1989 xjs v12 engine rebuild
#1
Join Date: Dec 2016
Location: Sunderland tyne and wear
Posts: 13
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3 Posts
1989 xjs v12 engine rebuild
Hello,
I posted in the summer about my newly restored 1989 xjs convertible dropping a valve seat in bank b. Over the last couple of months I have stripped my engine, as suspected, head is a write off, piston damaged and liner cracked longitudinally. On the plus side the other head and rest of the lump look fine. Now this is where I need to pick some brains! I have managed to get hold of a pair of later heads from a 93 car, in great condition and tested ok. I would like any advice/tips for putting it all back together, I have rebuilt engines before but I would like to avoid any pitfalls during the rebuild.I will also be improving the coolant system and electrical systems along the way. My biggest concern is timing the whole lot up again? the new heads came with cams but no sprockets so I will use my originals, also I would like to be gentle with the chain tensioner, its still in great nick.
As ever, any advice will be greatly appreciated!
Neil.
I posted in the summer about my newly restored 1989 xjs convertible dropping a valve seat in bank b. Over the last couple of months I have stripped my engine, as suspected, head is a write off, piston damaged and liner cracked longitudinally. On the plus side the other head and rest of the lump look fine. Now this is where I need to pick some brains! I have managed to get hold of a pair of later heads from a 93 car, in great condition and tested ok. I would like any advice/tips for putting it all back together, I have rebuilt engines before but I would like to avoid any pitfalls during the rebuild.I will also be improving the coolant system and electrical systems along the way. My biggest concern is timing the whole lot up again? the new heads came with cams but no sprockets so I will use my originals, also I would like to be gentle with the chain tensioner, its still in great nick.
As ever, any advice will be greatly appreciated!
Neil.
#2
You will need the cam timing tool
NEW Jaguar Camshaft Alignment Tool 3.4 3.8 4.2L XJ6 E-Type XKE XJS V12 C3993 | eBay
I am rebuilding a 6.0L ATM and this is what I have found with a low mileage engine.
As you are doing all this work, if I were you before I put the heads on I would make sure everything was up to snuff. Check valve clearance 0.010" intake, 0.012" exhaust. Then pull the valves out (you can do this without removing the cam carrier), label everything so it all goes back in the same place. Check valve stems for wear and roundness with a Micrometer 0.3092" - 0.3093". Check head mating surface for flatness and/or have it planed. As these came off a different engine there is a good possibility they will not mate flat with your block and could leak.
I would have the valves and seats re-cut just to be sure you have a good seal, if you do decide to do this have them 3 angle cut. At a minimum lap them in.
NEW Jaguar Camshaft Alignment Tool 3.4 3.8 4.2L XJ6 E-Type XKE XJS V12 C3993 | eBay
I am rebuilding a 6.0L ATM and this is what I have found with a low mileage engine.
As you are doing all this work, if I were you before I put the heads on I would make sure everything was up to snuff. Check valve clearance 0.010" intake, 0.012" exhaust. Then pull the valves out (you can do this without removing the cam carrier), label everything so it all goes back in the same place. Check valve stems for wear and roundness with a Micrometer 0.3092" - 0.3093". Check head mating surface for flatness and/or have it planed. As these came off a different engine there is a good possibility they will not mate flat with your block and could leak.
I would have the valves and seats re-cut just to be sure you have a good seal, if you do decide to do this have them 3 angle cut. At a minimum lap them in.
Last edited by warrjon; 12-09-2016 at 04:43 PM.
#3
Join Date: Dec 2016
Location: Sunderland tyne and wear
Posts: 13
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Received 9 Likes
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3 Posts
Thanks Warren, top man!
Totally agree with you, I have already started on the heads, it would appear the new heads I have seen very little action; no carbon build up and very little wear. The two will be skimmed regardless. Like I mentioned in my first post, the only thing making me nervous is getting it timed up correctly. As you will know the camshaft pulley sprockets have their own adjustment, I have been reading a lot of stuff on these; just hope I get it right :-)
Thanks again for your help, very much appreciated.
Neil.
Totally agree with you, I have already started on the heads, it would appear the new heads I have seen very little action; no carbon build up and very little wear. The two will be skimmed regardless. Like I mentioned in my first post, the only thing making me nervous is getting it timed up correctly. As you will know the camshaft pulley sprockets have their own adjustment, I have been reading a lot of stuff on these; just hope I get it right :-)
Thanks again for your help, very much appreciated.
Neil.
#5