X5 4.6is Engine Block from 4.4

[BRABUSBENZ21]

Originally Posted by kclow

My 4.6 block has developed 3 cracks behind one of the sleeve. I was advised by the machine shop that it will be risky to resleeve, and advised me to locate another block. However, finding a 4.6 block is tough. Has anyone managed to use a 4.4 block and rebored instead? Will it work? Thanks!

I just sleeved my 4.6is block with darton cast iron sleeves. I also had the sleeves diamond honed, and plated with a special chemical that makes the cylinder extra hard. So yes it is possible to resleeve your block. I also had the cylinders fitted with custom JE Forged Pistons. According to the guy at the Machine shop it is suppose be more reliable and have a higher compression vs factory. I should have my block back this week

[Nick P]

Originally Posted by BRABUSBENZ21

I just sleeved my 4.6is block with darton cast iron sleeves. I also had the sleeves diamond honed, and plated with a special chemical that makes the cylinder extra hard. So yes it is possible to resleeve your block. I also had the cylinders fitted with custom JE Forged Pistons. According to the guy at the Machine shop it is suppose be more reliable and have a higher compression vs factory. I should have my block back this week

JE pistons are made for iron sleeves you can't use them in alusil block (or you have to coat the stock pistons with ferrostane or similar material), but there's no need to sleeve the block - you can just bore it out from 92 to 93 mm and re-use the old pistins with new piston rings - it's much much cheaper, than putting the sleeves and new pistons.

1 mm bigger bore costs here in Europe about 600-700 Euro for 8 cylinders, a used 4.4 block is about 200-300 Euro max. a set of new piston rings is something like 150 Euros. Thats it!

[BRABUSBENZ21]

Originally Posted by Nick P

JE pistons are made for iron sleeves you can't use them in alusil block (or you have to coat the stock pistons with ferrostane or similar material), but there's no need to sleeve the block - you can just bore it out from 92 to 93 mm and re-use the old pistins with new piston rings - it's much much cheaper, than putting the sleeves and new pistons.

1 mm bigger bore costs here in Europe about 600-700 Euro for 8 cylinders, a used 4.4 block is about 200-300 Euro max. a set of new piston rings is something like 150 Euros. Thats it!

If you bore the block out, you will need to get the bore re-alusil or nikasiled.

[Nick P]

Originally Posted by BRABUSBENZ21

If you bore the block out, you will need to get the bore re-alusil or nikasiled.

I already wrote something about it in the post #5

Alusil is a material (the whole block is made of alusil), nikasil is a coating - in case of alusil you'll just need to use special bursting (not exactly a hone) to disclose the silicon crystals in aluminium matrix, but it's an easy routine process being performed daily.

[kclow]

Originally Posted by Nick P

JE pistons are made for iron sleeves you can't use them in alusil block (or you have to coat the stock pistons with ferrostane or similar material), but there's no need to sleeve the block - you can just bore it out from 92 to 93 mm and re-use the old pistins with new piston rings - it's much much cheaper, than putting the sleeves and new pistons.

1 mm bigger bore costs here in Europe about 600-700 Euro for 8 cylinders, a used 4.4 block is about 200-300 Euro max. a set of new piston rings is something like 150 Euros. Thats it!

ic. Will speak to my machine shop about this. Also, I just managed to buy a 4.6 block from ebay that had a 2-3mm chip between cylinders 1 & 2. My machine shop said in the worst case, they can fill it out and fit sleeves to those 2 cylinders. This will be a safer bet than using the 4.4 block I guess.

ebay link to block: 02 03 BMW E53 x5 4 6IS Engine Block 98K Miles | eBay