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Known Problems for 4.0 motors?

Old Dec 30, 2009 | 12:12 AM
  #1  
Andy Antipas's Avatar
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Default Known Problems for 4.0 motors?

We own a 1998 Disco I and just lost the motor. My mechanic pulled the plenum and found aluminum and metal bits back by number 7 intake trumpet. He did a compression check and cyl. number 7 is at 105 psi, while the other cyl. are at 150 psi. His guess is the valve stuck and the piston struck it. My mechanic worked at the local LR dealership for many years and said these engines are prown to sticking valves as well as cam thrust bearing failures. We have had the cam bearing knock for about a year now, and were advisted to live with it. He said the dealership repaired 40+ engines with sticking valves under warrantee while he worked there. I wanted to see if others have had that problem.

I have owned the disco for nine years and have been pleased with it. Prior to this LR we owned a 1987 and a 1990 rangies. Both had mileages much higher than the disco. We bought it used with 10,000 miles. It now has 115,000 thousand. Oil was changed every 3,000 miles, and was serviced per the Land Rover schedule. Other than needing an engine, the vehicle is in excellent condition.

The question is do we replace the motor and if we do where have people purchased engines? Any suggestions. I live near Carbondale, Colorado. Thanks for your time.
 
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Old Dec 31, 2009 | 12:28 AM
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Default Virility Ex

this is such a great post and i read this post, thats resion i say this is great post, thanks for shearing nice and informative post,


Virility Ex
 
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Old Jan 1, 2010 | 11:26 AM
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Originally Posted by rissaallia
this is such a great post and i read this post, thats resion i say this is great post, thanks for shearing nice and informative post,


Virility Ex
**** off. God I hate spammers...
 
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Old Jan 1, 2010 | 12:03 PM
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Without pulling the heads you shouldn't make any decisions. Yes some model years had valve guide issues, 98 wasn't known to be a common one though
 
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Old Jan 1, 2010 | 01:28 PM
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if the head is good and you can buy a valve or two then buy a short block and get a head job and you will be fine.

but you will need new lifters that dont come with the shortblock.

shortblocks can go for around 4 to 5 grand depending on availability.
 
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Old Jan 2, 2010 | 09:54 AM
  #6  
Andy Antipas's Avatar
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Thank you for the helpful replies. I'm not the one that will be doing the work, but I'm hoping for a reliable yet cost effective solution. It looks like new engines are $7,500 (Rovers North) and rebuilt engines are $4,500 (Rovers North). Are there sources for rebuilt motors people have experience with?
 
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Old Jan 2, 2010 | 12:42 PM
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I have seen a cylinder liner drop so low that the top compression ring actually snagged on the top of the liner shattering the piston top ( this was a disco I that had this issue ). The metal peices then scatter throughtout the intake and exhaust ports causing damage to the rest of the engine. Your only real fix is a new long block because the piston shards have probably damaged the combustion chamber on your #7 cylinder.
 
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