Here's another problem. My aluminum slant 6 blocked cracked around the left front corner about 1 to 2 inches below the bottom of the head bolt thread boss.

The crack goes around the corner of the block for about an inch to an inch and a half each way, along the front and along the side. The crack is parallel to the deck and looks like a hairline but goes all the way through and coolant seeps out.

Keith Black's weldor says he can fix the block, no problem, but I don't want to spend the time and money if there is some insurmountable phenomenology which will cause this to happen again.

Anyone ever encountered this particular problem before? Correct factory heads bolts were used and torqued meticulously per the procedures for an aluminum slant 6 in a 1962 service manual.

Bob Troy

rftroy@aol.com

I have never seen one cracked in that spot (just above the water pump mounting if I read your discription right) Weld it up, the welder is going to complain about how "dirty" the die cast alloy is, lots of silicon will "boil-out". (the Alm. alloy is hypereutectic so there is unbound silicon which floats to the top of the weld)

It is a good idea to grind clean the backside of the weld and apply some good quality epoxy to be sure coolent does not seep through the weld. (the weld can have pores, small stress cracks or pin holes)

Is this a performance Alm. Block application?
DD



Link to Alm. Block Head Gasket info:

DD,

Depends on how you define performance. I had this engine in a 68 fastback Barracuda with an Al OD4 and a late model (large bolt pattern) 7-1/4 2.76 sure-grip rear. Late model brakes and large bolt pattern up front too.

Car got 30 mpg on the highway (29.9 from S.F. to L.A.) and averaged about 25-26 around town. Also had an Al one barrel intake and a no longer made Holley Economaster carburetor.

Light weight and low gears do the trick.

Had to replace the block with cast iron when it cracked. Still ran beautifully, just leaking coolant. Setup is now in my 69 Barracuda convertible and I'd like return the aluminum block to service. Only worry is that I could have another failure of the aluminum block.

The cast iron, of course, will run forever. Other than the problem I have had are there any other common reliability problems with the Al blocks?

Bob Troy

rftroy@aol.com

Pre-heat the area to be welded with oxy-acetylene torch, this will help bring the contaminates up to the surface, repeat as needed until contaminates are gone.


budbandy@swbell.net

The head gasket seal has always been an issue with these engines. These days just finding an OEM Alm. Block head gasket is a challenge but I have to say that I can still pick-up the phone and fine them, trouble is they keep going up in price.

I have an aluminum block SL6 in my 65 Dart Convert, it was rebuilt in 1985 and run like a top, do it right and it will last a long time.
The ARP studs we just design will also help so now is the time to get some if you have any interest.
DD


Alm SL6 ARP Stud info.

Doug,

Thanks for the great info. I'll head up to ARP sometime this week. I've found they give you a big discount if you walk in the front door.

Another question: There are signs of leakage at the top of my cylinders. I would have to look up how any miles the engine had on it before it cracked, maybe 30,000. I remember once an old hand suggested milling the outer walls of the deck a few thousanths more than the cylinders themselves to enhance sealing. I didn't have Keith Black do it but it seems a good idea.

What do you think and how much height difference, if any.

Bob


rftroy@aol.com

These studs are so new that my bet is that none of the sales people know about them!
Call Al Nickels @ ARP first, these will not be sitting "on the shelf".
:
: Another question: There are signs of leakage at
: the top of my cylinders. I would have to
: look up how any miles the engine had on it
: before it cracked, maybe 30,000. I remember
: once an old hand suggested milling the outer
: walls of the deck a few thousanths more than
: the cylinders themselves to enhance sealing.

Key to a good head gasket seal is freashly machined surfaces, head and block deck, dead flat & a smooth finish. The gasket already has a double thickness "fire-ring" around each bore so all you need to do is sand a little around each bolt hole. You can see where to sand by taking a "finger print" off the block, sandwitch a clean piece of white butcher paper in between the mached & lightly oiled block & head, then torque. You will see / find the high spots and can work them down with a sanding block. (around each bolt hole seems to always need some sanding)
DD