ShiftyCapone

iTrader: (7)

Ok the new cam is in but I am confused wheather or not I am at TDC for the #1 cylinder. Let me see if I get this.......

Dot to dot (crank gear at 12 o'clock, cam gear at 6 o'clock) is #6 piston at top of compression stroke. So what allignment to get the #1 cylinder at TDC. I want to adjust the valves soon but I want to start at TDC for #1 and do it with the car off. I have conflicting data between magaizines and my Chilton's/Haynes. They contradict each other. GM high tech performace says dots 180 apart is TDC but chiltons say that dot to dot is.... I am boggled here...

GASGZLR

Crank gear dot at 12 oclock and cam gear dot at 12. The cam dowel pin will be on the passenger side now. It's also one crank turn after the marks are how you described them.

ShiftyCapone

iTrader: (7)

Ok that is what I thought until I read a cam swap artilce in the latest GM high tech mag. They said do to dot was TDC for #1 and I got all worried. I lined them up dot to dot and then rotated the crank 180 so that the crank gear is at 12 and the cam gear is at 12. Now I am at TDC for #1 and I can adjust the valve accordingly before I rotate 360 and do the other valves.

ronterry

I think a lot of acticals and books tell you to do dot-to-dot, because it's easier to align. This is how I've done it for years, but yes dot-to-dot is tdc 6.

Ron

ShiftyCapone

iTrader: (7)

Yea that is what I have gethered as well but that mag thre a monkey wrench at me by saying dot to dot was TDC for #1.

RB83L69

Dot-to-dot is TDC for #1. However, it is the instance of #1 TDC during the full engine cycle that is not #1 firing. It is #6 firing, and #1 end of exhaust stroke and beginning of intake stroke.

Dot-to-dot is easiest to see, for building purposes. Asemble the engine that way to make sure you get the cam correctly lined up with the crank. It will be at #1 TDC, but #6 firing. Turn it exactly one crank revolution, and it will then be at #1 TDC, #1 firing.

ede

you want both dots straight up. dot to dot is easier and it's how all the books tell you to do it, but they ought to put a disclaimer in that say's it's 180* out. i install the gears dot to dot then spin it a few times to make sure i'm not off a tooth on the gears then sdet both dots straight up.

ShiftyCapone

iTrader: (7)

RB83L69 and ede,

You guys are awesome. That is exactly what I needed to know and now I completely understand. Books and mags need to be carefull because they can really screw up their readers

Mkos1980

iTrader: (8)

I thought it was the firing of #1 for the longest time and it caused a weekend of car that wouldnt start. I just put my finger over the #1 hole and feel for pressure then once its felt I put the timing on the 0* mark

Pat Hall

iTrader: (31)

For future reference, if you're ever out 180 degrees again, all you have to do is pluck the distributor out, rotate it 180 degrees, and drop it right back in. Problem solved. I remember the first couple of motors I did, those procedures in the manuals made me screw up the cam timing too. It'd be belching and backfiring through the carb. So you flip the distributor 180 and drop it back in and you're done.