ANOTHER CAM TIMING QUESTION

[Corzette]

Here we go around the mullberry bush...OK still havent fixed my damper timing problem. Heres my question...here is what I read from another board on cam install and timing marks:

 

"Observe the position of the "dots" on the crank sprocket and cam sprocket. If your rotor was pointing at the No. 1 terminal and your timing mark on the balancer was at 0 Deg. TDC, the "dots" BOTH should be at the 12 o'clock position on their respective sprockets. Also note the position of the locating dowel on the cam. Should be at 9 o'clock. We won't be installing the new timing chain yet, of course, but just keep the positions in mind or you'll be in for some trouble later. :)"

 

With that said, here is how mine was done....I had the crank set at TDC (with Heads Off) and the crank dowel was pointing at 2 OClock with the dot on the crank sprocket at 12 OClock. My cam sprocket dot was at 6 OClock so the two lined up together . The cam dowel pin was at 3 OClock. The pointer was sitting at ZERO TDC. I put in my distributor at this setting and the rotor is pointing toward the #1 spark plug. This is not what the above post says but did I do it right? This could be the problem but it doesnt backfire or anything at the moment.....Grumpy are you tracking this?

 

Corzette

[Guest greimann]

I get caught by this snafu every time I change a cam. You install the cam "dot to dot" but before you install the distributor, you need to spin the crank one revolution so both dots are 12 o'clock. Now install the distributor at #1 and you will be close.

[Corzette]

Wow! this could be the problem. I installed dot to dot but it friggin starts and runs pretty good. The only wierd thing is when I take off a vaccuum line it doesnt make much difference and it runs rich but no popping etc. I do have to crank the cap all the way left though. Would an engine run like this? I definately did not turn the crank around one rev before installing the distributor. I hope this is the problem! Crossing my fingers...

[Corzette]

So actually its 180 degrees out then? I would just turn it to TDC with the rotor pointing to #6 and take out and reinstall to #1 right? My TDC is correct however. Man if that the case, this thing is really gonna be a screamer...It burns the tire easily now...how funny

[Guest greimann]

If it were 180 degrees out it would not run period. There is something else going on if it actually runs.

 

This may be elementary, but are your wires in this order?

 

[Guest Anonymous]

DELETE

[Corzette]

OK I give up...it runs fine so Ill run it till it drops then order a 383 short block and do it right next time. Okinawa sucks majorly...Thanks for everyones patience. Engine runs fine timing marks dont jive...is set at TDC etc....just dont make sense....Im done worrying about it. Ill dyno it and see where were at...

[grumpyvette]

don,t worry you did it correctly corZette

read this

how come its 180 degs out of phase? I get this question all the time, well heres something I see lots of guys don,t understand ONCE YOUVE INSTALLED A CAM WITH THE TIMEING MARKS YOU MUST ROTATE THE CRANK 360 DEGRESS BEFORE DROPPING IN THE DISTRIBUTOR while its true that if the

timeing marks are possitioned so the crank is at 12 o,clock and the cam gear is at 6 o,clock that the cam lobes will be in the possition that fires #6 cylinder that HAS NO EFFECT AT ALL (on finding TDC,) for aligning the degree wheel with TDC,or THE timeing tab pointer, for degreeing in the cam, the piston passes thru TDC TWICE in every fireing cycle once on the fireing/power stroke and once on the exhaust stroke, the cam rotates at exactly 1/2 the speed of the crank so to make it easy to line up the marks they install it with the marks at the closest point 6/12 for easy indexing, rotate the engine 360 degrees to the #1 TDC power stroke and the crank gear will still be at 12 oclock 12/12 but the cam will be at 12 o,clock also, rotate another 360 degrees and your back where you started. its simply easier to index the cam at the point where the index marks align closely. look at how the cam lobes themselfs open the valves when the cam is just installed the #1 cylinder valves are slightly open and the #6 are closed per "Lunati" YES YOU ARE RIGHT - WHEN CRANK IS AT TWELVE AND CAM IS AT SIX THEN #6 CYL IS FIRING AFTER YOU LINE UP YOUR MARKS AND INSTALL GEAR THEN ROTATE YOUR CRANK ONE REVOLUTION AND THEN DROP THE DIST. IN - AT THAT POINT #1 IS FIRING

[Guest Anonymous]

DELETE

[grumpyvette]

I am working on a new method that will revolutionize the whole industry!

NO!....YOU DON,T MEAN,IT!....REVOLUTIONIZE THE INDUSTRY!!!.........YOUR REALLY SUGGESTING.....PEOPLE THAT WORK ON CARS.....NO! ...........I JUST DON,T BELEIVE YOUR SUGGESTING PEOPLE ACTUALLY LEARN WHAT THEIR DOING!!!!!!! TRUE IT WOULD....REVOLUTIONIZE.... THE INDUSTRY!!!......... BUT HOW ARE YOU GOING TO GET THEM TO READ THE INSTRUCTIONS BEFORE THEY SCREW UP!!!!

 

the dots on the crank and cam gear were put that way so the early mechanics could put them 12/12 and line them with a strait edge on the crank and cam centerlines, THAT REQUIRED LINENING UP 4 POINTS, THAT PROVED TO DIFFICULT, SOME EARLY MECHANIC REALISED HE COULD SAVE TIME AND EFFORT BY JUST PLACEING THEM 6/12 AND GETTING THEM AS CLOSE AS POSSIABLE THEN AFTER SEALING THE ENGINE, TURNING THE CRANK ONE COMPLETTE TURN BEFORE DROPING IN THE DISTRIBUTOR, BUT AS USUALLY MOST GUYS ONLY READ DOWN TO THE FIRST PART AND THREW AWAY THE INSTRUCTIONS, SO TO THIS DAY THE RESULTS ARE 96% OF THE GUYS INSTALL THE CAM, PLAY WITH THE IGNITION ,FIND ITS 180 OUT AND PULL THE DISTRIBUTOR AND RESEAT IT 180 OUT (correctly) THEN WONDER WHY IT ALWAYS WORKS OUT THAT WAY?

[Guest Anonymous]

DELETE

[Michael]

Speaking of revolutionizing the industry – why don’t cam manufacturers alter their present practice, and start grinding the cam dot 180 degrees away from its current position?

[THUNDERZ]

I am working on a new method that will revolutionize the whole industry!

NO!....YOU DON,T MEAN,IT!....REVOLUTIONIZE THE INDUSTRY!!!.........YOUR REALLY SUGGESTING.....PEOPLE THAT WORK ON CARS.....NO! ...........I JUST DON,T BELEIVE YOUR SUGGESTING PEOPLE ACTUALLY LEARN WHAT THEIR DOING!!!!!!! TRUE IT WOULD....REVOLUTIONIZE.... THE INDUSTRY!!!......... BUT HOW ARE YOU GOING TO GET THEM TO READ THE INSTRUCTIONS BEFORE THEY SCREW UP!!!!

 

the dots on the crank and cam gear were put that way so the early mechanics could put them 12/12 and line them with a strait edge on the crank and cam centerlines, THAT REQUIRED LINENING UP 4 POINTS, THAT PROVED TO DIFFICULT, SOME EARLY MECHANIC REALISED HE COULD SAVE TIME AND EFFORT BY JUST PLACEING THEM 6/12 AND GETTING THEM AS CLOSE AS POSSIABLE THEN AFTER SEALING THE ENGINE, TURNING THE CRANK ONE COMPLETTE TURN BEFORE DROPING IN THE DISTRIBUTOR, BUT AS USUALLY MOST GUYS ONLY READ DOWN TO THE FIRST PART AND THREW AWAY THE INSTRUCTIONS, SO TO THIS DAY THE RESULTS ARE 96% OF THE GUYS INSTALL THE CAM, PLAY WITH THE IGNITION ,FIND ITS 180 OUT AND PULL THE DISTRIBUTOR AND RESEAT IT 180 OUT (correctly) THEN WONDER WHY IT ALWAYS WORKS OUT THAT WAY?

 

 

So would the car run at 180 degrees out?

[280zwitha383]

No.

[v80z]

I am one of the guys that did not read the whole thing. After 12/6 turning one crank rotation sound like a good simple method. My book had me turn the crank till certain lfters were rocking, I cant remember which. But I remember wondering why my ignition seemed off.

 

thanks Corzette and Grumpy.

 

Just proves to me there are no, fill in the blank, question!

[lbhsbZ]

Its really not that complicated....you guys are trying to make some kind of science out of it.

 

First off, you have do determine exactly where TDC is and mark it on your balancer/pointer, so you have an accurate reference point. Grumpy discussed this in another post.

 

After you know where TDC is, it doesn't matter where the distributor is, or if its a tooth off, a timing light will give you an accurate number. If the gear is a tooth off, you can spin the distributor to compensate for it, walk the plug wires around the cap 1 spot, or put it in right, it doesn't matter because your soul objective is to get it timed correctly, which involves ONLY the relationship between the time that the #1 plug fires and your mark on the crank pulley. I saw where you stated that you had confirmed the mark on your pulley and its correspondence with the pointer to indicate a true TDC. If this is true, and your timing light indicates 50 degrees of advance, then you have 50 degrees of ignition advance, no questions asked. If it starts and runs, and you've still got some room to turn the distributor a bit in both directions, you're within 30 degrees of where you need to be, which means you're on the right tooth.

 

If your cam timing is off, 50 degrees may be required to compensate for it. I would double check your cam timing....which can be done without pulling the timing cover and oil pan, if you have the cam card and a degree wheel. Put the degree wheel on the crank and an indicator on the pushrod...and make sure all the opening, lobe centerline, and closing points match the card. If they do, then your cam is in correctly. If they don't, tear the cover off and fix it.

 

I've had engines that wouldn't run unless the mark on the balancer was straight up or off to the right with a timing light....I dunno what the problem was, but thats where they like to be, so thats where I left them. I suspect the balancer was spun or something...who knows.

 

Make sure that the idle mixture screws are adjusted according to the carb manufacturer's specs(usually you play with them until the highest manifold vacuum is achieved) and then increase the idle speed using the throttle stop screws. Increase it enough to where you can pull the timing down to 16 degrees BTC static and it will still idle. If you have a mechanical secondary carb, open up the secondaries a little bit. The carb manufacturer has a spec on MAX idle speed screw adjustment so that you don't get into the transition circuit on idle. if the plates have to be opened up too much in order to make it idle with the timing set properly, then it may be necessary to drill small holes in the plates, so that you can close them more to get out of the transition circuit, but still maintain enough airflow through the carb to idle at the appropriate timing.