XK8 / XKR ( X100 ) 1996 - 2006

Jag 4.0 timing question

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Old 06-16-2016, 11:10 AM
97 Xk8 mayhem's Avatar
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Default Jag 4.0 timing question

I seen alot of info on setting timing on forum and other sources and generally on most right ups it gives directions to turn or retard bank b exhaust cam counter clockwise or anti-clockwise and remove slack from driveside of chain and then says repeat on bank A. I guess my question is do I take slack from drive side on bank A. Or do I turn exhaust cam counterclockwise. Cause if I'm not mistaken the flat or drive side of chain and the driven tensioner side is reversed on bank A so wouldn't you turn exhaust cam clockwise to remove slack from drive side. Of bank a
 
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Old 06-16-2016, 11:34 AM
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Although probably not unique, in my (admittedly limited) experience, the Jaguar 4.0 engine is unusual in that there are no marks, dots, dimples, keyways or slots on the engine in order to set the timing. The two crankshaft sprockets are "keyed" on to the crankshaft, but that's really to ensure they are in the correct position relative to each other, rather than for any other reason.
There's a slot on the flexplate attached to the torque convertor into which a "special tool" is inserted via the hole through which the crankshaft position sensor is usually fitted. This locates all 8 pistons in a position where they will not be at the top of their respective cylinders. The four camshafts are then installed so that the "flats" are all horizontally in line using two more "special tools" to keep them 'locked' in that position. At that point - with no sprockets, chains, tensioners etc in place, the timing is 100% perfect. The camshaft sprockets, chains etc can now be fitted in any position you like. The camshaft sprockets are a "taper fit" and are basically held on by friction (the correct torque is therefore crucial). As long as there's no slack on the 'drive' side of the chains (i.e. - the opposite side to the tensioners) - then you just tighten everything up to the correct torque - remove the three 'special tools' and .... job done. The important thing is to make sure that the chains are "tight" on the drive side which is the opposite side to the side where the tensioners are fitted.
Stuff like TDC or timing-marks are not relevant to these engines.
Hope that makes sense !!


Edit .............. having now read your other post about VVT etc., I realise you are way ahead of me in terms of knowledge and experience. I suspect you know all of the above and much more :-)
 

Last edited by DevonDavid; 06-16-2016 at 11:48 AM.
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Old 06-16-2016, 06:44 PM
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Well in the write ups it gives directions for bank b then instead of walking thru directions in bank a.it usually says you just set timing g on bank b and repeat on bank A. And this constant talk of counterclockwise. I'm wondering if it should not be reversed on the other bank because slack on tentioner side of chain or is it counterclockwise to retard vvt because aj26 unlike aj27 engine (that has a special tool to turn or retard vvt)has no tool to retard.and I want to make sure this isn't a over site by anyone.and when I set timing here once again I'm going to look more closely to the retard and advance of cam vvt to be sure it counterclockwise and not clockwise on the other bank.
 
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