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Seepage/bubbles around #8 head bolt

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wkilleffer

wkilleffer

Jedi Knight
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Hello Everyone,

While doing a bit of fiddling around (yes, that's the scientific name for it) under the hood of my '74 MGB while it was at normal operating temperature. I just happened to notice that the back two head bolts on the outside of the valve cover, number 8 and maybe 11 in the torquing order, were bubbling. Not a whole lot, but enough to notice.

So, I let the car cool down a bit and went on to retorque all the bolts in the order to 48 lb/ft. I also wiped the engine down to see if there were any other seepage areas. After running it back up to NOT, only bolt 8 had any bubbles, and they seemed less than before. There was no evidence of seepage or bubbles on any other bolts, nor from the area where the head and block come together. There's no evidence that oil and coolant are getting mixed together.

Now, aside from having a somewhat cleaner engine, what do I have here? The engine's from a 72 MGB, and I've had it rebuilt between 9.5k and 12k miles ago (can't find the receipt with the mileage) by a competent service here called Rivergate. I will confess that I was more ignorant about maintaining a car like this back then (5 years ago), and no one told me to retorque the head bolts once per year until recently. It never occured to me that was a maintenance item.

Has my ignorance caused me to ruin my engine? I could *almost* do a head gasket job myself now, but don't want to need to. This wouldn't be a terrible problem except that this car is my daily driver and the only alternative save my motorcycle unless I can borrow a car from a family member.

So, what do I need to do? Drive it, take it off the road, or something in between? Any suggestions and advice would be appreciated.

Thank you, and have a happy and safe Memorial Day, while remembering those who made the ultimate sacrifice.
 
Does not sound like you are haveing parking problems, keep a close eye ont it though.

You are going to have to change the head gasket to fix the problem properly. Not a big deal.
 
Looks like the hardest part of the job is getting the exhaust manifold off. But I have a bit of time before I need to tear into it as long as the fluids don't start mixing and no serious leaks form.
 
Keep your eye on the coolant level. Might also want to check/change your oil more often as well.

A head gasket is actually a fun job to do; better part of a Saturday morning, assuming you do a bunch of prep Friday evening. I like to spread this stuff out over a day or two to give me a mental break in case something goes wrong.

Some random thoughts:

While it's apart, replace the side cover gaskets; they are usually leaking by now.

I usually spray any fasteners down with penetrating oil (Kroil, PBBlaster, NOT WD40) at least the night before to let them soak.

Make sure you have all the parts you might need before you start; this sounds obvious, but I almost always find that I've missed some small part/gasket/whatever.

Most folks insist that you install head gaskets dry; I like to spray them with a thin, uniform spritz of Hylomar.

I also coat the head studs with a really thin film of Permatex antisieze paste (the silver stuff).

If the head won't budge, feed a length of cotton rope into the plug hole and spin the engine using the starter; this usually pops it loose.
 
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While it's apart, replace the side cover gaskets; they are usually leaking by now.

[/ QUOTE ]

Sorry if this is an obvious thing, but what's a side cover gasket?

I've had this car five years and the engine's been rebuilt about that long. Even though I am comfortable with working on cars, it's probably been only within the last couple of years that I got good at working on this one. Too bad that comes at a price.

Thank you,
 
Don't think your engine has side covers, they were on the 948 and 1050, the 1297 did not have but anyway, they were under the exhaust manifold and let you get to what is called the tappet chest.
 
[ QUOTE ]

Sorry if this is an obvious thing, but what's a side cover gasket?


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No probs. Side covers, AKA tappet chest covers. See #8 in this photo. If they are not leaking, might just leave them alone. They are a royal pain to get to, but you'll have everything apart anyway.

MGB-001.gif
 
The folks at Rivergate in Soddy Daisy are good people - run it back by them & get their opinion.
 
Also anytime you retorque the head, you need to re adjust the valves.

Oh and the side cover deal
A-series engines, which this person does not have.
850,948,998,1098 all had side covers, 1275 did not
B Series engines, all had them. And to elaborate a little more, the B series engine, many folks think of as just in a MGB was actually in MGA, Magnettes, Farinas, MGBs, Elvas etc., the B series engine like the A-series engine had many different series over the years. They evolved from under 1500ccs with three mains to 1800cc and 5 mains over the years.
 
Oh me, so much to know. Thanks.
 
The manuals say to torque the head bolts between 45 lb/ft and 50 lb/ft. Is there any harm to using the 50 lb/ft setting, or is this an as low as possible task? Should I also try to retorque again, this time to 50 lb/ft?

Thank you,
 
[ QUOTE ]
The manuals say to torque the head bolts between 45 lb/ft and 50 lb/ft. Is there any harm to using the 50 lb/ft setting, or is this an as low as possible task? Should I also try to retorque again, this time to 50 lb/ft?

Thank you,

[/ QUOTE ]

I'm not sure what you're asking, but I have not yet had my 3rd coffee and it's "monday" for me /ubbthreads/images/graemlins/grin.gif Is your lowest torque wrench setting 50#?

I've learned that it is best to torque anything in 'stages'. Follow the sequence and torque to 40#. Wait a bit/have a beer/cut the grass. Then follow the sequence again up to 50#. Readjust the valves, as the clearance may have changed between the valve stem (head) and the rocker arm (block).
 
One thing about head studs I larned a long time ago...never tighten the stud all the way down to the bottom of the hole in the block...take her all the way down & then back off about a half turn...then, when you torque the bolt onto the stud, you're not apt to push the bottom of the stud into the block if you overtorque.
 
[ QUOTE ]
The folks at Rivergate in Soddy Daisy are good people - run it back by them & get their opinion.

[/ QUOTE ]

I called and spoke to Will, who did most of the work on the rebuild. I told him what I've told everyone here. He said unless the engine is losing a significant amount of oil or coolant, overheating, or mixing oil and coolant in some way, that the head gasket isn't blown. It's not doing either of those things. He said on the B-series engine that it's pretty obvious when the gasket goes, as it typically goes between the #2 and 3 cylinder, and the engine loses alot of power. He said what I'm seeing is the engine warming up and building internal pressure, and that small bubbles and seepage aren't unheard of at that point.

They did such a good job on the engine that I don't see a reason to mistrust him. It sounds like a matter of keeping an eye on the fluid levels. After all, these engines aren't fluid-tight and probably never were. It could be my imagination, but the engine seemed to be running just a hair cooler on my drive in this morning.

Thank you, and please let me know what you think,
 
Hmm, might could seal that bolt with a bit of goop??

Just to keep the engine from getting messy you understand.
 
[ QUOTE ]
Hmm, might could seal that bolt with a bit of goop??

Just to keep the engine from getting messy you understand.

[/ QUOTE ]

Yeah, but we're under a heat advisory right now, and everything's subject to melting. /ubbthreads/images/graemlins/jester.gif

Engine tried to melt in slow moving traffic a bit ago. Temp gauge got 3/4 of the way through its scale, then the engine sputtered and stalled. Really cranky (no pun intended) about starting again. Sputtered a bit under accelleration, but soon smoothed out and cooled down.
 
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