My question is if there was any difference in the UK cam for the 95-97 xjr and the US cam for the same xjr? And what do you think about the performance cams offered at terrys jag?
http://terrys-jaguar-parts.terrysjag.com/camshaft

 

I don't think you realize that the cams are for the original XK/XJ 3.8/4.2 engines.
The cams are intended for the carburetted engines from 1948 to 1976.

bob gauff

 

Nope !

Cheers
DD

 

Thanks guys

 

The X300 cams are available as blanks as someone else had looked into this pretty sure Andy would know

The standard cams are pretty small would be nice to get a bit more overlap and lift that would certainly make it rev a lot higher

There was a post about this a couple years ago I think Andy even did a bit of designing for it too he would know
When they are done and developed Ill have a pair as well LOL

 

Please fine attached a bulletin in regards to a revise camshaft for the xj6, normally aspirated. Would this benefit the xjr6 as well?

 

Being that the xjr is supercharged wouldnt little to no valve overlap be desirable in order to achieve the most torque? Now, my understanding is the xjr has NO VALVE OVERLAP, is this true?. I was looking at the standard cam for the xj6 with decrease overlap to improve idle and torque, but if the xjr has no overlap already then a different cam would only hurt performance. Please chime in and give me your thoughts on this matter.

 

I was told by my Indie that behind the cam sprockets are splined allowing for advancing and retarding of the camshafts but after speaking to Andy about this I am sure he said that all that would achieve is moving the torque curve up the rev range and not make any more power

From my experience with turbo and S/C engines you want lift
in saying that the cams in the AJ16 engine are very small it would be nice to have a set of cams that actually made power to 6000 RPM instead of the the current power curve
I would have to look at my dyno sheets but the cam finishes very early for a 4 valve high performance engine like the AJ16

 

Would anyone know where I can get a hold of the camshaft blanks?

 

PM Andy AKA XJRengineer he did the research before and had made contact with a company that had blanks

 

Would anybody happen to know the specs on the xj300 cams. Would appreciate the info, this would save me the trouble of removing them to take measurements.

 

The cams that are used in both the naturally aspirated and supercharged versions of the AJ16 engine have the same profiles on the inlets and exhausts. They have 9.95mm of lift measured with respect to the base circle. The period is 242degrees measured from the ramp to lift transition point. The timing of the profiles is different between naturally aspirated and supercharged engines. The valve events for the supercharged engine are as follows:-


IVO = TDC
IVC = 62deg after BDC
IMOP = 121deg before TDC
EVO = 62deg before BDC
EVC = TDC
EMOP =121deg before TDC


I think that the naturally aspirated engines had MOP set at 110degrees, on both cams, but after 20 years, I can't remember for sure.


I don't know of anywhere that sells Jaguar AJ6/16 camshaft blanks, but it is possible to regrind the cams with a smaller base circle.

 

I would never use reground cams

I did that to my old 450 merc 3 months later one of the lobes was gone and so was $1000 ended up buying second hand set of rare AMG cams also a $1000 expensive learning curve

There was a member of the old XJR6 forum that did some searching and found a company in the UK that did new blanks you just needed to supply what specs you wanted on the grind

I would have someone over here interested in a set of cams he is building a monster aj16 engine with 2.3 twin screw massively ported head and custom pistons and con-rods
I just did a set of headers for him and he was asking me for a set of cams

 

Thank you for the information, I was about to send off a new set of cams to have them worked on. Need to be patient.. There was this new member who said that he makes steel cams to order but he has not answered my post. Thats ok, still have plenty of other things I can do while I wait.

 

Hi Jeremiahjaguar





Old thread but me a new member. Would be great if you have some update on this very interesting topic.

Reason for asking is that I right now is doing some winter overhaul and tuning on my XJR6 engine and is very much tempted to slightly alter the camshafts timing. As the engine is in a less heavy car with a manual 5-speed, better flowing inlet and exhaust, overdrive pulley and aftermarket ECU I belive that there should be some possible gains in finetuning the cams. Maybe get some more top end power.


Any further info on the camshaft topic would be very much appreciated.



Best regards
Jan

 

I have tried a whole variety of modifications in order to get that extra get up and go. When it comes down to it the best bang for your buck would be the andy bracket, change the diff to a 3.54, swap out air box for cone filter and possibly place a fan in front of the sc radiator. Maybe ecu mode by andy if you absolutely need more. I have spent much and these few mods are the cheapest with the most gains. I gave up on changing the cam a long time ago because they just are not any out there.

 

Engines fitted with positive displacement superchargers respond less strongly to changes in camshaft period and timing than naturally aspirated engines. The volumetric efficiency of the engine is dominated by the characteristics of the supercharger. Changing the camshaft period or timing just changes the amount of power consumed by the supercharger in pumping the same amount of air into the engine. Any change in engine performance is really only due to the change in power absorbed by the supercharger, not any change in the power produced by using a different amount of air to burn fuel. This secondary effect is small.

 

Many thanks gents for those verycomprehensive answers to my question about camshaft tuning.
Was obviously not that great idea tinkering with the timing. Project aborted!

And I very much agree with the best bang for the buck list although I´m in a little different situation as the engine is swapped into an old XJ6 series1. Have the 3.54 diff, the intercooler and electric fan (once a Honda Civic radiator), Bosch 010 water pump, boxed cone filter with cold air intake.
The engine did not come with any ECU, instead I´m using a quite basic Megasquirt2 so the Andy bracket would not be of any use at all but I would certainly buy one if I had the Lucas things though.
I also have the sc overdrive crankshaft pulley. Know that there is different opinions on the value of that but I think it made a big difference, no intensions to change back to the original.
As a winter project I could not resist to try some minor porting of the supercharger. What value that will give is still to see.

Once again, many thanks

 

Did you ever port the supercharger? Any results?