How To Find TDC The 'Easy' Way -EricTheCarGuy

[@oldschoolchevy1664]

This is the same method I use just remove the guage and zip tie a balloon to the end of the hose. You'll for sure know which one is the compression as it'll blow the balloon up almost the size of a 3-4" PVC pipe with a single turn of ur ratchet. Love the videos Eric! U sir have saved the day for me on numerous occasions. After watching my first video of urs I subscribed instantly and literally have found myself on more than 1 occasion coming on here & hunting for ur videos on parts I already know about or how to remove just to see your methods and techniques on how to do it! To me that says a lot about a mechanic! I'd let u work on ANY of my vehicles with the upmost confidence! Keep up the awesome work plz!

[@robertclymer6948]

I know this video is over 7 yrs old, BUT FINALLY a super easy understanding way to find TDC. Those videos with the piston stops, balloons, screwdriver, wood dowels, plastic straws in the spark plug hole were confusing and not very accurate. Thanks Eric, glad I found this video.

[@project1511]

This was a huge help. Thank you! Grabbed a $14 fuel pressure/vacuumed gauge from Harbor freight, worked perfect and came with connections for the spark plug hole.

[@Richard5873]

Have tried this on a motorcycle ?

[@project1511]

@@Richard5873 no, but it should work the same way.

[@brianphillippe1694]

harbor freight here I come. I know where I am going today.

[@Chubbypickletickler]

This is a great way to find TDC on a particular cylinder. For those saying use your thumb or finger and wait for compression to push your digit off, that's great too. Assuming you can reach it. I have both gauges but never used them in this manner as a shade tree guy. I'm working on doing a Timesert insert for a blown sparkplug on my nephews V10 powered Excursion. Try reaching a rear spark plug hole with one arm and rotating the crank with your other. No easy task. Especially as his has 8" of lift and 35" tires. The hood is at my shoulder and I'm 6-4. Regardless this worked great as I need the piston on #9 at TDC to cut new threads and install the insert. Thanks for this. Always learning, always going farther.

[@ericthecarguy]

That's a great idea and better than the 'screwdriver' method I've shown in the past. Just make sure you clean it off before you put it back in the engine. This method is great if you're already doing a leak down test as the hose is already in the cylinder and ready for compressed air.

[@RevDogg]

This worked perfectly on a '98 Chevy 350 Vortec. Needed to replace a distributor that had broken it's plastic base and jumped timing while trying to start on a -33 degree F morning. Being out in that cold, and with 20+mph wind for this, I was really trying to find a way to save time and avoid tearing everything out to see the harmonic balancer... Thanks for the GREAT tip! PS: To all those who mention having these tools laying around or not and whatnot.. I didn't have either the vacuum gauge or the compression tester already. Spent 60 bucks for both. ( Could have gone much cheaper on the comp tester, but I'll use everything again, and it's been on my purchase list for a while.) In my situation, that $60 was well worth my time and agony saved.

[@MudRFunR]

Great tip, Eric! It's guys like you that keep guys like me informed to be able to accurately share what we learn, in our own way. Thanks for sharing!

[@kurtiscal3msetccdwell618]

I love finding TDC this way. I dont do it often but when I need to I always look for this video because I always need the quick refresher.

[@dancroteau8138]

Works great, and pretty accurate. As long as the gauge moves in one direction or the other the cylinder is on the compression stroke otherwise it cannot since one or the other valves will be open. Going back and forth slowly until you find the point were the gauge doesn't move and that's TDC. I checked this method with a piston stop and the difference was unmeasurable. Very helpful not to have to remove a valve cover to observe the rockers to confirm your on the compression stroke and find TDC.

[@APrintmaker]

Thank you for posting this video. I needed to find the beginning of the compression stroke in order to install a Time-sert spark plug thread repair. Having the gauge hanging next to me under the vehicle while I turned the crankshaft worked well.

[@tomslover7512]

Mucho thanks. Saved me sooo much work as I am working on a BBC (454) in a motorhome with poor access to everything! You are the man! ❤👍

[@1960tpk]

for the shade tree mechanic you can put a balloon on end when inflated tdc ,if you pass it deflated

[@edgrrickett140]

Wow bro that is a great tip on how to get to TDC easily! Thank you I have the 30.00 timing light from hobofright gonna get me a 14.00 vacuum pressure tester and Im set!

[@switchest26]

So let me get this right...( pencil in mouth, wondrous look) I need:- Compression gauge and hose to suit.. Manufacturer relative, hose to cylinder block adapter ( spark plug hole bit) Vacuum gauge with PSI and vacuum markings Schrader valve remover Reduced ID vacuum hose Socket and ratchet/strong arm for crank The love of Christ Is that right?

[@jimmysapien9961]

Sounds about right .

[@donkeydiehard879]

Eh most people that work on cars enough that they need to find TDC have all of these. Also, compression test kit and vacuum gauge kit will have 98% of what you need.

[@plucky2115]

yup thats the easiest way unless you want do it the hard way 😅

[@SilverBullet93GT]

last one is the most important :)

[@TriodeLuvr]

I like Dave Farden's idea (below) to just use a hose without a gauge and put the end in your mouth. In my case, I only need to get each piston to the approximate top consecutively in order to replace valve seals (small block chevy). Both rocker arms will be removed before I position each piston, so it doesn't even matter which stroke it's on. Anyway, thanks for the video, it was a big help. I've used a dial indicator in the past to confrim accuracy of TDC on no. 1, but it's a huge PITA. Your method is much easier and quicker for what I need to do.

[@ericthecarguy]

It works well for tight areas where a screwdriver won't fit like this Subaru and is accurate enough in my opinion. Also, if you're doing a leak down test you can easily hook compressed air up and do the test without removing the hose from the cylinder. For me it's a real time saver.

[@jman4169]

Eric got a 1997 honda civic lx D16Y7 motor replaced the water pumpm after following your guid to doing so and no have no compression at all

[@reynaldogonzalez8209]

Can I use the normal compression test gauge to find the TDC? Thanks

[@bradyf8351]

@@jman4169what ended up happening can I get an update

[@dextermorgan9876]

The most accurate way of finding TDC that I have found is to do as Eric has done and then to fine tune it, push on some clear tubing and allow it to droop in a "U" shape. Put a little liquid into the tube and then work the crankshaft back and forth a bit. The liquid will move in the tubing up and down on each side. The point at which it changes directions is exactly TDC.

[@jonny5ive167]

what adapter do I need to screw into the spark plug hole?

[@chuckcregger8527]

Dude, I've been around gearheads for awhile, never seen it before. Real Cool.

[@travisvossler]

Got to say for someone who has talked down on this channel this is a great video

[@hollandrepair4013]

If you do not have a vacuum gauge, you can simply use a balloon, it will inflate on compression stroke. Then use screw driver to fine tune...

[@mitsumike6g729]

Someone watched old school Funk and is trying to be a teacher now ... get the fuck out of here LMFAO

[@jimmysapien9961]

@@mitsumike6g729 haaaaaaaaaaaaaaaa

[@pauls4995]

Great and informative video. Finding TDC was easy doing your way. It took longer to purchase the stuff, than to find TDC.

[@freddievilla6471]

Tks 🙂🙂🙂🙂🙂🙂🙂. I don’t know if I’m learning disabled but had to watch a lot of videos until I finally understood with your video. Tks

[@collinsup]

Thank you so much for this! I'm doing an engine swap into my '74 BMW 2002 and nothing anybody said made sense about finding TDC compression stroke. This did! :D

[@RC-Heli835]

I have the vacum/compression gauge but am not for sure that I'm top dead center. I think I'll run a piece of solid wire down the tube and bump the motor back and forth in addition to the vacum/ compression gauge. I can see where a clear hose atteached to the test hose with liquid added would do the trick as well. Thanks Eric. I've got the stay dirty part down pat, not sure if I'm having fun yet. LOL!

[@darylhawes4236]

+ILTSYC love it another thinking man.its the best and easiest way on diesels 2 . dummy pipe on number one at fuel pump and watch for spill

[@RC-Heli835]

That's a good idea as well. The positive / negative vacum gauge worked on the cylinders that weren't affected by the blown head gasket. Liquid in a tube worked best for me. You don't happen to need a decent wrench man do you?

[@177SCmaro]

An even simpler way (fewer tools) to do this is rotate the engine the same way it normally turns with a ratchet while putting your thumb over the spark plug hole until you feel pressure (compression stroke) then stick a long zip tie down the spark plug hole (long enough that it can't fall down into the cylinder) then continue to rotate the engine while watching the zip tie as it's pushed back out the spark plug hole. When it stops you've found (or are very close to) top dead center on the compression stroke. You can even rock the engine back and forth to be sure while watching the zip tie.

[@DENicholsAutoBravado]

When you can't reach both it's a life saver.

[@177SCmaro]

DE Nichols Both what?

[@DENicholsAutoBravado]

Both the spark plug hole and turning the crank. Referring to feeling for the air movement to know it's the compression stroke.

[@DENicholsAutoBravado]

Granted if you can see your timing marks that shouldn't be necessary.

[@177SCmaro]

DE Nichols Watching the timing marks usually only tells you if your at TDC and it can be on either intake/exhaust overlap or the compression stroke (50/50 chance). Also you don't absolutely need to have access to the crank bolt and the spark plug hole. You could also do this by putting a small piece of a paper towel in the spark plug hole (so that it can't fall in) and bump the starter with the ignition key until it pops out to find the compression stroke, then stick something like a zip tie in and continue to bump it until you're close to TDC compression stroke (best to do this with all spark plugs removed so the engine doesn't kick back). Or just pull the valve/cam cover and watch the valves. I have a solid roller cam in my Camaro, I'm always looking for lazy ways to adjust valves. But the best way, for me, is to set TDC Compression number 1 and turn the crank 90 degrees fallowing the firing order (dampener with 90 degree marks is a must).

[@Leon-d8j]

My crankshaft pully is so rusted I cant find the mark... this video is a real life saver! Now I can replace my timing belt!

[@pjneslo8979]

Awesome Idea Eric, I can see some are a little confused. ut this is a great idea for me. Some engines you cannot turn the crank shaft whole holding your finger over the number one cylinder to find TDC. I think this is accurate as hell, especially if you connect the hoses with fittings instead of wedging them in one anther. I get the point and it's awesome...Thanks mane !

[@spelunkerd]

Cool Idea, Eric. I wonder how accurate it is, though for a leak down I don't suppose it has to be exact.

[@privateproperty7337]

I shall use this method. First I'll find the compression stroke with this method, and feed th rope into the spark plug well, and then see if it'll go into TDC, but maybe with the rope I won't be able to bring piston to TDC, but I'll be able to tell the piston is as far up as it'll go.

[@adificut3299]

I'm sure this method has been around a while, but I feel like I just saw magic .... This will help me replace my valve springs .... Thanks!!!

[@brianphillippe1694]

Brilliant idea Eric! great video as well. I am going to use this method on my 88 chevy Scottsdale with 5.7 litre. Similiar to your dads truck. Happy New Years! Yelm,WA

[@DJDevon3]

Awesome tip. This actually sounds just as easy as the screw driver method so it becomes whatever tool is easiest and fastest to reach in the toolbox. Very neat thank you.

[@ericthecarguy]

I don't believe that would be an issue unless there was a LOT of slack in the belt. Also, even if you employed a different method you'd still have to move the crank back and forth to find TDC. In short there's no way around it really.

[@nicholasnagy2848]

Awesome stuff EricTheCarGuy. I have to replace a camshaft synchronizer on my Ford and this will help me.

[@trailerparkcryptoking5213]

How about just using that compression gage that you removed to use a vacuum gage? It reads compression the moment the intake valve shuts and then you have to “assume” the TDC mark on the harmonic balancer hasn’t shifted and is true!

[@zachhoyt92]

Man this is absolutely favorite method I've seen! I sub'd just cause of this video, keep it up 🤘

[@neutraltenn5803]

You didn't mention that the newer compression gauges don't seem to have a removable Schrader valve. That's also what the people at Advanced Auto Parts confirmed as well.

[@daveytn]

True, but if your timing an engine from scratch say for example an engine rebuild or replacing a broken belt, TDC is when the piston reaches it's highest point regardless, because you will have the camshaft(s) in the correct position anyway.

[@ericthecarguy]

This may not be useful to you but I believe it is useful to others. It's also a much shorter video that I usually post which allows more people to invest in it. It also applies to many other vehicles besides the ones that are normally seen in my videos. This addresses many of the concerns posted about other videos that I've made. If you don't think this 'educates' the viewer then perhaps this video is not for you. Thanks for your input.

[@ericthecarguy]

How are you going to find marks for more than just #1 cylinder?

[@ericthecarguy]

Funny you should say that because the valve in my tester was broken and I replaced it with a tire valve. This means the tool shown in the video is using a tire valve. So far, no problems.

[@ericthecarguy]

Good idea, thanks for the suggestion.

[@pappysminions]

I would think, TDC would only zero out in the vacuum/pressure test if it starts at tdc. If you are adding pressure to get to TDC, it should stay at the max pressure reached until it begins back down. Then you would lose pressure as the piston is lowered. Unless u get to tdc and then reset pressure to zero. All of this is supposing you don't have a valve leak.

[@jacobmay2284]

Nice! Just did this on my 1999 Ford Ranger XLT 2.5L 4 cyl 2wd. Thank you very much

[@chukchee]

I just did this and it worked beautifully. Great video!

[@mickblock]

Looks pretty good to me. Remember that even using the screwdriver method you still have to see compression, so this method leaves both hands free from the get go. Eric doesn't show working back and forth to get TDC, but I'm sure you could see the exact peak between Psi and vacuum.

[@usahakitabengkel6118]

never thought of it.. Great way to find a TDC!. Thank you...

[@dutchrazer]

Instead of a compression gauge, you could also fit a simple whistle in the hose coming from the compression meter hose. When the whisle starts making noise, the engine is in the compression stroke, when it stops, your at TDC.

[@zazazicerv2118]

I can do all that in a faction of the time that u used by putting my f...ing finger in the spark plug hole and avoid all the hoses,connectors, readers etc... thank u for taking the time to show your job anyway.

[@deonisp]

1ForAllandAllForAll you don't put it inside, you just cover the plug hole until the air pressure in the cylinder blows it off

[@jdc729]

For spark ignition engine without using vacuum gauge, it is much easier to just remove the distributor cap, taking note of the position of cylinder 1, align the rotor to cylinder 1 and position the timing mark to "0". Your cylinder 1 is now at TDC.

[@briancantrell1050]

In that method, any timing chain errors are added to the position of the rotor. So are any errors in mounting the timing pointer. TDC usually needs to be more accurately located than your method will allow.

[@pjneslo8979]

Yes this is true, Granted that you do not have a slop in the timing chain, or the chain has not jumped. This method is basically to start from scratch to find TDC a, in case your distributor was never set property to begin with

[@DENicholsAutoBravado]

RACIN DE I'm kick myself for not checKing on this on my first car. I bet the car was under performing.

[@squagimus]

I like your videos and this is a good tip.However the part about looking for a compression leak with "shop " air will work if you regulate the air pressure down to less than about 30 psi. Higher pressure would probably force the piston down and there by open a valve.

[@CTrane82]

I’m dumb. No disrespect. I was told you should go backwards (counter clockwise) when turning the crank. Was this a dirty lie or does it depend on the type of engine?

[@Anuskasv0]

What a great idea, definately trying this.

[@Dakineiswhy]

i swear you have the best radio voice

[@Good-Enuff-Garage]

this is great if you own all these gauges and tubes and hoses, if you don't just remove a valve cover and watch the rockers go up and down on the # 1 cylinder, also the thumb method works if you have three arms, LOL I can never turn a V8 over with one arm while holding my thumb over the spark plug hole

[@dannylincoln639]

neat idea, another use for tools i had to buy to get out of a jam but seldom use. i would mention that subarus are not too pleased with being turned backwards because of their belt and pulley issues as well as their tensioners. u can cheat a little but , cant recommend it. faster method, spark plug boot thats plugged . really pops when u tap the key at TDC and soft so it jams in nice and saves the threads

[@xxentre]

I love this method and I am going to try it. My timing is off on My K5 Blazer and I the timing marks are wrong.

[@yasinozcelikusa]

Yes, have you reminded somewhere in the video that matching time marks can only work to find the TDC for cylinder one?

[@kelanel]

Thanks eric, this will definitely help as i was planning a leakdown test sometime very soon actually!

[@richm.6220]

Geez that's a lot work rigging that vacuum gauge up. I just place my thumb over the plug hole until the compression blows my thumb off while cranking the motor over. I use a push button starter switch clipped on the starter solenoid. Then, I can adjust it to TDC with a wrench on the crank as needed.

[@jimmysapien9961]

I use A Screw Driver !!

[@kevintobin5562]

I really liked the way you explain things too bad you don't have an answer for the problem I am having or that you don't want to be asked any questions according to your website

[@ericthecarguy]

I believe you could do that very thing using this method to find TDC.

[@tonyamatucci1999]

Great tip!! I might just hollow out an old spark plug, so the vacuum hose will probably fit right over the porcelain.

[@fasttimestr]

Great work, my issue now is that the balancer bolt loosens when trying to go counterclockwise

[@jimmysapien9961]

@Carlos Manzanares for a fee $$

[@sryth1]

This sounds like a good method for ensuring the valves are closed to perform a leak down test on an engine that has a timing belt that jumped a tooth, no? Not looking for TDC in that case, just the position where valves are all closed

[@soshbogdanov6426]

Hey Eric . Great tip . Thanks

[@ericthecarguy]

Yea, that's about it.

[@delubyo5770]

Sir, I'm confused about knowing when your #1 piston is on tdc, intake and power stroke have the same setting of piston, it is set at tdc and both valves are closed right? How will you know if it the #1 piston is at the tdc intake stroke? Can you do a video about it or please help me by just explaining it Sir? Thank you so much your videos are really helpful.

[@sanctealphonse4510]

You're hooking the hose up to your #1 cylinder. When pressure builds it's the compression stroke which is the TDC you're looking for - you're timing marks at this point would be aligned and your valves closed. Likewise your timing marks could also be aligned at TDC for the exhaust stroke so just aligning your timing marks does not mean you're in time if you're doing a timing belt job. You'll have to verify that it's actually on the compression stroke which this video helps you to determine. You could likewise use a balloon or a rubber glove attached to the end of the hose and when it blows up you know you're on the compression stroke.

[@sanctealphonse4510]

P.S. You have some of your strokes backwards. You're not at TDC for either the intake or power stroke - those would be BDC. The only time you're at TDC is either at the top of the compression stroke or the exhaust stroke.

[@xe2bio64]

Nice guy, to share his knowledge to all of us,,

[@daver18qc]

Yes but in this case this is a working engine with timing belt installed and you didn't specify that part in your first post, so yes you are right but in this very case you can't use that method. And thanks for staying calm and explaining your point, seems it's a lost art these days on youtube :-)

[@Standingwithfeast]

Hello Eric The Car Guy, long time no write. Great video, and I never thought of that and thanks for sharing this video. I like this better than the clothes hanger method or the paper plug methods.

[@unknownride5253]

Great insight lam going to use the Mightyvac vacumn pump that does pressure also

[@hickstylez]

Can I use my compression tester to do this? Oh.. so using the vacuum part of the gauge let's u find TDC very cool dude thx now can u reply to this comment and tell me if I can Jack up the back of my truck put it in gear spin the rear tire to find TDC?

[@juansolo1617]

Hey, that's a neat trick for V and horizontally opposed engines. Thanks :)

[@room101935]

Hi Eric, I do the same trick just with a round whistle on the tube, just as the sound stops = TDC.

[@russellquinn5187]

Thanks man. So simple, yet overlooked.

[@SamSam-us2fh]

Great 👍🏻, next how to adjust the distributor?

[@grapecrusher799]

Eric was that a fuel pressure gauge that you rigged up? That's the only ones they have in AutoZone with the vacume and pressure

[@MattHumanPizza]

In aviation, you put your thumb in the spark plug hole, crank the crankshaft and feel for when the air blows on your thumb. TDC. It will suck on opposite stroke

[@jimmysapien9961]

Exactly -genius

[@ericthecarguy]

When finances permit I'm hoping to get a TDI of some sort to replace the Subaru.

[@ericthecarguy]

You can't match timing marks on every cylinder. This does work however and you can trust it.

[@jimmysapien9961]

True Harmonic Balance could move -snd cause false reading ,

[@jiwbink]

THE EXAMPLE IN VIDEO IS 100% ACCURATE,,THE ONLY WAY IT COULD POSSIBLY BE INACCURATE, IS IF THE CYLINDER BEING INTERROGATED IS IF THE PISTON IN THAT VALVE HAD WORN OUT RINGS. OR AT LEAST THATS THE WAY IM UNDERSTANDING THIS METHOD.

[@INTERNA9]

THANX again

[@mds2465]

I'm a Subaru guy myself, but I love TDIs although VWs can be expensive to repair and usually require a lot of maintenance.

[@robertclymer6948]

Hi Eric! I bought all the necessary tools to do it your way. I am experiencing compression bleed off on the dual pressure/vacuum gauge. I have my 14mm hose end as tight as I can get it and check all connections for leaking. Coming up on compression stroke, Pressure won't hold so i can go to zero on my gauge. Any suggestions? I know I am very close but prefer to be dead on. Cheers from Motown.

[@SuperStarCustoms]

I think this is a very good idea, especially on that type of motor. However, wouldn't turning the crank backwards cause you to jump timing on some engines? Honda motors come into mind cause when you reverse the crank the tensioner is no longer in play. Otherwise, this is brilliant and a great example of thinking outside the box.

[@762PONCHO]

Thank you for being a real car guy, time to install my timing tape and advance my timing!

[@catchmp82]

Great great video. That you Eric. I plan to use this method soon!!

[@williamcrazylacyfurmage9953]

I just learned to understand the compression stroke with TDC after watching a few youtubes, I checked that, the #1 spark plug hole - blows as it's coming up on tpd, that's how it should be, right?? On my 2.0 `1972 Pinto, it only runs good if I'm at like 20 before TDC, should be 6 before TDC. I can't understand whats going on. all my timing marks line up.

[@antiekeradio]

Hi Eric, now that you are busy with the vacuum/pressure gauge it might be a good idea to show us how you can use it to identify a leaking intake valve with the engine running. Easiest way to do this is to take an engine with a valve lash set screw setup, and set one of the intake valves to have negative valve lash. Intake vacuum will fluctuate in a very peculiar manner, unique to this fault condition

[@tyleri.163]

Thanks Eric. Another quality informative video

[@garysuarez9614]

Quick and dirty, my favorite!

[@Ashroyer86]

if your valve timing is off couldn't that mean that you're not neccessarily at TDC around the point when you see vaccuum?

[@dontaylor7069]

Eric perhaps you can help me!. I have a friend who brought over a 2002 Buick Rendezvous with a 3.4 liter engine v6 of course somebody had started to put head gaskets on it and looks like put back together except for timing chain cover and timing chain and gears I am trying to line up the cam gear with the crankshaft gear there is no chain on it yet I've been told this is an interference motor and I am having a terrible time lining up the gears !!! Both gears are marked and new as with the new chain and I been told camshaft gear mark should be at 6 o'clock and crankshaft gear mark at 12 lining up exactly with each other seems to be as I'm turning over the crankshaft where they half inch ratchet and socket I'm getting resistance until I turn the camshaft gear obviously piston is hitting a valve ! I am NOT exerting much pressure as I feared valve damage !! I now understand why whoever started the job did not finish it all they needed was a head gaskets! ! This is not a overhead cam engine it has push rods and rocker arms!. If whoever had started the job had put the number 1 cylinder at top dead center compression stroke and then disassemble it could you not have then just pulled the gears and chain and put the new ones right back on ? Anyhow the vehicle was towed over to my house with a box full of hardware nuts and bolts and such not too familiar with this engine but I am confident I can get it back together if I could just figure out how to line up cam and crank shaft gears!. I would appreciate any knowledge you have to share!. Thank you kindly!.

[@eckartct]

On subaru boxer engines there is a timing mark on the left cam pulley. TDC is 90 degrees apart for each cylinder.

[@ASMEQC]

Eric, I was thinking that using a camera to see if a car is actually in your shop would be of great educational value. Could you show us that.. Please?

[@DingDangg]

Another great ETCG video!

[@ereeves116]

awesome tip. definitely a new tool to make for the tool box.

[@kabomelangson9502]

gret tips indeed had a problem timing my old 323 sedan

[@Gearheadtom]

That's a little odd then. I remember my shop class in high school, and the teacher showed up both of them side by side, and let us feel the difference in spring tension between the two, and I remember him saying don't switch the two aswell. Maybe it's only if an engine has super low compression, it won't have the pressure to open a tire valve.

[@ryansauto93]

Eric that is a great idea! Very cool, thanks for sharing.