Replacing cam chains N62 4.4l

[Rick G]

I found a while ago the tensioners were cactus and decided that due to 215K km the chains would be a bit worn as well so purchased a kit. I now find that as far as I can see the oil sump needs to come off to replace the chains because the oil pump drive chain needs to come off to get the cam chains off or am I missing something.
I tried loosening of the nut on the oil pump drive in the hope that enough slack would allow the chain to slip over the teeth but no alas I was thwarted by the stupid engineers at BMW who are taught to think like zoobs when designing anything that needs to be replaced at a later time.

Any suggestions as to how or do I just suck up the cost of the new chains and use the old ones which aren't bad but are showing signs of wear and I would like to replace them as much for peace of mind as anything.

[X5Sport]

Have a look at newtis(dot)info for the BMW repair manual.  Might help 

Personally at that distance I would change the chains too given you’re going to have it all apart and they might have stretched.

[A Blair]

Hi
Is there any possibility of breaking the chains open and feeding them around?
Something closed them into a loop in the first place.
Just a thought.

[Rick G]

I wouldn't break those chains but may break the drive chain on the oil pump drive.
Newtis says remove the engine, remove the timing cover, remove the chains. Big help! That is worse than a Haynes Manual and the Bentleys hardly even touches on the N62, just sort of mentions the existence of it from MY 04 on.
I presume that by it saying "remove the engine" the answer to my question is no it cant be done.

[Greydog]

The guy who rebuilt my engine (ex BMW Tech and Porsche Specialist) has a love hate relation ship with these engines. Hates them as they are over complicated and fiddly, Loves them as he has a constant supply of them to work on.

I do know he pulled the oil pump sprocket to allow removal of it's chain but as my oil pump was toast the engine was on a stand not in the car!! He did say that he see's quite a few where the main chain guides have been renewed but there are still rattles because the Vanos chain tensioner's have been forgotten.

[Rick G]

I will investigate if I can get a high quality chain and joining link that is rivited and replace the oil pump chain that way.
I worked for Honda Australia for quite a few years and we used to replace the cam chains on many of the bikes that way and never had a problem. Honda even made a special tool for crimping the link closed bit it unfortunately doesn't fit these as its for a chain that is a bit smaller.
I will let you know so as not to leave the thread hanging.

[lezmtaylor]

I used to replace the old Jaguar 2.4,3.4,3.8 front timing chain the same way, with a joining link and feeding new chain in as old chain came out, after removing front timing chain chest cover.
Saved taking engine out and I made a few quid doing it for people. (I did not let on how it was done!!!).

Lez

[Rick G]

I am having trouble measuring the chain properly due to it being a bit inflexible on the sprockets. I have found a DID chain which is for the purpose but cant get my verniers far enough into a link to measure the dia of a roller.
http://www.did-coltd.com/english/produc ... 02-103.pdf
The DID 05S SDH is I think the correct size but cant confirm. If anybody has a chain not on the engine a measurement would be easy. Anyone someone please.