Snapped camshaft at idle.

[Nevadan]

After removing the head I've inspected the cam followers. You can't see much in the first picture, but it shows all the followers.



The next two pictures show the two followers that have the small cracks in them, follower #3 and #7, which are above cylinder's #1 and #4.



The bottom end is o.k. (no bent rods) since all the pistons get to the same height when turning the crank.

[Nevadan]

This unfocused picture shows the crud in the intakes. The manifold itself looked just as bad.

[Nevadan]

There's also this crack in the head between the intake valve and the prechamber.



So......it WAS a good head that now needs a repair to the cam bearing base. I'll take it to a machine shop this week and see if they think the work can be done. Depending on the price and the availability of a good used head I'll make a decision about what way to go. Any input is welcome.

[v8volvo]

Ouch, that is pretty bad, I pictured just a pulled bearing cap stud but that looks like it is toast. To get that ripped cam bearing put back together at best would be lots of welding and a good line-bore, big bucks if you can find someone to do it, long odds on it being possible at all, and with that crack in addition you're better off starting over. Small cracks between the valve seats are permissible but a long crack in that location is a serious problem, that one's a goner.

On the upside, no question that crack was there before this timing belt episode occurred, and good likelihood it would have caused an issue down the road and condemned the head at that point anyway.... so at least you can reassure yourself that, other than the loss of the cam, having that motor apart would probably have been happening in the near future one way or another and you would be in the position of looking for a head sooner or later. Plus, this way you get to put it together and do the timing belt job only once -- and if it would have broken down later on due to that cracked casting, chances are it would have been in a place a lot less convenient than your own driveway!

How does the bottom end look otherwise, no scored bores or big ridge? If it ran well before this then safe to assume it's healthy but seeing a crack like that suggests it may have gotten hot or experienced a major coolant loss at some point so take a good look, with the crack there but no evidence of a blown HG could indicate it got hot quickly but not for very long which would have protected the bottom end. Sounds like all your rods are OK, given the relatively minimal lifter damage I would expect no problems down below. Those two aren't pushed up too bad.

Given the situation your easiest way forward may be to locate a complete good replacement head, give it whatever attention it needs, and bolt it on. Unfortunately with your cam gone, valvetrain components questionable after impact and the head casting shot, you don't have a lot that is useable there, so you need the whole works. Getting one complete as a package deal is probably easiest way to ensure you end up with everything you need. Might take some searching but they're out there, at least a few of us here may be able to help you out.

[745 TurboGreasel]

Yeah, that precup crack was something else, was it losing coolant at all?

for sure do not reuse the valves that cracked lifters, they like to drop a head in your motor a month or two down the line.

[v8volvo]

Originally Posted by 745 TurboGreasel

for sure do not reuse the valves that cracked lifters, they like to drop a head in your motor a month or two down the line.

Definitely, matter of fact I would not reuse any of the valves in that head unless there are some you are sure had no contact whatsoever, even a light kiss from a piston can cause the effect 745 describes... it's not pretty when it happens...

[Nevadan]

Thanks for the input. A picture does tell the story. I agree v8 that the head would have gone anyway. I only drove the car about 60 miles when I purchased it and there was no coolant leak or loss so the crack hadn't gone all the way through just yet.

The good news is that the bottom end is solid. The pistons all protrude the same and the cylinder walls still have some crosshatching on them. No major ridges in any of the cylinders and only slight vertical marks in cylinder #6.

#2 and #3


#1


#6


So now my search for a complete head continues.

Anders if you're looking at this I may still want the cam. I'm looking at an N/A head that needs the cam. I'll PM you once I have a little more data.

[745 TurboGreasel]

#3 I presume precup looks to have been coming loose, and starting to eat the piston too.
I would not be surprised if there are marks on the precups where they were machined along with the head, removing the stickout that is supposed to hold them in place.

[Nevadan]

The prechamber wasn't "loose" as it still required a punch to tap it out and there was no visible mark on the piston, nor was the gasket deformed from any prechamber movement. See the photos for the extent of the crack. It does not extend into the exhaust port. I think I'll save this head for future welding and machining work. There's a guy here who welded and machined a prechamber: http://picasaweb.google.com/itzdshtz...15251611814002. You can tell from his blog that he has the welding and machining equipment to do the work, but at least there's proof it has been done with good results. I also have a 2.0TD that had the cracks between the valves welded and machined, it was done before I purchased the head, but again, at least I know it was done.
Considering the rarity of the head and the fact that it isn't warped I'll put it on my shelf. See the next post for the ripped off cam bearing cap base.

From the prechamber side:

From the exhaust port side:

[Nevadan]

So here's some pictures of the cam bearing cap mount that was ripped off. I cut the broken cam so I could insert it into the cam bearing to test the fit. I also clamped the cap onto the base.

Picture without the cam from the front of the engine:

Picture with the cam inserted half way viewed from the rear of the engine:

Picture with the cam in place viewed from the rear of the engine:

As mentioned previously I'm thinking a longer stud could be bored and tapped into the head itself (below the broken off piece where there's about 1" of cast aluminum), then when the nut pulls the bearing cap down it would hold the broken piece into position. The majority of the force on the bearing is pushing up into the bearing cap. I'm just throwing ideas out there as this head will be on my "spares" shelf, and may only get used if we live in the world of "Mad Max" or "Book of Eli", but I like to have my options.