What is Top Dead Centre or TDC. TDC Explained.

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  • เผยแพร่เมื่อ 25 พ.ย. 2024

ความคิดเห็น • 74

  •  4 ปีที่แล้ว +10

    At 06:15 i say i am turning the flywheel 180 degrees. It is wrong. I am turning it 360 degrees.
    A piston is at Top Dead Center whenever it is at its at the highest point in the cylinder. We just need TDC at the compression stroke for valve adjustment.

    • @jonanthony6078
      @jonanthony6078 4 ปีที่แล้ว +1

      Do you have to be on compression to adjust valves

    •  4 ปีที่แล้ว +2

      @@jonanthony6078 yes

  • @lthutchins9473
    @lthutchins9473 5 ปีที่แล้ว +5

    Excellent explanation. This is the 1st video I've come across for motorcycles specifically that visually showed what TDC is supposed to look like. Thanks!

  • @vtwinrtx5670
    @vtwinrtx5670 ปีที่แล้ว

    I've been riding for a few years (Honda Shadow Aero), but still fairly new to Honda engines mechanically and have wanted to do more service on my bike including the valve adjustment but never could find a decent video that explains HOW to find the TDC. This video was very simple yet precise, and explained the process and the points to pay attention to VERY WELL! Especially even though there are marks on the flywheel, it might need to be turned a couple times to be certain that the piston is at TDC which is a crucial part that is overlooked in other videos I've seen. Very helpful, very well explained, and very well done!

    •  ปีที่แล้ว +1

      happy to help. thank you

  • @jayman826
    @jayman826 6 ปีที่แล้ว +5

    I have watch over 20 videos about T.D.C and no one ever explained it like you do. I was puzzled that I know I was T.D.C and never understood why the exhaust valve were so tight after one revolution. The way you explained it makes a lot of sense. In order to get to fully .T.D.C no The valves has to be clear meaning it has to be two revolutions clearing both and on the flywheel T.D.C is between the Line and the 'T'.......Thanks this help and I will definitely do this to my bike that has been sitting for 2 weeks now

    •  5 ปีที่แล้ว +1

      Nice you hear that. I learn from others so i should give it to others also.

    • @jamieteal2107
      @jamieteal2107 3 หลายเดือนก่อน

      👍🇦🇺

  • @yahoozooltan
    @yahoozooltan 5 ปีที่แล้ว +1

    Great explanation. Thank you!
    I just wanna add something. I had to change the cam chain tensioner on a Yamaha TDM 900 2003 because the factory one is not strong enough(later appeared an improved version). For this the pistons must be on TDC at compression stroke.
    Obviously you do not want to remove the valve cover just to see when the valves are closed. There is a simple method to tell which is the TDC compression stroke and not the exhaust stroke. When the valves are opening you will feel a greater resistance as you twist the cam shaft. So immediatelly after you cross the TDC mark if you fo not feel an increased resistance than that was the compression stroke. After that you have to turn 2 more turns, but if you felt a greater resistance than it was the exhaust stroke and you have to twist 1 more turn(360 degrees). You can twist it more times to have a better feeling of it.
    I hope it helps someone!

    •  5 ปีที่แล้ว +2

      i am sure it will help at least one person which is you:) When we use our logic we usually find a way around. Feeling the resistance of the cam lobes/springs is a way to feel TDC. Why not. Will be hard if a person never did TDC related stuff but if one did TDC before then sure its possible to do it by feel. My explanation is the explanation for the ones who had no idea about TDC or for the ones who are confused.

  • @DualRiderAdv
    @DualRiderAdv 3 ปีที่แล้ว

    You truly saved me alot of frustration during my valve adjustment. Big thanks!

    •  3 ปีที่แล้ว +1

      You're welcome

  • @TheUniversalEyes
    @TheUniversalEyes 10 หลายเดือนก่อน

    Good video, many do not understand that you have two TDC, one for exhaust and one for intake (compression) when adjusting valves, you want to be on the compression TDC.

  • @neilbuffham3546
    @neilbuffham3546 3 ปีที่แล้ว

    Thanks. As a rookie I appreciate the explanation a lot.

  • @shreda125hilux7
    @shreda125hilux7 4 ปีที่แล้ว

    Very informative video explaining TDC. I was the 200th like! This is the best video explaining the concept compared to many other videos on TH-cam. Well done , you helped me with my honda Lead 100cc scooter

    •  4 ปีที่แล้ว +1

      :) I dont think it is the best :))) But thankfully it is not the worse :))))). It is nice to see that it helps people.

    • @shreda125hilux7
      @shreda125hilux7 4 ปีที่แล้ว

      @ (: well done mate , keep up the great work. All the best from Australia

  • @jps8941
    @jps8941 4 ปีที่แล้ว

    Like LT Hutchins said excellent explanation best i sean for a motorcycle too. Now i know why you check for play in the valves. My bike does not have the
    marks they say put a screwdriver or a straw down the spark plug and turn the motor until it reaches TDC i am going to try an endoscope to be precise.

    •  4 ปีที่แล้ว +1

      You can try a digital caliper but I just messed the TDC of my car while changing the timing belt. I used a screwdriver to see where the piston is at the top of its travel. Worked very well but keep in mind that when the piston reaches the top it will stay there for short while you still turn the crank. Turn the crank till screwdriver starts going down again. Stop and mark the angle of your wrench which you use to turn the crank. Turn the crank opposite direction. Stop when the screwdriver start going down again. Mark the angle of your wrench. The middle point of these two angles is the top point of your piston and crank. TDC is actually very easy once you understand the movement sequence of the valves.

    • @vishalwarale5937
      @vishalwarale5937 ปีที่แล้ว

      ​@please don't placed screwdriver it might be stuck when piston goes upward direction ..chances of scratching cylinder innerlines

  • @alisdairolavhorgen2173
    @alisdairolavhorgen2173 2 ปีที่แล้ว

    Excellent. Very helpful 😊👍

  • @VassiliySmith
    @VassiliySmith 3 ปีที่แล้ว

    Thank you Parcala. One question left. What is for that < | F > mark near < | T > on fly wheel

    •  3 ปีที่แล้ว +1

      Ignition mark for the spark plugs. Ignition Fires the spark before piston reaches top dead center so they have different timing marks

    • @VassiliySmith
      @VassiliySmith 3 ปีที่แล้ว

      @ thanks. so I should adjust valves in position < | T > ?

  • @ravenwear
    @ravenwear 2 ปีที่แล้ว

    Excellent break down. Thanks.

  • @sudhirvishwakarma5558
    @sudhirvishwakarma5558 5 ปีที่แล้ว +1

    very good explained . keep it up

  • @endurider22motovlog79
    @endurider22motovlog79 4 ปีที่แล้ว +1

    I think, the marking in the timing gear is more reliable than on the flywheel

    •  4 ปีที่แล้ว +1

      Double, triple checking is the best way in the end. Parts can be replaced with others which has non matching markings. Happened to me.

  • @PaumotoRacing
    @PaumotoRacing 5 ปีที่แล้ว +1

    VERY WELL EXPLAINED THANKS!

  • @martinlaw5644
    @martinlaw5644 3 ปีที่แล้ว

    Excellent video! Thank you

  • @wheelsonground2104
    @wheelsonground2104 3 ปีที่แล้ว

    I find it very helpful thankyou for the explaination

  • @alexstrobeck3367
    @alexstrobeck3367 6 หลายเดือนก่อน

    Hello! Thank you for this. Do I need to empty oil before opening the holes for turning and checking the T?
    Thanks!!

    •  6 หลายเดือนก่อน

      It depends on the motor design. The engine in the video did not need. Your engine may need.

    • @alexstrobeck3367
      @alexstrobeck3367 6 หลายเดือนก่อน

      Alright, will have to check, thank you!

  • @wodeyaeric5351
    @wodeyaeric5351 5 ปีที่แล้ว

    U seem to have clarified my doubts. In either cases of crankshaft alignment,what determines compression or exhaust stroke is about what valves r doing? What happens when the crankshaft is aligned to the timing mark but the intake valve is fully open? Can the engine rotate in that case when u install a timing belt or chain.

    •  5 ปีที่แล้ว

      Pistons and crankshaft has no timing or lets say they dont have 4 strokes. They are either up or down. So yes valves/camshafts bring the timing problem. When you install a timing belt you can mess up this whole timing. It is not hard to correct it but if you are doing it the first time it is very confusing.
      So if you try to bring the engine to top dead center and the intake valve is open then it means your timing is off. Get yourself a repair manual if you can and correct it.

    • @wodeyaeric5351
      @wodeyaeric5351 5 ปีที่แล้ว

      @ u guys r so kind and generous with info. So,it is the valves that determine what tdc the piston is at? Tnx so much.

  • @alexanderhadjikrastev4023
    @alexanderhadjikrastev4023 3 ปีที่แล้ว

    thank you a lot it was very helpful

  • @communicate17
    @communicate17 ปีที่แล้ว

    Hello
    What happened if the chain jumped and no way to tell if youre on the compression stroke

    •  ปีที่แล้ว

      Then you disconnect timing chain from the valves. Find a way to check when the piston is at the highest point in the cylinder and adjust the timing while you keep the piston at the top of cylinder. When you do this you should also watch the timing marks of the engine. Complicated if you do it the first time but with patience it can be done. I did it once. It was confusing but not impossible.

  • @vaman86
    @vaman86 5 ปีที่แล้ว +1

    Rotate 360? For erroneous TDC? =TDC exhaust?

    •  5 ปีที่แล้ว

      sorry i am not sure if i understand what you mean. If the T mark is lined up but the valves are in exhaust stroke, you should rotate 360 degrees. I say 180 in the video but it is wrong

  • @vishalwarale5937
    @vishalwarale5937 ปีที่แล้ว

    explained very well but I have query .if I rotated magnet clockwise at some point to align t mark is there any problems.

    •  ปีที่แล้ว

      I am sorry but i dont really understand the question. If you mean the magnetic pick up for the spark plug ignition then moving things will make a difference.

    • @vishalwarale5937
      @vishalwarale5937 ปีที่แล้ว

      @ thanks for reply..my que was..by mistake I have rotated flywheel clockwise instead of rotating counter clockwise..during t mark alignment..is there any problem or can this affect engine timing..

    •  ปีที่แล้ว

      @@vishalwarale5937 If you make a mistake with the engine timing valves may hit the pistons and it will be a very bad day. Check everything 5 times if you are not sure

  • @Hercules-gh9yg
    @Hercules-gh9yg ปีที่แล้ว

    It is correct if you set the timing mark then play the flywheel left and right the rocker arm should not move then you are in tdc compression stroke? Thanks!

    •  ปีที่แล้ว

      correct

  • @bskXxx
    @bskXxx 4 ปีที่แล้ว

    If we are confused we can check the intake valve opens and then rotate anti-clockwise 360° and there is t.d.c?
    Or if all the valves are tight we are sure that we are at t.d.c.?

    •  4 ปีที่แล้ว

      If you want to understand TDC you need to practice. If i tell you what you should do i will confuse you. Watch the video carefully and practice on a simple motorbike

    • @bskXxx
      @bskXxx 4 ปีที่แล้ว

      @ you were very helpfull thanx

  • @revive_moto
    @revive_moto 2 ปีที่แล้ว

    So are the valves opened or closed during compression stroke?

    •  2 ปีที่แล้ว

      Closed

  • @zanathzanath7236
    @zanathzanath7236 3 ปีที่แล้ว

    How to find tdc compression if you don't have cams and chains connected?

    •  3 ปีที่แล้ว

      You can't. You need valves, cams and chains connected to bring the engine TDC at compression.

  • @ouzytheoriginal
    @ouzytheoriginal 4 ปีที่แล้ว

    tebrik ederim gurur duydum, türk olarak İngilizce içerik üretmeniz

  • @morris9839
    @morris9839 5 ปีที่แล้ว

    i have a 140 stomp pit bike and if it ant timed up right would it course it to run bad like it ticks over fine but when you rev it it bogs and engine gets hot very quick like with in a min or two but when u put the t for time at the mark its ment to be at it hits the valve so iv had to put the timing in a spot that i think its in iv even took off the head to see if the piston is at the very top and it starts fine but dont run fine and its on the exhust stroke any help please on how to solve this

    •  5 ปีที่แล้ว +1

      If it is a second hand bike previous owner/owners probably mixed parts from various bikes etc. If it was running fine and now you have the problem then it is possible that you made a mistake with the valve timing etc. If this is the case take the bike apart and try to find a mistake/ misalignment etc. Direction of the piston if it has grooves for the valve heads etc.
      Other than if you want to find the top dead centre you need a precision tool. A digital caliper or a dial indicator will work. Digital calipers have long sticks which you use for depth measurement. Dial indicators dont need explanation they are very simple. Google them if you need to know how to use them. You also need a solid rest for this tool so your measurement will be right. If your spark plug is right above the piston than it is a good spot. If not you have to improvise. Watch the valves and put the engine in which it should be in top dead center. If you dont have a marking on your engine case mark it so you can compare it to the flywheel later. Then turn the flywheel and watch the mesaurement tool.
      It will happen like this. You will turn the crank. The piston will begin to rise. At some point piston will hit its highest point. But since the crank is reciprocating piston will stay at its highest point for a little while even though you turn the crank. Keep turning the flywheel till piston starts to go down. When it begins to go down put a mark on your flywheel. But dont put the mark in a random spot. Put the mark opposite to the marking on the engine case. Turn the flywheel back to the starting point. Turn it till the piston hit its highest point and immediately stop. Put another marking on the flywheel opposite to the marking on the engine case.
      Now you have two markings on the flywheel. There should be a small gap between them. Put a third mark in the centre of these two marks. When you match that centre mark with the marking on the engine case you have your top dead centre markings for adjustment

  • @Coast2Cairn
    @Coast2Cairn 6 ปีที่แล้ว +1

    Thank you

  • @faqeer152
    @faqeer152 4 ปีที่แล้ว

    What happens to valves when at exaust stroke tdc

    •  4 ปีที่แล้ว

      Your exhaust valve will be open. Your intake valve also may start to open. Depends on the engine design

  • @CuongHoang-qz7cz
    @CuongHoang-qz7cz 6 ปีที่แล้ว +1

    Thanks sir

  • @norbb3092
    @norbb3092 6 ปีที่แล้ว +1

    thanks

  • @04poppop
    @04poppop 3 ปีที่แล้ว

    Why my engine is even much more noisy now than was before I touch it.

    •  3 ปีที่แล้ว

      re do everything and be sure that timing marking are corrects. if you or somone installed aftermarket parts to your engine you cant adjust your timing using these markings.

    • @04poppop
      @04poppop 3 ปีที่แล้ว

      @ All parts are original, just replaced the air filter, but not sure if it's original honda sh 125i, but fits good. Can new air filter be the reason for noisy engine. I did the job several time. Tried right on mark line with groove on the frame, then a bit in front and a little over but no difference. Intake 0.004 exhaust 0.010

    •  3 ปีที่แล้ว

      @@04poppop Perhaps correct valve adjustment causes problem because something else is wrong. I dont think air filter is the problem but you can just remove the air filter and try. Try a wider valve adjustment like 0.005/0.02 and also try making a tighter adjustment. Maybe your cam lobes are worn. Who knows. Make tests to see if valve clearance is the problem.

  • @MaduraPrabath-i7d
    @MaduraPrabath-i7d 4 หลายเดือนก่อน

    Tdc time fllyweel magnet senter pickup coils im curette

    •  4 หลายเดือนก่อน

      I didn't understand what exactly you ask. What you wrote didn't make any sense.

  • @MaduraPrabath-i7d
    @MaduraPrabath-i7d 4 หลายเดือนก่อน

    Please riplay

  • @booomer300
    @booomer300 5 ปีที่แล้ว +1

    Thank you nice vidio

  • @jcjerry2010
    @jcjerry2010 3 ปีที่แล้ว

    please plan what you should say.. so annoying always repeating words unneccesarily

    •  2 ปีที่แล้ว +1

      There is someone who tries his best to help people. And then there is you who benefits free content in his own language while being literally at the other end of the world. And still complains.. I shot this video in the middle of the night while I was awake for 20 hours already. Did it just to help people who may need it. If you want proper service Jerry then pay for it alright? Then I can set up lights, capture proper video/audio and write a script.. For your viewing pleasure. This is what you get for free.