craykent

Active Member
Hi 10 days ago my lse boiled and after we got it home two days later i comprssion tested it and ended up removing the odds head .
On inspection the head is fine but theres a fine crack in no 1 cylinder liner
So do seek another 4.2 or settle for a 3.9 as a replacement .
if so whats likely to be difficult :confused:
autobox could do with replacing as well :(
thanks :)
 
Hi 10 days ago my lse boiled and after we got it home two days later i comprssion tested it and ended up removing the odds head .
On inspection the head is fine but theres a fine crack in no 1 cylinder liner
So do seek another 4.2 or settle for a 3.9 as a replacement .
if so whats likely to be difficult :confused:
autobox could do with replacing as well :(
thanks :)
cant see why not
if you offer the right money you could take the 4.2 lse engine and box out of my bobtail
or you could buy the whole thing
 
well the block is the same just the crank, rods and pistons are different.

Hi 10 days ago my lse boiled and after we got it home two days later i comprssion tested it and ended up removing the odds head .
On inspection the head is fine but theres a fine crack in no 1 cylinder liner
So do seek another 4.2 or settle for a 3.9 as a replacement .
if so whats likely to be difficult :confused:
autobox could do with replacing as well :(
thanks :)
 
Putting a 3.9 to replace the 4.2 will give you a Hugh drop in mpg or as suggested swap the internals into a good 3.9 block or get the original top hat linered
 
Right so whats the difference between 3.9/4.2 then if i can use a3.9 block ? were doe's the extra capacity come from ?. I thought it was bore & stroke that altered cc ! . perhaps a dull moment on my part :confused:
 
the 3.9 is the same bore as the 4.2, however, the 4.2 has a slightly longer stroke and i should imagine shorter pistons. this is where the extra 0.3L comes from. you could therefore use a 4.2 crank, conrods and pistons in a 3.9 block to make a 4.2 engine. its all rover did!
 
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Ahh so thats it . now that widens the scope for repair a bit :rolleyes:
So if i find a good 3.9 block what heads do i use 3.9 or 4.2 will it make any difference
 
the efi heads are the same from the 3.5 upto the 4.6 engines so it doesnt matter which you use. they didnt even change the size of the valves! its a good idea to only use 10 head bolts per head, leaving out the outer four(if you have an earlier engine). ive done this on my lse.
 
Ahh so thats it . now that widens the scope for repair a bit :rolleyes:
So if i find a good 3.9 block what heads do i use 3.9 or 4.2 will it make any difference


cam is the same also - only difference is the crank, rods and pistons
 
the cam is different on the 4.2 it is different to the 3.9 i have one in my 3.9 much better than standard
 
So if i can find a 3.9 i can rebiuld a 4.2 using my internals . will it be much trouble to use a serpentine belt version ? if i find a good block i would rebuild it myself :)
 
Land rover using different part numbers for the same part?
As Je developed the engine did use a different cam and so did land rover and that comes from Roy Burrel who worked at Je when the 4.2 was developed for land rover slightly longer duration over a 3.9 cam though it had the same lift as a 3.9 so is coman to be misinformed
 
different part no. same profile

Land rover using different part numbers for the same part?
As Je developed the engine did use a different cam and so did land rover and that comes from Roy Burrel who worked at Je when the 4.2 was developed for land rover slightly longer duration over a 3.9 cam though it had the same lift as a 3.9 so is coman to be misinformed
 
getting back to craykent's latest question, i believe that the earlier (pre-serp) engines were stronger but you could bolt on the front end of a serp onto the earlier engine to simplify the pulleys to a single belt. this will require different water pipes, alternator etc but it reduces the no. of belts from 4 to one. your best bet is a low (ish) mile 3.9 block with v groove belts. regarding cams, it may be an idea to replace the camshaft and tappets whilst the engine is apart. i fitted a piper torque max cam to my 4.2 and am pleased with the results. all the other internals can simply be swapped over to create your 4.2 engine.
 

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