Reringing a 400
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Senior User
Joined: Jan 2004
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From: Masontown, WV
Reringing a 400
My 400 is burning about a quart of oil every 300 miles. It runs good oil pressure, about 55 psi running 20 psi idle with 10w30 oil and 70/ 35 with 20w50. It runs quiet and is very strong.
I was going to tear it down and do a complete rebuild but I am short on cash right now so I may try to just rering it if I can. This is something I have never done. I always have had my engines machined.
What do I look for to do just a rering? How is it done?
Thanks,
Gregg
I was going to tear it down and do a complete rebuild but I am short on cash right now so I may try to just rering it if I can. This is something I have never done. I always have had my engines machined.
What do I look for to do just a rering? How is it done?
Thanks,
Gregg
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Joined: Sep 2003
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Pull the pistons out. Hone the cylinders. Install the new rings, and reinstall the pistons. This can even be done with the motor still in the vehicle.
All you are doing is buying some time. Cylinder taper always gets worse, not better. Now that you are putting new rings in worn cylinders, you are accelerating the wear process.
All you are doing is buying some time. Cylinder taper always gets worse, not better. Now that you are putting new rings in worn cylinders, you are accelerating the wear process.
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Joined: Dec 2003
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What scroob says, except, is all the oil really going through the rings? How much is going through valve guides and leaking seals? Valve seals can be replaced without pulling the heads and many leaks can be fixed without pulling the engine completely apart.
It is possible reringing it would help but you can only find out by tearing it down. Another problem with reringing is that the ring grooves in the pistons are worn too. The engines I have reringed still used oil. Maybe a qt. every 500 miles. Oil is cheap! Run it!
It is possible reringing it would help but you can only find out by tearing it down. Another problem with reringing is that the ring grooves in the pistons are worn too. The engines I have reringed still used oil. Maybe a qt. every 500 miles. Oil is cheap! Run it!
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Senior User
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From: Masontown, WV
Thanks for the info. I think I'll just wait and do a complete rebuild. Sounds like I would be wasting time reringing. I already replaced the valve seals and that helped a lot. I'll just keep pouring the oil to it till then.
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Joined: Oct 2002
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If it's standard bore and you didn't find a lot of ridge, you can find replacement stock pistons and put rings and rods on them fairly cheap. Then pull her down and change them out in about a day if you've got all the parts ready. I've done it before and spanked another 100K miles out of a worn bore.
My dads 350 Chev has 600K on the original bores. It's on the third set of standard pistons. Last time we miked the bores there was .005 taper on the worst one and .003 on the best. Since the rebuild he has put another 110K on it and it runs like a top and doesn't use any oil. It leaks like a typical old style 350, but it doesn't burn it.
Just 2 cents from somebody who's got better things to do with his money than waste it on unnecessary things.
My dads 350 Chev has 600K on the original bores. It's on the third set of standard pistons. Last time we miked the bores there was .005 taper on the worst one and .003 on the best. Since the rebuild he has put another 110K on it and it runs like a top and doesn't use any oil. It leaks like a typical old style 350, but it doesn't burn it.
Just 2 cents from somebody who's got better things to do with his money than waste it on unnecessary things.
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Anything that will catch a fingernail after you scrape off the carbon. Best way is to measure it with a micrometer. I took my block to a machine shop and they did it for me on the cheap. But I had to replace my clutch and rear main seal, so I had to take the whole motor out.
As long as you don't have more than .007 wear at the very top of the ring travel, you should be o.k. And even if you do have more, the oil rings and second ring is what keeps the oil where it belongs. Just replacing the rings will usually solve most of the problems till you can afford to fix it right. A lot of times when you buy engines from reman places, they hone the bore out straight from top to bottom and either put back the stock pistons or get stock replacements and put back in.
For a stock, or mostly stock engine, they will tolerate a lot of things that a HP engine will not. It may be something as simple as that somebody may have overheated the engine bad enough at one time to burn out the rings. They may not be worn out, just lost tension from being too hot.
Post back if you need anything else.
As long as you don't have more than .007 wear at the very top of the ring travel, you should be o.k. And even if you do have more, the oil rings and second ring is what keeps the oil where it belongs. Just replacing the rings will usually solve most of the problems till you can afford to fix it right. A lot of times when you buy engines from reman places, they hone the bore out straight from top to bottom and either put back the stock pistons or get stock replacements and put back in.
For a stock, or mostly stock engine, they will tolerate a lot of things that a HP engine will not. It may be something as simple as that somebody may have overheated the engine bad enough at one time to burn out the rings. They may not be worn out, just lost tension from being too hot.
Post back if you need anything else.
