Splitting Windsor blocks
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From: Boise, Idaho
Splitting Windsor blocks
About two years ago, someone on the corral web site posted pictures of his split 302 block. The block had been converted from hydraulic flat tappet lifters to roller lifters and the lifter valley featured a serious gypsy-job welded-in boss for the lifter spider.
The block split right through the holes that were drilled for the roller-lifter conversion. The owner of the block is convinced that the reason the block split is because his engine made so much power. I'm convinced it split for a combination of four reasons; the welding stressed the cast iron of the lifter valley, the drilled-in holes further weakened the lifter valley, they uses those jam-nut things to jam the bolts into the holes, and the way the intake bolts onto the engine further stresses the block. The intake has four bolt holes that pull the intake straight down, applying pressure that pushes the heads apart and applies strain on the lifter valley.
I'd been musing about the split block ever since I first heard about it, but today it hit me that the bolts that hold the intake was the missing clue about why the block split.
I've been planning to do a roller lifter conversion on both a 351C and a 351W that I have in my garage. I won't be using the jam-nut method of attaching the spider, and I will be very careful about how I tighten the bolts of the intake.
The block split right through the holes that were drilled for the roller-lifter conversion. The owner of the block is convinced that the reason the block split is because his engine made so much power. I'm convinced it split for a combination of four reasons; the welding stressed the cast iron of the lifter valley, the drilled-in holes further weakened the lifter valley, they uses those jam-nut things to jam the bolts into the holes, and the way the intake bolts onto the engine further stresses the block. The intake has four bolt holes that pull the intake straight down, applying pressure that pushes the heads apart and applies strain on the lifter valley.
I'd been musing about the split block ever since I first heard about it, but today it hit me that the bolts that hold the intake was the missing clue about why the block split.
I've been planning to do a roller lifter conversion on both a 351C and a 351W that I have in my garage. I won't be using the jam-nut method of attaching the spider, and I will be very careful about how I tighten the bolts of the intake.
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From: East Flat Rock NC
Ive heard that the 302s will split if they are stroked past the 347 (limit) .I have read about 302s that were stroked further (bigger) .
P.S I think that it has something to do with the forces that are aplied by the
pistons and the extra stroke .
P.S I think that it has something to do with the forces that are aplied by the
pistons and the extra stroke .
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I'm willing to consider the idea that something about a stroked engine is causing a force that wants to separate the two cylinder banks, but I can't figure what that would be. And nobody has explained the cause-and-effect relationship between stroked motors, and case splitting.
302's have been tuned for power for a long time. Back in the 60's Ford was using the 302 Windsor (not Boss/Cleveland 302's) for Formula 1 racing. If there was a problem with cylinder case separation, you think they would have fixed it back then. There wasn't a problem, so there was nothing to fix.
302's have been tuned for power for a long time. Back in the 60's Ford was using the 302 Windsor (not Boss/Cleveland 302's) for Formula 1 racing. If there was a problem with cylinder case separation, you think they would have fixed it back then. There wasn't a problem, so there was nothing to fix.
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From: Still under the hood in O
The Formula 1 blocks were NOT production blocks. They were special race prepped blocks.
As you have mentioned, I agree that welding on the block in the valley is what weakened it even more. The other stuff about the intake??? Dart blocks do not have the same problems as the production blocks do, so I don't think that's valid at all.
Whether it's stroked or not, if it is making alot of power (500HP or more) or constantly revving it to the moon (over 7K RPM) it WILL crack. It's not a matter of if, it's WHEN. I have cracked more than a few blocks in the past and have learned to get a Dart block for the power motors. But you have to admit, that split block was a riot!
As you have mentioned, I agree that welding on the block in the valley is what weakened it even more. The other stuff about the intake??? Dart blocks do not have the same problems as the production blocks do, so I don't think that's valid at all.
Whether it's stroked or not, if it is making alot of power (500HP or more) or constantly revving it to the moon (over 7K RPM) it WILL crack. It's not a matter of if, it's WHEN. I have cracked more than a few blocks in the past and have learned to get a Dart block for the power motors. But you have to admit, that split block was a riot!
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Yeah, I think it's the intake that's putting the most pressure on the block. As I recall there are four bolts, one on each corner of the intake, that pull the intake straight down. The sides of the intake would then press against the intake port sides of the heads, pushing them apart and, in turn, straining the block straight across the lifter valley.
The obvious solution is to make sure that it all fits properly. If the heads get milled on the combustion chamber surface, the intake port side of the heads needs to be milled, too. Otherwise, the head's intake port surfaces will be closer together and the intake won't fit down between them properly.
With aftermarket heads, you don't know what you're starting with anyway. You have to trial fit it and then have the surfaces milled until it all fits together. If it fits together right, the intake will strengthen the assembly, if it doesn't fit, it will put strain on the block. And don't overtorque the intake bolts.
The obvious solution is to make sure that it all fits properly. If the heads get milled on the combustion chamber surface, the intake port side of the heads needs to be milled, too. Otherwise, the head's intake port surfaces will be closer together and the intake won't fit down between them properly.
With aftermarket heads, you don't know what you're starting with anyway. You have to trial fit it and then have the surfaces milled until it all fits together. If it fits together right, the intake will strengthen the assembly, if it doesn't fit, it will put strain on the block. And don't overtorque the intake bolts.
