I need 401 opinions

[Guest rsteere]

I am looking at buying a '65 Wildcat to add to the mix. The question I have is the 401 engine in it has a crack all the way down the length of the block on the left side below the frost plugs (front to back). It is about where the block comes straight up and then turns out. The crack is into the water jacket and is opened about as wide as the depth of a penny. My bet is the block has a bad casting and should be tossed. I can't see where that block can open up that far and not start to effect the rest of the integrity of the whole left bank. The present owner thinks it can be welded. Has anybody tried something like this with good results?

Randy

[Guest REX STALLION]

Boat anchor methinks

[60FlatTop]

When in doubt, throw it out. Always works for me.

Bernie

[Guest Rob J]

Not worth the $$$ to fix it. 401's are plentiful. I wouldn't bother trying to fix that block. It's toast.

[JZRIV]

You mentioned your block being a bad casting. What you are seeing is the result of water freezing inside the block, expanding and cracking the casting and not a defective casting.

The left side seems to be the weakest side on these engines. It can be welded. People who specialize in this type of repair are not that common but cylinder block and head welding is done everyday. They can fix holes in the side of a block the size of a baseball. Having said that, not all blocks can justify this approach. The welding process requires heating the whole block in an oven and welding while its really hot. This process in turn requires boring the cylinders, possibly align honing the crank mains and cam bearing journals. Worst case the lifter bores may need sleeved. If the cracks radiate up to the edge of a freeze plug, the size of the plug may need machined to the next larger size.

So you see costs can and will mount after the welding process. You could pay $800-$1000 to have it welded then another $1000-$2000 in machine work and thats just for collateral damage created by welding. You still have all the normal costs of a rebuild to tack on. If your block is cracked that bad on the left side, most likely its cracked on the other side as well and just isn't as noticeable and would require magnafluxing to show up.

Replacement 401 blocks/engines aren't too hard to find in good rebuildable condition in the $300 - $500 range making the welding option look very unattractive. Locally there is a complete 64 425 for $400 obo on craigslist.

Edited December 26, 2011 by JZRIV (see edit history)

[Guest rsteere]

The current owner thinks the block has been built/rebuilt. I am not sure. The front cover is off and there is a new chain etc. The valve springs looked new and rocker arms looked old. There was one old exhaust valve in the trunk. My guess that the build/rebuild was a patch/repair. I have a couple of extra 401 engines so I could swap blocks. I just have never seen a block split open like that. I have a brother in law that owns a welding shop and has done block welding work for me. My thinking was like Jason. All the machine work and etc. to make sure he rest of the engine is ok.

Randy

[RivNut]

The only reason to even consider welding or stitching the block back together is if you're stuck on having a numbers matching car.

Uses for the old block? I saw a block one time that made a good planter. It was pulled from a car that was in our flood here in '93; there was enough dirt in the cylinders to grow a good crop of milo in them. (Heads were off the car as it sat in the field before the flood waters came.)

Ed

[1965rivgs]

This type of freeze cracking is very common on the Nailheads and is one of the issues I look for when considering buying one. I have had a crack like this repaired many years ago. There was/is ? a shop in Chicago that peens soft steel into the crack and seals it. This was done while the engine was still in the car and took 2 hours on the lift. The charge was $150 but that was probably 2 decades ago. I was very skeptical but decided to give it a try because the engine had been freshened up and was a number matching GS, ran great! The repair held up and stayed absolutely dry without any sealer as I drove the car thru summer and cool fall conditions for the next year. I was truly amazed. But if you think about it, this is not a stressed area of the block which only needs to hold 15 pounds of coolant pressure in the worst case scenario. If I had to contemplate such a repair at this point, I would do the same thing but add the block filler that the high perf guys are using so coolant would not be exposed to the inside area of the crack. Good luck!

Tom Mooney