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Head Gasket - Which way is up?

Moss Motors
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dhall7088 Don H
DeMotte, IN, USA   USA
Hello All,
I have a rookie question. I am replacing the head gasket on my 1976 Midget. I rebuilt the engine some time ago, and it failed in very short order. I have pulled the head off and found the area between cylinders 1 and 2 was completely burned away. My initial task as I see it is to determine the reason for the failure. One of these reasons I have considered was that the gasket was installed upside down. I know the gasket itself has one side in which the fire rings are flush with the gasket, the other side protrudes a bit. I installed the gasket with the protrusion side down (in contact with the block), with the flush side to the head. Was this correct or not? My reasoning for doing so (the gasket had no markings indicating orientation) was that the block has indentations surrounding the cylinders. I assumed these indentations were meant to accommodate the fire ring protrusions.
I have also considered the possibility that the head was warped, even though it had been completely reconditioned by a reputable shop. Using a straight edge and a feeler gauge (.002"winking smiley I examined the head surface and found no evidence of warping. The block looks equally good. What am I missing?
Thanks in advance for your help.
Don

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oleanderjoe Avatar
oleanderjoe Gold Member Joseph Baba
Fresno, CA, USA   USA
DON: You did it right. The "TAB" on the edge of the Gasket should match up with the "TAB" on the engine. Recently, like Last month a shop here in fresno had an issue with this exact thing. The gasket coming from MOSS was wrong for his application. Double check the gasket number and any stampings on the gasket and talk to MOSS, if that is where you got it. smileys with beer


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oleanderjoe Avatar
oleanderjoe Gold Member Joseph Baba
Fresno, CA, USA   USA
DON: One other quick thing to check. Inspect the holes where the "HEAD STUDS" screw into the block. From the factory, the "TOP" thread was countersunk a little, MGB Motors are the same way. On MGB Motors, if the block has been surfaced sometime in the past, it is a good idea to counter sink the holes, so that the top thread is not PULLED up during the torqueing and not allow the gasket to properly crush. Midget & (Triumph) motors of your year are not usually surfaced to heavily, so as not to "REMOVE" the recessed groovethumbs up.


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dhall7088 Don H
DeMotte, IN, USA   USA
Thanks Joseph. Nice to know I did something right for once. The original gasket came from VB. I just ordered the Payen variety from Moss. Hope I have better luck.

oleanderjoe Avatar
oleanderjoe Gold Member Joseph Baba
Fresno, CA, USA   USA
DON: Perfect, I am sure you will. I actually did that one time years ago, I had the machine shop deck the block, and they took off too much. It leaked like crazy, Three new gaskets later, I figured out what was wrong. I had them RE-DECK, it again and removed the recessed groove completely. I used a 1300cc gasket and all was good. Raised the compression a little also. smileys with beer


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jmac Avatar
jmac Silver Member Jere McSparran
Greenup, IL, USA   USA
1970 MG Midget "Joy Ride"
1978 MG Midget "Therapy"
1978 MG Midget "(SOLD)"
If the block was decked you need to check the recesses, as mentioned. Lay a straight edge across the cylinder and measure the depth of the recess with a feeler gauge. You need .030. If less than that the gasket rings around the cylinders will not crush enough.
Also, how often did you retorque after the rebuild? It should be retorqued after initial warmup, then again at 1000 miles.



JMac
JMAC Engine Shop
http://www.jmacengineshop.com

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