Timing Chain to Timing Belt Conversion?

[gautam]

Has anybody done this? Is it even possible to convert the BHF engine from a timing chain system to a timing belt? I remember seeing a kit when I was first researching the car 2 years ago before I bought my B6, I remember being put off by complaints of timing chain rattle and failure and thought well maybe I could convert it to a timing belt instead.

The reason I ask is, I'm buying a used 4.2 engine with a buddy and we're going to take it apart and rebuild it. He wants to install it on a B5 project he has so we're debating between doing the timing chain fix (even though the engine has crazy low miles) or other alternatives.

[roboto_1337]

Seems like more trouble than it's worth... If you're pulling the engine to replace the components I don't see how a belt would solve any issues. Other than not giving you indications that your tensioners/adjusters/check valves are going to need attention.

[SprintBlueWorld]

Anything is possible but its not worth it for any redeeming reason.

If you have the motor out i would definately change out all the plastic guides, especially the middle one that can be replaced with an RS4 style metal one.

[emilio]

putting aside the engineering complexity, i think the only thing this would accomplish is that you must replace the belt every 20,000-40,000 miles, while you maybe have to service chain parts every 100,000-150,000 miles. other than parts cost, chain systems are superior in nearly every way.

and the belt would still be on the back, necessitating an engine pull.

- emilio

[gautam]

Yeah I didn't think about how often you have to replace the timing belt lol.

I think the older A8's had a similar v8 engine with a timing belt though, I'll look into it after work for s's and g's.

The best way to go about the project is definitely stick with a timing chain and redo the chain guides. We'll probably start working on it sometime next week.

[melomandn]

Yeah I didn't think about how often you have to replace the timing belt lol.

I think the older A8's had a similar v8 engine with a timing belt though, I'll look into it after work for s's and g's.

The best way to go about the project is definitely stick with a timing chain and redo the chain guides. We'll probably start working on it sometime next week.

The older 4.2 V8 in the C5's and D2's was indeed belt driven, but it was the traditional style with the belt up front. The main reason they moved to a chain was for space savings.

If swapping into a B5, you'll be better off using the belt driven V8. The swap is fairly "common" now, and you can find write ups and wiring diagrams all over. If you use the S8 engine, you get an additional 20hp over our chain driven 4.2 as well.

[Bordom]

putting aside the engineering complexity, i think the only thing this would accomplish is that you must replace the belt every 20,000-40,000 miles, while you maybe have to service chain parts every 100,000-150,000 miles. other than parts cost, chain systems are superior in nearly every way.

and the belt would still be on the back, necessitating an engine pull.

- emilio

Uuuuhm, not even close. 60-80k miles is standard belt interval. The 077 belt driven V8s are the bees knees.

Yeah I didn't think about how often you have to replace the timing belt lol.

I think the older A8's had a similar v8 engine with a timing belt though, I'll look into it after work for s's and g's.

The best way to go about the project is definitely stick with a timing chain and redo the chain guides. We'll probably start working on it sometime next week.

The early D3 A8s still used a belt driven V8 until 05 or so. One of those was successfully swapped into a B5 and runs very well. Installation was OEM+

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[gautam]

Uuuuhm, not even close. 60-80k miles is standard belt interval. The 077 belt driven V8s are the bees knees.

The early D3 A8s still used a belt driven V8 until 05 or so. One of those was successfully swapped into a B5 and runs very well. Installation was OEM+

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Does the D3 V8 have the belt up front? Might even be possible to swap it into a B6.

[BCsniper]

Yes, they had better intake manifolds and I think cams.

However the reason they switched to a chain setup is the old belt V8's were like 3 or 4 inches too long, so swapping one into a B6/7 would not work without moving a bunch of other stuff.

And I've never heard of a conversion kit to change a chain motor to a belt. I've been around for a bit, and never seen/heard of it. So I'd like to see this supposed kit if it does exist.

[Bordom]

Does the D3 V8 have the belt up front? Might even be possible to swap it into a B6.

Yessir, just a lot better tech. I'd take a belt over a chain any day. I may even do the swap into my B5 S4, since the build thread he has on it is very detailed

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