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Cam Belt Snapped
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=79770		 Page 1 of 2
Author:  RTTT265 [ Sun Aug 03, 2014 4:55 pm ]
Post subject:  Cam Belt Snapped
OK Cambelt Snapped, have a few silly questions, but ill start with a little what happened.

Its my wifes truck, service history unknown, I had already purchased a new OE belt and tensioner, it was sitting on the shelf.

I was off work for the day as daughter was sick, and had the wifes car, I was driving and it just stalled accelerating slowly about 40 km/h. No noises, coasted to side of road.


Sent truck in to get cambelt installed and check for damage

They installed belt and I was told that engine was totally stuffed, and to get a new engine, with belt installed they
said it would not turn over by hand and would lock up.


I was thinking worst case, it would be broken rockers and I will give this a go myself as I have nothing to lose.

Then I was thinking the mechanics have no idea what they are doing and have put the new belt on wrong.


I have ordered a cam tool pin kit. While waiting I made some pins, have number one injector out, moved the crank to TDC, marked then moved another 90 degrees, pin slipped into flex plate, rotated intake cam shaft saw hole come around through oil fill, put pin into intake camshaft, lined up exhaust cam as well but was having trouble getting homemade pin in, but have cam close enough for now, until kit comes.

I ren-installed belt and can turn engine over by hand fine wiithout it locking up.


Questions:

1) Turning the cams over there are no horrible noises, and they are hard to turn and spring over like they are pushing valve springs, not a guarantee, but does this suggest rockers may be OK ??

2) How hard is it to turn the crank over on a CRD with one injector out, I feel like it should be harder to turn over, its like a normal low compression petrol engine???

3) On a budget is it worth me putting as much back together, ie get diesel pump hooked up, and trying to start it, before buying the new serp belt, water pump, thermo, and all the other bits i need to do if the engine is still OK ??

Thanks for any good advice given (not so much the 'should of changed the belt before it happened' ) :roll:
Author:  naturist [ Sun Aug 03, 2014 6:18 pm ]
Post subject:  Re: Cam Belt Snapped
You were driving at 40 km/h when the belt broke. The odds of no further damage are Zero. This is a seriously interference engine, and if it was turning over (when else would it break?), I guarantee valve heads hit pistons. If you are lucky, only the rocker arms broke, and I'd replace all of them. If you were not so lucky, you might also have bent valves and/or holes or cracks in pistons. You will need to pull the head to check for that damage.

I'm sorry to hear of this happening to you. I guess you just waited a teeny bit too long to install that new belt. Good luck, and let us know how it goes. I guess this is your chance to contribute to the Common Body of Knowledge about these little tractors.
Author:  papaindigo [ Mon Aug 04, 2014 10:26 am ]
Post subject:  Re: Cam Belt Snapped
1) no the rockers are not ok. I concur with naturist. Best bit the bullet and get rockers from idparts, you might consider ARP studs while you are in that far.
2) turning over by hand with/without one injector in is not terribly hard; the "spring over" is passing thru the compression stroke and doesn't tell you anything about rockers to speak of. However the fact that you can turn it over suggests the valves are ok.
3) no, see 1)
Author:  Hexus [ Mon Aug 04, 2014 11:07 am ]
Post subject:  Re: Cam Belt Snapped
Rockers are shot, and possibly a lifter is broken as well. You can (pretty cheaply) scope the pistons when you do rockers/lifters to check for any damage, i would visually inspect the head from the top first before I contemplated pulling it, if there's no damage but some slotting on the top of the rocker arms and maybe a crushed lifter or popped lifter, then I would scope the pistons through the head and check everything visually there.

These engines are designed to fail at the rockers/lifters before they do any damage to the pistons, in fact I cannot recall a time when the pistons were damaged that didn't have something to do with eating an injector or dropping a valve.

The fact that you can turn by hand is a good sign, but still doesn't say if there's broken rockers or lifters, mine drove 20 miles with a broken lifter and severely damaged rockers, it just had no power.

If you need help, you definitely came to the right place. Keep a cool head, take your time, it's not that difficult.
Author:  geordi [ Mon Aug 04, 2014 2:23 pm ]
Post subject:  Re: Cam Belt Snapped
Hey, I saw you in the other thread - Follow the advice in both of these threads.

I'm willing to be flown to Middle Earth if you want me to do the work for you... :mrgreen: :mrgreen: :mrgreen: But I don't think you want to pay for the airfare! :ROTFL:

Anyway, what everyone has already said is correct: You have one or more trashed rockers. This is the designed failure point, so you might as well get cracking on disassembling everything else. LABEL THE INJECTORS as they are specific to their holes. Other than that, it is fairly simple wrenching, just a lot of it.
Author:  RTTT265 [ Mon Aug 04, 2014 3:50 pm ]
Post subject:  Re: Cam Belt Snapped
Thanks for all the advice, I guess ill get cracking on taking the rocker cover off.

I have seen some posts, in the Australian forum of guys that have snapped belts while running, and got

away with changing belt (which surprised me as I was expecting rockers minimum).


One can only dream, thanks for all the advice, I just need to harden up like they say down here, get some Hobbits to help pull the rest of this tractor apart.

Cheers :5SHOTS:
Author:  geordi [ Mon Aug 04, 2014 5:23 pm ]
Post subject:  Re: Cam Belt Snapped
The aussies are crazy - If the belt breaks while running (and why would it break at any other time?) then rockers HAVE been broken.

It is moderately possible that only one rocker per side of a given cylinder could be affected, so you break 1 intake and one exhaust on the same cylinder, it is theoretically possible that the engine will continue to run off the other two... But you are now only getting HALF the air in and out of that cylinder!

It would be fairly obvious that something was still wrong and the engine would be running like crap. I don't see how they could say that all was OK with just replacing the belt. I think they probably were saying that for the forum, but forgetting to mention that they had to tear it back down shortly after to do the job properly.

There just aren't any two ways about it. If the timing changes, pistons WILL FIND VALVES and the results will be messy. Tony found 8 broken rockers from an engine that broke the belt at IDLE. You were driving. There isn't any point in even making the bet - you should have as many or more trashed rockers.

Good luck on taking it down, hope you have enough room in the shed!
Author:  RTTT265 [ Sat Aug 09, 2014 12:04 am ]
Post subject:  Re: Cam Belt Snapped
Just developed KJ Tourettes

and some new swear words

not sure if i call myself lucky or not, just got the rocker cover off after cambelt snap 50kmh or so

no broken rockers go figure...............

how do you clean this SOAB the intakes well caked ill get a picture and post

Cheers

Hobbitland
Author:  geordi [ Sat Aug 09, 2014 12:32 am ]
Post subject:  Re: Cam Belt Snapped
I don't see how that can be possible. All 16 rockers are intact?
Are the rollers in the center all smooth and raised above the stamped steel that holds them? No wobbling or play in any of them?

As far as cleaning the intake out, on the TDI, my preferred method is to sink the entire intake in a bucket of diesel and let it marinate for about 2 days. When you pull it out, a quick rinse and its all clean and shiny. HOWEVER, on the CRD, you have the bearings of the camshafts to think about. I wouldn't suggest the diesel bath as it may endanger the greasing in the bearings.

Other than that, maybe you can come up with a way to fill the intake runners with diesel or brake cleaner and a whole lot of paper towels? A wire brush (bottle brush) on a drill could also work, IF it is either brass / copper, or a plastic brush instead. You don't want anything to hurt the aluminum. On reassembly, you want to clean the injector bores to a brilliant shine with a shotgun bore mop. You cannot use too much brake cleaner on this.
Author:  RTTT265 [ Sat Aug 09, 2014 12:39 am ]
Post subject:  Re: Cam Belt Snapped
ill go through them one by one, im going to change them anyway, water pump and ARP studs, block egr new boost hose

its the head im worried about cleaning, but the intake is half blocked with gunge
Author:  RTTT265 [ Sat Aug 09, 2014 1:12 am ]
Post subject:  Re: Cam Belt Snapped
Image

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Author:  RTTT265 [ Sat Aug 09, 2014 1:19 am ]
Post subject:  Re: Cam Belt Snapped
Off Topic

My Hemi 6 Valiant Charger

Image

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my old turbo hemi 265 ute

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dedicated LPG turbo

Image
Author:  racertracer [ Sat Aug 09, 2014 6:37 am ]
Post subject:  Re: Cam Belt Snapped
Wow, very cool..... you messed up the steering though.

The steering wheel is on the opposite side.
Author:  rmartin [ Sat Aug 09, 2014 1:25 pm ]
Post subject:  Re: Cam Belt Snapped
So, at what scheduled mileage should the cam belt be changed? Richard
Author:  RTTT265 [ Sat Aug 09, 2014 4:00 pm ]
Post subject:  Re: Cam Belt Snapped
Officially 160,000 Km realworl 80,0000 Km

Actually wait for someone else to chime in, Im the last person to ask :ROTFL:
Author:  papaindigo [ Sat Aug 09, 2014 6:37 pm ]
Post subject:  Re: Cam Belt Snapped
Factory change interval is 100,000 miles or km equivalent per FSM and Gates. However, many of us are of the opinion that the life span of a "rubber" belt is also influence by time hence IMHO a safer bet is 6-7 years or 100,000 miles whichever occurs first.
Author:  RTTT265 [ Sat Aug 09, 2014 10:42 pm ]
Post subject:  Re: Cam Belt Snapped
So spent the day cleaning my intake messy horrible surprised it ran at all.

Also took the rockers out to have a closer look

6 of them have cracks and most likely already broken

I'm glad I have thever cover off and replacing them all :SOMBRERO:
Author:  rmartin [ Sat Aug 09, 2014 10:57 pm ]
Post subject:  Re: Cam Belt Snapped
Factory change interval is 100,000 miles or km equivalent per FSM and Gates. However, many of us are of the opinion that the life span of a "rubber" belt is also influence by time hence IMHO a safer bet is 6-7 years or 100,000 miles whichever occurs first.

Uh OH! 8 years and 79K miles!! Thanks for the inputs. Richard
Author:  papaindigo [ Sun Aug 10, 2014 8:32 am ]
Post subject:  Re: Cam Belt Snapped
Changed mine and stoutdogs at (05 and 06) earlier this summer at ca. 50k. Not willing to bet $75 belt lasting another 8-9 years until 100K.
Author:  naturist [ Tue Aug 12, 2014 8:00 pm ]
Post subject:  Re: Cam Belt Snapped
RTTT265 wrote:
So spent the day cleaning my intake messy horrible surprised it ran at all.

Also took the rockers out to have a closer look

6 of them have cracks and most likely already broken

I'm glad I have thever cover off and replacing them all :SOMBRERO:



Yeah, when you posted they were all good, I figured you would soon change your tune. There is simply no way a valve head and a piston are going to occupy the same physical space at the same time without SOMETHING having to give. And like old dad used to say, if you are going to do something, do it right just once and be done with it, or plan on doing it wrong over and over until you DO get it right.
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