There was a lot of up/down and side to side movement on the broken end of the crank so distinctly possible that that was the cause of the oil pump (lower edge) casing fracture and I would have thought valves meeting pistons might chew up the piston but I can't see it breaking the crank, but I'm not a TDV6 expert! Just a greatful customer.
17th Mar 2015 9:12 pm
hugeviking
Member Since: 08 Jun 2010
Location: cotswolds
Posts: 1482
Oh, so it wasn't the upper part of the oil pump casing that failed, where the tensioner is mounted ?
Andi.
There was a lot of up/down and side to side movement on the broken end of the crank so distinctly possible that that was the cause of the oil pump (lower edge) casing fracture and I would have thought valves meeting pistons might chew up the piston but I can't see it breaking the crank, but I'm not a TDV6 expert! Just a greatful customer.
Without doing a full strip down and inspection its a bit hard to really tell what was the primary cause and whats just secondary damage. However I would make the guess that the broken crank may have been the primary damage. Failed timing belt is enough to mash valves and pistons but shouldnt be enough to bust a crank
17th Mar 2015 10:10 pm
Nodge68
Member Since: 05 Sep 2014
Location: Newquay
Posts: 1014
DaveM wrote:
The crank had broken in two and split the block and broken the front off of the oil pump casing, that was the visible damage, I suspect there was allsorts of assorted horridness inside. Not sure of the cause as oil levels and pressure and engine temp where fine right up to the point it stopped. Apparently (and I really don't know if this is conjecture or based on evidence) it has been know for the main bearing to move in its cap and block the oil way.
Do you know what condition the crank damper was in?Freelander SE 2005 Auto.
D3 TDV6. Gone.
Apart from only being able to upload photos upside down The failure was main bearing according to the garage. Nothing to do with the the oil pump tensioner. The cracked block and oil pump housing crack (and all the hideousness inside) were consequences of the crank seizing.
18th Mar 2015 10:11 am
Robbie
Member Since: 05 Feb 2006
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You can turn your pics the right way round in your gallery....Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 05 Sep 2014
Location: Newquay
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I'd love to strip one of these rogue engines to find the actual cause of the crank failure. I know that the bearings can move, blocking the oil way. Oil system failure, on most engines I've looked at over the years, seldom causes the crank to snap. It's much more common for the engine to seize. This can feel like it's loosing power while accompanied by lots of noise. For the crank to be snapping between main bearing 1 and 2, something could be wrong with the design of the crank or assembly of the engine.
First off, what causes the bearing to rotate in the cap? This would appear to be the common failure mode. The crank snapping appears to be a secondary failure to this.
So the question is why do the bearings rotate. Maybe the "crush" isn't high enough? Being modern tang-less bearings, crush is all that keeps the bearing from moving. This shouldn't be a problem as the tang is only for location purposes during assembly anyway.
If the bearings seize solid enough for the crank to snap, the crush must be pretty tight to start with. This makes me wonder how it turned in the cap in the first place?
There is another scenario. If the crank is failing in use, what is causing it? First of if the crank is failing at the nose end, is the damper working effectively? This is the main cause of crank nose failure. The crank at this point isn't really heavily loaded, certainly nowhere near as loaded as the crank tail would be. If the crank has failed due to the damper, how would this explain the turned bearing? This is my thought on that one. First off if the crank snaps, huge diagonal forces are exerted on the bearings. These forces could literally twist the main
bearing in the cap, blocking the oil way and the feed to the big ends. The engine could well run on for some time before the crank locks solid, giving the wiped out bearing appearance.
The only way to tell what and why the failure occurs, is to investigate every failed engine. Unless this is done, no definitive answer will be available.Freelander SE 2005 Auto.
D3 TDV6. Gone.
18th Mar 2015 1:09 pm
hugeviking
Member Since: 08 Jun 2010
Location: cotswolds
Posts: 1482
I had an auto D3 courtesy car for a few day's some years ago and when cruising the box would change up, I thought, quite early, and when cruising would change up so that the rev's were barely above 1000. I think that is too low and puts strain on the crank. I like to keep my manual spinning above approx 1300 RPM. I may be talking complete but that is what I believe. As a wild card, could the auto box be to blame ?, are engine problems equal between auto/man. Obviously the built volumes of auto are higher than man and need to be allowed for.
just a thought.
Andi.
18th Mar 2015 8:13 pm
Disco_Mikey
Member Since: 29 May 2007
Location: Dundee, Scotland
Posts: 20733
Nodge68 wrote:
I'd love to strip one of these rogue engines to find the actual cause of the crank failure. I know that the bearings can move, blocking the oil way. Oil system failure, on most engines I've looked at over the years, seldom causes the crank to snap. It's much more common for the engine to seize. This can feel like it's loosing power while accompanied by lots of noise. For the crank to be snapping between main bearing 1 and 2, something could be wrong with the design of the crank or assembly of the engine.
First off, what causes the bearing to rotate in the cap? This would appear to be the common failure mode. The crank snapping appears to be a secondary failure to this.
So the question is why do the bearings rotate. Maybe the "crush" isn't high enough? Being modern tang-less bearings, crush is all that keeps the bearing from moving. This shouldn't be a problem as the tang is only for location purposes during assembly anyway.
If the bearings seize solid enough for the crank to snap, the crush must be pretty tight to start with. This makes me wonder how it turned in the cap in the first place?
There is another scenario. If the crank is failing in use, what is causing it? First of if the crank is failing at the nose end, is the damper working effectively? This is the main cause of crank nose failure. The crank at this point isn't really heavily loaded, certainly nowhere near as loaded as the crank tail would be. If the crank has failed due to the damper, how would this explain the turned bearing? This is my thought on that one. First off if the crank snaps, huge diagonal forces are exerted on the bearings. These forces could literally twist the main
bearing in the cap, blocking the oil way and the feed to the big ends. The engine could well run on for some time before the crank locks solid, giving the wiped out bearing appearance.
The only way to tell what and why the failure occurs, is to investigate every failed engine. Unless this is done, no definitive answer will be available.
I have a TDV6 in the shed, with a snapped crank.
All main, and big end bearings look fine, with no scoring or pick up on the surfaces of the shells, or crank...
Just a clean break between cylinders 2/3. Failed when the engine was warm, and pulling away from a junctionMy D3 Build Thread
Member Since: 05 Sep 2014
Location: Newquay
Posts: 1014
That's very interesting Mike and contradictory to other failures I've been reading about. Most documented failures seem to come from SA. There's a chap over there who has torn down many failed TDV6s. He is suggesting that cold start oil starvation and bearing corrosion are the main causes of failure. Basically the bearings, particularly big ends 1 and 2 suffer wear / corrosion over time. This wear rattles the rod caps, causing the cap retaining bolts to fail. This in turn throws the rod, snapping the crank.
Maybe SA has high Sulphur fuel, necessitating more frequent oil changes. Obviously if this isn't done, damage he describes could be happening.
If we suffer simple crank failure, I wonder what the cause is? It's a little worrying for us with high mileage TDV6 engines.Freelander SE 2005 Auto.
D3 TDV6. Gone.
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The failure was main bearing according to the garage. Nothing to do with the the oil pump tensioner. The cracked block and oil pump housing crack (and all the hideousness inside) were consequences of the crank seizing.
but that is what I believe. As a wild card, could the auto box be to blame ?, are engine problems equal between auto/man. Obviously the built volumes of auto are higher than man and need to be allowed for.
