followers.  Clearly we were not communicating well.  I know replacing the lifters doesnt address corrosion on the cam lobes but it would give a great view of the cam without pulling cylinders and give you a clean surface on the lifters.

Thanks for everyones feedback.

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On 3/4/2022 at 9:17 AM, HawkGT said:

Yesterday I was watching a Mike Bush video on cam and lifter corrosion.  Most of the video was focused on Contenintal engines discussing how Lycoming lifters have a larger tip which requires splitting the case to replace them where Contenintal engine lifter look more like traditional automotive lifters and can be easily replaced.  He also talked about how Continental permacast cases had a oil galley plug that can be removed to view a few lifters/cam by boroscope, however sandcast cases dont have this feature.

Are the TSIO-360 engines used in M20K Mooney's sand cast or permamold?  Better stated, do these engines offer the oil galley inspection point?

I was talking to an IA yesterday about whether it would be a good idea to replace the lifters on a engine that has sat for an extended duration since it is easy to do on Continentals, based on the above video. He corrected me by saying the lifter can be easily replaced but not the follower which is the point of interference between the cam and lifter.  Im used to the lifter riding against the cam lobe and the pictures I have seen seem to show the same.  Is replacimg lifters an option on a M20K TSIO-360 with potential corrosion issues?  Searched both questions but couldnt find the answer.  Thanks!

 

Jason

Regardless of what people call them, they can be removed fairly easily on most Continental engines I’m familiar with.  I don’t know of an easier way to inspect the lifter faces as well as the camshaft lobes.  As mentioned there are only a few Lycoming models with the same style of removable lifter, most are a “T” shape and can not be removed without splitting the engine.

Clarence

457B6061-9738-4750-904C-EBCB6BBE970F.jpeg

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Keep in mind, if the lifter face has corrosion and has already started eating the cam lobe, the hardened surface of the cam has been removed and is only running on a softer “core” of the cam lobe.  I have no clue how much it affects the relative  life of the lobe, but I’m sure it’s a variance greater than zero. Just something to consider if you are assuming a fresh lifter would completely eliminate any heartache down the road. 

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