REPLACING TIMING CHAIN GUIDE RAILS

[J.Belknap]

If your friend is good with a wrench, and parts are bought from Tischer, and you get a hold of some procedures, it shouldn't be that bad on the wallet for what you're about to do.

It's a tough break... Plastic guides are easy on the chain but when heat cycled over years in any vehicle (or even your oven if you tried) the stuff will get brittle.

[amacman]

J.Belknap s list of parts seems reasonable but if you want to wing it go ahead .
as you say though , check everything before making decisions .

[Isambard]

Glad it kind of worked out for you in the end James, bit of a raw deal, but what can you do without x-ray specs?

Spoke to my friend today, and he has just taken delivery of the timing tools needed for the job, so he's going to make a start early next week. We spoke about all the things you guys said to think about changing whilst he's there, and he agrees and is certainly on the same page as you guys.

At least I can certainly be more confident seeing that he already knew all that stuff. Though thats not to say I thought he wouldnt know, or at the least be aware of what is required, hell, it was him that said what it is most likely to be the second he heard it!! Like I said before I think I must be still in shock, particularly looking at the pictures of an opened up engine on another forum. I've pulled the engine apart a little when I did my oil separator, but this situation just looks like another game entirely..

Kinda crapping myself at the cost and the possibility of finding many things wrong and the worry afterwards of a small but vital part overlooked in the process of rebuilding, then a few thousand miles down the road, and BANG again!!

Oh well no point in worrying, whats done is done, and what will be done will be done, just have to wait and see how it all unravels nexts week..

[m5james]

Keep us posted...I hope the carnage is minimal.

[c4racer]

I believe they use plastic chain guides to keep it quiet, since the chain is metal. Metal guides against a metal chain would be rather noisy. Also you want the guides to fail before the chain. So the use of plastic guides is pretty common and done on purpose. Now, as to what plastic they use - that's another matter....

Audi V8's have the same issue and some very small % of motors have this failure for seemingly no reason. It can't really be related to maint or use, just some low level failure mechanism.

[Isambard]

[QUOTE=c4racer;778028]I believe they use plastic chain guides to keep it quiet, since the chain is metal. Metal guides against a metal chain would be rather noisy. Also you want the guides to fail before the chain. So the use of plastic guides is pretty common and done on purpose. Now, as to what plastic they use - that's another matter.... [QUOTE]

I believe you're right on the money with that. As much as I hate to admit it (preferring to rant on at BMW) engineering sense prevails here. I did wonder if it was something I had done wrong, or the previous owner(s), ie maintenance, for the guides to 'prematurely' fail. I wondered if it might be the spring-loaded chain tensioner that may have contributed in some way.

I mean there was always a slight knocking sound ('marbles in a can' as its been termed on several forums including this one) at start up from cold. Perhaps it had gotten worse than I originally noticed due to the slackness in the tensioner which caused the chain to slap about on the plastic more than it should have. But because I've had the car for 2 years now I suppose I didnt notice the gradual degradation and increased knocking, and length of time of knocking on start up increasing to about 3-4 seconds. Is this theory of the failed/failing spring-loaded chain tensioner being a contributor to the premature failing of the guides something that anyone else shares?

[m5james]

The knocking at startup can be both VANOS or the timing chain tensioner, it's just most replce the tensioner first since it's a $20 something part and can be done far easier than VANOS seals.

[Isambard]

Ok, thanks James. I wonder if the jerkiness when cold for the first mile, regardless of whether in sport mode or not (yes I have looked at ALL the possibilities contained within this site for the lunging/jerkiness maladies) has anything to do with the VANOS system. I know very little if not nothing about it, but I'm sure I saw somewhere a post either here or on another forum where the solenoid seals were leaking causing a jerking movement.

And with my next-to-nothing knowledge about VANOS I was linking that with my lunging/jerking when cold... Any opinion on that? Do the solenoids have anything to do with the oil circulation, and perhaps its taking a while for the oil to be circulated due to them being faulty in some way? Hence the car needing to be driven for about a mile before it runs as smoothly as it should.. Or am I thinking and talking absolute garbage?

And what VANOS seals are you talking about? Could they be checked/replaced if needed (or just change them anyway) while mine is in for major surgery?

[m5james]

While the I6 and V8 (and even the V8 has different types), most people describe VANOS problems as jerky, loss of power, etc. This site is unrelatable to us, but read up on www.drvanos.com and or Beisan Systems as I bet their symptoms are similar to what you're experiencing.

If it's in fact the VANOS solenoids, that's exactly what you're hearing...oil starvation. There are check valves in there that are supposed to stop backflow, but apparently they fail and or the seals don't do their job. I personally run 0w40 and on maybe 3 occasions total I've heard a startup rattle, and that usually happened after the X has sat for at least a week or so and/or the rare occasion it sat overnight outside in the cold (visiting family in Reno winters), which makes some sense since seals shrink up in the cold.

The seals can be replaced, but as far as I know, BMW hasn't changed the gasket material, so eventually it'll happen again. I've tried contacting both sites above in regards to V8 kits, but neither has produced anything as of yet.

[Isambard]

I've had a look on Realoem and the only thing that I can see 'seal/gasket' related are no's 3 and 16 here: RealOEM.com * BMW E53 X5 4.4i timing gear timing chain top - VANOS Is no. 3 what you are talking about?

I just want a better understanding of how these things go together and what is needed, so that I can talk to my friend next week, as even though he is good, he MAY not know as much as you guys/BMW techs know and may NEED to know. Or at best he WILL know and I can then have a better understanding when I discuss it all with him!

Thanks again James, for your time and input in all of this.