Dot to dot timig problem!
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From: Under a hood in Alabama
Dot to dot timig problem! Has any one ever run in to a H/C swap and the dots matched when ya got threw but the piston #1 is not at top dead center! I've run into one now where if ya put it on TDC from the plug hole the cam dots at 7 oclock and the crank dot not visable! Any thoughts could something have come loose and made the crank dot loose its timing relation with the dot like the key or something with the sprocket! 
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From: Under a hood in Alabama
No rollmaster double non adjustible dots are very visible looks like yours in the pic you posted its dot to dot but #1 isnt at TDC! Never heard of this yet but I masy be the first I have done tons of these and never run in to this!
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Not today, the key may have sheered and the crank sprocket has moved. The only way to tell is pull the oil pump and see, unless you are installing them now. If so the dot isnt machined in the right place so use the TDC method.
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From: Under a hood in Alabama
When we pulled the old cam out #1 was at TDC but when we got the new one in we noticed that by the time we got the new oil pump on the cam lined up and everything taken car of #2 was almost at TDC dot to dot so we turned the car over by hand and nothing hit! It has a double master chain they have severel key ways but we didn't mess with it and bout we sheered the key way with a 3/8s ratchet!Its just weird!We are fixen to go back out and mess with it somemore! where going to take it down where we can see the key way and see how everything lines up and if it some how don't know how got like it did!
. Thats why I put my springs on yesterday, gotta run the best I can at the moment. 
If your going to install a Rollmaster or different cam you should turn the crank (spark plugs removed) until #1 is at TDC on the compression stroke. At this point your at "DOT to DOT" or very close to it and if your not it's just a small bump in one direction or the other to get there. Once you get at "DOT to DOT" the crank is NOT moved until AFTER the new cam is in or double chain is on or what ever part it is that your installing is bolted down. You must have moved the crank.
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Originally Posted by eallanboggs
If your going to install a Rollmaster or different cam you should turn the crank (spark plugs removed) until #1 is at TDC on the compression stroke. At this point your at "DOT to DOT" or very close to it and if your not it's just a small bump in one direction or the other to get there. Once you get at "DOT to DOT" the crank is NOT moved until AFTER the new cam is in or double chain is on or what ever part it is that your installing is bolted down. You must have moved the crank.
If it has more then one keyway on the lower gear you have to make sure you have the keyway on the one with the dot if you want the dot to line up at TDC. With #1 at TDC the dot on the crank gear should be pointing straight up and the keyway should be around 2 o'clock if its the 'zero' advance key.
If someone advanced or retarded the cam with the keyway on the lower gear then the lower dot wont line up any more, you have to count so many teeth on either side of the dot when you arent using the 'zero' degree keyway in the gear to make sure they are lined up right.
If someone advanced or retarded the cam with the keyway on the lower gear then the lower dot wont line up any more, you have to count so many teeth on either side of the dot when you arent using the 'zero' degree keyway in the gear to make sure they are lined up right.
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From: Under a hood in Alabama
Found prob. It has a rollmaster double chain When I removed it I had the #1 up but puting in the new cam I moved the crank some. So I put it dot to dot like everycar I do! But heres the thing!The company that built the short block must have pressed the lower crank sprocket on the wrong keyway and didin't feel like removing it! They just put some engraved X's for TDC and I couldn,t see them because there where covered up. But we found them once we turned the crank to TDC with the sparkplug out we found them.Glad it had big releafs and where dished.with the crank pulley at 6oclock ,the crank was off 4 teeth clock wise on the crank pulley! Put here back togeter and so as we hit the key it fired right up!What a pain in the but didin't take long to figure it out but some one could have got messed up if they didn't know what was going on!No one should make there own marks for timing marks especially if someone else does something and that person doesn't know it! Glad some valves didn't get bent!
Last edited by TA TECH; Jan 2, 2006 at 02:06 PM.
If the heads are off it's a little difficult to tell whether or not your at TDC on the compression stroke for #1 unless the cam is installed and the timing chain is in place. If the cam is in you can tell for sure. The cam is like the brains of the engine and the crank is the backbone. Back to basics: I,C,C,E. That's the 4 stroke cycle. Who dictates the 4 stroke cycle? It's the camshaft of course, not the crankshaft. So the cam gives the orders and the crank follows the cams instructions. #1 piston is going to be at TDC twice during every 4 stroke cycle, but your only interested in the one cycle when compression is being made and that's when BOTH the intake AND exhaust valves are CLOSED. If the heads are off watch the intake lifter for #1. As your turning the crank the intake lifter will roll over on its' back. As it does the piston will start coming to the top of its' bore. Both valves for #1 are now on their backs(closed) so your on the compression stroke. With the heads on you can watch your rockers to tell, but with the heads removed you can still tell with the lifters out by watching the cam lobes themselves. If the cam is removed there is no such thing as TDC or BDC or I,C,C,E anymore because the brain has been removed sort of like the scarecrow in the Wizard of OZ. I figured the crank had been moved, but I'm a little confused by the explaination. The crank pulley is not keyed. It's an interference fit. The cam chain/oil pump drive sprocket IS keyed. Is this the sprocket that was installed improperly. That would explain the DOT to DOT problem.
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From: Under a hood in Alabama
Yes the crank sprocket was put on the wrong key by the company that built the short block and they made there own alignment mark on the crank sprocket that noone knew about so that ended up being the whole problem!Seeing how the rollmaster double has several keyways it would be how it all happened guess they didn't feel like pulling it back off the crank on something so they just done there own thing! They should have told someone it wasn't dot to dot and this would have never happened!But thanks for the lengthy last reply after we got it going! 
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Originally Posted by eallanboggs
If the heads are off it's a little difficult to tell whether or not your at TDC on the compression stroke for #1 unless the cam is installed and the timing chain is in place. If the cam is in you can tell for sure. The cam is like the brains of the engine and the crank is the backbone. Back to basics: I,C,C,E. That's the 4 stroke cycle. Who dictates the 4 stroke cycle? It's the camshaft of course, not the crankshaft. So the cam gives the orders and the crank follows the cams instructions. #1 piston is going to be at TDC twice during every 4 stroke cycle, but your only interested in the one cycle when compression is being made and that's when BOTH the intake AND exhaust valves are CLOSED. If the heads are off watch the intake lifter for #1. As your turning the crank the intake lifter will roll over on its' back. As it does the piston will start coming to the top of its' bore. Both valves for #1 are now on their backs(closed) so your on the compression stroke. With the heads on you can watch your rockers to tell, but with the heads removed you can still tell with the lifters out by watching the cam lobes themselves. If the cam is removed there is no such thing as TDC or BDC or I,C,C,E anymore because the brain has been removed sort of like the scarecrow in the Wizard of OZ. I figured the crank had been moved, but I'm a little confused by the explaination. The crank pulley is not keyed. It's an interference fit. The cam chain/oil pump drive sprocket IS keyed. Is this the sprocket that was installed improperly. That would explain the DOT to DOT problem.
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From: Under a hood in Alabama
No not right a rollmaster doudle as several key ways and you can have them installed wrong or as in our case some one else installed wrong and the dots are not going to line up! They made there own dots with a engraver as a small X.The dot ended up on the crank at 3 o'clock while the cam shaft was at 6 where its supposed to be! If your using the factory sprockets they only have one keyway on the crank sprocket so ya can't really mess that up!
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Originally Posted by TA TECH
No not right a rollmaster doudle as several key ways and you can have them installed wrong or as in our case some one else installed wrong and the dots are not going to line up! They made there own dots with a engraver as a small X.The dot ended up on the crank at 3 o'clock while the cam shaft was at 6 where its supposed to be! If your using the factory sprockets they only have one keyway on the crank sprocket so ya can't really mess that up!
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From: Under a hood in Alabama
Yes it would be TDC with the factory sprocket! I always use the LS2 chain on all the other stuff I do so this certain car already had the double rollmaster chain! Just wished we would have know about the way the company where the short block came from had assembled it and the make shift marks!But yes dot to dot factory sprockets are good plus ya ain't got to really remove them!