AJ16 Cylinder Head
#1
AJ16 Cylinder Head
Just fitted the best AJ16 cylinder head in the world to my car, first one produced and sure not the last with an impressive flow sheet too, I shall follow up on pics of the inside works in a later post.
The inlet valve seats recut to Max insert diameter using state-of-the-art single point contour CNC machining.
The inlet throat diameters increased to match seats.
The inlet & exhaust ports hand profiled and polished by technician with many years of F1 engine building experience.
Roy
The inlet valve seats recut to Max insert diameter using state-of-the-art single point contour CNC machining.
The inlet throat diameters increased to match seats.
The inlet & exhaust ports hand profiled and polished by technician with many years of F1 engine building experience.
Roy
#2
#3
#4
Here are a few of Andy´s photo´s of the inside works of the (Andy Stodart) AS AJ16 head and a big thank you to Andy for letting me motivate him into producing his brilliant engineering idea & planning when he did.
As to the gains made, thats a question I couldn´t give you any exact figures on, that would be one for Andy. I would say the extra air movement combined with a M-112 SC from the V8 and an improved air intake, upgraded exhaust flow then finished off with a bespoked ECU would be an even more enjoyable sport Jaguar at a very competitive price and still good for every day driving.
My objective is to hang on to the beautiful straight 6, we all know the story it was something Jaguar couldn´t do due to management & politics. Having grown up with 6 cyl Jaguars I think it’s schade that we are not able to buy a straight 6 Jag, look at all the fun the Beema boy´s are having with there bi-turbo 6és and this can be had with a Jaguar without loosing the refined feel these cars have and at a fraction of the cost.
Roy
As to the gains made, thats a question I couldn´t give you any exact figures on, that would be one for Andy. I would say the extra air movement combined with a M-112 SC from the V8 and an improved air intake, upgraded exhaust flow then finished off with a bespoked ECU would be an even more enjoyable sport Jaguar at a very competitive price and still good for every day driving.
My objective is to hang on to the beautiful straight 6, we all know the story it was something Jaguar couldn´t do due to management & politics. Having grown up with 6 cyl Jaguars I think it’s schade that we are not able to buy a straight 6 Jag, look at all the fun the Beema boy´s are having with there bi-turbo 6és and this can be had with a Jaguar without loosing the refined feel these cars have and at a fraction of the cost.
Roy
Last edited by RoyJ; 01-17-2014 at 07:15 AM.
#7
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#8
Here are a few of Andy´s photo´s of the inside works of the (Andy Stodart) AS AJ16 head and a big thank you to Andy for letting me motivate him into producing his brilliant engineering idea & planning when he did.
As to the gains made, thats a question I couldn´t give you any exact figures on,
As to the gains made, thats a question I couldn´t give you any exact figures on,
I've been doing modified and flow bench developed heads for this engine for more than a decade now.
I reckon the flow bench figures for my last one would blow yours out of the water.
There's nothing quite like doing the job properly.
#9
FYI I had a very close look at the photos you posted.
The valve sizes you have on that head of yours are STANDARD (or very close to it).
I know this, because fitting genuinely larger ones entails relieving the chamber (in my case quite a bit).
You also HAVE to remove all the inlet seats, which clearly yours hasn't had, that starts to put the price through the roof. (At least 600-800Euro just to do that operation).
The difference in prices are absolutely enormous, especially when talking about putting a 2mm larger inlet valve in there, fitting a pair of proper steel camshafts with steel buckets, bespoke shims, bespoke titanium valve caps and springs.
The exhaust valves you have are also STANDARD.
Those don't flow so great on that late head, I know this because I've measured it and made valves which are better with a different shape.
Also the inlet port is too big.
That is a major defect of the design of that late head, and once you have modified it in the way you have, there's nothing else can ever be done to get back the lost flow at low lift.
LARGE PORTS ARE BAD FOR FLOW.
This is undeniable.
I know all this because I haven't done just ONE of these heads, then turned around and said "this is the best head in the world".
Sorry to say that's just bollox.
A head has to be properly developed for what you want to do with it, as do the cams.
A n/a racing head is a completely different animal from a short duration high lift cam type forced induction type.
This is something Janspeed could never understand either on the turbo cars.
I've measured them all, and the earlier head flows MUCH better as a basis for what you want to do than the AJ16.
The STD XJR cams are just crap, bodged up rubbish from a factory that hadn't a clue what they were doing, which is why they used such little lift, when the head is crying out for MORE.
The valve sizes you have on that head of yours are STANDARD (or very close to it).
I know this, because fitting genuinely larger ones entails relieving the chamber (in my case quite a bit).
You also HAVE to remove all the inlet seats, which clearly yours hasn't had, that starts to put the price through the roof. (At least 600-800Euro just to do that operation).
The difference in prices are absolutely enormous, especially when talking about putting a 2mm larger inlet valve in there, fitting a pair of proper steel camshafts with steel buckets, bespoke shims, bespoke titanium valve caps and springs.
The exhaust valves you have are also STANDARD.
Those don't flow so great on that late head, I know this because I've measured it and made valves which are better with a different shape.
Also the inlet port is too big.
That is a major defect of the design of that late head, and once you have modified it in the way you have, there's nothing else can ever be done to get back the lost flow at low lift.
LARGE PORTS ARE BAD FOR FLOW.
This is undeniable.
I know all this because I haven't done just ONE of these heads, then turned around and said "this is the best head in the world".
Sorry to say that's just bollox.
A head has to be properly developed for what you want to do with it, as do the cams.
A n/a racing head is a completely different animal from a short duration high lift cam type forced induction type.
This is something Janspeed could never understand either on the turbo cars.
I've measured them all, and the earlier head flows MUCH better as a basis for what you want to do than the AJ16.
The STD XJR cams are just crap, bodged up rubbish from a factory that hadn't a clue what they were doing, which is why they used such little lift, when the head is crying out for MORE.
#12
Camshafts with decent lift, wow makes me crazy like a dog. please send me a private message with price. Also for all of use please describe how your cams differ from the ones on the xjr6, as I know several people would be very very interested. Specifically, how much more lift can we get out of these cams before we run into trouble with the valves and cylinders smacking into eachother. I believe our cams are at .110 or .114, how much bigger can we go?
Last edited by jeremiahjaguar; 02-14-2014 at 08:04 PM.
#14
This is aj6engineering take on revised cams.
aj6engineerig
To Me
Today at 3:34 AM
Changing camshafts on these engines is only advisable for a full race application because of the loss of low and mid-range torque.
The Tornado was concocted by Chasseur who have been out of business for a long time. The most notable thing I remember about it was that the engine mods cost almost as much as the new price of the car! I think it probably used standard cams anyway.
Regards,
Roger Bywater.
From: David Avila
Sent: Thursday, February 20, 2014 2:56 AM
To: aj6engineering@ntlworld.com
Subject: aj16 camshaft
Hello, I was interested in a camshaft for my 1995 xjr with a bit more lift than stock. I remember an old top gear program that introduced the jaguar tornado, the motor, a aj16 4.0, was bored out to a 4.2 and might you know what cam was used in the build. Would you recommend grinding my present stock cams as I have not found a set of ready made performance aftermarket cams for my car. How much lift would you recommend?
aj6engineerig
To Me
Today at 3:34 AM
Changing camshafts on these engines is only advisable for a full race application because of the loss of low and mid-range torque.
The Tornado was concocted by Chasseur who have been out of business for a long time. The most notable thing I remember about it was that the engine mods cost almost as much as the new price of the car! I think it probably used standard cams anyway.
Regards,
Roger Bywater.
From: David Avila
Sent: Thursday, February 20, 2014 2:56 AM
To: aj6engineering@ntlworld.com
Subject: aj16 camshaft
Hello, I was interested in a camshaft for my 1995 xjr with a bit more lift than stock. I remember an old top gear program that introduced the jaguar tornado, the motor, a aj16 4.0, was bored out to a 4.2 and might you know what cam was used in the build. Would you recommend grinding my present stock cams as I have not found a set of ready made performance aftermarket cams for my car. How much lift would you recommend?
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