Head gasket help

Topics related to the engines for the later MG Midget series.

Head gasket help

Postby boxfullofyertoys » Mon Feb 23, 2009 2:21 pm

Hey everyone!

I'm hoping someone in this forum can help me out a bit. I purchased a 1976 MG Midget last summer, and in the process of working on it and driving it a bit, I discovered a leak from the head gasket right at the back of the block by cylinder #4. I figured that the car probably needed a new head gasket. So, I got the new gasket and went about changing it out. I pulled the head, cleaned everything up, put the new gasket on, and fired her up. The good news was she didn't seem to be leaking. The bad news is there is white junk under the valve cover cap, and the exhaust is white. Looks like I swapped one leak for another lol

Two steps forward, one step back...

I've since re-torqued the head, and it def needed it, but she still seems to be leaking coolant. (I've run it once since the re-torque). There's no sign of coolant on the dipstick or plugs, which leads me to believe the leak isn't huge. Is it possible that the residual coolant in the oil hasn't evaporated out yet? I've also been told that the head might be warped and needs to be milled a bit, but that essentially means the whole engine has to come out (and that means all the shop work and trans stuff I wanted to do later down the line I'd probably want to do now so I won't have to pull the motor again). I'd like to avoid a motor pull, but I'll do it if need be...

Any thoughts on how to solve the problem?

Thanks in advance!
-Dave
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Re: Head gasket help

Postby hoggie » Mon Feb 23, 2009 8:40 pm

I think your going to have to pull the head again and have it checked out at a machine shop. It either needs to be milled to square the surface or has a crack somewhere. Hopefully resurfacing will fix it and they find no cracks. In that case, should be relatively inexpensive. But once you pull the head, you may find that it may be best to bring everything up to speed. Valves, springs, valve seats, valve guides, etc. Just depends on how far you want to go and how much money you want to spend.

Mike
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Re: Head gasket help

Postby Charlie Tolman » Tue Feb 24, 2009 2:07 am

If the exhaust gases from the tailpipe are white, and the gases smell like maple syrup (if the coolant is 'anti-freeze' or ethlyene glycol), then there is a coolant leak into one or more of the engine cylinders or head combustion chambers.

Good advice from 'hoggie' in the previous note.

To have the head milled, you do not have to remove the engine from the car.

Charlie Tolman
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Re: Head gasket help

Postby boxfullofyertoys » Tue Feb 24, 2009 3:18 pm

Thanks for the advice!

I knew there was a definitely coolant leak, but wasn't totally sure of what my options were after re-torquing the head. My concern was that if the head needed to be milled, you essentially need to get the top of the block milled as well in order to make sure everything is square. If that's not case (which it sounds like it isn't), then pulling the head again isn't a huge task. I'll probably get a valve job done as well to ensure everything is up to snuff...might as well considering the head is going to the machine shop anyway :)

Thanks again!
-Dave
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Re: Head gasket help

Postby hoggie » Tue Feb 24, 2009 8:47 pm

The block has too much mass to change very much, but the head can warp fairly easy. Especially if the engine got overheated at some point. Of course you will want to examine the block closely when you pull the head to make sure it didn't get gouged at some point. Just a little gouge or debris left on the block can keep a good head from sealing.

Mike
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