Potential Blown Head Gasket 😫 Any help is appreciated
#41
#44
#47
Picture if you will to straight rods next to each other. If one gets bent / warped it will put pressure on the other. as in they are no longer parallel. Same for the head, if it warped, say .030 or so, it effected its straightness, resurfacing the head, flattens the surface /face of the head. but does not address the straightness of the head itself.
Jack
Jack
#48
Picture if you will to straight rods next to each other. If one gets bent / warped it will put pressure on the other. as in they are no longer parallel. Same for the head, if it warped, say .030 or so, it effected its straightness, resurfacing the head, flattens the surface /face of the head. but does not address the straightness of the head itself.
Jack
Jack
cool
I won't post here going forward (unless I have a question about the OP and folks responses). This thread seems to be getting off from helping with the dilemma this dude is facing.
#49
#50
If the head is bent longitudinally the bore through the cam bearings is no longer straight. Skimming the head surface leaves the cam bearings out of alignment permanently. The head should really be straightened in an oven rather than skimmed. And aluminum heads will pull down straight a lot easier than cast iron. I just repaired the head gaskets on an overheated XFR 5.0 SC. One head was 7 thou bent in the center. Jaguar specify a max tolerance of 0.2mm which is around 8 thou. It pulled down fine (so far 1,000 miles).
#51
If the head is bent longitudinally the bore through the cam bearings is no longer straight. Skimming the head surface leaves the cam bearings out of alignment permanently. The head should really be straightened in an oven rather than skimmed. And aluminum heads will pull down straight a lot easier than cast iron. I just repaired the head gaskets on an overheated XFR 5.0 SC. One head was 7 thou bent in the center. Jaguar specify a max tolerance of 0.2mm which is around 8 thou. It pulled down fine (so far 1,000 miles).
#54
Of course on a head with integral cam bearings, assuming the head is warped longitudinally, this top and bottom machining option is not available, and your point is valid.
The following 2 users liked this post by Greg in France:
Grant Francis (11-03-2020),
kansanbrit (11-03-2020)
#55
The following users liked this post:
89 Jacobra (11-04-2020)
#56
I think this is the reason that if a V12 head is machined, BOTH the top and the bottom surfaces must be done to ensure they are parallel. As the cam carrier is a separate casting, and assuming it is straight, the cam bearing alignment problem should not occur. That is my understanding, but I am ready to be corrected.
Of course on a head with integral cam bearings, assuming the head is warped longitudinally, this top and bottom machining option is not available, and your point is valid.
Of course on a head with integral cam bearings, assuming the head is warped longitudinally, this top and bottom machining option is not available, and your point is valid.
Last edited by kansanbrit; 11-03-2020 at 07:50 AM.
Thread
Thread Starter
Forum
Replies
Last Post
jmcGoBlue
S-Type / S type R Supercharged V8 ( X200 )
59
03-11-2011 04:34 PM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)