The easier way is to gind the dwell on the bottom of the lobe and fit lash caps, I know a XKR that gave an extra 3mm lift, there is a big but though, the engine timing needs to be altered as the over lap was too much and lost all the gains and the car was worse...... Can't remember off hand what the difference was but it does need to be set up properly

 

I think i will leave that to the experts who have all the right tools to know exatly what duration and lift are. Looks like a camshaft upgrade is the only upgrade u can make to the 4.0 with out haveing to change ecu, tcm, man jag really makes it difficult to enhance thier product when we feel its lacking something. Dont get me wrong the xk is and awesome unit but . Well i leave it at that......... I will squeeze out a few more horses . And start looking for a tcm tuner so that i can change out the rear gear ratio for something more to my likeing....... will update when project gets under way. Starting to consider either a xkr or corvette might be an option if power is what i really want.........

 

Cams for forced induction should be different than NA, as too much overlap will cause the incoming air/fuel to be blown out the exhaust.

 

With the 4.0L they may well be, given that the N/A cars have VVT and the S/C cars don't.

That was also the case with the 4.2L to begin with, BUT the last series of S/C 4.2L engines also got VVT and the cams were then identical to the N/A engine.

 

Hello where can I get performance cams for my 98 xk8 engine?

Who is the guy that was modifying the Cams?

Does he still do them?

Thank you

 

I have done mine with Catcams in Belgium : CAMSHAFTS | CAT CAMS performance camshafts

 

Did you have to shime/ readjust the lifters?

 

Yes you do, they are called lash caps, as described in post #21 by xkracer.

 

have you got the guys email address about the came upgrade for my xj8 4.0

 

To user jgaxkr, a quote from your post “Instead of selling it and buying an R.....If u want more bottm end all we have to do is change the rear end gears from the 3.06 to a 3.46 this will give us some ump and may be we could spin a little tire ,.”
well I don’t know about everyone but if I push the “asc off” button, the “s” sport button, and at a dead stop floor it my 97 xk8 will spin tires. If I turn a hard left from a dead stop and do the same (floor it ) I will spin so hard I lose control and end up in someone’s front yard. I still have stock motor with nikisil liner but just did my timing chains. I got 69k miles on it.

 

On an XKR I would think higher boost is a much easier way to get more performance, while also being more daily driver friendly.