benwahballs

About to attempt the start-up of my 89 pu w/ 3.0 after hg job. Noticed that my crank pulley had been turned sometime during the re-install (I'm thinking when installing and torqueing ps and alt pulleys with belt tightness) and I wasn't sure how far it gone turned.

So I think I'm at TDC right now, but not 100%. Is there any easier way to check besides either pulling my valve covers (AHHHHHHHHHH) or pulling my timing belt and camshaft pulley bolts (again, AHHHHHHHHHHH). What if I fired her up and it wasn't at TDC? could i destroy my distributer or something or will it just sound terrible and not run?

thanks in advance for any help.

DCS

There's a TDC mark on the inner hub of the crank pulley. Line it up with the TDC mark on the block directly behind the hub, at the 12 o'clock position. You can seethose marks even with the belt in place around the crank pulley; just get a bright flashlight. When those marks are lined up, #1 is at TDC.

Some people talk about "#1 at TDC on the compression stroke" when timing the engine. This is technically incorrect. If you roll the engine over and over without the timing belt installed to turn the cams, then there is no "compression" or any other stroke because the valves aren't cycling. There is only "up" or "down". The #1 piston is either up, or it ain't.

So line up the crank pulley mark with the block mark = TDC #1. Line up the cam pulleys with their marks, and install the belt and tensioner.

Roll the motor twice, check to see that the marks still line up perfectly. If not, undo and redo. It's easy to "miss a tooth" on the belt because of belt slack while installing. Tip - do the driver's side campulley first, then belt-over the other cam pulley while sweating and grunting to fight the slack. Hold your tongue out. Struggle to engage the tensioner while holding the belt snug over the passenger-side campulley with one hand.

No grunting = bad timing job.

3.0 = non-interference motor. No valves will collide with pistons if timing is off. This is very niiiiiiiice. Enjoy this. Appreciate it. Most engines, if you time them wrong, will jam valve heads into pistons and just wreck everything.

A distributor is never damaged by whacked timing. If a distributor is too advanced, the motor will sound like it is "running into itself" when you crank it. It's a very distinctive sound, like adding a strange wheeze sound after each individual crank sound.

If a distributor is too retarded, the motor will sound normal when cranking, and it will just crank and crank all day.

Either way, it won't start, but nothing gets hurt by it except the batery and the starter motor if you just sit there and crank it.

Good luck!

benwahballs

Ok, i was under the impression that the crankshaft pulley mark could be at 0 at the different positons of the pistons and cams. Im only asing because I know my crankshaft pulley match-mark reads 0, but for installation of the distributer I thought it had to specifically be at the TDC 0, not the other spot where the same match-mark will sit at 0.

(thats why you have to do two complete revolutions of the crankshaft pulley when checking that timing belt is installed properly, to return it to TDC. at least thats what I thought...)

snap-on

you guys are partly right

when doing a rebuild from scratch say, if you line the cam wheels up with the marks, and the crank up with its mark... that will be correct

IF (<--- see the if)

the distrubutor is set right. it COULD be 180 out.

best way to find out, if the distrubutor is in is to line everything up and then look at the rotor postion. if its pointing at 1 your on the right track.

alexe

or theres always the redneck way. stick a long screw driver in your spark plug whole and turn the crank pulley till it go to the highest point.

not recommended of course but ive seen techs do it

surf4runner

a 'real' would use a pencil. and if it broke theyd still fire it up to smell it burn.

GSGALLANT

Like DCS said, when installing your timing belt, it doesn't matter if you're at TDC compression or exhaust. Every full revolution of the crank pulley to line up the marks will bring you back to #1 and #4 cylinders at the top of their stroke.

When it matters is when you go to re-install your distributer. To set it up right, you have to know whether you are at TDC compression or not. Since every second revolution of the crank shaft will get you to TDC compression on #1, you have a 50% chance of getting it right by guessing. If you want to know for sure, connect a compression guage to your #1 spark plug hole, use a ratchet on the crank bolt, turn the engine over one revolution as fast as you can, and see if you build up any pressure. If not, you're on the exhaust stroke. Go another revolution and you should build up some pressure, which will confirm that you're on the compression stroke. Keep in mind it will be very low pressure, but on the compression stroke, you can build up a psi or two by hand if you rotate it fast enough. You may not see it register on the guage because of the scale, but you will hear it when you press the relief valve.

benwahballs

thanx to all for information and ideas. I LOVE THIS FORUM!
neways, i went redneck style last night and stuck my dipstick down spark plug holes to see where piston was sitting, and found that my no. 1 was up and my no. 2 was farther down, so I had guessed right.

Good idea alex, and thanx for posting it. I'll never chirp a redneck again.. (at least not today, anyway)