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Buick Straight 8 Camshaft Removal


Carsnz123

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I'm rebuilding a Buick 233 straight 8 and have hit a problem. the valve lifters are seized and I need to remove the camshaft to get at them. the problem is that it doesn't want to come out. no amount of hammering and twisting makes it move more than 5 or 10mm. is there some trick to getting it out? or do I have to hit it harder and hope I don't damage it. The block is bare except for the camshaft and the lifters which are up and out of the way of the lobes on the camshaft. I'm pretty sure the drive gear for the distributer is not hitting them either.

Has anyone had this trouble before and if so how did you fix it?

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Guest Straight eight

I'D soak the valve train in Marvel Mystery Oil for a week, each day a gentle tap, DON'T USE FORCE, OLD METAL BREAKS!!

Even if the lifters are out of the way.

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I don't understand how the valve lifters can be seized, and also up out of the way of the cam lobes at the same time. The way I figure it, they probably seized right where they were when the engine last turned over. And right where they were was riding on the cam. Those lifters need to come out to remove the camshaft. Keep soaking them with whatever penetrant you have. I've seen documentation that a 50/50 mix of automatic transmission fluid and acetone it the most effective penetrant. Apply, let soak, give the lifters a light tap from the top, then the bottom, then repeat. Don't rush it. After a few days, you should be able to get those lifters out. If the cam has 10mm of movement, it is probably not rusted in place. But I'd soak the cam bearings while I'm working on those lifters.

Edited by Pete O (see edit history)
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Machinist's Workshop Magazine (March/April or May/June, 2007) actually tested penetrants for break out torque on rusted nuts. They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a "scientifically rusted" environment.

*Penetrating oil ..... Average load*

None ..................... 516 pounds

WD-40 .................. 238 pounds

PB Blaster ............. 214 pounds

Liquid Wrench ..... 127 pounds

Kano Kroil ............ 106 pounds

ATF-Acetone mix....53 pounds

The ATF-Acetone mix was a "home brew" mix of 50 - 50 automatic transmission fluid and acetone. Note the "home brew" was better than any commercial product in this one particular test. Our local machinist group mixed up a batch, and we all now use it with equally good results. Note also that "Liquid Wrench" is about as good as "Kroil" for about 20% of the price.

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I don't understand how the valve lifters can be seized, and also up out of the way of the cam lobes at the same time. The way I figure it, they probably seized right where they were when the engine last turned over. And right where they were was riding on the cam. Those lifters need to come out to remove the camshaft. Keep soaking them with whatever penetrant you have. I've seen documentation that a 50/50 mix of automatic transmission fluid and acetone it the most effective penetrant. Apply, let soak, give the lifters a light tap from the top, then the bottom, then repeat. Don't rush it. After a few days, you should be able to get those lifters out. If the cam has 10mm of movement, it is probably not rusted in place. But I'd soak the cam bearings while I'm working on those lifters.

i turned the camshaft to push them up out of the way then tapped them with a wooden rod to get the lifters a little further up. Seized was probably the wrong word to use the lifters were able to move but it took a lot of force. I didn't realise the valve lifters could come out the top once you remove the plate on top I thought they had to be removed through the bottom.

The camshaft is out now, it took a lot of crc 556 and a big wooden mallet but it came out with no damage. Now the next task is finding one of the high performance camshafts.

I never heard of ATF and acetone as a penetration oil mix but ill try that in the future.

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Where does a person get off the shelf Acetone? Ace Hardware? I thought it was pretty volatile and most places stopped carrying it. Geez just threw out a bunch of 8 year old ATF. might have turned to Acetone by the smell of it.

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