there is a HUGE difference between having the crank keyway at 12:00 to line up the timing chain marks (where you have a lot of fudge factor due to the chain only being able to go on with the marks close enough that you aren't off an entire link) and finding TDC to accurately set timing, degree a cam, or anything else where accuracy matters. To suggest otherwise is ludicrous.
Just a little side note,,,when the dots on the cam & crank sprockets are dot-to-dot,number six is at the top. on its compression stroke(ready to fire)----NOT#1. Reason I mention this is a lot of guys I knew/know line up the dots & then leave it alone.They then drop the distributor in & point the rotor at #1 & it wont start. Happy Timing!
Well you are correct, sir, which is why you mark the damper some degrees off TDC (using the piston stop) going one way, then reverse and mark it going the other way, then split the difference to mark the damper for true TDC. My point was, it doesn't matter whether you do this on the compression stroke, or on the exhaust stroke.
That key position it is about 3 teeth to the right of the dot. Almost inline with number 1 cyl at tdc. But he needs a piston stop as previously explained. Some sbc have pointer about 12:00 (van) and some close to inline with number 1. wrenchn
Jeez, I'm really happy that I know how to do this, and don't have to try to figure it out based on ALL of the postings in this thread. I use the piston stop and degree wheel method as pointed out by several of the replies, any method without a degree wheel isn't going to be as accurate.
so does your new balancer have a TDC mark on it? if so then after you find TDC you adjust your new pointer to match the balancer TDC mark.
Go ahead and find the numbers on the pointer once you bolt one on. Bolt it on anywhere on the timing cover, just as long as you can see it. I always like to put it somewhere thats easiest for me to see it, so mount it kinda high up so its closer to you. This will help you out for future timing checks. Next, stick your pinky in one of the front sparkplug holes as far in as it will go. Either side will work, but I usually pick a front one cause theyre closer. Remember, workin on cars is suppose to be fun, so make it easy on yourself when you can. Remove your pinky ring before you do that last step! (ask me how I know! LOL) Then tell your buddy to "bump" the starter using a long pipe or screwdriver. Make sure to diss-attach the coil wire before that last step. Once you start to feel somethin with your finger, pull it out. Tell your bud to bump it again right after that. Like, two more times is usually good to get it spot on, or "money". Then the last step is to see if your pointer lines up with your marks on the balancer. If they do, youre golden! Hook up that coil and fire her up!! If they dont, you got three options here. First, go ahead and mark your own line on the balancer to match the pointer. Second option would be to adjust or "modify" the pointer to line up with the marks. Re-drilling the pointer is usually a good idea to make that work for you. Or you can adjust the pointers angle by bending it. Last option, simply loosen up the rubber ring of the balancer by soaking it in gasoline or applying heat from a torch until you can move the outer balancer ring seperate from the inner one. This is the easiest way. Just slide that puppy on the crank after a good soakin or heat session and then just twist the outer balancer until it all lines up. DONE! Hope this helps. Let us know how it goes. (BTW, due to all the many ways of finding TDC discussed on this thread, this technique is a ......J-O-K-E.... just in case you were actually thinking this was a serious contribution )
correct... as the factory does it, and at that precisest time the factory sets the 6 up valves.. turns it over to 1up and sets the 1up valves while dropping in the distributor.
I've made numerous timing pointers for Chevys. I always use timing tape on my balancers, so don't need a pointer with timing marks. Once I find TDC I use piano wire to make a pointer that attaches to the closest timing cover bolt and points to the TDC mark on the balancer. I've got a big roll of piano wire, and a torch allows me to bend an eye in it, and set it. Works well, and the wire is springy, so if bumped it springs right back to it's position.
Sounds like good way to loose a fucking finger. Then tear the heads off to get the finger out . Especially like the balancer trick. This kind of shit needs a special name.
'Piston Dwell' can be increased when read at TDC by lengthening the piston stop. This fits with some of the posts here...
Agreed - hillbilly mechanical engineer - Indian name "No Pinkies" While you're there, you may as well light that gas soaked balancer, just cause.
Autozone, there are many sources Be a good idea to order a 360 timing tape Chevy Adjustable Timing Pointer 19.95 on the bay
Hummm, I guess I didnt make it clear enough that I was mocking all the different approaches to finding TDC in this thread. LOL! Read it again man!! I edited the post in case anyone else might think its real advice.
Question--- What happend to the original timing tab? Have you changed the timing since the tab disapeared? what is it timed at now total? If you have hard answers for these questions and just want to put a new pointer on then all you need is a timing light that has a dial on the back. Turn the dial to what you know the timing is and the TDC marks on the dampner will show you where to put the pointer , and by adj the dial to "0" will show up as deg* advance when the rpm gets up. Its only a number that applys to your engine and if you are happy with the way it runs this give you a baseline. Advanced or retard at that point to see if it runs better or worse and no one here can feel the difference of 1-2 deg while running on the street unless its pinging
After all the few good answers and the bs and hilarity there are a number of SBC engines that have the timing timing tab at 12 O'clock on the front cover and you have to look down behind the water pump (long) to see the timing tab. The 79 350 I just pulled out of my 71 GMC a couple of weeks is that way. If you have one of those you will have to change vibration dampers or make a new timing mark to use an adjustable tab over on the side in the traditional spot for one.
And how. Guys wants to know about locating a pointer and says he KNOWS how to find TDC, but 90% of comments are on how to find TDC.
This is real good reading entertainment. I just wanted to know, are we setting TDC on a top fuel or a formula one engine. If not, I think the Bruce Lancaster and Hotroddon technique would do just fine. Ken
TDC is an acronym for Top Dead Center. Top - should be self explanatory but refers to when the piston is at the top of the cylinder. Dead- when the piston has no movement either up or down. Center - referes to the crank degrees located within the dead spot of the piston and the exact center of the dead spot located at the top of the bore. TDC is just exactly that, nothing more nothing less and exact. Doesn't matter if its a lawn mower or top fuel engine TDC is the same meaning refering to an exact location of crank degrees and finding it is the same process for all piston powered engines. It requires a positive stop for the piston and that can be done heads on or off. The cam does not need to be installed. Can also be done with a degree wheel and a dial indicator heads off. As far as marking it, you can reference mark it any place you want, you could put the mark behind the balancer with a pointer off the oil pan if it suited your needs, mark it for passenger line of site what ever suits your needs.
The Jalopy Journal
