finding TDC without heads or cam

[crm318]

i have a 350 short block that im trying to assemble. im about to install the cam shaft and heads, but how do i know if its at top dead center? i know that the no 1 and no 6 pistons will be at TDC, but is the compression stroke or the top of the exhaust stroke? what position should the sproket dots be lined up at? the 12 or 6 clock positions?

[Jtrux]

When you put the cam in the crank dot will be facing straight up and the cam dot straight down.

[Longhorn321]

Jtrux beat me to it but here you go anyway.

[68gmsee]

If those two dimples are lined up as shown, it really doesn't matter about TDC for now.

It's when you put the distributor in that you have to indure it's set up properly.

[cdowns]

before trying to go any further let me suggestr a trip to the autoparts store and getting a book om rebuilding the smallblock chevy engine you might also try at a local library //they're real cheap compared to the price of replacing parts damaged due to lack of knowledge

[LONGHAIR]

Just so you know: When the dots are lined-up as in the above picture, that is the compression stroke for cylinder #6. So to simplify matters, just stab the distributor pointed toward #6 rather than the traditional #1.

[Longhorn321]

Originally Posted by cdowns

before trying to go any further let me suggestr a trip to the autoparts store and getting a book om rebuilding the smallblock chevy engine you might also try at a local library //they're real cheap compared to the price of replacing parts damaged due to lack of knowledge

[67dragtruck]

Just so you know. There's no such thing as a the compression stroke till the cam is there. They are telling you right, line the 2 dots up the way the pics show. Once you finish adjusting all the valves and put the intake on, spin the motor manually with your finger over the #1 spark plug hole. When it blows at you you are on the compression stroke. Bring the motor up to 10 degrees before tdc and line the rotor up with the #1 plug wire terminal. This is the way I do it and I almost never have to mess with the timing to get it to fire up. You'll still have to adjust the timing with a light after it's running. It's just meant to get it close enough to fire up easily. It put's about 10 degrees of initial advance in the distributor.

By the way it's always very good practice with a new motor to check TDC on your motor before putting on the heads for the first time. Then you can verify the accuracy of your timing pointer. You would do this with a dial indicator. If you position the dial indicator over the piston. Basically you want to bring the piston up as high as it comes up on the normal rotation and make note of what the pointer shows. Then rotate the motor the other way and do the same. The true TDC is between the 2 readings from each rotation. You can also accomplish the same thing with a piston stop, which is probably even easier. You rotate it each way till it contacts the piston lightly and the middle is still TDC. You'd be surprised how often people have mixed up pointers with the wrong diameter balancers and had the timing off in left field.

I ended up writing a novel here, but the advise they gave you about getting a book to reference is great advice. I've built a lot of motors, but still reference a book for stock type torque specs when I need them.