3.4 cam bearings

Does anyone know if it is possible, or a least feasible to machine the center two cam bearing bores. My motor spun the center two bearings and snapped the camshaft in two. I am thinking that this could get more costly
than the engine is worth. By the way what is up with the hollow camshaft? I have never seen one before!
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"Doug Adams" wrote

Better to simply get another engine. The machine work can be done, but who knows what the cost will be. Availability of oversize cam bearings is another question. I've seen a few of these engines fail this way. Usually, it's just not worth fixing them. The problem stems from the coolant getting into the oil... the old intake gasket problem.
GM used the hollow camshafts on these engines. Simple to manufacture, really. It's a hollow tube, the lobes are positioned correctly on the tube, and then they force a ball thru the tube....expanding the tube and holding the lobes in place.
Here is a blurb on the camshaft:
The cam phasing creates "dual equal" valve timing adjustments. In other words, the intake valves and exhaust valves are varied at the same time and at the same rate. The cam phaser vane is attached to the camshaft on the front journal - a technique made easier by the award-winning "assembled-camshaft" design pioneered by General Motors. With this design, separate camshaft lobes are installed on a hollow camshaft tube rather than the traditional method of grinding a camshaft from a single piece of stock.
Ian
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Interesting manufacturing process, but I would suspect that it would tend to have quality issues unless extremely meticulously developed. GM does not always cross all the "t"s and dot all the "i"s when they bring a new process to market.
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I think Ford uses the same process on their 4.6
Lee Richardson Mech-Tech

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I honestly dont know about Furds. I woudnt buy one, but I feel they have not made as many faux pas as GM has done.
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Turns out I was lucky enough to find an engine on Ebay. Just hope it is as advertised, because it also sucks to pull one of these engines out of a Venture van.

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"Doug Adams" wrote

If you are planning on pulling the engine yourself....and you do not have the equipment to pull the subframe/engine and trans down.....there is another way. If you just remove the intake and cylinder heads, there is just enough room to pull the bare block out thru the top. I've done it this way a couple of times. Pulling the cylinder heads is easy.....common repair on these engines.....so I've switched from dropping the sub, to simply removing the heads and then removing the block.
Hope this helps!
Ian
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I already have the engine out by dropping it through the bottom. This can be done with two floor jacks, one on each side of the subframe, once I got it dropped down on the jacks I then raised the van off it with a chain fall. Taking the heads off in the vehicle didnt look easy either.
Do you pull the trans with the engine? It looks as though it would have been impossible to get it off the trans in the subframe.
Oh well it is out now and awaiting the delivery of the other engine.

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"Doug Adams" wrote

Good work! Hard to imagine doing it this way, I have a hoist that makes it so simple if the sub is to be dropped.

No, just pull the engine, leave the transmission on the subframe.
Ian
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