98sub2500leg Posted June 14, 2009 Share Posted June 14, 2009 After all that work, engine was being warmed up at idle, tb came off & broke the top left (passenger) side cover car stopped. Car stopped, heard a winding down like TB was skipping on the cam sprockets (it was pretty fast). Most likely have bent valves. Other than removing the timing covers for initial inspection, what is the best way to test it, compression, vacuum, both? Quote Link to comment Share on other sites More sharing options...
Olnick Posted June 14, 2009 Share Posted June 14, 2009 Oh man, I feel so bad for you. Now to try to figure out the "why?" Could the tensioner have failed? Is it the old style or the new one? Hang in there--you'll get it sorted out. Quote Link to comment Share on other sites More sharing options...
98sub2500leg Posted June 14, 2009 Author Share Posted June 14, 2009 Oh man, I feel so bad for you. Now to try to figure out the "why?" Could the tensioner have failed? Is it the old style or the new one? Hang in there--you'll get it sorted out. Thanks, yes I did replace the tensioner, used all OEM. Well the only consolation is that I have been through the learning curve. Spent a lot of time researching,documenting and cleaning engine & parts. Tear down should go a lot quicker. Quote Link to comment Share on other sites More sharing options...
ron917 Posted June 14, 2009 Share Posted June 14, 2009 Oh, man, that sucks! I feel bad for you, after all that hard work! Quote Link to comment Share on other sites More sharing options...
idosubaru Posted June 14, 2009 Share Posted June 14, 2009 You can reinstall everything and do a compression test to see which side is hosed. A leak down can be done without reinstalling everything though. I pulled a perfectly good timing belt off a 98 EJ25 wagon in the past week you can have it if yours is broken or damaged from skipping. Quote Link to comment Share on other sites More sharing options...
98sub2500leg Posted June 14, 2009 Author Share Posted June 14, 2009 Yeah, quite the bum deal. I pulled the left(passenger) side TC to find the left intake cam sprocket completely shattered, and that shattered the rear TC. All that started to puch the timing belt onto the cylinder head, but to my amazement, the TB may not have skipped, it actually looks like it may be held in place. Not sure if the new TB is compomised also. It only had 2-3 minutes of time on it. I did read from one post somewhere that someone recommended changing the cam sprockets when doing the TB. That was the only one, seemed that replacing them would have been overkill so I didn't. Anyone ever hear of them shattering before. I more of wonder why it would have shattered. There must have been something else wrong for that to happen. Too much of a coincidence for it to happen just after replacement. Quote Link to comment Share on other sites More sharing options...
98sub2500leg Posted June 14, 2009 Author Share Posted June 14, 2009 Oh man, I feel so bad for you. Now to try to figure out the "why?" Could the tensioner have failed? Is it the old style or the new one? Hang in there--you'll get it sorted out. This is the hydrolic type, align belt, pull pin. So far there is still tension on the belt (as much as I can see). Quote Link to comment Share on other sites More sharing options...
idosubaru Posted June 14, 2009 Share Posted June 14, 2009 your guess that's it's not a coincidence that you just did all this work and the pulley broke like that is dead on right. that cam pulley was previously stressed in some way to break like that. that woudl be sweet to have no damage. Quote Link to comment Share on other sites More sharing options...
ron917 Posted June 14, 2009 Share Posted June 14, 2009 I had a cam sprocket shatter on my '99 Outback. The camshaft had seized - same one, the passenger side intake. I really hope that didn't happen to your engine. Try turning that cam with a wrench, you'll know if it's seized. Quote Link to comment Share on other sites More sharing options...
davebugs Posted June 14, 2009 Share Posted June 14, 2009 Bummer. I've sold a few used cam sprockets but I've never had or seen one fail - and I get a lot of broken cars. If you go used and noone closer had one let me know. I believe I'll have to start to tear down a complete engine with bad bearings to get the parts. Did you remember to pull the pin on the tensioner? Did all seem well when you made 2 complete revolutions as part of teh TB replacement? Quote Link to comment Share on other sites More sharing options...
98sub2500leg Posted June 14, 2009 Author Share Posted June 14, 2009 I had a cam sprocket shatter on my '99 Outback. The camshaft had seized - same one, the passenger side intake. I really hope that didn't happen to your engine. Try turning that cam with a wrench, you'll know if it's seized. This can be useful info here, did it shatter after a short period of time when it was removed then reinstalled? What happened to the engine? the new TB was compromised a little bit, enough to replace. I took a break, getting back on the job. I will repost on update soon. Thanks for the input. Quote Link to comment Share on other sites More sharing options...
98sub2500leg Posted June 15, 2009 Author Share Posted June 15, 2009 Bummer. I've sold a few used cam sprockets but I've never had or seen one fail - and I get a lot of broken cars. If you go used and noone closer had one let me know. I believe I'll have to start to tear down a complete engine with bad bearings to get the parts. Did you remember to pull the pin on the tensioner? Did all seem well when you made 2 complete revolutions as part of teh TB replacement? Yes, I did remove the pin, in fact I spent an extra day making sure everything was in check; cam sprocket positions, timing marks, tooth count, pulled pin, rotated at least 2 full rev's. The car seemed to run well when I started it. I am thinking it either misfired and the force of the opposing sprockets jammed into that pulley or possibly the pulley was not quite seated all the way on the key way. They were all a tight fit. I'm talking maybe a few thousands of an inch then the bolt when torqued possibly could have put undue pressure on it. They seem to be made of phenolic material. Phenolic is stout, but brittle. It obviously broke due to some stress, question is from what. Since the cams are currently not at TDC position, I will have to wait until I get a new sprocket, then reinstall TB and position crank to TDC. I can probably move them by hand a little bit in the current position to see if they are frozen I still have my old TB, just need another right intake sprocket. I will test remove the old & repost. Thanks for the offer Dave, I will check if there is any locally first and get back with you. Quote Link to comment Share on other sites More sharing options...
ron917 Posted June 15, 2009 Share Posted June 15, 2009 This can be useful info here, did it shatter after a short period of time when it was removed then reinstalled? What happened to the engine? It went 13,000 miles after the HG job. I was driving, heard some chirping, then a thud, and the engine just quit. I knew the sprocket broke because a chunk of it was sitting on the block. After getting towed home, I found I couldn't turn that camshaft with a wrench. I don't know exactly what happened. The oil level was fine, and only 2,000 miles on the oil and filter. There had been some occasional rod knock (I thought it was piston slap at the time) in the days leading up to the cam seizure. I ordered a rebuilt and sent the old engine back as a core without opening it. Quote Link to comment Share on other sites More sharing options...
98sub2500leg Posted June 15, 2009 Author Share Posted June 15, 2009 Sounds like the same event here. The right intake cam sprocket exploded, but the right lower cam is locked. The left intake & exhaust cams seem ok. It's hard to tell what happened. I can't help wonder if it misfired (faulty crank or cam connection to ecu), stress on sprocket, bad tensioner? Thanks for the input Ron. Everything disconnected again, almost ready to pull engine. Has to come out in light of the stuck cam. This is a puzzle to me though why only one cam is stuck. I suppose it would depend on where in the stroke the valves hit. I would think both upper & lower would be bent. I suppose it would be more cost effective to buy a used head than have the one fixed if it can be fixed and also if it is only the one side. Quote Link to comment Share on other sites More sharing options...
mdjdc Posted June 15, 2009 Share Posted June 15, 2009 I have several heads in my shop. Let me know if you want one and we can work out a deal. Quote Link to comment Share on other sites More sharing options...
98sub2500leg Posted June 15, 2009 Author Share Posted June 15, 2009 I am still deciding on either replacing with a used head, or repairing existing. By the time I pay to have the existing one tested then fixed, it would probably be way more cost effective to replace with a used head. What would be the best way to go, try to find a sprocket, re-install the TB and dry test the engine with it still in or remove it, pull the heads and have them tested? Last time it was pulled, I should have tried to rig up the starter with the one bolt to the block and tested it at higher revs. Not sure if it is achievable with only the one starter bolt, but I believe that the torque on the one bolt should hold it. With the valve stuck, I figure a valve must be bent and can't clear the cylinder wall. If the cylinder wall is not scored the head may still be useable. Any ideas on the best way to go about this dilema? Has anyone ever re-used a new head gasket? Those weren't exactly cheap. Hate to have to buy new ones. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted June 15, 2009 Share Posted June 15, 2009 never reuse a head gasket, they are not designed for that. you'll likely be fine either way. use your existing heads and have a valve job done, i usually do a valve job anyway when i'm doing head work. i don't like leaving the old valve stem seals in there. or get new heads from mike, he's a good guy, that's always nicer than dealing with unknown yards. Quote Link to comment Share on other sites More sharing options...
davebugs Posted June 15, 2009 Share Posted June 15, 2009 I have trouble getting valve seals. But I've never had any be bad. And the shop I use for headwork says they don't even stock them for Suby's cause they almost never go bad. I was gonna offer a head that I have but they shouid be bent - idler failure. The other heads I have are 97's (that have the shims) and a 99 good engine that I wouldn't tear down to sell a head. Quote Link to comment Share on other sites More sharing options...
98sub2500leg Posted June 15, 2009 Author Share Posted June 15, 2009 I have trouble getting valve seals. But I've never had any be bad. And the shop I use for headwork says they don't even stock them for Suby's cause they almost never go bad. I was gonna offer a head that I have but they shouid be bent - idler failure. The other heads I have are 97's (that have the shims) and a 99 good engine that I wouldn't tear down to sell a head. I appreciate the thought. What would you say is the best way to check mine? If there is one or more bent valves, that is one thing, but if the head is damaged, I am resigned to buying used. Quote Link to comment Share on other sites More sharing options...
98sub2500leg Posted June 16, 2009 Author Share Posted June 16, 2009 Update: Engine is out, rt (passenger) valve cvr removed -right side cylinder is oil starved(haven't got to left side yet, but expect the same). Valves themselves seem ok from initial inspection. Front cam cap is scored, mid & end cam caps seems ok. The right exhaust front cam cap froze to the cam front bearing journal. Initial visual inspection of the Rt Ex. cam lobes look ok (haven't yet measured them) and the bearing journals also look ok except from the front which looks like aluminum residue from the scoring. I believe these only come in a set (cam & bearing caps). So far suspect oil pump or clogged oil passages. Anyone have this happen before with an oil pump where it fails to work after changing out the o ring? Since it worked before, I failed somewhere, and there is no way to test the system before install. I am leaning towards either a new pump or rebuilt. Anyone know a reliable source(s) for rebuilt oil pumps? or is there a reliable way to test the existing one? I'm sure a new one is an arm & a leg. Since I already lost my arm in when the cam seized I only have a leg left (just joking). Quote Link to comment Share on other sites More sharing options...
98sub2500leg Posted June 16, 2009 Author Share Posted June 16, 2009 Latest update: Removed left (drivers side) valve cover, which was loaded with oil. However, to me this isn't conclusive that the pump is working because the oil spout(fill) is on that side. The right side never saw a drop of oil. The oil filter was loaded with oil, but it's on the low side so I would expect it to fill regardless of pump operation. Still not sure if the pump just failed or just never primed. Maybe the oil was too thick to prime, I used 5w30. The lower cylinder oil passages are too huge to be clogged though and there is 2 of them on each side approx 1/2" x 1.25" on each port. Only lube that kept the right side going was the assembly lube I used, which on the bearing surfaces pretty much dried up. The lifters or buckets seem ok and still had a lot of grease on them. Their duty cycle is a fraction of that of the bearing surfaces. As scored as the bearing surfaces are, looks like the head needs replacing. Quote Link to comment Share on other sites More sharing options...
mdjdc Posted June 16, 2009 Share Posted June 16, 2009 The little tiny passages to the cam got clogged. I've not had this happen before, but i know people that have had it happen to them. Quote Link to comment Share on other sites More sharing options...
ron917 Posted June 16, 2009 Share Posted June 16, 2009 The builder of my rebuilt engine stated that clogged cam passages was the most likely cause of my camshaft seizure. They said that they see it often on these engines. Quote Link to comment Share on other sites More sharing options...
The Dude Posted June 16, 2009 Share Posted June 16, 2009 If you look through the archives you'll see that cam shaft seizure is a problem with 2.5 L DOHC engines. The oil passages to the cams are very narrow. Usually the failure occurs after engine work. The culprit? Almost always a piece of silicone sealant. Be very wary of slicone sealant ''squeeze out" when sealing any parts on this engine. Even a very tiny of stray silicone sealanr can cause cam failure. I thnk that the early 2.5L SOHC engines had narrow cam oil passages as well. Quote Link to comment Share on other sites More sharing options...
98sub2500leg Posted June 17, 2009 Author Share Posted June 17, 2009 If you look through the archives you'll see that cam shaft seizure is a problem with 2.5 L DOHC engines. The oil passages to the cams are very narrow. Usually the failure occurs after engine work. The culprit? Almost always a piece of silicone sealant. Be very wary of slicone sealant ''squeeze out" when sealing any parts on this engine. Even a very tiny of stray silicone sealanr can cause cam failure. I thnk that the early 2.5L SOHC engines had narrow cam oil passages as well. Yes dude your right, very narrow passages. I just posted update in another post. So far the ultragrey RTV that I used was confined to the gasket area and hardened very well. So far can't see any visual cloggage in the ports. I believe maybe using red dye and air may help to find if there is an internal passage clog. If not either the pump failed (still need to check pump specs. & measure) or the pump didn't prime due to too think oil (5w30) and/ or poor initial startup procedures. The main block cylinders had plenty of oil. The right side head(the good head with the oil spout over the valve cover) was saturated. Seemed like 1/3- 1/2 qt of oil came out when that valve cover was removed. The other head hadn't seen any oil. Quote Link to comment Share on other sites More sharing options...
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