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Exhaust Rockers broken
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=82225		 Page 1 of 2
Author:  bugnout [ Mon May 25, 2015 1:26 pm ]
Post subject:  Exhaust Rockers broken
Ok, My liberty has been collecting dust for 6 months, finally got around to taking it apart to see what was wrong with it. Looks like I broke all the exhaust rockers. This occurred immediately after I put it back together last August after re-torquing the ARP head studs. I'm pretty sure I got the timing off by a tooth.

When I inserted the pins this time, I had no trouble getting the cam pins in, but I had to rotate the engine slightly to get the flexplate lock in. Everything is locked in place now. So question to anyone has done this, Should I replace all the rockers? The intake rockers look good, no bending, but I'm leaning toward replacing all rockers now. Timing belt has maybe 15k on it. Should I replace it as well? could it have stretched or is it more likely I just was off 1 tooth on the crank?

Opinions?
Author:  geordi [ Mon May 25, 2015 1:52 pm ]
Post subject:  Re: Exhaust Rockers broken
bugnout wrote:
Ok, My liberty has been collecting dust for 6 months, finally got around to taking it apart to see what was wrong with it. Looks like I broke all the exhaust rockers. This occurred immediately after I put it back together last August after re-torquing the ARP head studs. I'm pretty sure I got the timing off by a tooth.

When I inserted the pins this time, I had no trouble getting the cam pins in, but I had to rotate the engine slightly to get the flexplate lock in. Everything is locked in place now. So question to anyone has done this, Should I replace all the rockers? The intake rockers look good, no bending, but I'm leaning toward replacing all rockers now. Timing belt has maybe 15k on it. Should I replace it as well? could it have stretched or is it more likely I just was off 1 tooth on the crank?

Opinions?


The rockers don't have a maintenance schedule, they are a "replace when broken" type of part. So it is really a coin flip to me. The main thing I look for is that the bolt holes in the crank are perfectly vertical and horizontal, and that the cams are held with a counter-hold device AFTER the belt is installed and BEFORE the bolts are torqued to 80. The factory device may not match where the teeth in the belt want to be, which can stress the system to not being perfectly in time when the clamp is removed.
Author:  olypopper [ Mon May 25, 2015 1:58 pm ]
Post subject:  Re: Exhaust Rockers broken
Do the rockers AND the belt! You are right there, may as well start fresh.
Author:  papaindigo [ Mon May 25, 2015 2:00 pm ]
Post subject:  Re: Exhaust Rockers broken
Comments:
1. "I had no trouble getting the cam pins in, but I had to rotate the engine slightly to get the flexplate lock in." Can I assume you mean you had the cam pins in; timing belt off; and then had to rotate the engine to get the flywheel pin in? If so then yes you were off probably more than one tooth. Any way best double check that flywheel pin as there are multiple holes in the flywheel. Two things to look for 1) the bolt holes on the crankshaft for the damper should align at 12/3/6/9 o'clock and the dimple/witness (somewhat hard to see but it is there) mark must be at 3 o'clock and 2) grab a long shaft 6mm or 1/4" hex key and insert it in the flywheel pin hole-use it to tap around the hole in the flywheel to make sure you are inserting it into a small hole-once in the "handle" end should be vertical as in the 05 FSM illustration.
2. you know 8 are damaged so that's $240 from idparts and the other 8 might be damaged so that's $370 from idparts and you are already in there. I think the answer is obvious why worry about $130 when it's only the life of your engine.
3. pretty much the same for the timing belt which is all of $75 on Amazon. Assuming you did your "pulley" type things associated with the timing belt they should be ok but I'd check the back side for leaking grease just in case. I recently was involved in a TB job at 50K miles and both idlers were leaking grease.
Author:  thermorex [ Mon May 25, 2015 5:30 pm ]
Post subject:  Re: Exhaust Rockers broken
+1 checking the pulleys for leaking Grease, I saw on mine when I inspected them few thousand miles back when I had a bearing squeal (which ended being the fuel pump pulley) and one of the bearings had a small leak. I ended up replacing it just in case, even though it "behaved" like the good one, and it may have been just some extra grease that was pushed out.
Author:  bugnout [ Mon May 25, 2015 6:47 pm ]
Post subject:  Re: Exhaust Rockers broken
thanks guys, pulleys both look good, no grease. I guess for the money, might as well replace the other rockers and get a new belt.

Papa, your description is correct, I was able to get hex key into the hole at an angle. Moved the crank to get it lined up straight then inserted the Sealy ping through the whole. Just went out to look at it, and seems the bolt holes for the crank shaft damper do not align vertically and horizontally. Guess I'll remove the pin and stick a dowel down the #1 injector hole and verify 90 past TDC. Is the witness mark on the damper plate or on the block side of the timing gear?
Author:  geordi [ Mon May 25, 2015 9:19 pm ]
Post subject:  Re: Exhaust Rockers broken
It is a little rectangular divot right at the base of the nut. That declares TDC, and should be under one of the bolt holes. Turn 90 clockwise from that point and stop when the bolt holes are perfectly vertical and you will be set.
Author:  papaindigo [ Tue May 26, 2015 8:37 am ]
Post subject:  Re: Exhaust Rockers broken
Go to http://www.greendieselengineering.com/j ... st/72.page and click on the document link then go to page 10 and enlarge the page. The bottom image shows the crank and the mark properly aligned.
Author:  Mountainman [ Tue May 26, 2015 1:56 pm ]
Post subject:  Re: Exhaust Rockers broken
working yourself to death. crank mark at 3 o'clock exactly with the holes vertical and horizontal. Then if both cam pins line up with nothing more than a slight bump (crank holes still perfect) that's it. Tighten it down, and then rotate the engine two revolutions, with the crank holes perfect again, and if the CAM pins go back in like before (you might have to slightly bump the crank one way or the other), you got it. A level on the vertical axis might be a way to make certain that the holes are perfect, if you can see the bubble, but the cam pins won't go in if it's off. If they won't go in, loosen cam gears and try again.

Forget the crank pinning, it's a waste of time :2cents:
Author:  bugnout [ Tue May 26, 2015 8:44 pm ]
Post subject:  Re: Exhaust Rockers broken
I wonder what hole the pin was actually in, certainly not the correct one. Looks like the crank was off by more than a couple of teeth. I've got it at 90 past TDC now and as you said, damper bolt holes go north south and east west.

Just to be sure, there is no other timing concern for crank position other than 90 past TDC on number one cylinder right?

Wasn't able to see the mark on the crank, but I'm going to paint a mark on the bolt and on the mounting surface for the damper
Author:  Mountainman [ Tue May 26, 2015 9:07 pm ]
Post subject:  Re: Exhaust Rockers broken
bugnout wrote:
I wonder what hole the pin was actually in, certainly not the correct one. Looks like the crank was off by more than a couple of teeth. I've got it at 90 past TDC now and as you said, damper bolt holes go north south and east west.

Just to be sure, there is no other timing concern for crank position other than 90 past TDC on number one cylinder right?

Wasn't able to see the mark on the crank, but I'm going to paint a mark on the bolt and on the mounting surface for the damper


That's right, but I would get a good light in there, and maybe some wire brush work to get the mark visible. It should be just to the right of center/3 o'clock.
I imagine you already know, but the cams will only line up every other time, so hence the two rotations for verification. Or, in other words, a person might get confused when the crank is in the right spot, but the cams won't pin, and they just need to rotate the crank 360.

The two rotation verification is mandatory as far as I'm concerned. I'd check it even if I did 100 of these, just to make sure that I'm not off a tooth.
Author:  geordi [ Wed May 27, 2015 1:39 am ]
Post subject:  Re: Exhaust Rockers broken
I ALWAYS do the double rotation, and I've done enough of these that I could probably assemble the engine blindfolded.

At no point is the crankshaft pin worth anything more than annoyance and a backache from getting up and down so many times. Forget about it.

The reason you have to rotate the crank twice is simple fractions. The crank is 1/2 the size of the cams, so it spins at twice the speed. The fuel pump (which has a timing divot in the shoulder of the pulley that matches a raised bump just under that small bolt right next to the fuel pulley) is 2/3 the size of the cam pulleys, so spins at 2/3 the speed. This is how a 4-cylinder engine can have a 3-lobed pump match up with every single cylinder injection event.

I always time the fuel pump too when I'm doing it. It has a mark, so why not? It must be important to be there. As far as setting the cam locations in relation to the crankshaft - the cams should have the pins fully threaded in, and then the pulleys should be UNLOCKED if you need to adjust the position of the crankshaft to the correct spot. If you encounter resistance, you can remove the pins (put a tiny amount of torque on the cam bolts first) and then "bump" the cams clockwise slightly. They will roll off the lobes and all the valves will snap closed. Now you can rotate the crank until next Tuesday and not bother anything at all.

Once the crank is in the proper 90 ATDC and the holes are vertical, rotate each cam 360 using a socket wrench and feel when the pin will re-insert, and thread it back in. Now you can un-torque the bolt (tiny bit of torque, remember?) and resume assembling the timing belt - with the cam bolts backed out just a touch so the pulleys can rotate freely until the belt and everything else is satisfactory - then tension the belt and FINALLY torque the cams to 80 lb-ft with the holding bar. NOW, pull the pins and rotate twice, check (fix) the tension when the pins are verified... And you are finally ready for the test start.

Yes - I hold my breath each time too at this point. It is a scary motor.
Author:  bugnout [ Wed May 27, 2015 10:53 am ]
Post subject:  Re: Exhaust Rockers broken
Excellent advice, thank you.

Knowing now, that there are multiple holes in the flywheel, I'll never try to pin it again. Much more confident that I can get it lined up now that I know what I'm looking for. I like the idea of rotating the cams 360, builds confidence that the valve train is working smoothly.

Parts are on order but probably be a couple of weeks before I can reassemble. Work keeps getting in the way of fun...
Author:  papaindigo [ Wed May 27, 2015 11:10 am ]
Post subject:  Re: Exhaust Rockers broken
With respect to the flywheel holes see the link I posted above and scroll to page 13 for pics of using a hex key and the actual flywheel holes. For what it's worth the Miller tool is pretty much useless a) the threads are likely crudded up so the tool won't thread in anyway and b) in theory it is possible to slip the tool into one of the big holes and not know it. Using a hex key it's very easy to tap around the hole and be positive the key it going into the right place. Just a bit of added comfort if the crank bolt holes and dimple are in the proper location.

Just to make it crystal clear. My comments on how to do the tb job are based on starting the job with at engine that you are absolutely positive is in time. In the 2 cases I was heavily involved in both engines were at about 50k miles and had never been opened up.
Author:  Rixram [ Mon Jun 01, 2015 12:40 pm ]
Post subject:  Re: Exhaust Rockers broken
bugnout wrote:
Ok, My liberty has been collecting dust for 6 months, finally got around to taking it apart to see what was wrong with it. Looks like I broke all the exhaust rockers. This occurred immediately after I put it back together last August after re-torquing the ARP head studs. I'm pretty sure I got the timing off by a tooth.

When I inserted the pins this time, I had no trouble getting the cam pins in, but I had to rotate the engine slightly to get the flexplate lock in. Everything is locked in place now. So question to anyone has done this, Should I replace all the rockers? The intake rockers look good, no bending, but I'm leaning toward replacing all rockers now. Timing belt has maybe 15k on it. Should I replace it as well? could it have stretched or is it more likely I just was off 1 tooth on the crank?

Opinions?


I'll just say that if it were mine, I'd replace all the rockers at once. Keep them all the same age and wear level.
Author:  Dent [ Tue Jun 02, 2015 12:37 am ]
Post subject:  Re: Exhaust Rockers broken
geordi wrote:
Once the crank is in the proper 90 ATDC and the holes are vertical, rotate each cam 360 using a socket wrench and feel when the pin will re-insert, and thread it back in.


Why do you do this? If I understand you correctly, the engine is at 90 ATDC, the cams are pinned. The timing belt has been removed. You then remove the cam pins and rotate each cam 360 degrees and repin? Is that to just make sure that there was no stress on the cam pins? Why not just pull pin and rotate cam a little back and forth to make sure pin goes in without binding. Not contradicting, just trying to understand. I guess when #1 is at 90 ATDC none of the other pistons are at the top? If they were, rotating the cams would be bad. Or am I completely missing something?
Author:  WWDiesel [ Tue Jun 02, 2015 6:40 am ]
Post subject:  Re: Exhaust Rockers broken
With the crankshaft setting at 90 degrees ATDC, all the pistons are at half stroke in the block, so rotating the cams and operating the valves is allowable since no valves will contact any of the piston tops.... :wink:
Author:  geordi [ Tue Jun 02, 2015 10:30 pm ]
Post subject:  Re: Exhaust Rockers broken
Dent wrote:
geordi wrote:
Once the crank is in the proper 90 ATDC and the holes are vertical, rotate each cam 360 using a socket wrench and feel when the pin will re-insert, and thread it back in.


Why do you do this? If I understand you correctly, the engine is at 90 ATDC, the cams are pinned. The timing belt has been removed. You then remove the cam pins and rotate each cam 360 degrees and repin? Is that to just make sure that there was no stress on the cam pins? Why not just pull pin and rotate cam a little back and forth to make sure pin goes in without binding. Not contradicting, just trying to understand. I guess when #1 is at 90 ATDC none of the other pistons are at the top? If they were, rotating the cams would be bad. Or am I completely missing something?


This is what I had posted above: "the cams should have the pins fully threaded in, and then the pulleys should be UNLOCKED if you need to adjust the position of the crankshaft to the correct spot. If you encounter resistance, you can remove the pins (put a tiny amount of torque on the cam bolts first) and then "bump" the cams clockwise slightly. They will roll off the lobes and all the valves will snap closed. Now you can rotate the crank until next Tuesday and not bother anything at all."

The point is that if you can get the cam pins in, but someone didn't do the timing correctly and the bolt holes in the crankshaft aren't vertical and horizontal, you have a very limited amount of rotation before the pistons impact the opened valve. Normally it should be more than enough... But it might not be. The reasons you might need to rotate the cams off the lobes include checking a fresh rocker install or just feeling that they feel OK before repositioning everything into perfect time.
Author:  bugnout [ Sat Jun 13, 2015 5:15 pm ]
Post subject:  Re: Exhaust Rockers broken
ITS ALIVE!!!!!

Timing is right on. Found the crank mark, rotated the cams after I torqued the intake bolts down just to make sure all the rockers and valves were working. rotated the engine twice and reinserted the pins without an issue. rotated until the fuel pump mark lined up again and checked tension which was still ok.

Got the fuel rail and #4 injector wiring reversed, easily fixed, then blew off the charge hose on first spool up of the turbo. I, of course, forgot to pack tools with me so drove the 2 miles home blowing smoke. Second test drive went without a hitch, no codes, good temp, turbo spools right up. Nice to be back on the road after 6 months in the garage.
Author:  Rixram [ Sat Jun 13, 2015 7:11 pm ]
Post subject:  Re: Exhaust Rockers broken
Congrats!
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