Setting Up A Degree Wheel And Finding True Top Dead Center (TDC) 

Nice demonstration of TDC. A very critical point, especially for larger engines, is to ensure that the piston is very snug up against the piston stop. This removes any tolerance (space) in the piston pin & connecting rod that will alter your readings. I speak from experience here. It’s tempting to just “kiss” the piston stop to avoid leaving a mark in the piston. If you do this, like I did, your TDC reading will not be accurate by 1-2°. If you are concerned about putting a mark in the top of the piston, tape a flat piece of metal on top of the piston where the stop makes contact. Do not use something soft like a vacuum cap on the piston stop. Anything soft will compress and screw up your readings. Don’t slam the piston into the stop, of course, but when you make initial contact with the stop, place a little pressure on the breaker bar to ensure the piston is tight up against the stop. Do this clock and counter clockwise and you will get accurate readings like Brent did.

Wow this was the simplest video of how to find the true dead center an engine. So easy for anyone to master this explanation.

That CD idea is genius!

Excellent Video Sir, I will be using this procedure to reassure my 4 stroke 912 rotax non certified ultralight aircraft engine did not knock itself out of "Sync" by a propeller strike, as it has a press on crank journals. ty so much!! 100-100 perfect explanation,and detail. best video on Utube!!

My new favourite channel. The description is truely a tour de force. Thanks for sharing pal Tom Sydney Australia.

Easiest and best explained method I've seen yet

Of all the videos about tdc this one is the best explained with a piston stop good job

Hi Brent. Another great and informative video... I also just watched your video on calculating compression ratios... A lot of that info was above my pay grade and I will probably never do those calculations but I feel like it was good for me to know what is involved... Where did you learn so much about engines??? You are the smartest guy that I have found on RU-vid.I learn something new every time I watch one of your Videos... Thanks for sharing your knowledge...

Great video, easy to follow. Thanks for sharing.

Amazing video.. so very well explained.. bravo mate.. thank you very very much for this.👌👌👌👌

Excellent demonstration/instruction

Thank you for making this video!

best explaination ive seen, thank you

Well explained and demonstrated. Very useful thanks

very helpful, thank you!

Great explanation, thank you

Excellent explanation brother

Excellent job of explaining.

Thank u, excellent video

Well explained!

My friend asked me what is 15 ° I do not understand I'm Vietnamese but you answered my questions thanks

Well presented.

Great teaching. 👍🏾

great explaination. Thanks helpfull

Excellent video sir, fans from ph

very well done

Very neat...thank you.

Great video

this is so much helpfull thanks

brilliant videos dude! thanks heaps :-D

i saw these degree wheels in videos but did not know how they are used. thanks!. i would very much like to know how they are used for multi-cylinder engines like inline to v-types.

Brilliant movie, at last I understand.

I know how to use pressure gauges, but I don't know if PSI can convert to a compression ratio, so I ask you, please let me know thank you.

for example in open 30 degrees in close 70 degrees and 30 + 70 + 180 = 280: 2 = 140-30 = 110 so 110 it is the right time to install the camshaft. Am I wrong? Please let me know

Many thank's

excellent

Love it, when you said "Stick that on CD"

Correct, i like it

Great video. Finally helped me understand.

Great video as always even though I've watched it more than a few times. You didn't state if you need to put pressure on your piston stop tool like if it was torqued down so there's no deviation with TDC. Oh one thing what size were your spacers in know it will very with each engine.

This is a timely video for me. We have two 139QMB scooters. One was always a bit slower than the other. While installing a big bore kit on the slow one, I realized that the cam gear holes did not line up parallel with the cylinder head when the flywheel indicated TDC. I took the head off to verify that the flywheel was made properly and it did seem to accurately point to TDC. So I'm assuming the cam was installed one tooth off from the factory. 1) Could being one tooth off account for the scooter's lethargy? 2) Have you ever heard of them coming screwed up from the factory like that? Simultaneously fixing the timing and jumping up to 81.3cc should provide nearly limitless fun! Just waiting on jets in the mail. Thank you very, very much for your channel and all of its content. My GY6 experience would have been greatly diminished had this content not been here.

I love the bolt mark you now got on your piston! If that piston does break, that will be the reason!

Great video thanks for sharing.

Great video.Any chance you could show us the process of finding the LCA as I have a 4 valve head on a pitbike that needs to be set to 100 degrees.Because I don't have a cam card I got no idea how many degrees the cam is set to.Hope this makes sense

a dial indicator would be much faster to check tdc and if your timing marks are correct .

THE ONLY RELEVANT INFORMATION TO MY SEARCH ANYWHERE ON THE INTERNET! Jesus! Thanks for taking the time to create this video. I'd like to confirm where in the range of 12 degree to 15 degree my stock ignition actually is on my 08 2t zuma (I heard it can range). Do I use the center of one the stock stator bolt locations in my case as a reference point for zero and then count the amount of degree marks I find that to be away from TDC, to find BTDC?

You ask what is 15 ° I do not understand very well I'm Vietnamese butt you answer my question thank you for answering my question

If i use higher cc example honda wave dash 110cc .i use different wheel or same???? Im from philipines 😁😁

Nice vid. Im now getting hook with 2t motors and i want to understand how timing works. In this vid you talked about tdc. If i get the tdc, do i need to get ex and in timing or getting the tdc will cover both?

Great video and explanations but It would have been much better if this war demonstrated on an engine where the timing is off of indicated markings Visually TDC markings on my engine seems to be ok. But just how much degrees off is to be concerned with?

I just bought an aerox, once you go 2 stroke you can't go back to 4, just that kick in the pants when you hit powerband on a 2 , you just miss so much riding a 4 banger. just gonna put a mild taiwanese 70 kit in this one (the one in it, the PO busted one of the studs off of the cylinder, I kinda wondered why it wouldnt run properly at low revs) so I have to replace it, and buy another one to put a polini 94cc full house kit in. You can buy them cheap as chips here, especially unlicensed ones, and everything is still available for them on the web. nothing beats having that storage area under the seat for around town.

👍👍👍👍

I've found that it's both easier* and more accurate** to simply measure DURATION and divide it by 2, to get your #'s... *easier because you don't even need to find TDC, heck I made my last wheel a 'fixed' wheel so it only counts degrees it doesn't tell me "relative to TDC" but I don't need that because I simply check duration from when exhaust closes before TDC on piston's way up, to where it cracks open on the way down. **more accurate because you're measuring a distance on the wheel 2X as long, but the wheel's precision is fixed....so you're getting a sharper reading when you get duration and divide by 2, than simply measuring from TDC w/ a properly zero'd wheel! Would love your thoughts on this, I mean I *know* it works (as I, of course, do multiple checks and they are consistent as can be), and I can't "fault it", but am surprised it's not the norm simply because it forces a 2X larger measurement using the same wheel IE same margin of error on a 2X larger distance, automatically a tighter reading for true timing #'s!

You can indicate how the camshaft is calculated

could you use indicator to find tdc, and then just set degree wheel on zero ? thanks

Did the timing Mark at the flywheel match at the end ?

sir....will i get a wrong reading if the dial indiactor is not aligned with valve retainer when measuring duration??please reply

Really interesring how to used a degree wheel how about the 4 stroke cams how to get using degree wheel

👍👍👍👍👍

Thaks to u people turn into mechanics and some breakanics lol.

Q. How much depth does your piston stop, have to be the lil screw in the middle?

I have a question my friend when you have the calculated done on how much degree is going to be how I know if I have to add or minus before or after tdc

How about when checking valve clearance?

What for full dome piston?

I can ask you this. Can PSI convert the compression ratio? Please let me know thank you very much

Bro.. Cant download tht wheel degree sticker link u uploaded ...

Can someone explain how he knew exactly how much depth he needed to screw down his screw on this home made head stud bolt plate ?

Hi; why the wheel says "intake open BTDC" AFTER the TDC mark actually? I mean if you rotate the crankshaft CW; BEFORE would be at the left hand of the TDC mark viewing the wheel as you rotate it...

Dang ol' tell ya 'hwhat man!

Saly the link to the degree wheel doesn´t work anymore...

The link on the forum no longer exists it seems.

top

Couldn't you use a plunger indicator or finger indicator to find absolute true TDC?

I really wish you showed your flywheel so we could see if it was off! :)

I hope you reply and thank you

Damn so the marking on the magnet is not always right?

The cam valves set how new to fit them always confused me

What about intake center line

You sound like the guy from Ferris Buellers.

Small roundness of large roundness gives us more accuracy?

Your link doesn't work.

You can give a formula for calculating the camshaft and placing the camshaft in the calculated formula

The bigger your disk, the higher the accuracy, right?

That piston stop is a horrible idea because you would always be stopping the piston somewhere before top dead center leaving you a few degrees off when you need to be between 34-36 degrees. Just take the spark plug out and use a plastic pen. Stick the blunt end of the pen in the hole. Look to see when it is in between rising and falling. Or better yet, use a compression gauge.

I hope you will respond

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Wow, way to overcomplicate a simple process!