I pretty much determined that my aluminum SL6 block is trash.
I'm just curious if anyone has seen this type of cracking before
These pictures show the front driver side corner of the block. There's a horizontal crack that goes around the front and side of the block roughly 4 inches on each side, and appears to go all the way through the block wall. I can't remember how many months I had driving in the car before coolant started spraying out of this crack.
I pulled the block out of storage, after several years now, to figure out if it could be repaired.
For the first time I noticed the vertical crack on the front of the block that goes from the deck of the block down to the raised water pump mounting surface. That front driver's corner at the bolt hole is raised up. If you put a straight edge across the block, it's all fine till you get to that hole, then you see a gap of at least 5 thousandths at the number one cylinder.

I don't see this as being reliably repairable. I'm just curious if anyone knows how this crack might've happened.

Robert

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Robert Troy
69 slant 6 OD4 Barracuda conv
68 383-S 4 speed convertible

My guess is over-torquing the head bolts? It seems to be right at the bottom of the head stud pocket area from what I can see. I could be waaay off but that is my guess.

Greg

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http://www.youtube.com/hyperpack

Might be I could help you out. Where you located?

Roger

It wouldn't be head bolt torque directly. If the block deck and heads are both flat, tightening the bolt would would only put a load onto the block from about the top three threads, and squeeze the block on the head together. There wouldn't be any stress applied to the wall of the block itself.
If the head was badly distorted so that that corner was high, had a gap, when put on the block, torquing the bolt would pull the pieces together, and then put a load into the wall of the block.
Head and block deck were both flat. No clue what other history it might have had since 1962.

For Roger: I'm in Los Angeles

Robert

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Robert Troy
69 slant 6 OD4 Barracuda conv
68 383-S 4 speed convertible

Ouch! I have a completely empty block in fair condition, but the shipping would hurt pretty bad, coming from Iowa.

Roger

Don't be so sure. I've shipped aluminum Slant-6 blocks across the US by bringing them into a FedEx Office location and having them box it up and send it out. Price was entirely reasonable; it's 76 pounds and certainly not the biggest item they've ever had to ship.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Roger,

Go ahead and send me a few pictures of the block, and how much you want for it. I will look into the shipping. What is the current bore?

I'll consider it, but I've already taken the internals and put them into an iron block and it's running beautifully.

This is my 69 barracuda convertible built for mileage; thus the aluminum six.
I did a lot of light weighting and modifications for mileage. Fiberglass front clip; Al intake and oil pump, etc.; Al OD 4 speed; 2.94; Holley Economaster.
The cool things part of my brain would like to put an aluminum block back in.
The logical technical part of my Engineering trained brain tells me it's a waste of time and money to pull a perfectly running engine, rebuild it in aluminum form and put it back in since any increase in mileage would be negligible.

I'll make a decision when I get your information. Fortunately, I have a head gasket. Otherwise, I wouldn't waste my time.

Robert

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Robert Troy
69 slant 6 OD4 Barracuda conv
68 383-S 4 speed convertible

Looked through my posts, and it doesn't appear that I have ever put up a picture of my Barracuda.
This is what it looked like just after it was finished being refurbished in 2010. The first time I restored/refurbished it was in about 1989 or 90. It was my daily driver for about 27 years.
The car looks just like this now......from about 50 feet.

Rethinking today - If I end up getting an Al block, I expect that I can get a SL 6 core pretty cheaply and rebuild it into the Al block. That way, I can just swap engines, which is a one or two day job.

My original questions remains: Has anyone seen this particular failure in an Al SL block.?

Robert

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Robert Troy
69 slant 6 OD4 Barracuda conv
68 383-S 4 speed convertible

I have not seen that particular failure. Could be frozen with no antifreeze, on some wildly cold day in/around LA, or up in the mountains? I also have a couple of spare alum blocks, and I might consider parting with one.

I have my first car (68 Dart) still - since 1988. It's under the bodyshop knife for the 3rd time since I got it almost 40 yrs ago. Should be better than ever. We lived in LA from 1995-2002 and had a ball. Just bought a 68 Barracuda and enjoying modifying and driving that too...

Lou

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Home of Slant6-powered fun machines since 1988

I hadn't considered stresses due to water freezing. Of course, I live in LA.
I don't remember where I got the block, but it could've come from anywhere in the country, so freezing is definitely something to consider.

I'll think about the load paths some more, but freezing seems like a good candidate.
The block has no freeze plugs. It also has an open deck, which means as the water freezes there will be a tremendous amount of force, pushing the head and the block apart. Those head bolts are now putting a large load into the walls of the block; loads it was never designed to take.
if I can squeeze the time at some point, I'll make a simple 3-D model and put the loads on it and see what happens.
In the meantime, I think I'm gonna closely inspect the other four corners of the block.

Robert

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Robert Troy
69 slant 6 OD4 Barracuda conv
68 383-S 4 speed convertible

You may be able to find a skilled welder to fix it. I have seen welded Al blocks in smaller areas that seemed sound.

Lou

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Home of Slant6-powered fun machines since 1988

Gill Welding, Heiskell,TN.

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http://www.youtube.com/hyperpack