95 Lumina 3.4 DOHC Timing

[colt]

Hello, i have a 95 Lumina that was given to me by my Grandma, I just rolled my other car(the day after i bought it, drunk like a jack ass. never again) anyway it had blown head gaskets, but in good shape other wise, only 75k miles. I already replaced the head gaskets, but i tried timing it without the hold down tools using the factory marks, and its so off it wont even run. So i started researching how its supposed to be done, and really haven't found a good write-up on it. Though i think i pretty much understand the idea, my main concern is the hold down tools. I'm short on cash, and really don't want to pay that much for them. Does anyone have a blue-print or a template for them? Pics of homemade ones? Any help is appreciated. Also while I'm at it, how strong are these motors stock? I'm thinking about trying to pic up a m90 and rigging it up, but that's down the road. Right now i just really need to get the timing figured out.

[Psych0matt]

I used the factory marks successfully... once. I got to the point once where I was able to tear it down and line up the marks and have it all back together in under an hour. That was with a different top end, so something wasn't lining up.Luckily with as much other crap I've had to do I haven't had to time one again. What procedure are you doing, and what have you replaced?

[White93z34]

I would never trust whatever paint gm called timing marks, If they happen to line up with anything its dumb luck

 

Since you have a 95' you should be fine without a cog remover.

 

Basically, the hold down tool is just a flat piece of metal with a hole in it and a bolt to bolt to the top of the cam carrier. I can take pictures of my original Kent Moore ones If you'd like

 

If i were to guess the bolts are M8 or M10, probably 1.5 thread pitch

 

You could make them rather easily.

 

But basically:

 

Turn the crank to the timing mark on the lower cover.

 

install cam hold down tools on the cam falts, IIRC 10ft lb, its not much.

 

break all the bolts on the cogs loose and get the cogs spinning free

 

turn the spring tensioner back with a small screwdriver through the bottom, pin it in the rubber plug up top

Fill the spring tensioner with oil through the rubber plug on the bottom

 

put the belt on, add tension to it.

-remove the spring, and I THINK add 10ft lb to the tensioner idler

 

**Its been a long time since i did this, check my directions to a manual**

tighten the rear cogs, remove front hold down tool

 

rotate engine 360* back to timing mark, rear cam flats should be down, fronts still up.

 

tighten front cam cogs, remove tool

 

rotate engine a few times observing timing is correct.

 

Done.

[Galaxie500XL]

The timing marks were around 6 degrees off on my '95 when I replaced the timing belt. It's easy, though to verify.  All you need is a wooden dowel, and a way to mark the balancer. I'm getting ready for work right now, I'll explain later how to do that. 

[colt]

I would never trust whatever paint gm called timing marks, If they happen to line up with anything its dumb luck

 

Since you have a 95' you should be fine without a cog remover.

 

Basically, the hold down tool is just a flat piece of metal with a hole in it and a bolt to bolt to the top of the cam carrier. I can take pictures of my original Kent Moore ones If you'd like

 

If i were to guess the bolts are M8 or M10, probably 1.5 thread pitch

 

You could make them rather easily.

 

But basically:

 

Turn the crank to the timing mark on the lower cover.

 

install cam hold down tools on the cam falts, IIRC 10ft lb, its not much.

 

break all the bolts on the cogs loose and get the cogs spinning free

 

turn the spring tensioner back with a small screwdriver through the bottom, pin it in the rubber plug up top

Fill the spring tensioner with oil through the rubber plug on the bottom

 

put the belt on, add tension to it.

-remove the spring, and I THINK add 10ft lb to the tensioner idler

 

**Its been a long time since i did this, check my directions to a manual**

tighten the rear cogs, remove front hold down tool

 

rotate engine 360* back to timing mark, rear cam flats should be down, fronts still up.

 

tighten front cam cogs, remove tool

 

rotate engine a few times observing timing is correct.

 

Done.

 

So i dont need to puller to get them off? and yeah a picture would be nice, the only picture ive found specifically for this is like an illistration, what gauge bar do you think it would need to be made out of?

[Galaxie500XL]

...and I'm back.

 

Finding true TDC is easy with nothing more than a wooden dowel that's the right diameter to fit in the spark plug hole, a wrench and socket to turn the balancer, some chalk, and paint to make a permanent mark.

 

• Remove #1 spark plug
• Insert dowel in the spark plug hole...make sure the dowel is long enough not to fall completely into the cylinder
• Rotate the crank until the point the dowel JUST STOPS rising.
• Rotate backwards just a little, then forward again to verify where the piston stops rising.
• Make a chalk mark on the harmonic balancer, using the timing pin on the timing cover as a guide...make the mark directly below the timing pin.
• Rotate the engine a complete revolution in the opposite direction you originally turned the crank, and again stop at the exact point the dowel stops rising, checking again at least twice to make sure the piston is at the top of travel, and make a second chalk mark directly below the timing pin on the cover.
• At this point, you'll  have two chalk marks separated by several degrees.  Exact TDC is a point exactly midway between the two marks.  Make a permanent paint mark at this spot, and erase the two chalk marks to eliminate being confused which mark is which.

If yours is like mine was, you'll discover the new mark is actually several degrees off from where the slot is cut into the harmonic balancer, because the outer portion of the harmonic balancer has rotated a bit over the years.  From this point on, use only the paint mark to know exactly where TDC is.

[Galaxie500XL]

On my '95 I found breaking the timing gears loose from the cams, even with the bolts on the end completely removed, was something of a nightmare.  On these later engines, the timing gears are "locked" to the cams using a cone shaped collet, with a small split in it.  Theoretically, once the bolts are removed it should be easy to get the gears turning freely on the cams, but I found that a small bit of corrosion had sort of "welded" the timing gears to the cams.  A soft-faced hammer finally freed the collets from the cam gears, and allowed them to move, but it took way more effort than you'd expect to get the collets to move enough to surrender their death grip on the timing gear and cam.

 

Once I finally got them moving freely, I took a soft cloth and metal polish, and hand polished the end of the cam, and the cone shaped areas on the timing gear and collet, to remove the roughness corrosion had put there.  Made it very easy to do the rest of the job, and hopefully, make it easier the next time I had to take it apart.

 

Whatever you do, make sure to mechanically support the timing gear when trying to remove the large bolt, or install.  My first timing job, I naively assumed the cam hold-down tool would give me enough mechanical support to remove the timing gear bolts, and instead, I completely stripped the threads from the cam carrier that held the cam hold-down tool in place.  I ended up having to helicoil the cam carrier thread, and then bought the Kent-Moore specialty set to do the job.

 

Unfortunately, I had problems with the Kent-Moore gear support tool, too--the square drive in the tool quickly rounded, making the tool more or less useless.  I bought a cheap extension, and welded it permanently in place on the tool, and had no further issues.

[GOT2B GM]

I found on the 94+ taper lock style cam gears, if you loosen the bolts then hit the back of the gear with a piece of wood and a hammer (as to not damage the gear) they should pop free of the taper

Edited March 29, 2017 by GOT2B GM

[White93z34]

Like the other guys said the 94-97 cogs should come right off after you remove the bolts, but not always. follow their advise.

 

here's a picture of the hold down tools

 

 

The bolts are M8x 1.25

 

hopefully this helps

[colt]

I'm not really understanding how they work, there's only one bolt? What does it bolt to? Does one side hang over the edge of the cam carrier? Does any one have a picture of them in use?

[Galaxie500XL]

See if some of these pics and descriptions help. 

 

http://www.w-body.com/topic/48847-figured-thisd-be-interesting-csc/page-3

[colt]

I see now, thank-you. That's way different than what the real ones look like

[Galaxie500XL]

It can seem a little intimidating, but if you're comfortable with following instructions to the letter, and have some experience in working on your own car, it's not that bad.

 

I probably spent at least twice as long reading and reviewing the steps before beginning than it took to actually do the work.  Once I had them pretty much memorized, and completely understood, it really wasn't all that bad.  I ended up having to do mine twice...the second time, the actuator failed after only about 30,000 miles.  It took much less time to do it a second time.