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My machine shop has converted several 7A heads to ABY/ADU spec now. It includes all the machining for the IM, EM, water manifold and it uses a genuine OE hall sender.
Every head we have converted has been in better condition than all turbo heads we see.
If anyone is interested in this work, get in touch for prices and options.
sodium filled valves are used on the 7a heads - some 7a are not sodium filled.
The Hall sender has to be a close enough fit not to rub! These 7A heads have dowelled holes machined into the head so the adapter is as good as the adapters used on the early aby heads.
Oh I knew this thread was about somewhere - I have a 7A head coming my way soon and am very interested in this route for an engine build project - attaching it to a block from a well known 3B owner on the forum (when I get my grubby mitts on it - the block I mean).
Anyway - I was wondering about the hall sender - rather than machining the head to accomodate the ABY/ADU (and late AAN) setup behind the cam sprocket...
The early AANs had the hall sender in the location provided by the distributor of the 3B engine. The upside is that a 'normal' vernier camshaft pulley can be used on the head without worrying about the hall sender. The downside is that its probably driven by a cog on the inlet camshaft ?
Just thinking that engine setup & serviceability might be easier with the hall sender in the early AAN position and it simplifies the head build a little bit.
Maybe there's nothing in it and I should just get the head up to ABY setup and expect to eat the extra cost for a more expensive cam vernier pulley.
Oh I knew this thread was about somewhere - I have a 7A head coming my way soon and am very interested in this route for an engine build project - attaching it to a block from a well known 3B owner on the forum (when I get my grubby mitts on it - the block I mean).
Anyway - I was wondering about the hall sender - rather than machining the head to accomodate the ABY/ADU (and late AAN) setup behind the cam sprocket...
The early AANs had the hall sender in the location provided by the distributor of the 3B engine. The upside is that a 'normal' vernier camshaft pulley can be used on the head without worrying about the hall sender. The downside is that its probably driven by a cog on the inlet camshaft ?
Just thinking that engine setup & serviceability might be easier with the hall sender in the early AAN position and it simplifies the head build a little bit.
Maybe there's nothing in it and I should just get the head up to ABY setup and expect to eat the extra cost for a more expensive cam vernier pulley.
You would use a 3B inlet cam and ensure your dizzy had a metal gear attached. Once you have extended the wiring bob's your brother's aunt
Simple but effective but it does mean there is an element of alignment error
Define 'higher power' here Doug - I'm thinking RS2 spec essentially with a lighter stronger bottom end to give me a free-revving engine with all the torque I can muster on that turbo (maybe going to GT30R in a future incarnation, but money will limit things here).
So realistically for me its <400bhp and <600Nm - should I fear for the dizzy / cam sender gear at that level ? Probably wishing to stick with 3B/ABY inlet timing to give me torque as early as possible (knowing the 7A inlet comes good for max power later in the revs).
Hadn't really thought about it before, but knowing the inlet timing on 3B is same as ABY I guess the only difference on those cams is the dizzy gear ?
Maybe its not worth the grief - anybody got a vernier cam pully that works with the hall sender as per ABY/ADU - bug money or not ?
higher power - I know 470, 530 and 600 bhp cars have snapped th cam gear off. I xpect it is hitting rev limiters that are breaking them or it could just be high revs and these cars have been using it more.
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You know what I mean 
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