If you are just wanting to find TDC so you can drop the distributor in, then these other methods will work. The whistler device will only tell you that you are on the correct stoke. If you want to time in a camshaft (This is very important), check the damper, or put timing bushing on the camgear, you must use the method of rotating cw and ccw against a stop. Let me tell you why. When I was restoring the 71 Chevelle, I purchased the camshaft from Crane and had a friend of mine in the inspection department do a total check including the dowel pin to the 1st lobe location. The cam was perfect. When I timed the cam in the motor, the cam was too far advance. I used the forward/backward TDC method (I was also taught this method in my 22 year employment with Crane Cams). The cam was 9 degree advanced, this is too too much advance. I had to use a bushing in the camgear to correct. When the damper was installed and I rechecked TDC I found that the dampner was off by 6 degrees. This would have meant that when I was using a timing light, I would have always been off by 6 degree. I purchased a new dampner. Every motor had some clearance. When you use the Forward/Reverse method of TDC you take that into account. Every cam company will tell you that this is the true method of finding TDC. But again, if you just want to drop the distributor in then the other methods will work fine. This true method is usually done when the head are off. You can check TDC with the head on, using a long TDC stop in the spark plug hole. You should have all the spark plug removed to make it easier to rotate the engine MANUAL:LY.(never use the starter) The engine can be rotated in both direction by using a Flywheel rotating tool or by using a screw driver against the three bolts on the dampner that hold the pulley on (Remove the crank pulley, reinstall the three bolts, and use the long screw driver to turn the motor using the bolt to lever against) (You can not use the center bolt on the crank, when you try to go CCW you will be loosen up the bolt.) 1) quick and dirty, the other methods work fine. 2) timing in a cam,checking the dampner,looking for motor error, the Forward/Reverse method against a stop is the true method. If your installing a new camshaft always use the true method and check the cam timing against the spec card. You also need to be as close to TDC as possible because it is very important that the motor starts fast. You do not want to crank and crank on the motor when you are start up a motor with a new camshaft installed.
Keith Cooper I will be starting up my Chevelle today with the engine swap done. This motor has a stock camshaft (Boo,sad,Boo). But I will have my car back (Yea,happy,happy) ----- Original Message ----- From: "Wayne Kline" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, April 06, 2002 7:50 AM Subject: Re: [Chevelle-List] Finding #1 TDC > This is the EXACT way I find TDC when building a engine. across the cyl bore > and a stop bolt or with the heads on and just replaced the bottom end the > sparkplug stop bolt. > The wistler was another option as mentiioned. > My be I am wrong ,but I ASSUMED Tony was trying to stab a distributor ! So > again I ASSUMED all the assy stuff was on the engine already. So the > cork,finger,wistler or watching the intake rocker arm( I like ti rest my > palm on it) while viewing the dampner will give you #1 fire @TDC > disclamer if you dampner has not sliped, the cam was not put in backwards > > ----- Original Message ----- > From: <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Friday, April 05, 2002 2:55 PM > Subject: RE: [Chevelle-List] Finding #1 TDC > > > > Imagining that 12:00 is TDC, 1 revolution of the crank > > from TDC to TDC is a symmetric operation. With the > > piston at BDC (6:00) and the piston stop in place, the > > piston will encounter the stop at the same height in the > > bore (distance from TDC) whether the crank is turned CW > > or CCW. For example, say the stop is installed in such > > a way that starting at BDC and going CW, the piston > > contacts it at 10:00. Conversely, going CCW the piston > > will contact it at 2:00. The midway point, or 12:00, > > would then be TDC. Basically the piston stop prevents > > you from completing the circle. The midpoint we're > > interested in is the midpoint of the uncompleted arc > > (TDC), not the midpoint of the completed stop-to-stop > > arc (BDC). > > > > Note that you don't have to start with the piston at > > BDC, but if done this way the amount of CW crank > > rotation will be different from the amount of CCW > > rotation. However, that doesn't matter because the > > piston stop will still contact the piston with the > > piston at the same distance from TDC regardless of > > rotational direction. > > > > Brad > > > > > I think I need the hand puppets and/or flash cards, because I'm still > not > > > getting how TDC is between the tops of the two upstrokes. Wouldn't that > be > > > the bottom? You're drawing random marks and saying TDC is between them? > I'm > > > obviously just not getting this. Well, the cork and straw method never > lies. > > > You also never mentioned how you know which stroke you are on when the > > > piston hits the stop, so it sounds like a good way to end up with your > > > distributor (the reason this thread started) 180 degrees out roughly 50% > of > > > the time. > > > > > > John "lost cause" Nasta > > > > ------------------------------------------------ > > Get the award winning ISP, AT&T WorldNet Service > > http://download.att.net/webtag > > > > ----------------------------------------------------- > > To Unsubscribe please visit www.chevelles.net/list.html > > To start a new topic, send mail to: [EMAIL PROTECTED] > > > > > ----------------------------------------------------- > To Unsubscribe please visit www.chevelles.net/list.html > To start a new topic, send mail to: [EMAIL PROTECTED] > ----------------------------------------------------- To Unsubscribe please visit www.chevelles.net/list.html To start a new topic, send mail to: [EMAIL PROTECTED]
