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Bad Hone or out of round?
Topic Started: Dec 4 2011, 12:43 PM (1,324 Views)
clarkdw


Old Man
Dec 4 2011, 10:13 PM
before I would take it into a shop and say "overbore it" I would ask them to hone it till it clears up and THEN take measurements to determine if it actually NEEDS to be over bored...........
+1
A lot of the reason that more cylinders don't look like this when they are honed is that ball hones are used. If this engine was honed with a ball hone you would not even see the appearance of an unhoned part. Bar hones show even very slight differences in the size of the bore or ridges at the top of the cylinder.

IMHO this is not a serious situation unless the cylinder is too large or out of round after the marks are honed out. While I don't particularly like the appearance of the cylinders I don't think that it is bad enough to require a rebore. Finish honing out the bore if you feel like it is needed, measure it for size and roundness and then decide. Don't ball hone it and when the marks disappear think that it is straight and round. Ball hones conform to whatever shape the cylinder starts out as and just hide the evidence.

Remember, engines for years and years were built with up to .005" clearance on the pistons and they worked fine for 100k miles. These engines are built with less than .001 clearance so there is a fair bit of "wiggle" room in fitting the pistons to the bores without fear of instant failure.
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Memphis metro


No way around it, his pictures do indicate a ridge, but thats nothing unusual. I would have to agree though, if he used a ball hone it would clean up nicely.
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clarkdw


enginedoctorgeo
Dec 5 2011, 11:17 AM
No way around it, his pictures do indicate a ridge, but thats nothing unusual. I would have to agree though, if he used a ball hone it would clean up nicely.
Part of my point was that ball hones mask a lot of problems. It may give the appearance of cleaning up nicely while being hugely out of round or having a fairly large top ridge which promptly becomes invisible. I used ball hones extensively when freshening up race engines that were known straight and round and the hone was only to assist in ring break-in. In older bores with more extensive wear I much prefer the bar hone that shows the imperfections and aids in reducing the top ridge and keeping the cylinder straight much better than the ball hone. Often the bore ends up looking like these pics but is quite usable after checking size and roundness.
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Tofuball
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Strange Mechanic

bogs
Dec 5 2011, 12:29 AM
Being a small one man shop is no reason to see a job like that, I've been a small one man shop, and have done business with many small one man shops myself.

Plenty of small one man shops are run by thorough going professionals and / or people who will go out of their way to make something right if they can.

I don't know the guy you originally took this to, but I would give him the benefit of the doubt and ask him to correct it first, it is obviously botched, and it is just as obvious he is the one that botched it.

However, if he looks at that job, and asks you with a straight face "whats wrong with that?" that will tell you everything you need to know about his level of workmanship and expertise and you can proceed to take your business elsewhere since you could have done a better job than that with a hone and a drill.
I second this post.
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musquoni
New Member
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I own a one man shop and I give my customers something i would expect to get. Mistakes can happen and i make them right before projects leave my shop and I also inform them that a mistake was made and I'm going to fix it. Also if a project didn't come out the way i expect it to then i re-do the project.

The block was at this shop for over a month. I told him there was no rush and to look it over very well. I would at the very least expect them to tell me there was something wrong instead of giving me something that is probably usable but won't last very long. I would like to give them the benefit of the doubt and take it back, but with the level of honesty that he has shown me I'm afraid he will do something to damage the block even more and I don't want to get another block.

So I asked a few mechanic shops and they guided me to another machinist. I feel more comfortable with this shop. This guy pointed out what was wrong with the block and informed me that he gets a lot of dead engines that had been rebuilt (some as soon as 500 miles) by other machine shops. He also gave me a tour of what was behind his office door and what he was working on. The other shop just took the block and told me they would call me when its done.

I know what its like to own a one man shop and how hard it is to see companies go to the bigger shops when I can do exactly of not even better work than they can. But it is because of the bad quality of some of the other guys that make it hard for some companies to consider the good ones. Instead they go with the biggest shop with the bigger portfolio and happy customers and they never look for anything else, so the small shops stay small and the big shops keep getting bigger.
Edited by musquoni, Dec 6 2011, 09:57 AM.
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