Late-model AAA upper chain on an ABV?

[Stonejag 10]

Been reading up on timing chain replacement since I got some 263 cams in the group buy. I have a recently-rebuilt cylinder head which I'll be building back up to include the new cams and some shiny new innards, and then swapping out this head for my old one - which lets me take my time over the rebuild. Not sure as yet whether I'll be enthusiastic enough to replace both chains or just the top one!

 

Since I'll be fitting new camshafts, and they don't come with the timing gears, I wondered if I could swap over to the timing setup from late-model (post-'97) AAA engines - with a single-row chain and the improved low-wear upper chain guide. In theory this would just involve swapping the chain, upper tensioner, timing gears and outer intermediate sprocket, then it'd let me run for much longer without ripping everything apart again. Anybody done this or am I being hopelessly optimistic? :)

 

Cheers,

 

Stone

[dr_mat 0]

It's not worth going to the single upper chain setup - you wind up replacing too many parts, but you CAN use the later model tensioner even with the ABV double-chain. Stealth Racing do this regularly I believe. The late model tensioner is significantly more reliable (it's a single piece).

[Stonejag 10]

I'll be buying extra timing gears anyway so I can fit them to the cams in advance (don't much fancy doing them up to 100nm in the bay!) so on top of that it'd just be the intermediate sprocket to change, no? I also thought the intermediate sprocket had to come out to do the upper chain..?

 

Thanks for the tip :)

[dr_mat 0]

I recall there's a reason it's not that simple.. Maybe you'll find it impossible to time it up properly or something? Ring Stealth racing if you need more details, but I don't see that there's any justification for going single-chain anyway - even if you're taking a load of stuff out.