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County cast iron cylinder head warning

Posted by Speedracer 
Speedracer Avatar
Hap Waldrop
Greenville, SC, USA   usa
1967 MG MGB "The Biscuit"

Before you go "oh crap", is Hap about to tell it's junk, no not harldy, it doesn have it's shortcomings, no aftermaket head that I've ever seen, cast iron or aluminum has as nice of casting as a stock MG cylinder head, and these heads are no different, this one I working with now, it had to be pocket ported to just get it back to the bowl ID of a stock head, and they tend to be a little more lumpy and bumpy in the ports in general than a stock MG head. No what I'm about to tell you about could cause a little stress, a few curse words and a little bit of work if it happen to you, like it did me. On the back left side of all MGB cylinder heads is a brass plug, this plug closes up a hole that was drilled in the head during manufactuering that intersects another drilling that take oil passage from the the block up to your rear rocker arm pedestal for oiling the rocker arm assembly, valve spring and such, the only oil the cylinder head gets bascily. Ok, as mentioned in stock MGB head they use a brass plug, to plug this hole. On the County heads it turns out they threaded the hole and use a set screw, of course it well covered up wth excess paint and such and nothing you would ever expect to be a problem later, but something you may want to pay closer attention to this, as I found out.


I rebuilt a MGB engine for Harry Watkins that post here, and it was installed by Bob White that post here, so I knew in was in good hands with Bob doing the installation. Well Bob called me and told me the engine was leaking form the rear and we all just assumed it was the rear seal, even though the uprated viton seal was used, I didn't use a speedi sleeve, because the rear crank hub looked perfect. Anyway I decided to go up to the Charlotte, NC area and trailer the car back here, and address this at my buddy's shop where we could get it up on the lift, I had already planned on it being the rear seal, had a new seal and speedy sleeve on hand. Well with the car up on the, lift, it was for sure a leaking at the rear, the bottom of the rear scetion of the engine was wet with fresh motor oil, so we started investigating, the first clue that this was not rear seal leak was the inspection hole on the rear engine plate, I could stick my finger in there and it was dry as a bone. At this point we started looking upward on the block and sure enough I could see a trial of oil dribbling down the block from upward, now the two plugs on that side of the block and lifter covers were dry as a bone, so that was not it, it was coming from further upward. A little more looking with the car back on the ground showed a puddle of oil collecting at the rear of the cylinder head where the block and the head join each other. We wiped the area dry, and cranked the engine, and sure enough about 2 seconds we got a squirt of oil from the back side of the cylinder head, at this point we knew the cylinder head had to come off to investigate this further. Once the cylinder head was off, that's when we discovered the the new replacment cylinder heads had the set screw, not a brass plug, and that's where the leak was coming from, it was loose and and had no sort of sealer on the threads when removed, Ok we now had the smoking gun. I clean and de-greased the area, and used expoxy to seal tghe threads of the plug and reinstalled it, and put everyhtintg back togehter, let it sat a few days day, recrank the engine and had no more oil leak.

In closing this is somehwere you would never expect a oil leak from, but these cars never cease to educate us, and this is where actually installing and working with these parts far excells the education over just selling theses parts. I will be calling the wholesale vendor that sells us these heads today to make they are aware of this, because without feedback like this, the vendor would never know of a possible issue. it obviously doesn't not happen on every County cast iron replacment cylinder head, but we know one thing for sure now, it can happen and the set screw needs to be checked and made sure it is sealed and tight.

I probably worked with a couple of dozen of these cylinder heads over 6-7 year period and this is the first I've seen of this, but something that is so easy to check with the head on the bench and not so easy to fix with the head on the car, you could fix this on the car, knowing what I know now, but we didn't know what we were dealing with, so we removed the cylinder head. Bottom line, check this before installation and your life will/could be a bit easier.



Hap Waldrop
Acme Speed Shop
864-370-3000
Performance Street/Race engines- modified heads, and DIY engine rebuilt kits
New alloy wheels options for MGBs, see vendors forum for details.
http://www.mgexp.com/phorum/read.php?68,2657584
Be sure to check my engine rebuild kit thread in the Vendors forum for weekly tips. http://www.mgexp.com/phorum/read.php?68,1828263



Edited 1 time(s). Last edit at 03/05/2012 09:32AM by Speedracer.

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Basil Adams Avatar
About 12 miles from Sears Point, CA, USA   usa

By chance did you take a picture? Thanks.



Basil C. Adams
1956 MGA Coupe (Show Car)
1957 MGA Roadster (Driver)
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1972 Alfa Romeo Montreal
A coupla late MGBs
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More Cars than Brains
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Speedracer Avatar
Hap Waldrop
Greenville, SC, USA   usa
1967 MG MGB "The Biscuit"

In reply to # 2002630 by Basil Adams By chance did you take a picture? Thanks.

Basil no, but it's the same place as the brass plug is on all B series heads, they just stuck a set screw back there instead of brass plug, back side, lower left of the head, near the deck surface. It was covered up pretty well with paint, so well hidden and are no one would ever check there on one of these heads for potential leak, well up to now anyway smiling smiley I plan on calling Leyton this morning and making him aware of it, I don't blame them, they didn't make the head, they just sell to most of us, Moss sells the same head as well, as you already know, and needs to know about this, so hopefully Kelvin reads this as well, but it would be a good thing to to check this before the sale, or at minimum make sure the customer is aware of it.



Hap Waldrop
Acme Speed Shop
864-370-3000
Performance Street/Race engines- modified heads, and DIY engine rebuilt kits
New alloy wheels options for MGBs, see vendors forum for details.
http://www.mgexp.com/phorum/read.php?68,2657584
Be sure to check my engine rebuild kit thread in the Vendors forum for weekly tips. http://www.mgexp.com/phorum/read.php?68,1828263

Member Services:
MG/ Triumph Performance Street/Race Engines - Cylinder Head Porting - Modified SU HS Carbs - DIY Engine Rebuild Kits With Tech Advice - Alloy wheels for MGB/TR6
GILMGA Avatar
Gil Dupre
Chattanooga, TN, USA   usa
1962 MG MGA
1974 MG MGB GT

In reply to # 2002630 by Basil Adams By chance did you take a picture? Thanks.


Ditto



Gil
Robert White
Monroe,NC 28112, USA   usa

Looks like just when we thought we knew where these engines have issues there becomes another area to check. Good info. Thanks for sharing. Bob



Bob
63 mgb x2
67 mgbgt ,74.5 Rubber bumper BGT x2
99 miata 10ae
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Speedracer Avatar
Hap Waldrop
Greenville, SC, USA   usa
1967 MG MGB "The Biscuit"

Well, here's a stock MGB cylinder head, well it's not exactly stock anymore thumbs up smiley , anyway, and here's the stock type brass plug, so it's same location on County head, just that the hole has been threaded and has set screw used there instead of the brass plug. I've actually had to remove this plug on a race prepped head one time, and used a 1/16" NPT plug to go back in there, so nothing is wrong with the method of using the threaded plug, it's just that in this case, the set screw was not tight and had no sealer on it.



Hap Waldrop
Acme Speed Shop
864-370-3000
Performance Street/Race engines- modified heads, and DIY engine rebuilt kits
New alloy wheels options for MGBs, see vendors forum for details.
http://www.mgexp.com/phorum/read.php?68,2657584
Be sure to check my engine rebuild kit thread in the Vendors forum for weekly tips. http://www.mgexp.com/phorum/read.php?68,1828263

Member Services:
MG/ Triumph Performance Street/Race Engines - Cylinder Head Porting - Modified SU HS Carbs - DIY Engine Rebuild Kits With Tech Advice - Alloy wheels for MGB/TR6

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twigworker Avatar
Jack Austin
Blowing Rock, NC, USA   usa

You are SUCH an asset to this group Hap !

Jack



---------------------------------------------------- Services to Interesting British Automobiles-- www.jackscars.net ----------------------------------------------------------------
-------------I like to think that I don't service automobiles so much as I provide entertainment, fulfill dreams and revive wonderful memories --------------

I am in the northwestern North Carolina mountains, right up against the Blue Ridge Parkway. Lawn chairs are in the shop and always time to talk. Drop in any time.
Speedracer Avatar
Hap Waldrop
Greenville, SC, USA   usa
1967 MG MGB "The Biscuit"

In reply to # 2003106 by twigworker You are SUCH an asset to this group Hap !

Jack

Now if I just had the cult-like following you had sir grinning smiley



Hap Waldrop
Acme Speed Shop
864-370-3000
Performance Street/Race engines- modified heads, and DIY engine rebuilt kits
New alloy wheels options for MGBs, see vendors forum for details.
http://www.mgexp.com/phorum/read.php?68,2657584
Be sure to check my engine rebuild kit thread in the Vendors forum for weekly tips. http://www.mgexp.com/phorum/read.php?68,1828263

Member Services:
MG/ Triumph Performance Street/Race Engines - Cylinder Head Porting - Modified SU HS Carbs - DIY Engine Rebuild Kits With Tech Advice - Alloy wheels for MGB/TR6
chris Avatar
Chris Roop
Pendleton, OR, USA   usa

Amazing. Thanks for the heads up! smiling smiley

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twigworker Avatar
Jack Austin
Blowing Rock, NC, USA   usa

You do much more and much better engine work that I have time left to learn Mr. Hap.

Just keep doing what you do the way you do it.

I look at it as "paying forward", and the day will come, if it hasn't already, when all of your late night work and the freebies that you have handed out will come back to you in spades.

A cult following is easy to acquire, but not in expensive. All you have to do is visit the Botox parlor regularly and follow the plastic surgeon's advice for "a new and better you". It also helps if you serve cold "Kool-Aid" in the summer to shop visitors.cool smiley

Jack



---------------------------------------------------- Services to Interesting British Automobiles-- www.jackscars.net ----------------------------------------------------------------
-------------I like to think that I don't service automobiles so much as I provide entertainment, fulfill dreams and revive wonderful memories --------------

I am in the northwestern North Carolina mountains, right up against the Blue Ridge Parkway. Lawn chairs are in the shop and always time to talk. Drop in any time.
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tazman72 Avatar
Bruce Smith
Interlachen, N. Fl., USA   usa

Never noticed the plug either...went to check, yep there it was. Not leaking tho.
dhartlein Avatar
Dave Hartlein
Suwanee, GA, USA   usa
1980 MG MGB
1991 Volvo 240

Phew - you guys helped me with a casting failure awhile back (see the picture below), so I ran out and checked my county head as soon as I read this post. Looks like a plug and it's dry as a bone.

I've been really happy with this head - no problems. The first one, not so much, but it did afford the opportunity to become a lifetime Moss fan. They shipped a replacement from California by air - unbelievable service.

All remains well.
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Speedracer Avatar
Hap Waldrop
Greenville, SC, USA   usa
1967 MG MGB "The Biscuit"

In reply to # 2003274 by dhartlein Phew - you guys helped me with a casting failure awhile back (see the picture below), so I ran out and checked my county head as soon as I read this post. Looks like a plug and it's dry as a bone.

I've been really happy with this head - no problems. The first one, not so much, but it did afford the opportunity to become a lifetime Moss fan. They shipped a replacement from California by air - unbelievable service.

All remains well.

Dave, you would have known it, had it been loose, it would be like a nasty rear main seal leak, it for sure isn't a problem on every County head, and hopefully this happening to me me as well as Harry, who owns the car, will help the folks selling these heads and we, the folks buying these heads to check such a simple thing before installation. Leyton at BPNW was even going to talk to the main supplier and let them know, I think someone at County had a bad day and forgot to tighten and seal the plug on this head, but it's so simple on our end to double check it.



Hap Waldrop
Acme Speed Shop
864-370-3000
Performance Street/Race engines- modified heads, and DIY engine rebuilt kits
New alloy wheels options for MGBs, see vendors forum for details.
http://www.mgexp.com/phorum/read.php?68,2657584
Be sure to check my engine rebuild kit thread in the Vendors forum for weekly tips. http://www.mgexp.com/phorum/read.php?68,1828263

Member Services:
MG/ Triumph Performance Street/Race Engines - Cylinder Head Porting - Modified SU HS Carbs - DIY Engine Rebuild Kits With Tech Advice - Alloy wheels for MGB/TR6
dltpilot Avatar
Dennis Taylor
Holly Springs, NC, USA   usa

I posted this earlier today after not finding any hits on the Forum to my query "mgb cylinder head oil plug" Live and learn or as we find out with our MGs own and repair.

Just had an interesting experience with my 74.5 GT while driving around town, thankfully. The little brass plug at the back of the cylinder head, driver side, popped out. What little brass plug you say? Look at the Moss catalog under Cylinder Head, page 10 of the August 2011 edition, item 30. This plug seals off a hole in the oil system that was drilled for production purposes. Neither I nor any of my MG buddies had ever paid any attention to said plug before, but we will now. Not knowing any thing about the size or depth of the hole I thought it best to remove the head to determine the best way to repair it. It seems the factory just hammered the brass plug into the hole as an expeditious means of sealing the oil system. No room to do that with the engine in the car. After removing the head and inspecting the hole I found it was only a couple thousandths bigger than the drill size for a 1/4-28 tap, so I tapped it and installed a
1/4-28x3/8 socket head bolt,$.40 at Ace Hardware, which I applied some Permatex brown gasket maker to. Seems to seal and tighten up just fine. Don't know if it could have been done in the car if I had known the hole size, maybe. In the future anytime I have a head off of a B motor I will just replace this plug with a socket head bolt. Simple when it's on the bench.
Montrose Avatar
Robert Carley
Campbellville, Ontario, Canada   can

Never even knew that plug was there.

Thanks, Hap. I always know I am going to learn something when I see one of your posts.

smileys with beer



Imperial by choice; Metric by force.
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