Hey there, I'm in the middle of a head gasket job on an 02 with 140k. Bout ready to remove the heads, new gaskets on their way. I've heard people say that you need to have the heads' mating surfaces skimmed by a machine shop, but the RAVE makes it sound like it's only necessary if the heads are warped or pitted. So is it necessary? I don't know if this Disco has overheated because I just bought it as a fixer upper. Doesn't make any weird noises at least. Thanks
Do I need to have the heads skimmed here?
- Thread starter sholden7
- Start date
Yep, good advice. I can't remember what the acceptable tolerance is but I think its pretty small and may not be discernable with the human eye. My take is this. While a HG job isn't terribly difficult its a pain in the ass. Now throw in the time you invest and new non-reusable parts and ask yourself us it worth chancing it and flushing that time and money? For me its not worth chancing it. Get the heads milled. Shop around, you're in the Chicago area and could get raped if you mention its for a Land Rover. Just tell them they're old Buick heads.Tugela said:
Will do. I'm actually out in the sticks about an hour from chicago so people don't even know what a land rover is; thusly; they will not charge extra. It's crazy though, I'm selling D2 parts and ALL my business comes from Chicago. Seems backwards. Thanks, I will shop around, see what I can do.
If you don't have a straight edge, a set of feeler gauges, and the knowledge of how to check for head straightness; you should send them to the machine shop to be checked.
I'm probably not that competent. So you're telling me I should have the shop check to see if it's straight?group captain mandrake said:
Yes.
My opinion is if the heads are not warped, and if the guy who was in there before didn't fuck up the surface with grinder pads, then they don't need to be machined.
My opinion is if the heads are not warped, and if the guy who was in there before didn't fuck up the surface with grinder pads, then they don't need to be machined.
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Looks like mine are going to have to be machined anyhow. The gasket that was on there left a bunch of little pits on the head.
ptschram
Well-known member
group captain mandrake said:
It is virtually impossible for a Land Rover V8 to go through more than one hot/cold cycle without having to have the heads machined.
Even following the proper torque sequence, yadda, yadda, yadda, if the engine has been run any time at all, it is folly to not have the heads machined.
After at least 100 head jobs, I have never had a set of heads NOT need to be machined true.
The tolerance is only 0.002"
(Chapman voice on) only the truest of fools does not machine his cylinder heads if he has taken them off (Chapman voice off)
Let me explain my position on this subject.
For years, every time I did a headgasket job, the heads went to the machine shop for resurfacing. Then a regular customer blew a headgasket on his Civic. I had the head resurfaced (it was indeed warped), and it went back together uneventfully. For the next couple of years, that Civic came back with repeated headgasket failures. Everytime I had the head resurfaced, and each time I searched further for a cause (all manner of cooling system checks: flow, rad, fans, ect...) with no real conclusion. Finally I sent the head to a different machine shop. I can't remenber the precise details, but they found the head to be not level. They asserted the other shop had resurfaced it improperly. The new shop resurfaced the head and the headgasket problem was cured.
I don't know precisely how machine shops resurface heads. I presume, like most things, there is more than one way to do it. All I know is that a machine shop with whom I had no other prior problems dicked-up a head resurfacing costing me hundreds of dollars and scores of hours.
I understand that this was a very isolated incident. However, since then, if a head is not warped, the mating surface is in good shape, and it is not going in for a valve job, I don't have it resurfaced.
My wife daily drives a '02 Disco and I daily drive a '98 Disco. They both have more than three years and I don't know how many miles since I did headgasket jobs on them without resurfacing the heads.
For years, every time I did a headgasket job, the heads went to the machine shop for resurfacing. Then a regular customer blew a headgasket on his Civic. I had the head resurfaced (it was indeed warped), and it went back together uneventfully. For the next couple of years, that Civic came back with repeated headgasket failures. Everytime I had the head resurfaced, and each time I searched further for a cause (all manner of cooling system checks: flow, rad, fans, ect...) with no real conclusion. Finally I sent the head to a different machine shop. I can't remenber the precise details, but they found the head to be not level. They asserted the other shop had resurfaced it improperly. The new shop resurfaced the head and the headgasket problem was cured.
I don't know precisely how machine shops resurface heads. I presume, like most things, there is more than one way to do it. All I know is that a machine shop with whom I had no other prior problems dicked-up a head resurfacing costing me hundreds of dollars and scores of hours.
I understand that this was a very isolated incident. However, since then, if a head is not warped, the mating surface is in good shape, and it is not going in for a valve job, I don't have it resurfaced.
My wife daily drives a '02 Disco and I daily drive a '98 Disco. They both have more than three years and I don't know how many miles since I did headgasket jobs on them without resurfacing the heads.
ptschram
Well-known member
group captain mandrake said:
Um, I'm confused.
Because you had a warped cylinder head that a machine shop did not resurface correctly, Unless a head is warped, you don't do the resurfacing?
Why would you resurface a head that wasn't warped?
Your post contradicted itself a few times.
Perhaps I should have stated things a little differently.
How about, as I feel that the incidence of cylinder heads to no longer be true, one should have a competent machinist measure the heads and determine if they nee to be machined.
My experience has been that they are always out more than the minimum.
Honda civics with the 1.5 and 1.6 engine from 1988-1991 (and sometimes from 1992-1995) had head gasket issues. I believe it had to do with a couple of the cylinders being Siamese, and this causing a hot spot. If the engine ever got hot enough to blow a head gasket, you could be sure it would come back again. Eventually Honda released an updated gasket and bolts and the problem went away.
What's stupid, is that you could buy the parts from the dealer, and if they don't know about the TSB, they'll sell you the bad parts.... the computer doesn't show the update in the pretty pictures catalog, you have to look it up by part number.
What's stupid, is that you could buy the parts from the dealer, and if they don't know about the TSB, they'll sell you the bad parts.... the computer doesn't show the update in the pretty pictures catalog, you have to look it up by part number.
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That is exactly my point. I don't.ptschram said:
I don't think so.ptschram said:
It was an '83 Civic Wagon.jafir said:
What's really kind of funny is that the OE honda gaskets were composite, and to correct their head gasket issues they switched to a tri-metal gasket.
Land rover started with metal gaskets and then to "fix" their head gasket issues, they switched to composite.
Land rover started with metal gaskets and then to "fix" their head gasket issues, they switched to composite.
ptschram
Well-known member
group captain mandrake said:
You said you didn't resurface them unless warped due to the experience with the Honda-yet it WAS warped.
The fact that the Civic head was warped was not really relevant to the story and may have just caused confusion.
I started out in the business at a Nissan dealership where it was SOP to send any head removed for any reason to the machine shop for surfacing. In the years following, I continued that practice until the Civic incident.
The point I was trying to relay was that I always used to resurface heads whenever they were off, until I got burned by the machine shop in the Civic incident. Thereafter, I only resurface heads if they need to be.
My apologies if my story was wordy or unclear.
I started out in the business at a Nissan dealership where it was SOP to send any head removed for any reason to the machine shop for surfacing. In the years following, I continued that practice until the Civic incident.
The point I was trying to relay was that I always used to resurface heads whenever they were off, until I got burned by the machine shop in the Civic incident. Thereafter, I only resurface heads if they need to be.
My apologies if my story was wordy or unclear.