4.6 gems from 4.0 thor

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dove

Active Member
Posts
393
Location
Fife,scotland
anybody built a 4.6 gems motor from a 4.0 thor motor?i know the crank and rods are different,but what about sensor locations on the block?the crank sensor mount looks different and i think i remember seeing a sensor somewhere near the starter motor on the gems(near block drain)but on my top hat thor engine there doesnt seem to be one,dont know if this is coolant or knock sensor.any body done this swap?any info much appreciated.hoping to build it up soon ,anyone put a high lift cam or similar in theirs?what type and noticeable improvemet?
 
basically same block 2 x knock senors unscrew to change crank sensor opposite side to starter usually tack weld as well as roll pin locator resecure with suitable adhesive ie brg fit locktite ,coolant sensor on inlet manifold
 
i cant see any where on the thor block where the knock sensors would fit:confused:have you done this conversion?is there any benefit to using alloy sump pan and oil pick up from thor?the engine code on thor is 58d,thanks for replying
 
yep ,found them they are studs:)thought they were for engine mounts,i will be doing full rebuild on it so new timing gears will be going on,:)can you buy new crank sensor holders?would save knackering my other block as nothing wrong with liners etc(there is a hairline crack between the starter side 2 rear core plugs:eek:)was like this when i bought it with hg failure,previous owner forgot the antifreeze i think when topping up:mad:going to get it welded up and put it in my kitcar probably.anyone suggest a good cam while i am at it?thanks for replys
 
where do you start
blocks are all the same just swap the fly wheel sensor plug in the block and fit the studs for the knock sensor's you could swap the 4.0 litre pistons onto the 4.6 rods and make a 10.4-1 comp engine very powerful as for hi lift cam you will need to get the pistons pocketed for a piper 285 cam well worth it!
if you look on the vids on my web site the disco d2 v8 is a
4.6 hi comp full ported heads and inlet manifold piper 285 cam pocketed pistons was pulling 340 bhp before the clutch failed on the rollers
 
thanks vougese.i done google search about cam and people recomend h180 or h200 for the 4.6 would this also need the pistons machined?i thought the 4.0 and 4.6 pistons were the same.i take it there is only very slight difference in gudgeon pin height.by using 4.0 pistons would i need to get block refaced with pistons at tdc .so they dont stick out the top and then remachine the pockets to equalise the compression cc?would your setup be built using composite gaskets or tin ones?as this would affect compression ratio.the block i am using has top hats fitted,but1 or 2 are slightly above alloy block face,so was going to get them reskimed to ensure perfect flat surface on the block i realise this is also going to effect compression ratio too.also read that you are better running higher comp ratio if using lpg (which will be fitted soon)as the octane of lpg is higher.was the 4.6 engine built originally with tin or composite gaskets?thanks for the advise
 
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