i just put in a new cam and now the car runs like crap and seems to be impossible to time.

i have a '75 350 in my iroc.....do i line it up so that both dots are at the top of the gears, or so that the crank dot is at the top and the cam dot is at the bottom. help

 

The dot on the crank goes straight up and the dot on the cam goes down straight.

 

THe easiest way to line them up is like cntrvrsy said, put them so they are right next to each other. With most aftermarket timing sets however this is actually #6 firing. This is the other TDC (besides the firing one - it's where the piston comes to the top of the exhaust stroke and starts to go down for the intake stroke) for #1, so it's perfectly OK to assemble it that way, just be sure to find #1 TDC by compression or some other method rather than believing that the motor will be at #1 firing when aligned that way.

Your problem, if the engine does run but runs terrible, is probably that the distributor is a tooth off. Usually this happens with the dist retarded. If so, the engine will be hard to start, have no throttle response, be louder in the exhaust than one would expect, will run very hot very quickly, perhaps make the manifolds or headers glow red, have a tendency to spit back through the intake and die when you give it gas, and not be able to get the timing mark onto the scale even with a known good balancer and timing tab. If that sounds like your motor, then you should pull out the dist; rotate the distributor shaft and oil pump drive rod about 1/12 of a turn CCW; and drop it back in.

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"So many Mustangs, so little time..."

 

make sure the dots are both at the TOP when the #1 piston is at TDC, or as they said.. with the dots TOUCHING when #6 is at TDC.. as for the timing off one tooth, that's the biggest misnomer in all of mechanics. There is no such thing! Timing is the relationship between where the rotor is in respect to the #1 spark plug with the piston at TDC.

Example: can the rotor be pointed at #4 cylinder when your motor is at #1 cylinder TDC and still run? Absolutely, as long as you have #1 plugwire over the rotor! You see, it doesn't matter where the rotor is pointed, as long as when the engine is at TDC, #1 plugwire is directly over the rotor. Lost? Email me at admin@IROC-Z.org or check out my FAQ on my site how to stab the distributor with the rotor in any position.. Talk to you later..
Colin Opseth
www.IROC-Z.org/tech/StabbingDistrib.html



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'86 IROC-Z 305/auto with no cat, performance chip, shift kit, and 4.11s
'87 IROC-Z factory loaded with every option, 84,000 miles

Webmaster: www.IROC-Z.org

 

when the dot on the crank is at the top, then the engine should be at #6 tdc. right?

BINGO you decribed my engine perfectly(symptoms), accept i have not seen the manifolds glow yet. but i do know that is stall when i give it gas and blows out the intake.

now how do i fix this?

 

right, from what i can remember from my motor rebuild both dots at the top == #1 TDC.. dots touching == #6 TDC.. when the cam is at the bottom the motor is at #6 TDC because the motor is now one full revolution and #1 cylinder is starting to open the exhaust valve.. as for the headers glowing, that would be a lean condition.. i had that problem with my car, i was setting my timing by ear and my distributor was a little too loose (i was dirving around setting it) and it turned and my ESC retarded my timing.. light came on, the whole bit... anyways, it was at night, and it was running so bad... it was smoking and would hardly run.. i pulled over and my exhaust was red hot! i guess the gas had been igniting in the exhaust manifolds and was literally heating them up red hot... that could be your problem, advance your timing by turning the distributor counter clockwise.. not much though, just until it pings under WOT and then back it off a tough... hope my $0.02 helps

 

The problem with having the distributor in the block wrong is that then the plug wires don't go back in the right places. Sure, if you don't mind your engine looking like the guy that says "Gee boss I always wanted to work on an automatic transmission" rewired your ignition system, i.e. you want your wires to be neat like from the factory not a huge rat's nest, you need to orient the distributor correctly. If however you're not a perfectionst, you can just crank the distributor around and move the plug wires around the cap. I won't leave you-know-what tracks like that under my hood though.

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"So many Mustangs, so little time..."

 

Just curious here, but does your crank gear have more than one keyway? If so, you may be 4* adv. / ret.

Regardless if you do or not, the dots are to line up with the crank gear dot up and the cam gear dot down. Get them as close as you can.

Then role the #1 piston to TDC compression stroke and drop the distributor to where the #1 cap wire position should be (get it as close as posible). If the rotor is off, get a stout screwdriver and turn the oil pump drive shaft (carefully) to get the dist to drop in at the #1 plug wire location.

The only way I install a timing set anymore is with a degree wheel and indicators. You can get a kit for about $100 and it will come with the indicator, indicator base and adaptor, degree wheel, piston stop, temp vavle springs and a wire pointer. It really is the best way to install a cam or new timing set.

Good luck
Mike