Two months ago, I rebuilt the lower end of my B18 and removed the cam and distributor drive gear for inspection. I also installed an IPD support ring on the shaft's oil pump drive ears. Now, with engine assembled, I get flashes to my timing light (spark gets to plug wires), but it won't run and I'm getting really confused about the timing...have started to wonder if I made the mistake of misaligning the distributor drive. Help: DIY tips needed!

TDC is when A) the cam gear marks align and B) #1 cyl is at top of stroke, right?

How do I confirm distributor drive alignment?
What is the proper position for this gear shaft, viewing the drive notches from top with dist. removed, at TDC? With dist. installed, where should the rotor be pointing at TDC?

If needed, what is the chance I can pull this drive shaft out from the top and successfully get it back in the oil pump drive without opening engine case? I imagine a long screwdriver would help. Or, is that a waste of time: should I just drop the oil pan again?

?

If the advice of other posters is still not enough, see also: http://www.sw-em.com/Volvo%20Ignition%20from%20Scratch.htm

Cheers

While there is an optimum position for the distributor/oil pump drive gear,
it REALLY doesn't matter as long as you get the firing order right and the
rotor pointed to the same connector on the cap that has the wire going to #1
cylinder at TDC AND when both valves are completely closed.

Don't waste your time pulling the gear! Just be sure that where the rotor points
is where the #1 wire connects and the other wires are in the right order.

BTW #1 and #4 are at TDC at the same time but when #1 is at firing TDC, with both
valves closed, #4 is at overlap TDC with both valves slightly open. I would guess
that at least half of us, maybe more, have tried to get an engine to run with it
timed to fire at overlap rather than the end of the compression stroke once or
MORE!
--
George Downs, Bartlesville, Heart of the USA!

I'm going from memory, and another poster may have more accurate information, but, yes, TDC should be when the timing marks on the timing gears line up, and this should put cylinder #1 at TDC and its two valves closed. At this point, the distributor rotor should be pointing at approximately 9:30 or 10:00 o'clock when looking down at the distributor, with the front of the engine to your left. If this is true, then rotate the distributor body so that the small notch on the rim of the distributor is directly under the rotor. If this can be done, then you should be close enough with the timing to start the engine.

If the alignment of the rotor is a little off, and you can rotate the distributor as outlined above, you're OK. If the distributor drive gear is so far off that this doesn't work, then you can still get it fixed. Remove the distributor and reach down into the engine with a pair of needle-nose pliers, and lift the distributor drive gear up enough to be able to rotate it. Turn it one way or the other as needed to correct the mis-alignment, and then slide it back down. It will rotate as the teeth engage with the cam, so you have to anticipate how much it will change as it goes in. It may not engage with the oil pump, depending on how much you had to rotate it, so you may have to pre-align the oil pump shaft with a screwdriver first.

(The first time I rebuilt an engine, I had the distributor in 180 degrees off because I timed it to cylinder #1 at TDC on the exhaust stroke. Rookie mistake).

Hope that helps. Not exactly 10,000 words, however, I hope it gives you the picture.

Steve

Thanks, this helps, I think. However, I just located the old green Volvo service manual (it gives about 3 sentences on this topic) and it mentions and pictures an angle for putting the drive gear in when the TDC is on #1 as descrbed. However, it also states that "when the line-up marks on the timing gears coincide, #4 piston is in its TDC position". How do I interpret this? Is there a good web tech bulletin someone can refer me to?

Regarding the info in the "green book" -- when installing the cam and gears the marks align with the #4 cylinder in TDC-firing position--it is confusing. Don't take your pan off. Remove your valve cover, turn the motor by the pulley bolt until the timing mark on the pulley and timing gear cover align and you have clearance at both the intake and exhaust rockers on #1 cylinder. If they are tight and the rockers for #4 have clearance, rotate the motor another full turn. Now you can withdraw the distributor drive gear and set it in place as the book shows, so the distibutor rotor will point forward and a little towards the block when looking at the motor from the front. You can rotate the oil pump shaft easily with a long screwdriver--it only has to be close. With a wrench on the front pulley bolt rock the engine back and forth while pushing the distributor drive gear down to seat it into the oil pump. The distributor should fall into place with the hash mark on the top edge for #1 in the forward/slightly towards the block position. That position will allow for the vacuum retard/advance to have clearance.

Here is the easy way to check top dead center remove the #1 plug insert finger into the plug hole tap starter(wifes Job) till it blows your finger out look at the timing markes on the cover they should be close if not take your 13/16 wrench and aline it up remember the rotor goes counter clock wise Dick