Cherockee

I'm an nearing the end of my motor build and I'm having some trouble getting the distributor to line up. I paid particular attention to the valve timing marks on the gears when installed. They lined up perfectly, except... what I've read in my manual is that you're suppose to turn the crank over until the dot on the cam gear is in the 3 o'clock position (assuming that 12 o'clock is along the center line of the crank and cam centers). Then you're suppose to count the number of pins between the cam gear mark and the crank gear mark- there's suppose to be 15 pins. Now maybe I'm missing something, and this is why I'm posting, but if the crank gear has 24 teeth, and the cam gear has 48 teeth, I can't see how I'd ever get 15 pins between the marks. And there are 64 pins btw.

After I put the harmonic balancer on and lined up the timing mark on compression stroke and at 0*, the distributor does not line up the the mounting hole in the block. It almost looks like I'm one tooth off because if I place the HB timing mark at 20* BTC the distributor would mount up fine. 24 teeth on the crank gear means 15* for each tooth. Am I thinking about this correctly?

I haven't pulled the timing cover off yet as its a real PITA but I'll attempt that tomorrow. Would it make sense to not have the timing marks on the gears line up but have the HB and distributor as they should?

Attached is the only pic I could find of the timing set installed... I thought I had another of the timing marks lined up together...
Any help is greatly appreciated.

Cherockee

So as I labored away trying to search this topic on the forums I found a few people who index their distributor ahead one tooth. I'm not ready to take that chance as this is a new motor build and hasn't been attempted to be started yet. I'd like things to line up like they're suppose to. Indexing the distributor this way will allow it to run but doesn't take into account that maybe the cam isn't running in time with the crank.

In another post some said the timing chain should only have 48 pins. Was there a change somewhere along the way and they added more pins?

Cherockee

Okay, I'm adding some info to help other who may search for this in the future. Although I still have a problem with getting the distributor to line up I was able to verify the number of pins between the dots should be 20, if you have a 24 tooth crank gear and a 48 tooth cam gear.

Old engine that was running before being taken apart (note the slack in the timing chain). Number of pins between dots=20


New timing set, number of pins between dots=20


This confirms I have the marks correctly lined up between the cam and the crank. Distributor still doesn't line up- next call is to the manufacture.

89 xj stroker

I just got done building my motor, and i followed the manual to get 15 pins between the two specified spots, then i just threw the rest together. I then put the #1 piston at tdc, used a screwdriver to turn the pump to where the distributer would slide in and dropped it in pointing a little bit in front of the #1 spark wire, and fired it up. It runs real good, no probs, i was especially happy because it was my first motor build and i did it all myself. Good luck!

Cherockee

This is how far off my distributor is:

cherokkee98

Cherockee

After putting my cap and rotor on last night I found I needed to bring the distributor counterclockwise one tooth to get it to point at the #1 cylinder plug. That really brings the cam sensor way off. I've come to the conclusion that the gear that drives the dizzy was not properly indexed on the cam when they created it, probably a flaw that was written into the program that grinds the cams. Looks like I might grind those "ears" off after all....

lawdog1068

I am having the same problem. I have line the gears and chain up as per the book said but after putting every thing but together it will not run over 2000rpm. It backfires thru the intake and the cel is giving a code of p1391 (intermittent loss of either camshaft or crankshaft position sensor ).

89 xj stroker

Have you tried starting the motor? I know that even if the cam sensor is off, after so many rotations, the computer takes over and just starts firing the injectors until it starts, and then it figures everything out.

89 xj stroker

Just replace the cps. Ive had that problem, and i just replaced it and it worked.

caged

there is a discussion on another site about this same topic.
i won't post the posters name here, but this is his post. it's better than what i could say, so i'll just copy his post here for you.

"Even though you can't adjust the timing the distributor still has to be indexed properly. I believe the max adjustment is 42 degrees before the rotor and hat distance is to much for the spark to jump but i could be wrong. Thats one of the main reasons they switched to coil packs- no limit. The tang on the bottom of the distributor is just for the oil pump. If you turned over the engine at all while the distributor was out then the cam moved and the oil pump didn't so it will be wrong. Also if you played with the distributor a bit putting it in and out then it could have rotated the oil pump as well. I really never trust the tang even if I pull it straight out and back in. If you have a new distributor then you are in luck because they usually come with a plastic alignment pin. Start by pulling number one spark plug and place your thumb over the hole. Rotate the engine manually until you feel pressure, you are now on the compression stroke. There should still be a timing tab by the harmonic balancer. Turn it until the indexing line is lined up with 0 degrees - this is TDC. If you have a new distributor with an alignment tab then all you have to do is use a long screwdriver to turn the oil pump so it will line up properly then drop the distributor in and pull the alignment pin. If you don't have the pin then start with the distributor turned about 3 cm from the place you want it to end up and drop it in. To know where you want it to end up put the cap on and draw a line on the side of the distributor where the plug for number one spark plug wire is. You want the rotor to point to just before or on that line. Next time you pull the distributor set the engine to TDC and mark the rotor prior to pulling it out and you will save yourself tons of problems."

hope this helps ya
cheers

lawdog1068

Ok riddle me this batman. I line my crank and cam up and it s on the ex stroke?

Cherockee

Wait, you have your timing marks on the cam gear and crank gear lined up dot to dot at their closest point of rotation and you have 20 pins between the timing marks when you turn your gears the way I have pictured them? The valves should be "timed" with the crank at this point. Keep in mind the timing mark on the HB will line up with TDC with both the exhaust stroke and compression stroke. You should be on compression stroke when you install the distributor.

Unfortunately when I have a pin inserted in the cam positioning sensor and try to drop the distributor in it will never line up with the mounting bolt in the block. The only reason this would happen is if the gear machined into the cam is not indexed properly, and again unfortunately this can not be corrected by doing anything other than grinding off the tabs (or having the cam ground corectly).

No, I have not started it yet, it's still on the engine stand. When I have this much time and money invested into this build I want it to be right. I have not brought myself to make what should be un-necessary modifications to my parts. I am also not willing to roll the dice and hope that the computer can "figure out and correct itself" with my $2500 motor.

Cherockee

Update: Still haven't got this straight yet.

After a call to the manufactur of the cam and speaking with some engineers that actually machined the cam, I found out that the drive gear is not idexed- they pretty much just put it on there and figured everyone would just adjust their distributor to correct it. One mystery solved, on to the next.

I may have picturs of this later, but with a drift pin in the alignment hole of the cam positioning sensor and distributor housing, the rotor doesn't point towards any spark plug wire. It's inbetween, which doesn't make any sense unless #1 cylinder doesn't fire on 0* TDC. So I'm wondering, would it make more sense to line up #1 spark plug wie with the rotor while the HB is pointed at 0* TDC, or... well, I dont' know what else? I suppose the cam positioning sensor would be more forgiving if its off, fuel will just pool behind the valve until it opens, right? I wouldn't want it to be late and fire the fuel injector after the valve closes... so frustrating.

Oh, and for the record, the FSM is wrong about the number of pins. Aparently the timing set was updated at some point and no one bothered to write a revision. Leads me to wonder if there should have been an update to how to install the distributor...

Help, please!!

lawdog1068

I was fighting my dist for days. I returned your message I put my cell number in it if you want to talk the problem over. And I can send pics too if you need it.