Calling all big block Guru's

[J/D/S]

My brand new big block that I had built for my truck got up to 249 deg the other day only for about 5 minutes but then started smoking really bad out of the right side exhuast, So I figured that I had blow a head gasket but there was no coolant in the oil, so I take it back to the shop that built it and they tell me today that it's fine that all it did was get hot enuff to leak past the valve guides but that it's fine and has been running for 2 hours without any smoking.

Has anyone heard of this happening? And if so is it that easy?

[SSC's76]

Going past the guides.... ahh ok... not while running, just isnt going to happen.

As far as the heat issue could have been an air pocket but its hard to say how many miles do you have on this rebuilt engine? Ive seen rebuilt engines "crate" engines do strange things had a 460 that lost compression after the customer drove from colorado to florida and back plenty of time to seat the rings. I dont remember who the engine came from but they said it happens. Ive never had it happen to an engine i built but heck followed the builders directions and drove the crap out of it compression came back up. I suggest if its fine now drive it see what happens have them document you had an issue even just a service ticket that says you took it back for inspection to cover your bases.

[Restrorob]

Originally Posted by J/D/S

started smoking really bad out of the right side exhuast

What color was the smoke ?

What did the smoke smell like ?

As SSC's76 mentioned...... I've never seen any engine start smoking from guides then magically stop.

[J/D/S]

Originally Posted by Restrorob

What color was the smoke ?

What did the smoke smell like ?

As SSC's76 mentioned...... I've never seen any engine start smoking from guides then magically stop.

pure white, and it smelled just like antifreeze

[J/D/S]

Originally Posted by SSC's76

Going past the guides.... ahh ok... not while running, just isnt going to happen.

As far as the heat issue could have been an air pocket but its hard to say how many miles do you have on this rebuilt engine? Ive seen rebuilt engines "crate" engines do strange things had a 460 that lost compression after the customer drove from colorado to florida and back plenty of time to seat the rings. I dont remember who the engine came from but they said it happens. Ive never had it happen to an engine i built but heck followed the builders directions and drove the crap out of it compression came back up. I suggest if its fine now drive it see what happens have them document you had an issue even just a service ticket that says you took it back for inspection to cover your bases.

There's 2-3 miles at the most on it.

[J/D/S]

Is it even possible that it could leak coolant pass the valve guides? Do they(valve guides) pass threw a coolant passage?

[Restrorob]

To answer both questions ^^^^^^ NO......

They likely dumped some stop-leak in it to avoid having to go back into it, Antifreeze out the exhaust and none in the crankcase is a sure sign of a blown head gasket right at a cooling passage.

[overloaded]

That sucks! Its tempting to write it off as a one time thing and ignore the problem, but would be nice to know what's causing it.

Here's something that just came to mind - a machinist I know recently built a healthy street 427 for his chevelle. It would randomly run funny, smoke a little, then return to normal. Long story short, he traced it back to a rocker arm stud that had been poorly repaired - it had pulled out and was replaced, but the repair had either been drilled too deep, or it cracked the head when reinstalled...Either way it was just enough to allow coolant to seep into the cylinder at random.

(have you had any port work done on your heads? hogging out ports close to the water jackets can do the same thing)

[overloaded]

OP, any progress?

[SSC's76]

well with just 3 miles on it id suspect the overheating to be just an air pocket it happens. as far as the smoke that's a hard call what would cause it then go away like mentioned above with the rocker are that was repaired those are little things that can pop up every once in a while then cause failure. I suggest take the truck out for a nice long drive follow their break in guidelines and if it it doesent happen again it could have been a fluke. if it happens again take it back or take it to someone else. I always suggest going back to the shop you went to 1st but sometimes things happen and they will try to patch it up without fixing the issue.,

[J/D/S]

So the shop said that the exhaust guides go right threw the water jacket and thats why it smoked when it got hot. He said that the needed to go threw acouple oh heat cycles but since the temp jumped up fast like it did that it smoked alittle and that its nothing to worry about.