Engine knocking on one bank (m70 v12)

Rocker Arm

I had the same issue on my 850i and it turned out to be a "racker arm" that was not aligned correctly - a bit of a b****rd to diagnose and fix, but managed to get it sorted!

Rocker Arm

Meant to type "rocker arm", sorry!

Sounds like the inevitable banjo bolts to me.

Removal of intakes to get to the valve covers is needed. A full days job if you know what you are doing, if not learn as you go and allow the weekend....

Just do a search for banjo bolts and see what comes up.. Talked about a lot in the past....

3 options,

1. Locktite
2. Locktabs
3. Drill and lockwire.

Hope this helps

Alex

Hi, check out my tale of woe (it has a happy ending) http://www.8er.org/forum/showthread.php?t=8330.

The ticking (it could be described as knocking) was getting fairly loud by the time i fixed it. My car was trashing a cam shaft through bad banjo bolts which were starving the cam of all oil so i would avoid driving until it's fixed. If you hold a screwdriver to your ear (the plastic bit ) and then put the metal end against the cam cover and move along you should find the noisy cam/lifter. Mine was obvious. If it is a valve/cam/lifter issue then look through my post, piece of cake!!! I can lend you the tools too when I get them back from Lloyd. I suspect you're looking at well over £1,000 to have this done at a garage as it is very time consuming, but this is only a guess so if you're not comfortable doing it yourself get some quotes.

As Nick and Alex said loose banjo bolts will cause a lot of noise. If you read my recent valve stem seal thread you will see that had one very loose and another on its way (crossed drilled all of them and lock wired them in place) I know I have already said it on my other thread but she is running like a beauty

Anyway its just a very time consuming job but possible and whilst your are there you could renew the valve stem seals you wont regret it.

P.S Nick I have just put you tool back in a jiffy bag and it will be on its way to you tomorrow, thanks again mate

Lloyd, no hurry on the tools. If you're going to Gaydon you can give them to me then?

Nick it was sent recorded delivery today (with a small thank you inside)

First of all: Buy new banjo bolts from BMW. Those new (upgraded) parts are designed to address the loosening of the bolts. They already have Locktite on them. Do NOT mess around with wires and that stuff. (Really, guys: what IN THE WORLD makes you think that saving pennies by messing with the old bolts is a good idea???)

Then: No special (as in BMW-only) tools are required. Just make sure that you find the appropriate pdf (somewhere here on the server) with the instructions to renew the intake rubber thingies.

Then, finally: The fuel smell indicates fuel. If the whole shenannigan is, indeed, rocker related, then the intake valve rocker is broken, disabling fuel to enter the engine. But since fuel is still injected, it has to go somewhere. Fuel always prefers noses; in this case: yours

Cheers,
Dieter

REASON i reused banjo bolts was that i had no idea "upgraded" ones were available? No-one has ever mentioned these in the hundreds of posts i've read on the subject. In what way are they different from applying loctite to the old bolts?

The fuel smell will almost certainly be the short fuel lines just behind the fresh air intake by the bulkhead. They are very prone to leaking. Replace all the hoses whether you do take the intakes off or not. They can cause a fire.

I doubt you'll get away with just tightening the banjos. Whatever is causing all that noise may have been caused by loose banjos but chances are something will now need repairing. In my case i located the noisy pair of cam lobes and replaced the 2 rockers and lifters for those lobes. I can't be sure what was causing the noise but i suspect if i'd just tightened the banjos the noise would still be there. My guess would be that the lifters were empty of oil due to oil starvation. It's a lot of work getting the valve covers off so you may as well do the rest of the work while you're there. The valve seals take an age (ask Lloyd ;)) so you could pass on those, but fix any duff lifters or you'll have wasted your time.

Zitat von NickF;66315

REASON i reused banjo bolts was that i had no idea "upgraded" ones were available? No-one has ever mentioned these in the hundreds of posts i've read on the subject. In what way are they different from applying loctite to the old bolts?

I too had not heard about upgraded banjo bolts which is why I lock wired mine. Penny pinching is not something that either I or Nick (speaking for you Nick) would do for the sake of a few quid. Anyway mine are now locked and thats how they will stay.

Sorry, fellows. Didn't mean to insult anyone.
The new banjo bolts have pre-applied locktite on them (in a dry state that is smeared into the threads by screwing them in).

I learned about them myself in the German part of this Forum and mistakenly thought that to be known.

Locking bolts with wires is, actually, a valid engineering approach. It has been one of the favored approaches (aside from using position locking plates around the face of the bolts) back in the good old mechanical engineering design days. Many of these designs have been superceded by chemical adhesives (like locktite) as they are cheaper.

So, please forgive my directness.

On a side note: Many of the replacement parts supplied by BMW have been upgraded/improved over the years. You will (sometimes) find indications on such upgraded parts in the ETK (parts catalogue like available on bmwfans.info).

the fuel lines are 8*13mm and you'll need 2m (you may need more (total 2.5m) if the lines from the fuel breathers to the DKs are also shot like mine were). Buy from BMW, they are expensive but don't mess with cheap rubbish as they don't work. There are a whole load of gaskets required, but you can work it out by going through realoem which will help you understand the job. Read my previously linked post and Lloyds and you will have more questions. If you're going to do the job let me know and i'll post you the tool.

In your PM you said you'd ordered the fuel line and valve cover gaskets. You will need more gaskets. It depends on what you're planning on doing while you're down there. You will need 8 new crush washers for the banjos. Plus, if you plan to paint/coat your intakes you'll need 4 gaskets for DKs and end covers. If you remove the VCVs from the valve covers you'll need the rubber grommets. I would buy new nuts for the intakes to make it easier to spot if you drop into the V, also get a magnetic pickup tool, v important. Buy 20 BMW fuel hose clips.

Lloyd - what have i missed?

make sure you ID where the noise is coming from before taking stuff apart. In my case it was obvious (cam lobes looked nasty) but there's a chance yours will all look fine. I don't know of a way to diagnose a bad lifter by looking at them.

Nick I think thats it.

Maybe a suitable sealant for the intake manifolds if using the original IM gaskets