Aluminum heads leaking coolant!

Hey guys. I was looking to change the starter on my 427 stroker ford and I noticed that coolant was dripping down the side of the engine block. I traced it to the area where the heads meet the block. It is only a small leak but it is still a leak. I just changed the headgaskets due to another leak that was internal and causing the cylinders to hydraulic. I spoke to Vic Edelbrock himself and he said that sometimes you have to cycle the engine temp a few times when using his preferred gaskets. I also spoke to Mark Brewer who used to own the "Just Falcon Around" 65 Falcon AA gasser and he said that this is not an uncommon problem with fiber gaskets. The heads are straight and flat, as is the block. The heads are new and everything has been magged and pressure tested so I doubt it is a block or head thing. I put sealant on the head stud threads and everything has been put together well. The engine only has about two hours on it combined and while I am not saying these guys are wrong but this is getting to be a pain. Have any of you ever had anything like this happen before? It's a first for me but I am have only been doing this for around forty years and I haven't seen everything yet.
Give me some opinions guys because I'm going nutz over here!!!:banghead3:
Dave

 

Did you use a recommended torque sequence and a value, then a break in re-torque? It sounds like it might just be part of it!

 

I used a single sequence torque setting. (Vic recommended it!) I thought about breaking and retorquing the whole thing but I wanted some opinions first.

 

Since cast iron and aluminum have different coefficients of expansion relative to temperature change, gradual warm-ups are recommended. I used to do that with my first aluminum-headed cars (except with the Honda Civic which used an aluminum block as well). Especially, with a Renault LeCar I had which used wet liners. I'd start it and let it idle for some 10 to 20 minutes (I never really kept track) and then shut it down for a while, before starting it up again to drive. The Renault had a loud rod bearing, when cold. After I warmed it up, the noise disappeared. I used that as a reference point for knowing the engine was warm enough to drive.
Never re-torque your engine warm. This is only done on metalurgically equal engines.
Here in Germany, they have this stupid law which requires you to drive the vehicle immediately. Otherwise, when the converter operates cold, unburnt gasses pass through to pollute the atmosphere. Despite what manufacturers say, headgasket failure is a common event on, for example, the smaller Volkswagen products. I suppose, Volkswagen has nothing against earning money from avoidable damage.
Another law prohibits one from driving with an obstructed (through fogging and icing) windshield. When you are compelled to driving a cold vehicle or else, you can still get fined because the cold engine can't heat up the windshield. Damned if you do. Damned if you don't.
Another source for temperature-related damage is the decorative and functionless engine coverings on German cars. I myself prefer to see my engine. If you ever own something like that, the first thing you should do is to tear the stupid thing off

 

aluminum heads coolant leak

A rod knock in the morning is probably a piston. Rod bearings go away and stay away in my experience. A product that works very well for coolant leaks is Iron Tite. Works best when there is just water in there so drain and save the coolant and then give it a serious flush with a garden hose and then add the IT and give it some cycles. Aluminum is famous for porosity especially American castings (the Japanese and Europeans seem to know something

 

What about torque and specified turn which is the most accurate?

 

Machined (not surfaced) head? I always go in stages.

 

I stand corrected. It was definitely wristpin clearance. Probably borderline to excessive

 

Been thinking about your problem. Because of the different coefficients of expansion, iron blocks with aluminum heads usually require "stretch to torque bolts." The seat bosses in the heads are usually thicker to provide extra strength in that area. The head bolts themselves are necked down between the head and the threads. These are usually tightened in 3 stages, commonly using a degree adapter on your torque wrench; or using 3 different torque readings....whichever the factory recommends. Head bolts are never re-used, often with new ones being packaged with the head gasket set. Your problem seems to lie somewhere in the above description. I also seem to recall that GM calls for a bottle of Bar's Leak to be added to the system on their aluminum equipped engines as insurance.

As an aside, one doesn't usually blow a head gasket as a result of overheating. Instead, the overheating causes the "stretch to torque" bolts to relax, thereby resulting in a leaking head gasket because it is no longer tight.

 

Do you mean new headbolts are packaged along with the gasket for aluminum-block engines only?
I never have once used new bolts

 

You can't reuse torque to yield head bolts.
I doubt very much that those were used in any case.
I was searching around and three things keep coming up for head gasket leaks with aluminum heads.

The heads aren't flat or the cylinder head isn't flat. Measuring under a straightedge with a feeler gauge there can't be more than .002 thousandth clearance.

The finish on the cylinder head is too rough, has to be smoother when you use aluminum heads or the gaskets will bind and loose cohesion because of the differing expansion and contraction rates.

The bolts going into the water jacket aren't sealed or not sealed well enough.

 

Reread the 2nd sentence in my post. Report back.

 

I was working for Nickey when the L-88's first came out, and remember the Tech's asking for Coppercoat [?] Spray when encountering leaks.
Might only account for a .002 - .003 difference, but cured the problem.
Don't know if it's still out there, though.

 

Still out there. I used it on my rebuild.
Some weird looking stuff.

 

Son said they use something like that in the motorcycle speed shop. "Coppercoat"