Why is it important to understand top dead center vs. overlap on a 4-stroke? #DOHC #how2wrench

One of the most misunderstood areas when working on 4-stroke engines is the placement of the piston for inspection and assembly procedures. Check out this video for close-up photos and in-depth explanation of the two positions. For some reason, I find many entry level techs all too often “choose” the overlap position when setting TDC. They soon learn that this just simply requires re-work.
There’s a lot that could be wrong. It would really require a conversation and photos/videos to help you without causing you more headaches or wasted money…we do have two solutions for you.

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[SA-hkxj]

Wish I had a teacher like you in school, I would have gone into this field or at least attempted it. Keep teaching the youth of tomorrow, because many of them don’t realize that all things need “service” and my generation was taught that manual labor was not the “proper” way to go. Sorry I listened. Either way, great videos 👍

[effgee]

Good video, got to pick the correct TDC. On small engines I use my finger to feel the pressure build, on large engines where I can't reach the hole and turn the crank at the same time I use a gutted plug with a whistle fitted to it, works well to be sure you're on compression stroke. Already subscribed and hit the bell, don't want to miss any of your excellent work. Love that you stress attention to detail and professionalism. That's how I was taught 40 years ago and it makes me happy to see someone still believes in performing work with integrity and teaching the importance of same. Keep up the good work!

[mies-bvd]

Great video that explains all the missing clues about Valve Adjustment. Because of the mistake that can be made surrounding TDC and Overlap :).
Thanks for your time!

[roadrash]

your video definitely helped me i thought tdc was after the exhaust stroke still learning

[jodytucker]

I just went through this with my sons atv, it needed the valves adjusted, had 2 different people do them and both times it was ting tinging. I finally wrapped my headed around what was going on and did it myself. I’ve been a 2 stroke my whole life.

[Trumplican]

Very cool video. I remember when I was 13 setting the valves on a Honda 200x I thought I was at tdc compression but was actually at the overlap period of the cycle. Needless to say I never made that mistake again! But your right it isnt mentioned enough and too often taked for granted.

[ronanrogers]

Shane Instructor is the perfect name for a teacher

[BenStrong]

Thank you for taking the time to teach!

[mxcollin]

This video is worth it’s weight in gold!!! You’ve got an awesome channel and I’m sure you’ve helped thousands of people sharing your knowledge! I really appreciate your channel. Do you have a Patreon account?

[Ozzierob]

Very great video. As an ex mechanic here in Australia myself not once I have been taught this. Thanks mate and G’day from Australia.

[bigkahoonas]

Mate, absolutely awesome, very easy to understand with the cutaway engine. The explanation with the intake valve opening and closing with the next revolution always being at TDC in invaluable. Cheers mate, great video. 👍👍

[rosewood]

Brilliant this explains why some engines get set up 180 degrees out!

[noeperez]

For those of you that are confused when cyl 6 is in over lap meaning when exhaust valve is starting to close and intake is beginning to open cyl 1 will be at tdc

[spelunkerd]

I like your cutout model and your clear demo. On a car engine with rocker covers off it's pretty easy to identify the end of the exhaust cycle because both rocker arms are moving. That happens nowhere else in the sequence, and you don't need to be sure which rocker is exhaust and which is intake. On a typical car the cylinders are often paired, so when you identify one cylinder at the end of exhaust phase, the other of the pair will be at TDC. If there is no clear cylinder pairing, you just rotate 360 deg more to get TDC on that cylinder.

[BoujeeCowboy]

Omg this was my coupdegras of timing information. Mission set ready to execute properly. Was wondering what I was doing wrong. Thank you so much

[chrismarx]

What an education! I always assumed that both valves would be fully closed every time the piston goes to TDC.

[michor]

This was really interesting to watch. Great video!

[stanwerner]

Thank you, I appreciate your response and education...great video

[TheReverb]

Hello; would be really good to explain how to find lobe center (degreeing a camshaft) with that cutaway engine.
Nobody; and I mean nobody explained the technique right for an student or a rookie. Always says something like "put TDC; rotate engine the way it rotates; stop when the valve is open ...etc" Do not working regarding understanding
Thanks

[monkeywentbananas]

Thanks for the video ! Made finding TDC easy for Me !