I asked a question in a recent post about the pumps or blocks being the problem area on 2003 dicovery's.
http://www.discoweb.org/forums/showthread.php?t=55250
Reason I asked, Is i pulled apart our 108K 2003 for a cam change, and thought I'd replace the pump rotor for good measure with one I purchased from Turner-Engineering (along with all my other parts).
This is what i was greeted with - an outer rotor in four pieces. Great - this means I've got the magical 2003 problem... Interestingly, I had previously done hot/cold tests on the engine, and oil pressure was totally in spec, a nice 13psi when fully upto temp at idle for example. The rotor has also been broken for a long time looking at the galling between the fractures.
Here is the pump pics:
So, no-one seems to 'really' know 100% if the block or pump was the problem part, so I decided to take a closer look.
Firstly, a trial fit of the cover between the locating dowels with the rotor out showed it slid on quite nicely. Clearly the dowels are aligned to each other well.
Next, a trial fit of the cover with the (new) pump rotor, and it did not slide on as smoothly. It did slide on - but not cleanly. I removed the cover and pulled the bottom dowel out aroud 2mm. This allowed me to partially re-fit the cover , aligning the bottom dowel and the pump rotor, to see where the top dowel wanted to 'fall' - ideally this would be in the middle of the 'free play' of the pump rotor between the crank and the front cover rotor recess. As it was, the dowel was right on the edge of the free-play, basically the weight of the housing taking up all the free-play 'just' aligned the top dowel.
Clearly, this is not right, and further investigation continued.
First suspicious area - all the bolts are tight against the side of the clearance holes in the cover - two so tight that they can't be spun in by hand (but can with the cover off).
http://www.davecoxon.co.uk/Cover_bolts.JPG
Next is the dowels,
This is an interesting picture I put together that shows there is a counter-sink and pilot hole around the dowels, and that is offset from the hole the dowel locates in.
Now, I don't know the order that these things are machined, but I know when we machine transmission casings in our industry, the mainshaft and coutershafts are first line-bored, then these act as the location dowels for the housing machining (milling / drilling clearance or tapped holes and dowels) on a different machine.
I imagine a block would be done similarly; but in 2003 the tool change coming in to do the dowel holes for some reason came in a different place than the countersink / pilot hole. Put simply, having this big of an offset between the dowel countersink and dowel holes just doesn't seem right.
What I'd appreciate is if someone has a block to hand that is either an '03 or not, and say if your dowel holes have this big offset to the chamfer. If they all have a wide scatter like this one, then I'm barking up the wrong tree. If they all look reasonably concentric to each other, then it would be a reasonable assumption that the 2003 blocks, not the pumps were faulty.
Incidentally, I'm going to put a lever DTI on the crank tonight and measure the run-out of the seal bore relative to the crank. This miggt not be conclusive as it's machined from a different side to the dowels / gerotor pocket however...
If it all looks like the only thing that is wrong is the dowel holes themselves, I might turn up a few offset dowels and try those to compare the free-play. I need some insight into other blocks first however!
Thanks!
http://www.discoweb.org/forums/showthread.php?t=55250
Reason I asked, Is i pulled apart our 108K 2003 for a cam change, and thought I'd replace the pump rotor for good measure with one I purchased from Turner-Engineering (along with all my other parts).
This is what i was greeted with - an outer rotor in four pieces. Great - this means I've got the magical 2003 problem... Interestingly, I had previously done hot/cold tests on the engine, and oil pressure was totally in spec, a nice 13psi when fully upto temp at idle for example. The rotor has also been broken for a long time looking at the galling between the fractures.
Here is the pump pics:
So, no-one seems to 'really' know 100% if the block or pump was the problem part, so I decided to take a closer look.
Firstly, a trial fit of the cover between the locating dowels with the rotor out showed it slid on quite nicely. Clearly the dowels are aligned to each other well.
Next, a trial fit of the cover with the (new) pump rotor, and it did not slide on as smoothly. It did slide on - but not cleanly. I removed the cover and pulled the bottom dowel out aroud 2mm. This allowed me to partially re-fit the cover , aligning the bottom dowel and the pump rotor, to see where the top dowel wanted to 'fall' - ideally this would be in the middle of the 'free play' of the pump rotor between the crank and the front cover rotor recess. As it was, the dowel was right on the edge of the free-play, basically the weight of the housing taking up all the free-play 'just' aligned the top dowel.
Clearly, this is not right, and further investigation continued.
First suspicious area - all the bolts are tight against the side of the clearance holes in the cover - two so tight that they can't be spun in by hand (but can with the cover off).
http://www.davecoxon.co.uk/Cover_bolts.JPG
Next is the dowels,
This is an interesting picture I put together that shows there is a counter-sink and pilot hole around the dowels, and that is offset from the hole the dowel locates in.
Now, I don't know the order that these things are machined, but I know when we machine transmission casings in our industry, the mainshaft and coutershafts are first line-bored, then these act as the location dowels for the housing machining (milling / drilling clearance or tapped holes and dowels) on a different machine.
I imagine a block would be done similarly; but in 2003 the tool change coming in to do the dowel holes for some reason came in a different place than the countersink / pilot hole. Put simply, having this big of an offset between the dowel countersink and dowel holes just doesn't seem right.
What I'd appreciate is if someone has a block to hand that is either an '03 or not, and say if your dowel holes have this big offset to the chamfer. If they all have a wide scatter like this one, then I'm barking up the wrong tree. If they all look reasonably concentric to each other, then it would be a reasonable assumption that the 2003 blocks, not the pumps were faulty.
Incidentally, I'm going to put a lever DTI on the crank tonight and measure the run-out of the seal bore relative to the crank. This miggt not be conclusive as it's machined from a different side to the dowels / gerotor pocket however...
If it all looks like the only thing that is wrong is the dowel holes themselves, I might turn up a few offset dowels and try those to compare the free-play. I need some insight into other blocks first however!
Thanks!
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