What kind of sealant for the cam cover?

[BlackBart]

In reading through my guides, it appears that as long as the cam wheels are close to correct position, once the cover is on and the tool locked, there is adjustment in both the big cam bolt and the three sprocket bolts to get the timing alignment right. I'll check again but that's my reading.

Re: an earlier post, Volvo's instructions specify to apply the sealant to the underside of the cam cover and not to the head. If I had to guess, I'd say this is for the following reasons:
1. You can easily take the cam cover out and put it on a workbench or other clean and proper work surface to make the job easier.
2. There's less chance of the sealant dripping into the head and gunking things up if you apply it to the cam cover.

I think this is right, and another important thing - the valve cover has the oil galleries cast into it, the top of the head is flat. If you roll sealant onto the head surface, there will be goop exposed inside the galleries.

[BlackBart]

On the cleaning issue, I gave it another try after it cooled down a bit last night. I just used brake cleaner and a beat up brass tooth brush and scrubbed. Slow and steady, it got all the varnish off the upper cover. Run a bit of weed eater line through the cam bearing oil passages and give them a squirt of brake cleaner to flush them out.

The top of the head surface is just stain in the oil galleries as RickHaleParker mentioned above. There shouldn't be any sealant on those areas anyway.

[BlackBart]

OK, I'm a dope and being too careful.

The VVT hubs have to come off anyway in order to replace the oil seals, so it's not necessary to install the hub on the cam before setting the top of the head. Besides, the sprocket wheel bolts get in the way when you're trying to align it on the dowels.

But finally some progress!

Some notes:
- The cam lock tool bolts are likely a hair too long and will bottom out in the hole before the tool is snugged down. This is what caused my mistake in the first place - trying to crank it down snug and I snapped the bolt. So I stacked some washers under the bolt head - a 1/4" or more - and snugged it down with one hand on the ratchet. Plenty tight, the teeth are engaged with the cam. The big cam bolt came off easily with a T55, 1/2 to 3/8 adapter, and a normal breaker bar.

- The anaerobic stuff is very sticky. Hard to get it spread evenly on your roller. You don't want globs on the upper head. Even with a very thin film, there is some squeeze out - this is a very precise fit between halves. I used most of a tube.

- Be careful of the wire you use to "hang" the cams from the upper head when upside down. The only big mistake I made (other than sticking my thumb into the sealant) was getting that wire (mine was almost coat hanger thick) pinched on the oil seal flange of the intake cam. I had started to snug all the bolts down and realized the wire wasn't coming out. Had to back off all the bolts, pry it up a couple of mm, then pull the wire out. No damage done, just time.


My surgical "clean room." All good until the cat jumped in the window and almost walked across it.

The cam lock tool has a little flange in the center that swings - hook it over the top of the cam cover to hang the tails of the cams from the cover. You DON'T want to put any leverage on those aluminum "fins" in the cover at the sprocket end.

Be careful of the wire. I would use something lighter than this. The bolts will keep falling out until you get it flipped over. Don't touch the red goop!

Clean, new o-rings, assembly lube at bearing surfaces. I shop vac'd all my grit out of the lifter cup recesses, removed and cleaned all the cups, liberally oiled them, and slid them back in. ONE AT A TIME - PUT THEM IN THE SAME HOLES.

I rented the pull-down tool from my friend the VW-Audi mechanic. Goes much faster. Be careful of your spark plug threads however.

Stack some washers to prevent bottoming these little bolts and over-torquing them.

My homemade timing scratch marks in lieu of paint.

[BlackBart]

Where to set the front cam seals?

When I read "flush with the head," I'm thinking that means flush with the outer face of the cam cover. Or does that mean flush with the inside of the 45º bevel just inside the face?

I've seen mentions of putting them too far back into the hole, although the book tells you to tap them home.

<EDIT> most everything I've now read says flush with the outer face of the block (head). Otherwise the seal lip is too close to the end of the VVT hub sealing surface.

That's what I did.

[precopster]

It largely depends on the axial play present in the VVT hubs. Recently on a customer's car with around 2.5mm axial play I drove the cam seals about 1mm past the flush point into the head.....big mistake and leaks were so bad I had to redo it.

On the other hand you want them deep enough that they can't slip back out.

Axial play is easy to measure. When the VVT hubs are new there is zero axial play.

[BlackBart]

^^ thank you.

So I fussed with the belt and all the variables of dual VVT sprockets until....I think......I have it all lined up and tensioned.

Question - If the crank timing mark is on, both outer sprocket timing marks are really close on the plastic cover notches, both cams are locked, and the 3 sprocket bolts were never loose......it should be timed correctly, shouldn't it?

I found my old paint marks on the bodies of the VVT solenoid housings, but based on the guides and videos I saw, the "resting position" I marked was before the belt was off, and is NOT the farthest forward (clockwise rotation - towards the front of the car) position of the VVT hubs. It's somewhere in the middle. I rotated the sprockets all the way around clockwise (with the big bolt just barely snugged) until my paint marks were close on the back, aligned my fore & aft range marks on the head, snugged the bolts, then went to the front with the cover on and they were fairly close to the factory timing notches.

When you think you're just a hair off the plastic notches, measure the teeth on the cam wheels - there's almost a centimeter between teeth, so if you move the belt you'll be way off. I think this must be it, but I never felt like the belt from the crank to the intake wheels was as taut as it should be while installing it.

I torqued the big cam bolts (again) to 88. Now I'll pull the lock tool, install the rear seals, and turn it over a few times to see where it lands. Fingers crossed.

[BlackBart]

Judgement calls on engines drive me nuts. It's a mathematical device, it should be more exact than trying to see with one eye, between pulleys, past the flashlight, down to some fat marks on the crank to see if they're centered on a tab at a weird angle. I guess I should get an impact gun and pull the big crank pulley next time. Still a dumb angle, and "split the difference" between two teeth. Just cast a serious blade on the block that sits right on one tooth.

Then at the cams, you have fat notches in a flimsy piece of plastic in a totally different plane than the cam wheels. Strut tower is in the way, can't look straight at it.

"Oh, yeah, that's pretty close!" Why engineer all this precise valve timing gear if the marks are "close enuf?"

[BlackBart]

I think I'll re-do it from scratch. The exhaust cam seems to be right, but when all my crank and timing marks are close, the intake cam slots are not lined up at the back of the head.

Reading thru instructions, I don't know that I rotated the hubs to their clockwise limit at the timing mark before tightening. I set them at the paint mark resting position from before pulling the belt. (from the Paradox Tech video)

As many before me have said, it would be nice to have a keyed location for the hub on the camshaft. Then the hub internals could rotate the toothed wheel to advance or retard.

[abscate]

Once you have it in, turn the crank two revolutions and then check that the marks line up.

You might find it’s one tooth off, a top which point you will pop a code for cam limit, and then just slip it one tooth.

This quicker than trying to line up the imprecise marks, agreed.

Don’t forget it’s much easier to put the last belt loop back on the water pump than the idler pulley

[BlackBart]

You might find it’s one tooth off, at which point you will pop a code for cam limit, and then just slip it one tooth.

It really bugs me that guides say the timing marks on the sprockets are arbitrary, and might not line up - "just loosen the small bolts and spin the sprocket to align"...or "file a new mark on the wheel for next time."

But then the next time the marks are "arbitrary?" ??

Timing is on, or it's not on.