360 rebuild issues

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Lelo Dart

Lelo Dart

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Took my Magnum short block to a local machine shop, had some previous dealings with them so there were no worries. Turns out the owner turned it over to his son in law. He told me all it was going to need is a light hone and polish the crank. After dropping it off I stopped by a few times to talk with him and see how things were going. First red flag Chevy - Chevy - Chevy was all he kept referring to! But anyway had them clean up the block, hone the cylinders, and polish the crank. They also qouted me what I thought was a fair price for the bearings so got those too. Had him check my bearing clearances which he says are in spec but I'm not so sure about that. I bagged and labeled each part and then he dumped them all together to wash them! Gave me back bag o bolts.Painted over the rust on the block, painted where the oil filter plate goes. Sorry but just had to finish my little rant :-({|= First issue- small pitting / nick in one of the cylinder walls. Is this going to be OK? I can defenitly feel it with my finger. On closer inspection it looks like a series of small pits. I don't have a lot of experience but the machine shop must have thought in was OK.
 

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If you can catch it with your fingernail, I would be worried about it. It may catch on the rings also.

You may need to get it overbored to "clean it up"....
 
Lelo Dart said:
Took my Magnum short block to a local machine shop, had some previous dealings with them so there were no worries. Turns out the owner turned it over to his son in law.
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had some previous dealings with them so there were no worries.

This sounds good....



Turns out the owner turned it over to his son in law.

Now I would be worried.... :banghead:
 
"Bag of bolts?"

Does this mean he mixed up the rod caps????
 
Ditto on the fingernail test.
I don't see how they thought that was ok, and there is ZERO reason to pay for work and get that back.

(Unless you told him you didn't want to buy new pistons)
 
Man-More and More of this stuff happening here every day,What's going on in the engine building world???? This is the second post I read today about people being taken for a ride---Sorry to hear this--Steve
 
The Chevy thing wouldn't concern me as much as his overall competence. Being how that spot is lower on the cylinder wall, it may, and i say may, not be a big issue as far as ring sealing. Do all the other cylinders look fine? With that said, i personally would have brought you in to discuss it and give you the option and pricing of a overbore...
 
TrailBeast said:
Ditto on the fingernail test.
I don't see how they thought that was ok, and there is ZERO reason to pay for work and get that back.

(Unless you told him you didn't want to buy new pistons)
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I did tell him I was shooting for a re-ring because the cylinders looked so good (crosshatch). I also told him I needed everthing inspected for rebuild. I was told as long as everything checks out he would hone.
 
OldmanRick said:
Being how that spot is lower on the cylinder wall, it may, and i say may, not be a big issue as far as ring sealing..
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That "defect" is above the travel of the ring pack and may cause an issue.


If it were below where the ring pack travels like where the skirt travels, then it may be ok to use, but since the rings have to cross over it every time, I would be concerned.
 
If the pitting was at the bottom of the bore and NOT in the ring travel area, I would not lose any sleep over it. But its in the ring travel area and thats a Big problem. Look at it this way, its like a small pot hole. The more the ring hits it, the bigger its going to get, and its not good for the rings either.

The hone job looks like crap too, from what I can see. You could have done a better job yourself with a dinglberry hone and a hand drill!
 
I made the assumption that the OP was going to run it as is. I guess I was trying to be optimistic that the rings would smoothly pass the flaws and he could get some reasonable miles from it.

I understand it's not good, but his only real alternative is to start over. If he does go that way, I hope the shop will make it right for him, either mechanically, monetarily or both.
 
OK, so that is definitely a problem. What about bearing clearances? He measuresed my main bearing clearances at about .0033, which see said was good. I told him I don't know anything and for him to take care of these things for me. I am working out if a book and it says max is .0025. Is my book wrong?
 
Book is not wrong. Maybe .0033 is OK by Chevy standards, but we expect our motors to last more than a year... I've left Machine shops for less.
 
:angry4: I thought you were sopposed to trust a machine shops knowledge! Calling today! As of right now all I've got is a POS!
 
Your in race engine territory with that clearance, even on a lg. journal (big block) style engine. I'm sorry for your troubles and I take back everything I posted except for this........


OldmanRick said:
only real alternative is to start over.
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when you checked your main bearings did you check all of them because some crank grinders put .001 extra clearance on the rear main if its a stick car because when the clutch slips and people try to drive them home the heat will take out the rear bearing on the crank from it swelling up .I have seen the crank flange blue and fire from oil leaking on the flywheel .I know nobody here would do such a thing but in the real world it happens (one problem with of getting old is you just see too much)
 
He checked them all and wrote them down with permant marker on the block. Just got off the phone with him said he'll get me new +1 bearings and bore the bock if I buy the new pistons. Guess I'm out as far as the rings go but other than that I think he is going to take care it. Man, glad I double checked it, or maybe it might have been fine.:dontknow:
 
Lelo Dart said:
He checked them all and wrote them down with permant marker on the block. Just got off the phone with him said he'll get me new +1 bearings and bore the bock if I buy the new pistons. Guess I'm out as far as the rings go but other than that I think he is going to take care it. Man, glad I double checked it, or maybe it might have been fine.:dontknow:
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Maybe sell the rings to someone who can use them....



At least he's going to overbore it for you.



KB pistons have slightly higher compression than the Speed Pro, but the KB's also have a thinner skirt. I had one break on me while installing it. I didn't even bang it, it just chipped off and fell away. Speed pro has a thicker skirt, but it a little heavier. Keep that in mind while you decide on which pistons to buy.
 
You did the right thing. It wouldnt have been fine. Were talking about rebuilding a reciprocating assembly , not a birdhouse. tolerances are required for a reason, and that doesnt include "it'll be fine", regardless of what this "builder" says.
 
Abodybomber said:
X2... Had both,prefer the Speed Pro's. Just a personal preference.
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Me also.


After the KB just chipped on me for no reason, I have trouble trusting them. I like the thicker skirt on the Speed Pro's....



Just my preference.
 
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