Twin chains on an obd2 engine???

[Phat VR6 3]

Hello,

Ive just started rebuilding my VR, Its a 1997 model obd2, and from ive read on hear it is an obd2 engine but its got twin chains which I thought where only fitted on the older obd1 models? Is that right?

Also Ive hurd you can swap the chains over and convert it to single chains, Is this right and is it worth doing??

Cheers for your help

[Phat VR6 3]

bump

[6potmkII 0]

yes i recently rebuilt my 2nd engine obd2 and it was double chain. easily converted to single chain, you need both cam sprockets, the smaller bottom sprocket that both chains connect to and new top single chain. i think vw quoted me around 40+vat each for cam sprockets and around that for the chain too cant remem smaller sprocket

[Phat VR6 3]

Cheers for that, Is there any point in doing it?? And have you done it? If you have would you mind giving me the part numbers

Thanks alot Tom

[gav_113 0]

i did hear that, some early 0bd2 engines were still duplex? u can check by ur engine numba?? dont think ur benefit alot by converting to single chain.. think they just wear less.. and had better tensioner..

[Phat VR6 3]

Umm thats what I thought, They wear less but they have lasted 140,000 so I canr't see much point

[6potmkII 0]

i did it because i had the parts off another engine. the double chain will atleast last you another 80k from the time you replace it, so if you can see yourself owning the car for that amount of time it may be worth it, other than that you wont see any performance gains

[Phat VR6 3]

Ummm, Its a hard one tbf, Seems pointless in my situation,

You know the only problem the chains suffer is the fact the guides wear! How come people change the lot, as in, All the chains, guides, tennioners ect, When they could just change the worn parts (guides for exsample) ??

[gav_113 0]

i changed the whole lot coz mine had done 140k, and no history saying they had been done!! gd job i did!! the chains do snap, not very often tho. u dont wont to do the job twice, and if it does snap, then u will prob do alot of internal damage to the engine!!!

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[Phat VR6 3]

Yeah true. Better to be safe than sorry!

They realy are worn, Looks like its gone thought guide and onto metal.

Was that realy noisey??

[gav_113 0]

yer it wore thro the metal ha,ha... not really noisy?? bit raspy,.. only noticed coz i i had the head off coz the gasket went!! good job to, i reckon a couple more weeks and it would of let go??

[Phat VR6 3]

I guess the tensioner just keeps on taking up the slack, You think the metal on metal damaged the chain

[gav_113 0]

it would after a while..lol

cant be good ne ways..

[turbo_ted 0]

can you change the top guides without removing the gearbox?

[kilokilla 0]

its very rare for chains to snap and you can use the later tensioners for the single chain on the double chains aswell imo 2 chains are better than 1 if 1 snaps the other will keep the engine timing in tact and stop you from taking out valves and pistons but thats just my opinion.

[Steve @ 1]

Yeah as above i run the later top pad and tensioner on the double chain on the rado.

[FishWick 21]

imo 2 chains are better than 1 if 1 snaps the other will keep the engine timing in tact and stop you from taking out valves and pistons but thats just my opinion.

The duplex chain isn't two seperate chains as that comment implies, it's just double width for extra strength. Twice as wide, twice as strong......but double the noise, double the wear, double the weight and double the cost (to produce), hence why V downgraded to a simplex chain I suspect.

The duplex chain was part of the engine's original design and pretty overkill, so not really necessary any more.

As for advantages swapping to a single cam chain, I can't think of any!

[thegoth 5]

yer it wore thro the metal ha' date='ha... not really noisy?? bit raspy,.. only noticed coz i i had the head off coz the gasket went!! good job to, i reckon a couple more weeks and it would of let go??

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Mine where in the same state, top one at least didn't see the lower tensioner. The ball bearing noise comes from the chain rattling across the rivets which keep the plastic runner on. Once they wear away completely the engine quietens down again.

[Phat VR6 3]

Guessing mine are the same then 140,000 ect. Hears a list of parts when changing chains to make the best of both engines, I.E the better tenioner and bolt from the later engine,

(top chains, lower chain, lower tensioner, guide rails upper and lower,98 vr top tensioner rail and 98 tensioner bolt and sealing paste)

Much thanks to kilokilla for the help