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Differentiated Air Intake System (DISA) Maintenance

Well I did this maintenance today on my N52 engine(mainly because I've been having rough idle). Took about 2 hours(including breaks to smoke, drink some milk, watch some tv with my dad, and recover my back every 20 minutes from bending over[seriously working on this engine way down there is killer on my back].) I was thinking maybe I should have taken pics but oh well... After taking apart the entirety of the intake including engineering my ratchet wrench to a star driver so I could remove the 4 screws holding the adjuster unit in and the screw on the cable plate thingy and the screw on the resonator. After getting all of the bits and pieces of intake tubing out of my way that were necessary I finally got to the 4 screws on the adjuster unit. This was I pulled out my modified ratchet and went to work getting those screws out and to the side neatly placed on my work bench noting which screws came out of each hole just in case there was any variation.

Now I was ready to pull the adjuster out and discover any damage or carbon build up. I tugged, and pulled, and finally it popped out a little just to get stuck on that silly wire holder thing. After taking a break to relax my back and drink a big glass of milk I came back to the project excited to get back to work. I unscrewed that bracket thingy(just the screw at the top and turned the bracket). Now I was ready again to see what it looked like and I really should have taken a picture! It was emaculately clean with no play at all in the mechanism... :headbang: ..

Ok, well after figuring that out I went to take a break and show my dad how clean it was and then came back and put everything back together.. well except for the main tube.. I couldn't get it put back on the resonator. So I took it out and examined the situation of course after almost killing my arm and back trying to get that little tube back on. I decided to go get my star modded wrench again and pull out the resonator. After doing so I needed to use the bathroom so I gave the main tubing and the resonator to my dad and told him to connect them... I get back and he says he couldn't do it. So I examined it a bit more taking note of the design with the little nitch on the bottom to lign up with the nitch on the tube etc.. After a little toying around with it I finally got it on and suprisingly with less effort than I had been.(idk maybe I was trying too hard)... I went back to the z4 and put everything back together also taking note of the little nitches in which the metal screw parts of the clamp fit in. Everything is now nice and tightly fitted into the car. I started her up and let her idle for 10 minutes without the A/C then 10 with. Drove an 8 mile round trip and she seemed to be driving pretty decent but it kind of sounds a little different. The idle also seems to be a little more balanced but still rough around the edges. I know that there is a second adjuster unit on the exhaust manifold side of this car and am wondering if it may be dirty.

So a little while ago I went into wal-mart and got some seafoam. Poured it into the gas tank(well some of it went down the side of the car cause it wasn't going in very fast and I was getting impatient). Gonna put some in the oil tomorrow too and get everything nice and clean on the other sides of things.

If by the next oil change the idle doesn't level out good I'm probably going to take it in under warranty and see about it.

I also find it kind of odd that I didn't do anything and she sounds less whiny and more roary(she went from whiny to upset).. i don't get it... maybe it's just in my head though.(probably just dreaming it up) I'm sure I'll drive it tomorrow after she takes a nap and she will sound normal... :thumbsup: :thumbsup: :thumbsup: :P :D
 
tomTVR said:
Just changed mine myself. Considering how loud the rattling noise was i expected the old DISA using to be disintegrating yet in fact looked just fine with minimal despoits and only about 1mm of play. The new one solved the rattle problem all the same.

Can you remember roughly how much a new unit is please
 
Thought I'd give this a bash, not that I had any rattling but I do like a bit of preventative.

All very straight forward, with minimum deposits I think you'll agree, small amount of lateral movement on pin

Here's the pics, 03' 2.2 with 44k

DSCF1962.jpg


DSCF1963.jpg
 
While doing some work on the car this afternoon, I noticed a rattle from my Z4. After closer inspection its coming from the DISA :thumbsdown:

I'm going to order a new one from Soper's, but was wondering if there is much point in taking the current one out and giving it a good clean -
Bearing in mind it could take a few weeks to recieve a new one.

PS anyone have the part number to hand?

(Year 2003 / Miles 38,000)
 
Think this is it: Part # 11617544805

Can you post the price when you find out, I may swap mine.
 
Thanks,

I ordered a few days ago from sopers, £134 Inc vat and delivery


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n52 owners - going to try this tonight..does the m54 instructions above work for our n52s without much change? how long roughly did it take yous?
 
BluZiff, it is movement in the plastic pin at the top you're looking for I think. It is designed to move in the manner shown in your vids. If the pin is loose then that is a bad thing... Ranski or A N Other may give you a better opinion though, as mine is the N52 engine, which is different to yours.
 
The pin was solidly in place, i was a bit concerned about it not returning to the correct position by its own means. But if its no problem thats cool. :)
 
pharmed said:
How big a problem is this? Never heard of it until I stumbled upon a youtube video. Has anyone had any failures?!

I dont think you want to risk it. Preventative maintenance is much cheaper than having to trouble shoot and repair damages later.

Is reviving an old thread instead better than starting a new one?
I had the "ghost whistle" noise and stumbled upon this. Took it out and it looks like its really banged up. I have a few pictures i can upload. My valve is flopping around. Do you know where the spring is attached to the valve? Im just worried it has poped out and gone somewhere bad.


Also, what is the best method for cleaning out the intake? Id prefer not spraying stuff into the manifold while its still attached to the engine. Doesnt all that junk just end up in the engine? Is it better to remove the manifold and clean it out?
 
pharmed said:
How big a problem is this? Never heard of it until I stumbled upon a youtube video. Has anyone had any failures?!

The problem is well documented on M54 engines, just done mine 2 weeks ago , got the upgrade kit from sheffield £50..There was a little play in the pin on the end so it had to be done.
And yes a guy on the Zroadster.net forum had a failure which was attfibuted to this , and a very expensive engine rebuild.
So its better to invest £50. Now.
Cheers Moz.

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Well I bought one of these on my 4.5yr old/60k Z4, and over time I can hear it rattling again. Now I'm at nearly the same time/mileage interval again it's likely approaching needing doing again.

But I think I threw my old DISA away... a shame given they can be rebuilt like this. I'll have to have a dig around in my bits box to see if I still have it. Might send it off for a rebuild.

I think the DISA was £120 in early 2010 or so when I bought my replacement one. Not cheap given such a tiny piece is what fails.

Dave
 
Decided to have a look at my unit. As everyone says about 10 minutes to get off. Car is 10 years old and has covered 55000 miles. Not particularly dirty and the paddle bit turned easily with no noise and sprang back into place so no play there. However whilst the metal pin felt secure there was a bit of rocking between the metal pin and the plastic paddle. Not a great amount but enough to keep an eye on unless anyone says this is in danger of failing.
Incidentally I had a good look around in the intake seating and I dont see how even if it worked loose the pin would drop out. It would be held against the plastic intake as there is very little room. I came to the conclusion that if it does fail then removing the unit is the most likely reason for the pin to get further into the engine.
 
At the BMW parts department today to pick up drive belts (routine maintenance) so I asked how much the DISA would cost. I see above that someone paid £120 back in 2010. Today it will set you back £360 plus VAT - no wonder people go down the overhaul route!!.
 
The price of spares for these cars seems to be rocketing nowadays - must be scarce supply as the first gen e85 is now 11 years old... By 2019 they won't have to make or hold stock of replacement parts at all for e85/86s :(
 
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