This Is A Most Depressing Forum
#21
12-09-2013, 01:57 PM
It also makes sense. There is evidence that in earlier years they used the "better" QC blocks for the 4.6L, but with the 2003 model year, all NAS discos got the 4.6L, so how would they be able to be as picky as in earlier years?
#22
12-09-2013, 03:16 PM
Maybe I misread but I don't see how you determined a bad block/slipped liner when you moved a spark plug and the misfire moved to that cylinder.
Again, maybe I read it wrong, but you just said for sure the plug has a problem.
If you cannot the coolant leak, look again. Maybe a head gasket is leaking, check the back of the block and sniff the exhaust.
EDIT
I did misread. I didn't see the beginning where you said the coil, plugs, and head were replaced.
Two question. Was ONLY the head replaced? IE reusing rocker arms, rods, springs, and valves??
Numero DOS. Pretty sure the timing isn't adjustable,sooo... Before saying the block is just scrapped, look at what else can cause a misfire.
Fuel delivery
Ignition (sounds like you've got this all checked out)
valve timing-this is going to include most of the top end and all timing parts.
Some things are pretty unlikely to cause an issue but all of the valvetrain can cause a problem.
-pushrods
-lifters
-rockers
-springs
-camshaft
etc
I know the 4.6 has a bad rep for the tooling but you really should have the engine better inspected before just trashing it. Would be a shame to pay all that money and do all the work for a worn lobe....
Again, maybe I read it wrong, but you just said for sure the plug has a problem.
If you cannot the coolant leak, look again. Maybe a head gasket is leaking, check the back of the block and sniff the exhaust.
EDIT
I did misread. I didn't see the beginning where you said the coil, plugs, and head were replaced.
Two question. Was ONLY the head replaced? IE reusing rocker arms, rods, springs, and valves??
Numero DOS. Pretty sure the timing isn't adjustable,sooo... Before saying the block is just scrapped, look at what else can cause a misfire.
Fuel delivery
Ignition (sounds like you've got this all checked out)
valve timing-this is going to include most of the top end and all timing parts.
Some things are pretty unlikely to cause an issue but all of the valvetrain can cause a problem.
-pushrods
-lifters
-rockers
-springs
-camshaft
etc
I know the 4.6 has a bad rep for the tooling but you really should have the engine better inspected before just trashing it. Would be a shame to pay all that money and do all the work for a worn lobe....
Last edited by sidescrollin; 12-09-2013 at 03:27 PM.
#23
12-09-2013, 04:23 PM
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Maybe I misread but I don't see how you determined a bad block/slipped liner when you moved a spark plug and the misfire moved to that cylinder.
Again, maybe I read it wrong, but you just said for sure the plug has a problem.
If you cannot the coolant leak, look again. Maybe a head gasket is leaking, check the back of the block and sniff the exhaust.
EDIT
I did misread. I didn't see the beginning where you said the coil, plugs, and head were replaced.
Two question. Was ONLY the head replaced? IE reusing rocker arms, rods, springs, and valves??
Numero DOS. Pretty sure the timing isn't adjustable,sooo... Before saying the block is just scrapped, look at what else can cause a misfire.
Fuel delivery
Ignition (sounds like you've got this all checked out)
valve timing-this is going to include most of the top end and all timing parts.
Some things are pretty unlikely to cause an issue but all of the valvetrain can cause a problem.
-pushrods
-lifters
-rockers
-springs
-camshaft
etc
I know the 4.6 has a bad rep for the tooling but you really should have the engine better inspected before just trashing it. Would be a shame to pay all that money and do all the work for a worn lobe....
Again, maybe I read it wrong, but you just said for sure the plug has a problem.
If you cannot the coolant leak, look again. Maybe a head gasket is leaking, check the back of the block and sniff the exhaust.
EDIT
I did misread. I didn't see the beginning where you said the coil, plugs, and head were replaced.
Two question. Was ONLY the head replaced? IE reusing rocker arms, rods, springs, and valves??
Numero DOS. Pretty sure the timing isn't adjustable,sooo... Before saying the block is just scrapped, look at what else can cause a misfire.
Fuel delivery
Ignition (sounds like you've got this all checked out)
valve timing-this is going to include most of the top end and all timing parts.
Some things are pretty unlikely to cause an issue but all of the valvetrain can cause a problem.
-pushrods
-lifters
-rockers
-springs
-camshaft
etc
I know the 4.6 has a bad rep for the tooling but you really should have the engine better inspected before just trashing it. Would be a shame to pay all that money and do all the work for a worn lobe....
Rod
#24
12-09-2013, 10:20 PM
Super Moderator
You can believe what you like, but that won't change the truth. Doing a bit of research you'll find due to factory defects with the mis-drilled blocks(oil pump failure), porosity issues, and slipped sleeve failures in the 03/04 4.6 blocks that were not evident in the earlier gems blocks used in the P38 that it is based in fact not myths.
Most of the top builders will use only early 4.6 assemblies or use the crank and rods from a 4.6 in the 4.0 block.
Last edited by ArmyRover; 12-09-2013 at 10:23 PM.
#25
12-10-2013, 08:52 AM
Rock Crawling
You can believe what you like, but that won't change the truth. Doing a bit of research you'll find due to factory defects with the mis-drilled blocks(oil pump failure), porosity issues, and slipped sleeve failures in the 03/04 4.6 blocks that were not evident in the earlier gems blocks used in the P38 that it is based in fact not myths.
Most of the top builders will use only early 4.6 assemblies or use the crank and rods from a 4.6 in the 4.0 block.
Most of the top builders will use only early 4.6 assemblies or use the crank and rods from a 4.6 in the 4.0 block.
#26
12-10-2013, 09:33 AM
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You can believe what you like, but that won't change the truth. Doing a bit of research you'll find due to factory defects with the mis-drilled blocks(oil pump failure), porosity issues, and slipped sleeve failures in the 03/04 4.6 blocks that were not evident in the earlier gems blocks used in the P38 that it is based in fact not myths.
Most of the top builders will use only early 4.6 assemblies or use the crank and rods from a 4.6 in the 4.0 block.
Most of the top builders will use only early 4.6 assemblies or use the crank and rods from a 4.6 in the 4.0 block.
#27
12-10-2013, 11:24 AM
However, it generated a cylinder 4 misfire code each morning on first startup, to be fixed before I took ownership. They replaced plug(s), coil wires, coil(s) and finally the entire head to correct the problem. It ran flawlessly for approx. 6 months/5K miles, then the cyl. 4 misfire reappeared intermittently for a week or two, then went away for about a month. No overheating/loss of coolant issues. Then it came back consistently, accompanied by very rough running and the MIL lamp flashing under even medium load. Compression and spark on cyl. 2 & 4 OK. Moved plug to cyl. 2 and problem moved to cyl. 2. Replaced plug (looked OK), reset code, engine ran fine for a day, then MIL light came on again, and noticed coolant loss. No evidence of coolant in oil based on cursory inspection of dipstick.
Is it still misfiring first thing in the morning?
Does it clear up when warm?
How much coolant was lost?
I personally would pressure test the cooling system, get a flashlight and examine every inch of hoses, the radiator, the pump, and the front and back of the heads for leaks. This could easily be two smaller problems that look like one big problem.
#28
12-10-2013, 11:50 AM
Rock Crawling
In reflecting on my situation, it is obvious that I was remiss in not doing enough research before purchasing this vehicle. After 18 years of relatively trouble free LR ownership wherein LR was my primary vehicle in sometimes very adverse conditions I guess I lived in blissful ignorance. The sum of the problems I had in those 18 years were 3 front hubs (1 because of bearings, 2 because of ABS sensors, door latches (all the doors, drivers twice), front differential (water in oil), door window channels (2, rust) and of course oil leaks. The Carfax report for this LR indicated that the engine had been replaced at 1,000 miles and the 1st owner got rid of it in 10 months, but the second owner had it up until I purchased it, so he must have been relatively happy with it. Well, now time to evaluate my options.
Here are your options:
1. Sell it as is (I should have done this ...but I am hardheaded)
2. fix it/rebuild it (I tried this and the motor failed anyway)
3. replace motor with a much better rebuilt one with a warranty (I did this and now can sleep a lot easier thanks CannibalV8 motor choice up to you)
#29
12-10-2013, 05:28 PM
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Are you working on the truck or having it serviced?
Is it still misfiring first thing in the morning?
Does it clear up when warm?
How much coolant was lost?
I personally would pressure test the cooling system, get a flashlight and examine every inch of hoses, the radiator, the pump, and the front and back of the heads for leaks. This could easily be two smaller problems that look like one big problem.
Is it still misfiring first thing in the morning?
Does it clear up when warm?
How much coolant was lost?
I personally would pressure test the cooling system, get a flashlight and examine every inch of hoses, the radiator, the pump, and the front and back of the heads for leaks. This could easily be two smaller problems that look like one big problem.
Actually, neither. I am currently in Dallas, a long way from home, VT (I tow it behind a motorhome, 04 being the last year I can do that 4 wheels down)
"Is it still misfiring first thing in the morning?"
Probably. Hard to tell. Normally the misfire can't be felt (except when the plug gets fouled). The MIL lamp is on until some number of non event trips, or reset. MIL was off yesterday, on today. Code is ALWAYS cylinder 4.
"Does it clear up when warm?" See above. Before I bought it the 0304 code occurred at the first start of the day, did not reoccur until next day (shop reset the MIL each morning)
"How much coolant was lost?" I have added about one gallon in the last month.
My THEORY is that no (or minimal) coolant is lost when running due to pressure in the cylinder. When shut down pressure of the cooling system forces some coolant into the cylinder, which causes the misfire on startup.
I am currently getting quotes from CannibalV8 (Used block refurbished, modified) and a a LR specialist in Vermont (new factory short block), then evaluate my options, one of which is sell the LR.
Rod
#30
12-10-2013, 05:49 PM
Super Moderator
It off In my drive. I'll leave you a grand under my trash can.
Cannibal sounds great, but I found an extra disco with lowish miles cheaper than the cannibal.
https://landroverforums.com/forum/ge...-sleeve-48770/
Last edited by dusty1; 12-11-2013 at 10:32 AM.