THIRD BLOWN HEAD GASKET! please HELP!!!!!

[srvtribute]

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Here we go.. I assembled, torqued etc. Car ran MINT, 4 times around the block then lost cylinders 3+4 again. I disassembled the head again. Blown gasket in between 3+4 just like the previous time. NOW THE PLOT THICKENS. I compared both blown gaskets and they were identical, with burn marks in the same spot! Now, if you're leaning on the driver side fender and looking at the engine, there is a hole in the engine block at about 1 o'clock in relation to the #4 cylinder which doesn't seem to go anywhere, yet is blocked off by the head gasket. Both times the head gasket had a hole burned through it in that spot. before I reassembled the head, I assumed that this hole was an antifreeze port and there was antifreeze left in the hole before assembly. Could it be possible that the coolant in the hole boiled and blew the gasket?? HELP-

PHOTO ATTACHED

 

[Dave Russell]

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Could it be possible that the coolant in the hole boiled and blew the gasket?? HELP-


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I seriously doubt it.

First thing is to clean the block & head surfaces & check both for level. A straight edge over the surface areas. If you can see any light under the straight edge or insert a feeler gage that is more than .002" thick, a gasket will never hold for long. The only real remedy is to resurface which ever is needed. If two gaskets have already burned through, it's likely that the block or head surfaces are not level in that area. As was mentioned before, any raised threads around the block holes will also prevent the head from seating.

If a stud or bolt is bottoming out before the head is pulled all of the way down, it will never clamp the head.
D

 

[Banjo]

I second Dave. Double and triple check the block and head for straightness. It sounds like somethings warped (specifically the bridge between 3 and4). and check the stud hole threads too. that's an important point.
If nothing turns up from those checks, then start looking for cracks.

 

[PaulHanley]

I'd likely try to id that hole at 1 o'clock. If your gasket is covering it and it keeps burning thru there, then it sounds to me that it shouldn't/doesn't want to be covered. Are you sure you have the correct gasket? What year car? Perhaps you have a 3 main/5 main switcheroo.

Paul

 

[Keoke]

Sorry about your trouble,but I had expected this. Obviously, the mechanic who left the studs loose on the Ali head was not involved with the first blown head gasket and some alignment problem probably existed. Consequently, I join the majority and suggest you check the block and the head for flatness.Additionally I would replace all the head studs with new---Keoke

 

[PaulHanley]

Now that I look at things more carefully its seems we may not be talking MGB. Sorry. What car and year as the attached photo is nothing like the MGB head gaskets I have for reference.

 

[Keoke]

Hi Paul. The car is reported to be a 1977 MG Midget?.

 

[srvtribute]

The gasket in the pic is for reference only. The car is a 77 Midget and I definately used the correct gasket. I'm going to replace all studs,nuts, gasket etc. I'm gonna have the head checked. Just because it was remanufactured doesn't mean that it is up to specs. I hate to be a doubting Thomas on this , But I'm at wits end on this one. Also this morning, I took a small tube and blew into the antifreeze passages in the block to asure that they were clear.I thought there might be a hotspot between 3+4. As for the 2 holes that go nowhere, maybe they are alignment holes for machining???? Thanks for all of your suggestions-
Eddie

 

[Keoke]

Eddie; Be sure and have both the the Head and the Block checked for flatness as also suggested by others. Prior to installing the new studs, Clean the stud threads in the block out using a bottoming tap and compressed air. Run a die down the threads on the new studs.

 

[PAUL161]

Head gaskets burn or blow out 99% of the time because of a warped head, warped block, or crack in one or both. A warped block is fairly rare. Scratches on the top of the block are not. Naturally loose bolts will also be a contributor. Have the head magnafluxed first. Heads usually go bad before blocks. If the head is good, then you have bigger problems. If there are no cracks, I'd have the head and block shaved. PJ