Timing Chain Death Rattle

[matty 0]

Hi everyone I have just joined the Club and am now helping my busy son take care of his VR6 Golf 1995.

We bought the car privately and it naturally has a few problems at 93,000 miles and so far we have fixed a rear wheel bearing, rear window cable, boot lock and hopefully a water loss problem.

There is also a slight rattle from the timing chain which varies from time to time from nothing, to just about audible with the bonnet up - with the bonnet shut it can not be heard.

Looking on the site here it seems that this should be fixed asap but is there likely to be a serious problem in the short term (i.e. 10,000miles) if we keep an ear to it.

On the site many people seem to now have VR6s which have done about 100K miles and have a slight rattle, but what proportion of these have had a serious chain breaking or engine wrecking incedent later and after how many miles?

On a site such as ours even one serious breakage could make us all get in a panic and obviously the repairers will have seen the really bad ones and know what happens in the worst cases.

What I am trying to say is - is serious damage a frequent event on early 100K mile VR6s or do they run for some time with a light rattle?

There is wonderful information on the site to help us change the chains and tensioners should we diy. Both myself and my son are engineers with all the necessary tools, though he may be too busy and I too old at 70 to do the job - so we may have to get it fixed by one of the guys on the site who really know what they are doing !!

It will certainly have to be done some time fairly soon, but I am puzzled how to fit a new type top simplex chain onto existing duplex sprockets without changing the cam and lower sprockets - or have I missed something ?

I would be grateful for any advice on the above and think the car is a great drive - nearly as much fun as my Vincent HRD doing parade laps on the Isle of Man and VFR 750 Honda on the road!!!

Don't get old - it hurts, nobody tells you that!!

[antera309 3]

The chain itself is as tough as old boots, and cases of them snapping are VERY rare. The problem is the guide rails and tensioners. These are all made out of plastic (plastic riveted to a metal backing in the case of the top tensioner on OBD1 engines). Being plastic, they can crack and come apart once they get worn.

When this happens, the chain is no longer tensioned properly and this throws out the valve timing slightly , affecting performance. In some (but not all) cases, the slack chain can "slap" against the side of the chain cover, and it is this which causes the characteristic rattling noise. If left unchecked, the chain can become so slack that it jumps a tooth on one of the sprockets and this can result in piston/valve contact and a knackered engine. There is also the threat of a piece of plastic tensioner breaking off and getting jammed between the chain and one of the sprockets. I'm sure you can imagine what the result of this would be.

The 100,000 mile thing is only a guideline. On some engines, the chain tensioners & guides start to fail well before 100k, whereas other engines are fine up to 120k and beyond. It all depends on how the car has been driven, frequency of oil changes, quality of oil used etc etc etc. If any engine work has been done which involves disturbing the chain setup (for example, changing cams or replacing the headgasket), this will also shorten their life.

It is always the top chain tensioner and guide that go first, and the earlier OBD1 engines are worse for it than the later OBD2 ones (because the double-row chain inflicts more wear on its guides and because the OBD1 has a weaker top tensioner design).

My engine had only done 85,000 miles and there was no rattling at all. I only found out there was a problem when I came to fit some Schrick cams and noticed the top tensioner had started to come apart.

When the engine came out for chain replacment, I saw that the upper chain guide (which was not visible until the gearbox, flywheel and chain cover had come off) was in an even worse state than the tensioner I spotted earlier. It was in 5 pieces and there was nothing holding it to the engine!!

Witness the fragmented remains of my upper chain guide. This is supposed to be ONE piece of plastic!!:

Lord only knows how long the engine would have lasted if I hadn't have got the chains done.

The VR6 is a fantastic piece of German overengineering. It can have all sorts of crap wrong with it and it will still run. But it's not a good idea to ignore the warnings for too long....

By the way, it is not necessary to convert to a single-row upper chain. You can get all the standard OBD1 chain components (with double-row upper chain) brand new. Just quote your engine number when ordering the bits and you'll get everything required for a like-for-like swap.

There is a very detailed guide in the "Engine" section of the "Knowledge Vault" premium members' area. As well as a full fitting procedure, there is a list of part numbers there for all the bits required.

[matty 0]

Thanks for the excellent reply - However you've made a happy man very old !!!

However which guide is the one where it is best to use the one for the later version anddo you know its number please.

[antera309 3]

The timing chain replacement guide can be read here:

http://www.vr6oc.com/e107_plugins/forum/forum_viewtopic.php?107739.0

[matty 0]

Thought I'd put a reply to the last statement on this thread but it vanished into space - how do I start another page? Ill try this but don't know if it will continue with this thread or not.

The IT has beaten me as usual !!

On my old duplex chain engine I understand I could fit a newer type Upper Tensioner Rail OBD2 021 109 509E. If I do this do I also have to fit the newer type Upper chain tensioner bolt OBD2 021109 507B and is the mod OK and worth doing please

[matty 0]

The excellent replacement guide above does not refer to the "dodge"/improvement of fitting a simplex type Upper Tensioner rail to the old duplex chained engines

[matty 0]

How is a new page started by the way and thanks for all your help so far.

The replies seem to be working OK now by the way but I haven't done anything different !!

[antera309 3]

The excellent replacement guide above does not refer to the "dodge"/improvement of fitting a simplex type Upper Tensioner rail to the old duplex chained engines

Yes' date=' you can use the later type (100% plastic) top tensioner rail on an OBD1 engine (duplex chain) no problem. Here is a pic of one that's been done:

[img']http://img.photobucket.com/albums/v364/slowslc/NewStyleIn.jpg

Apparently, you can use the later type (spring loaded) top tensioner bolt too.

You learn something new every day...

[matty 0]

Thanks again have got some quotes for doing the job from two very helpful guys. Now also know details of what bits are needed and options for tensioners etc.

[matty 0]

Thanks again, have got some price/timescale quotes from two very helpful guys for the job and also know the options for fitment of newer Upper Chain Tension Rail and Tension Bolt.