4.4 and 4.8 interchangeability?

[alfamaniacs]

Good day,

I suspect that my 4.4 N62 is suffering from a bottom end knock (noise audible between 2000 and 3000 rpm on acceleration)

What I would like to know is when shopping around for a replacement could I look at the n62 4.8 as well as the n62 4.4 - I know that the 4.4 M62 and the 4.6 can be swapped since the engine management is the same, does anybody know whether or not the same would apply to the N62 B44 and the N62 B48?

Any advice would be appreciated

By the way, my car has only 70k miles on the clock but was driven hard (lots of full throttle and high RPM)

Regards

Andrew

[steelheader]

drop the pan and throw bearings in it ? its worth a shot

[alfamaniacs]

I think that we are on the same page - it sounds like the beginning of a rod bearing failure - I have a third party warranty but I am guessing that it will only contribute a max of around $3000 towards repairs or a used engine. Used engines in South Africa will go for upwards of $7000!!!

Thats why I asked if I could slot in a 4.8 N62 instead of a 4.4 - It all depends on what becomes available in terms of used engines

Maybe I will get them to pull the sump - maybe I will be lucky

Thanks

[nitrorocket]

$7000 for a used 4.8is is dirt cheap! A dealer long block cost $19,000 at the dealer. They are very rare engines and hard to find. Surprised you even found one.

FYI, I am an engine builder and tossing in new rod bearings will only be a temp repair. Usually a week or two from most my experience. But there are always exceptions to the rule.

Are you sure it's not a cat converter rattling? It's pretty common. Sounds like a rattling knock in midrange rpm.

[alfamaniacs]

Hi and thanks for your interest - I am not sure if its the cat, I had a slight cat rattle on my old e38 m62tu and though similar its not the same since this noise is cyclic in that it increases in frequency along with the RPM. I must point out that the noise is so faint that if the radio is on even softly or the interior fan is on low speed the noise is not audible - it comes in at around 1500rpm and is gone by 3000rpm.

I spent New Years with my folks and returned home this evening after a very fast trip - I figured if it was gone blow, then ......... but after 250 miles and average speed of 100mph with the odd 130 or so the noise appears to be no worse.

I guess i will have to get out my stethoscope doo-dad and try to isolate the problem. I am also considering draining the oil and sending it for analasis.

There is also the possibilty of just trading it for something else.

About those engines - I found 2 candidates, a 650i and a e70 4.8i both wrecks (rear damage) I would still like to know if the 4.8 will run off the 4.4 ecu?

Thanks again everybody

Andrew

[Rewmer]

As far as i can see all the later n62 2004 onwards use the Bosch ME 9.2.1 engine managment ap your theory seems to sound, you may have trouble if you have the earlier single vanos ME7.2
management.

[nitrorocket]

I would definetly tackle this little project. Get the motor/trans and then install it. For the electronics I would start by using the engine harness from the 4.8is truck along with the ECU. I would think it would need not much more then some minor repinning(if any) of the bcm interface.