Cylinder head wear...

[dhirocz]

...just trying to do my I's and cross my t's here.

Short background, my 871 suffered a cam failure at 685k miles. Engine still ran great up to that point. Waited for 4 (!*#$) months waiting for the company to keep their promise and assist me in an inframe. After getting the run-around, I'm not only told that they basically lied to me, but I was loosing my loaner truck.

Upon a second inspection, I found not only #5 intake pitted and chewing the cam, but #1 intake roller LOCKED UP and was skidding on the cam. I just found it...made a nice flat spot on the roller and just started eating the ramps on the #1 intake lobe as well. At this point, I'm committed to repair seeing as it won't last long.

Upon disassembly I find the cam bearings are shot, all injectors pass a cut off and leakdown test, bottom end in good shape minus the little bit of metal I flushed out of the pan. Liners are decent, I suppose typical of an engine of that age (boroscope/bottom of liner inspection) All other rockers were ok, crossheads in great shape. Engine has had regular oil changes since 605k (since I got it) and a bypass filter. All rockers were flushed with brake cleaner and did not appear to be plugged. Oil pressure was typical. Intake and exhaust port inspection shows slightly oily valve stems.

Keeping in mind I'm now on a very limited budget thanks to the loaner spending most of it's time in the shop, then getting taken away, I'm still wondering if the cam failure was a result of wear leading up to when I got it, cylinder head worn out, etc...

Up to this point, the plan was to swap cam bearings, injector o rings and valve stem seals, flush the engine, replace the oil cooler, valve cam and bad rockers, and reassemble to buy enough time to pay off the last $15k I owe and to save for an inframe out of pocket, since the company only cares to sell me a new $145k Pete with paccar power (no!).

Are there any other inspections I can do to the head, short of pulling the springs and inspecting the valves with my boroscope to gauge the condition of the head? At what mileage do worn isx heads typically break valves?

While I'd hate to pull the head, since I should really consider a piston and liner kit at that point, I also am kind of anal and don't want to only get a week of use before I get stranded somewhere. I need to consider that the locked up roller...which still rolled when it came off, by the way...might be a sign the head junk. I figure I really need to make sure this head is still serviceable before I go replacing cam bearings, etc...

It's a hard balancing act, seeing as I can't afford the head, piston and liner kit and the counterbore cutter.

Also, is there installed height and open/closed pressure specs available for the springs on isx heads? I do have a valve spring pressure checker. Also, if I knew the correct open height and acceptable range of wear for the seats I could judge the head that way by comparing those specs to my current open height.