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Discussion Starter · #1 ·
I'm changing the rear valve cover gasket on my 95 VR-4 and when test fitting the cover (with no gaskets installed) I noticed the cover does not sit flush on the head. Is this normal or should I replace the cover? It's had a small oil leak and I'm starting to wonder if this is the culprit.
 

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Lovbyts
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If you have time to get a new one why not? Im sure they should sit relatively flat without a gasket.
 

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In all my years, I've never seen one bent. But I'm sure it's possible! I have some pretty powder-coated ones for sale in the parts FS section. Or PM me for info.
 

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Discussion Starter · #6 ·
If you have time to get a new one why not? Im sure they should sit relatively flat without a gasket.
I tried to purchase a new cover but they're discontinued. I'll try with a different cover next week or so.
 

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Discussion Starter · #7 ·
In all my years, I've never seen one bent. But I'm sure it's possible! I have some pretty powder-coated ones for sale in the parts FS section. Or PM me for info.
When this cover sits on the head with no gaskets, there's about 1/8" gap which allows the cover rock back and forth.
 
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Discussion Starter · #8 ·

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You can always set the valve cover on a super flat surface like a glass table and check for warpage, if it is straight then the problem lies on the heads that is why i asked if the heads were machined...bunch of used covers on ebay
 

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Discussion Starter · #10 ·
You can always set the valve cover on a super flat surface like a glass table and check for warpage, if it is straight then the problem lies on the heads that is why i asked if the heads were machined...bunch of used covers on ebay
Unfortunately I don't have anything really flat/true besides a small mirror I use to check if pushrods are bent.
 

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Unfortunately I don't have anything really flat/true besides a small mirror I use to check if pushrods are bent.
I see well even if it is very slightly out of wack a good heavy duty gasket shall seal it, but if it is seriously warped just placing it on the floor and it wiggles side to side then yes its time to junk it.This is the first I have heard of a valve cover being warped but then again its all cast aluminum and anything is possible...
 

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I see well even if it is very slightly out of wack a good heavy duty gasket shall seal it, but if it is seriously warped just placing it on the floor and it wiggles side to side then yes its time to junk it.This is the first I have heard of a valve cover being warped but then again its all cast aluminum and anything is possible...
Its important to know if it is indeed the valve cover or the head itself....you can make a switch and put it up front and see if you have the same issue...but if it is the head then you will always have a leak regardless of how many valve cover you buy or type of gasket you use.....
 

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Discussion Starter · #13 ·
So luck would have it TWO DOHC 3000GTs popped up at a salvage yard this morning. I went there and found this:

Car A:
Rear valve cover (with no gaskets) had zero wobble on head.

Car B:
Rear valve cover (with no gaskets) had wobble on head.

Placed valve cover from Car A onto Car B's head and there was wobble.

Placed valve cover from Car B onto Car A's head and there was wobble.

Obviously I don't know the history of these cars, Car B might have overheated at some point. Car B's valve cover bolts were much more torqued down too, which could have tweaked the cover as well.
 

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I wouldn't worry about 1/8", it'll conform to the head once torqued down and the gasket will take up the rest.

Valve covers aren't machined parts so there will always be inconsistencies.
 

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I wouldn't worry about 1/8", it'll conform to the head once torqued down and the gasket will take up the rest.

Valve covers aren't machined parts so there will always be inconsistencies.
The question is having tight seal and not having the slightest oil leak due to internal pressure, there is not a whole lot of torque on those multiple size length 10mm bolts, a good gasket may compensate for any minor imperfections, however I dont think our valve covers were manufactured in this way meaning not being completely flush with the head, both of my valve covers sit on the head completely flush. Correct bolts need to be used if the factory ones are missing or just simply damaged, correct as in size and grade with factory recommended torque with a high quality gasket such as Mahle VS50269
 

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Lovbyts
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sorry for the spelling, I meant to say " My gut feeling is warped heads are to blame and not valve covers"
If the head is warped do you think its just a matter of time before the head gasket goes? Even though the valve cover is cast couldnt it have warped over time due to heat/cooling?

Hopefully the new valve cover doesnt wobble. I think I would have bought both of them just to be safe and sell the ones not used? Hmm then you are selling a possibly not good part. :( Not good.

As for a flat surface wouldn't a window work? Mirror in the bathroom?
 

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If the head is warped do you think its just a matter of time before the head gasket goes? Even though the valve cover is cast couldnt it have warped over time due to heat/cooling?

Hopefully the new valve cover doesnt wobble. I think I would have bought both of them just to be safe and sell the ones not used? Hmm then you are selling a possibly not good part. :( Not good.

As for a flat surface wouldn't a window work? Mirror in the bathroom?
Mirror in the bathroom, I dont think the wife would like that...valve cover wobble? its the first I guess not that Im an expert, but you never know whats behind those doors of a machine shop until you bring it home and then there is issues, just like when they damaged the valve cover sealing surface on mine and i did not even see it clearly until i used a head magnifier. Now speaking of heat, the heat needs to be significantly up in the numbers to warp a cast aluminium casing
 
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