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MG MGA - Over before it started

Today was just not a good day. I've been prepping my Coupe for the start of the driving season, which for me is the Missouri Endurance Rally. I was going to install my new modified cylinder head today when I discovered my block has cracked, from one oil gallery to another right across the head stud at the #3 piston. Needless to say, disappointed is an understatement. I may not bother with a new engine this year, as we have just embarked on a ZB restoration. So as we Cubs fans often say, "Maybe next year!"
Mark J Michalak

Bad luck Mark. What a downer at the start of the season.

Had the same failure a few years ago which only came to light when I was taking the block to get machined. Luckily getting a block reworked is not so difficult (if you can find a block).
I can see that working on 2 cars at once is a recipe for disaster though, I am working on an E-type and postponing any bodywork on the MGA until it is finished. I would otherwise have a garage bulging at the seams with parts!!

Can't help you on the Cub's issue!!
Neil
Neil Purves

Mark,
What year is your Coupe? I may have an extra block you can have.

John
John Progess

Mark,
Can you post a photo?
D Sjostrom

Mark, Bill Trusdale at APEX had an early 1500 block stuffed away in the back of his shop when I was there in the fall.
George
G Goeppner

John,

I'm using a 5-main 1800, but thank you for your offer.

George, I'll sniff around Bill's shop when I go to pick up my HS6s and see what I can find. Here's a picture of the crack.

Mark


Mark J Michalak

If you squint real hard and hold your breath, you can almost see that the crack goes from one oil drain hole to the other, right through the head stud.


Mark J Michalak

Mark, What have you got to lose by installing the the head as is? There is no connection to cooling channels. Perhaps the block has been cracked forever.Not a purist's approach , just an amateur's thought. Bob P.
rsa prentice

Mark,
You have a possibility of repairing the block. Your crack has hit both oil passages, and therefore, the crack cannot propagate further. Check with a tractor mechanic (old school) and see whether they can weld up the crack. Then file it smooth and give it a try.
good luck.
Mike Parker

I would certainly go with Bob, and rebuild as is, if it were my car and I was in the same situation regarding the preparation work.

If I still had doubts at the end of the season I would follow Mike's advice.

Again that's only what I would do and I could be proved wrong!
Neil McGurk

I wouldn't mind betting that if you had not spotted the crack , assembled the engine and used the car nothing disastrous would happen. I suspect there's lots of cars running about with hairline cracks in their engines as long as its not into a waterway. Theres one check you could do and that's to place some thin paper gasket material under the head and over the stud, tighten the head up and then release the head to see if theres any tell tale crack mark on the paper. Its possible that the tension in the stud might open up the crack.
J H Cole

AS long as the head stud torques properly it should go back together no problems. If the choice is run it or park it. I for one would run it. Nothing to loose but the chance to drive it. There was no problem before so there should be no problem now. Drive it now, collect parts to redo it. Once all the parts are collected cleaned machined and ready to go a day or two will do the trick. Keeping a spare engine is a good idea anyway.
R J Brown

Mark,
I also have a 5 main block or two. Is your block a 18V or what? Have a good day!

John
John Progess

Thanks for all the responses. John, the motor's an 18GK. I really wanted someone to tell me it was okay to put it back together and drive it. I'm going to do it today! I know that loctite generally is a bad idea for head studs, but would it make sense here?
Mark J Michalak

Of course. It certainly can't hurt. You could also grind the crack a little deeper and peen some copper into the crack. When the engine is running, the copper will expand quicker than the cast iron, and should seal the crack.
Mike Parker

Yes, loctite would seem to me to make good sense here. Obviously you do not want the stud tightening further into the block! You could also mark the top of the stud and tighten that one with a spanner (until final torque) to confirm that the stud doesn't turn.

Mike, I'm not sure about the copper, might that create pressure to open the crack? It doesn't matter if it "leaks" as it is between oil returns.

Enjoy driving!
Neil McGurk

This thread was discussed between 25/03/2009 and 27/03/2009

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