differens on the heads?

[porkkis]

Yes it is. My friend did the job because there aren't many 20vt heads lying around here in Finland and if you find one it probably costs pretty much. This was the easy and cheap option he took.

[Mark Halligan]

Not too much work to get them usable, here is a picture of a 7A head showing where the extra ports need to be machined (red blobs) for the water manifold

[Mark Halligan]

manifold and made a bracket for the hall sender

In fact on the early ABY heads the hall sender mounting point was an "add on" and only became part of the casting a bit later on.

[Doug_RS2]

Mark - is that another cast piece tha thas been pressed on? Or do the sensor bolts hold that lump of metal onto the head?

The other advantage of a 7A head is it is less likely to have been abused as a turbo head - and so probably does not have the common cracks at the spark plug threads.

[Mark Halligan]

Mark - is that another cast piece tha thas been pressed on? Or do the sensor bolts hold that lump of metal onto the head?

The other advantage of a 7A head is it is less likely to have been abused as a turbo head - and so probably does not have the common cracks at the spark plug threads.

Doug

as far as I can see it is a seperate piece that is bolted onto the head, those red circles are silicon rubber covering the bolts? The ADU head that I have on the car at the moment has the sender mount cast into the head.

You are right my old ABY head is cracked up all around the spark plug holes (although repairable and usable) but the 7A head I have is in very good condition, and much less abused. Worth stocking up LOL.

[Jamo]

If anybody ahs some definitive information on the Sodium valves. In the volvo world it was a big taboo when we modded the NA heads to go on Turbo cars (way cheaper) to use sodium valves.

Strangely enough the pre cat turbo engine on the Volvo had sodium valves the post cats didnt.

[pastures16]

The other advantage of a 7A head is it is less likely to have been abused as a turbo head - and so probably does not have the common cracks at the spark plug threads.

doug i can remember you saying those wise words

[BRY]

I know I shouldn't post details such as this but the MG Metro Turbo was a special A series engine as it had sodium filled exhaust valves

[pasi_]

I have lots of pictures from that 7A/turbo-conversion that porkkis mentioned. I'll put them to my homepage this weekend.

[pastures16]

send a link when you get a chance

[pasi_]

OK, here are the pics finally. Sorry it took so long, but I bought a new motherboard for my computer and I had to change it 3 times because of the compatibility problems.

Here are the pics. There's many engine removal/installation and engine rebuilding pics too, but also 7A/turbo conversion pics.

http://s90.5cyl.net/gallery/2_28

http://s90.5cyl.net/gallery/2_29

http://s90.5cyl.net/gallery/2_30

[Jamo]

Not all 7A engines have the sodium valves. Only the earlier ones. Late ones are std.

Sodium is the way to go in turbo cars IMHO. On extreme applications they might be not the way as the sodium channel makes the valve weaker...

My friend replaced his AAN head with 7A head. He drilled few holes for the turbo water manifold and made a bracket for the hall sender. That's all. His version had the "extra" EM stud holes.

Just to follow up on that IMHO sodium valves and turbo cars are a bad idea

http://www.80tq.com/EngineDamage.html

[BRY]

Just to follow up on that IMHO sodium valves and turbo cars are a bad idea

http://www.80tq.com/EngineDamage.html

They are still better than standard on a turbo car

My advice to anyone building a high output 10v motor is to ditch the stock sodium filled valves in favor of an aftermarket Inconnel or high temp alloy valve.

It doesn't say take the sodium filled valve out and replace it with a standard one does it?

[Azman]

Guys how do you tell if its a cast head or ally????

[volcano rs]

stick a magnet to it ha ha . the cast ones are normally heavier (damn brother dont you know the differance between aluminium and cast) the tubulor manifolds on 7a engines were used on the earlier cars because they were expensive to make so the cast iron ones on later cars .