Shelby Posted July 2, 2003 Report Share Posted July 2, 2003 guys read over this and see where i need to make corrections -------------------------------------------------------------------------------- ok this has been gone over many times , but i guess it won't hurt to do it one more time many times when guys are removeing the head they set the cam gear down on the holder make for that , but as things tend to happen in the world of cars , this can cause problems, what happens is with a worn chain and guides is theres a lot of chain slack , this slack will almost always fall on the long side so the crank gear and the chain get a lof of slack on the pull side, no bigie but this can at times alow the chain to slide past the crank gear and slip a tooth, so when you start to reinstall the cam gear it is now a tooth off on the crank , most of the time this causes the cam to be advance'd by 1/2 of a cam tooth and altho the engine will run it's way out of it's normal timeing spot and performance will suck to say the least , this can not becorrect'd at the cam gear in the normal way sence any one tooth is 2 crank gear teeth,, how to fix , well it's realy easy, first loosen the cam gear bolt,,then you start by seting up the timeing as you normaly would, but this time you set the cam pin in it's 12:00 position and don't pay any atention to the crank pully mark, if the crank and cam are in time the crank mark will be align'd at the tdc mark, but if the cam and crank are out of time the tdc mark on the crank pully will be off by a little say 5-10 degrees or nearly that , if this is the case then do the following MAKE SURE THE CAM PIN IS AT EXACTLY 12:00 now carefully remove the cam gear bolt and cam gear, but do not set it down on the holder plate but keep an up ward pull on the chain and gear , while keeping a strong upward pull on the gear and chain , use a wrench to turn the crank . lets say the crank was setting at 5 degrees befor tdc , ( as would be the case if the cam is fast)you turn the crank untill it's about the same atdc , now rotate the cam gear one link back . now you have move'd the cam one link back and the crank one tooth late, now if you are right and have not alow'd the chain to drop , when you turn the crank back to TDC both it and the pin will be at 12:00 and the gear will set right into the cam and every thing will be fine again here the short of it, you can't correct the crank gear timeing at TDC you must change it 1/2 a cam tooth off thus when it's put back to tdc it will now be in proper time with the cam , in essence you move't the crank one aditional tooth so now one tooth on the cam puts it right where it belongs now sence we're both confuse'd it 's time to quit __ Link to comment Share on other sites More sharing options...
importwarrior Posted July 2, 2003 Report Share Posted July 2, 2003 great info thanks! Link to comment Share on other sites More sharing options...
shift1313 Posted July 2, 2003 Report Share Posted July 2, 2003 thanks for taking the time Shelby. Its much appreciated! Link to comment Share on other sites More sharing options...
Shelby Posted July 2, 2003 Author Report Share Posted July 2, 2003 no problem Matt beleave me your not the first to ask, just hope that was understandable Link to comment Share on other sites More sharing options...
Tim_C. Posted July 2, 2003 Report Share Posted July 2, 2003 If it is off at all, isn't it easy enough to just set the crank pulley to line up at "zero", or "T". The #1 piston must be all the way up top. (you can tell by putting a long straw in the spark plug hole to see if the piston is up or down)Then do what it takes to put the cam gear roll pin at 12:00 straight up. A tooth off either way then, will be very obvious to see, and easy to correct. Link to comment Share on other sites More sharing options...
Shelby Posted July 2, 2003 Author Report Share Posted July 2, 2003 obvious and easy for you Tim isn't nessarryly so to a lot of the guys, and if the frt cover is on , explain how to slip the crank gear one tooth any this is only need'd when the chain has slip'd down while the head was off or some other reason for the cam gear to be off , and it does happen a good bit of the time Link to comment Share on other sites More sharing options...
conquest89 Posted July 7, 2003 Report Share Posted July 7, 2003 uhhh,, I switched my cam a while back , how do I know if it is off? I wonder if this could be he root beind my problem? Link to comment Share on other sites More sharing options...
GoldNBlack Posted January 18, 2004 Report Share Posted January 18, 2004 Alright Shelby. I can shift the cam gear a tooth back in forth but what I really need to do is make the crank skip a tooth. What's the best way to make this happen? Can it be done with a new chain and guides or not? I bought a modified adj. timing gear but with the new timing stuff already on there is no way I could find to get the cam gear out, just not enough slack. For an experiment I I just tried 1 cam gear tooth forward, It's too much but I'm thinking if I can move the crank gear a tooth that puts me 1/2 a tooth off on the cam gear thereby I go from having my cam at -2.5 degrees or +7 (9.5 deg change by rotaing cam gear 1 tooth) to being able to set the cam gear at +2.25 degrees advanced right? 1 crank tooth movement is 1/2 the distance at the cam gear. If it can happen accidently, here's to hoping I can cause it on purpose tomorrow. Steve A. Link to comment Share on other sites More sharing options...
fastquestMA Posted April 16, 2004 Report Share Posted April 16, 2004 :-/How are you holding up the tension of the chain from trying to pull the cam gear down into its little dish on the head? Otis at Midwest turbo gave me a good tip of changing the cam without losing the timing, he said he puts a socket under the cam gear to prop it up while removing the cam without taking off the timing cover. If anyone has any better ideas I would appreciate them, for I am about to install my new schnieder 274 cam, but i'm scared of chain coming off the gear and messing it all up! Thanks! Link to comment Share on other sites More sharing options...
Shelby Posted April 17, 2004 Author Report Share Posted April 17, 2004 to answer your question the chain tentioner is what pushes the gear down,, as it comes out,, it will push right back in if the chains are not too old and worn,,alowing the gear to reach the cam,, as for what to do with it as you change the cam,, thats what the little platform is for befor the cam gear,,the gear and chain just lower to the plate and let rest there the sole purpus of this plate is to hold the gear and chain up while removeing thhe head and or cam to answer the other question,, the crank is not at tdc when you walk the chain arround the gear,,it's eather adv or retard'd 1/2 a tooth , now when you turn the crank back to tdc it and the cam pin will align Link to comment Share on other sites More sharing options...
billhint Posted July 10, 2004 Report Share Posted July 10, 2004 Shelby You stated at the first of your post this problem could not be fixed by moving the cam gear then you say to fix it at the last of your post by moving the cam gear. this will still have it off. I will have to look at my spare engine and see if there is a simple solution. Bill Link to comment Share on other sites More sharing options...
mikec Posted July 10, 2004 Report Share Posted July 10, 2004 Bill - initially that's what it looks like Shelby is saying... the thing is he's also saying to turn the crankshaft a little bit. Thus, the crank sprocket moves about 1 link while the cam sprocket is hand-moved 1 link the other way. Since the cam sprocket rotates at half the rate of the crankshaft, the net result is a half-link change at the cam or a full link at the crank. Sneaky. mike c. Link to comment Share on other sites More sharing options...
Vanishing Point Posted July 11, 2004 Report Share Posted July 11, 2004 I would think that if your crank slipped a tooth then if you still had balance shafts they would now be off. Ive pulled alot of heads and never had it slip time(never with the balance shafts removed) so it would probably be a good time to tear into it and replace the chain and guides. If the balance shafts were removed, that is a good trick to get it back in time. Of course it can be tried with the balance shafts and if there is NO engine vibration call it good, but I think it would drive me nuts not knowing for sure. Tony Link to comment Share on other sites More sharing options...
billhint Posted July 12, 2004 Report Share Posted July 12, 2004 Mike With the chain tight on the crank gear you are still moving the cam gear one tooth in relation to the crank. Try this if you have a spare engine sitting where it is easy to get to. If I understand correctly the only way to fix this is move it one tooth at the crank. Bill Link to comment Share on other sites More sharing options...
Shelby Posted July 29, 2004 Author Report Share Posted July 29, 2004 you can not move the crank gear BUT if the crank is not at tdc when you move the cam, this is the part most are missing the crank is not at tdc, this is 1/2 a link on the cam, so seting the cam up then moveing it and the crank to tdc puts it all back in time Link to comment Share on other sites More sharing options...
Chris.RO Posted December 19, 2004 Report Share Posted December 19, 2004 Hy Shelby.I saw on manual and that's how my engine runs before. with timeing crank-can:on the chain are two shyni links;with the crank at TDC you put the short part in the right side one link on the crank and the other on the spot marked on cam gear.The pin in the cam request cam position.This is on tristarion.com pdf manual. I saw you recomend on forum:crank at TDC(cul no 1 on 0) and the spot on the cam gear at 12o'clock. In both sit. the piston didn't hit the valve,I've checked this ,but I didn't start the engine with cam at12. Please light me up!Am I missing somethig on the way of timeig or what? Bye. Link to comment Share on other sites More sharing options...
Recommended Posts