Timing 318 basics...

[Chryslerkid]

Hey guys,

I'm about ready to tune and start my 318. I have to turn the crank until the number one piston is on top dead center. I understand the simple concepts about how to setup the distributor and wires. Can someone describe what the rockers on piston 1 looks like when it is on top dead center position? I need basics here. Thanks!

 

[SirDan]

Valves are closed on #1 at TDC. Keep in mind the crank spins twice for one full camshaft rotation. So you could bring it to 0 on the balancer and be 180 off on the camshaft. But one valve should be open somewhat if your 180 out.

 

[67Dart273]

Actually, SirDan, both will be about equally open. In the old days, many cams were close to what was called "split overlap" which means that on the opposite stroke, both no1 valves are equally open, one coming closed, the other coming open.

So if you "look at the rockers" you need to be SURE that they are actually both closed. Easiest way I know of is to actually watch them. On the wrong stroke, any movement before/ after the TDC marker will result in valve movement.

And of course "the other way" is to stick your finger in no1 plug hole and feel for compression as the marks come up

Here:

http://www.forabodiesonly.com/mopar/showpost.php?p=1969686215&postcount=28

http://www.forabodiesonly.com/mopar/showthread.php?t=210714&page=2

"The thing" about timing traditional V8 engines. This does NOT apply to some V6s (even/odd fire) and some 4 bangers.

"The book" shows how to insert the intermediate shaft, that is the drive gear/ oil pump drive, and if done properly, everything comes out "OK"

THE REASON it is originally done that way is

so the assembly line folk can wrench, repeat

so the plug wires "lay" nice

so the tune up guys "see" what they expect.

The TRUTH is you can close your eyes and drop the drive gear in ANYPLACE, plug the distributor in "any" old way, and and then bring the timing marks up on no1 ready to fire, and plug the no1 wire in wherever the rotor points, and it will run just fine.

If the vacuum can is off interfering with something, you can simply turn it where you want, bring no1 up to fire, and plug the no1 wire into where the rotor is pointing.

HERE IS the steps to setting up an engine dist.

1---It is important to realize, that when the cam timing marks are set "by the book" that is cam at 6 o'clock, crank at 12 o' clock, this is NOT no1 ready to fire, but rather no6 ready to fire.

So you either have to plug in the dist. pointing to no6, or rotate the engine 1 turn

2---After the cam is timed, with the timing marks on TDC, the "book" shows how to insert the intermediate shaft. if yours is incorrect and you want to correct it, you can simply use a large screwdriver and "walk" the gear up out of the helix and move it whichever way it needs

The gear on a small block should have the slot pointing nearly straight inline with the crank, just a tad to the driver side pointing at the front most manifold bolt

A B/RB gear the slot should be essentially inline with the crank

3---With this in place, now bring up the no1 cylinder ready to fire NOT on TDC but rather WHERE you want initial timing to be. There are two ways to do that

A---If either valve cover is off, bring the timing marks up to where you want initial time, IE 10BTC or so for a bone stocker, 15-20 for a "cam" or maybe even a little more for a real hot cam
Look at either the no1 or no6 valves. Whichever set of valves is CLOSED indicates which cylinder is ready to fire. If no 6 are closed, you can either plug the dist. in with rotor pointing to rear (no6) or rotate the crank one turn, and plug the dist in for no1 (rotor pointing forward)

B---If the valve covers are on, pull the no1 plug, stick your finger in the hole, and bump the engine around. When you START to feel compression, watch the timing marks, and bring them up to initial time, IE 10-12 BTC

Now plug the dist. in, rotor pointing forward, and put the vacuum can approximately where it should be.

I always mark the dist. upper rim directly under the no1 tower so I don't have to argue with teh cap.

Rotate the dist RETARD (cw for small block, ccw for B/RB) to "get the slack" out of the drive, then slowly ease the housing back advanced until

the points open if you are using points

or until the reluctor tip is centered in the pickup coil core.

This procedure should get you close enough that the engine will start and run with no fuss. Then of course just take your timing light and adjust from there

An aside.

I'm a HUGE believer in checking actual TDC with a piston stop, which you can make or buy

Small block intermediate shaft below. The slot lines up with the front left intake manifold bolt. You can walk the gear up and around with a screwdriver

B, RB, 426 hemi:

 

[Chryslerkid]

Nice! Great info thanks! Any more pics of the rocker positions?

 

[67Dart273]

You really don't need to "know" that, all you need as I said is to watch them move. When the timing marks come "up," if you watch no6 and no1 rockers,

1--On the compression stroke for no1, as the timing marks come "up" to TDC and even past, BOTH no6 valves will be moving. For a few degrees before/ after TDC, neither no1 rockers will move.

2--If the crank is rotated one turn, the situation is reversed--this time no6 is ready to fire, and it's valves will be closed some degrees before/ after TDC, and both no 1 valve will be continuously moving.

The "few degrees" of non movement will depend on how hot the cam is in the engine.

Just think about what the engine is "doing." If you come up to TDC and both no 1 valves are moving, this is the piston coming up to the end of the exhaust stroke, so the exhaust is starting to close, and the intake is starting to open. As you go past the TDC mark, the intake will open wider, the exhaust will finish closing, and you are on the "intake" stroke. As the piston "heads down" to bottom, the intake will close, the piston comes around the bottom, and finally, back up to TDC ready to fire, both valves closed.

 

[Chryslerkid]

Okay thanks for all the help