Help with timing

[BillHilly]

I recently got a 1990 mightymax with the 2.4. I've replaced the computer and flipped the plug wires 180 to get the truck started, but now I want to properly time it. As far as I can tell I take the belt off, line up the notches on the crank, cam and balance shaft, while making sure the balance shaft is in place, and the slip the belt back on? I've also seen people take the distributor out and line up a dimple and put it back in. Also, is it okay for me to use a ratchet on the camshaft to turn the cam into place?

[geezer101]

Just take the cam sprocket cover off and check if the timing mark is aligned when the crank is at BTDC. Then you will know if it's timed with #1 cylinder or #4. Then you can reset the distributor.

[SubGothius]

Also bear in mind the crank turns twice for every single rotation of the cam, so if you don't see the cam timing marks anywhere near aligned with the crank at TDC, just turn it again.

[BillHilly]

Apologies, as I have never heard of that before. So, I take the timing cover and all that off, and bump the starter until the crank timing mark is at TDC, and then check the top cam gear? I know for sure it's 180 degrees out because i had to flip the plug wires to get it to fire up, and I'm certain it's a tooth or so off cause it runs at higher rpms just fine, but backfires and misses at lower rpm, and I have my distro I believe advanced all the way.

SO, I put the crank to TDC, and if my cam isn't at the right mark can I take the belt off and just take a ratchet, I think clockwise, and turn the cam until the mark lines up and slip the belt on, and take the distro out and line up the dimple on it and slip it in? I've never timed a vehicle but all the hillbilly mechanics around here don't wanna touch anything that says "Mitsubishi."

[BillHilly]

I believe the balance shafts are in line as it runs pretty smooth at higher RPMS, and I've watched the gravity trick and how to make sure to line them up. I'm pretty certain I can do it, but I will have about 5 hours to do so, and me and my GF are hopefully getting a good job about an hour away, so I don't wanna murk the poor little truck driving it long distance out of time.

[SubGothius]

Note the difference between valve timing vs. ignition timing! Your valve timing may be just fine, but your ignition timing could be way off if the dizzy wasn't reassembled or inserted properly.


I have my distro I believe advanced all the way.

This reminded me of something I discovered with my 2.6 (4G54 / G54B), tho' I'm not sure if this applies to the 2.4 (4G64):

When I disassembled and rebuilt my distributor, after inserting it into the head, I soon found I couldn't advance the ignition timing enough to get it in spec, as I reached the end of the slot in the distributor body for the timing adjustment stud.

Well okay, so the distributor drive gear must be a tooth off, right? No problem, I pulled the distributor out slightly, reinserted it one tooth over, and tried again. Waitaminit... now I couldn't retard the timing enough, reaching the other end of the slot and still way too much advance. What in tarnation...?

Took me a bit of puzzling before I realized the distributor drive gear has an odd number of teeth, whereas the other end of the distributor shaft has two opposing posts coupling it to the centrifugal-advance mechanism -- meaning, if you reassemble the distributor with the advance mechanism riding those two posts the wrong way around, your ignition timing will wind up, at best, effectively a "half-tooth" off one way or the other.

So I took apart the distributor again, reassembled it with the advance mechanism rotated 180° around, and was finally able to get my ignition timing in spec!

[camoit]

Did you set the cam timing correctly? See the pictures in this thread.
http://www.mightyram50.net/vbulletin/showthread.php/2258-G63B-2-0L-Cam-Timing-Mark

[geezer101]

If you have the distributor fully advanced or retarded to get it to run, that's a sure sign you've got it installed out of sync. It is acting like it's half a tooth out - can't get it to dial in either way as SubG has stated.

[xboxrox]

Could it be the #1 or all the plug wires are off 90° on the distributor cap ?

[BillHilly]

Sorry for so long for a reply. So long story short, i couldn't get the pulley off the bottom to take the timing cover off, so I did the top cover. I bumped the starter til the cam shaft mark was close and then tuned it in with a ratchet, and then just pulled the distro and set the dimple in line and slid it back in. A little bit of adjustment and it idles and runs MUCH, MUCH better. Still needs a full on timing job to get any last little bit, but it idles smooth and doesn't miss so I'm waiting on that.

[geezer101]

Excellent. When setting up the ignition timing you can find an extra bit of performance by experimenting with advance and plug gaps. Don't forget to put the ECU into diagnostic/tune mode by grounding the wire in the engine bay or it won't accept the new tune.