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Difference in 1275 heads?

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All this head cracking stuff has me worried.
My GT7 Longman head is a Cooper S type head with the big valves.
Has this problem somehow been addressed by Longman?
Is my head a ticking time bomb?
Lord knows I've flailed the tar out of the engine for about
3000 miles so far.
What symptom would give me a clue the thing is cracking?
Ignorance is bliss, as they say, but a little knowledge is making me nervous.
:crazyeyes:
 
Gundy said:
What symptom would give me a clue the thing is cracking?
Click to expand...

All scientific data points to the fact that if it hasn't happened in about 2999 miles you can get right out there and have more fun!
 
The cracking between the valve seats happens all the time. Going to bigger intakes and/or exhausts just increases the chances. A crack between the seats does not mean imminent catastrophic failure. I've got an engine with 20+ races on it and a visible crack between the seats in one of the cylinders. Water is a long way away in the head casting and as long as the crack stays small, it really is of little consequence. I've found them in heads before and have had the crack cut out during valve seat installation. Just intall one seat overlapping into the other and its gone.

Don't go jumping off the cliff, but if the crack if big enough and it propogates into the water jacket, the coolant system will immediately pressurize and the cap will lift and the coolant will puke all over the tarmac. The temperature gage will peg and you'll see a cloud of vapor behind you or around you. If it is really really catastrophic, the coolant system could pressurize enough to blow the head gasket or pop off a radiator hose or split the radiator core/tank.

Been there and done most of this one way or another, but the little cracks between the seats are usually rather benign. I've got a race head I had crack repaired and raced it for 6 years before I found multiple cracks that were rather onerous to fix. So, I'll just port up a replacement or get Indy Cylinder Heads to repair. Not cheap, not easy, but brings a $2K back from the dead.

Were kind of lucky. For a small crack between the seats, Dover in Greenville can usually fix it in a couple days.

Mike
 
David you shouldn’t fear at all, your 1380 is running cool as a cucumber with that aluminum radiator and electric fan. I know you’ve run it hard numerous times, I be willing to bet you have barely seen the temp over 180f. On top of that you have the copper AF470 head gasket and all ARP head studs which will keep everything nice tight. If you had a crack head or a blown head gasket you will see steam coming out the tail pipe or water in your oil. If you want you can check you head torque just to see if you have any change but I kind of doubt it. You’re running the 12G940 head same as me, with 1.44” intake valves which is pushing everything close. As you know that’s what it takes to get the HP. If it cracks we can always get it fixed!!
 
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