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  #46 (permalink)  
Old 07-10-2012, 10:57 PM
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I'm not sure I'm reading the shape of the cylinders correctly by the description, but if I am, the taper in the hole having the most wear is going to cause the rings to work a lot in their grooves, from the tightest to the loosest parts of the cylinder. I don't see the rings sealing well at all in that condition, and would have to recommend going to the next oversize (if there's enough bore, that is).

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  #47 (permalink)  
Old 07-11-2012, 06:19 AM
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Eeeeeww

That's not what I was hoping to hear, I was hoping for a ' you should be okay to put it back together'. I am probably not going to be able to get it out and back in this year so I think I'm going to take a chance and put it back together and try it . If it does the same thing, then I'll pull it out and strip it down over the winter send the block out and order new pistons and put it back in the car next spring. Thanks for all your help.
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Old 07-11-2012, 12:17 PM
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Aftermarket PCV valves are a crap-shoot. They may or may not open. If they don't open, then the vapor will go out thru the breather and you'll have oil in the breather and oil over the motor. I replaced the PCV valve with a disc with a 1/16" hole, so the motor is always sucking the vapor. Some cars use this and they call it "calibrated orifice", fancy name for a hole.
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Old 07-11-2012, 08:20 PM
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firing order???

if i recall, wasn't the 351 windsor one which if you use an aftermarket cam, changing the firing order was needed? somehow i remember something about that, and it could be another motor altogether. it might be worth taking a look at. i could easily, however, be wrong with this part of memory.
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Old 07-11-2012, 08:32 PM
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No

The firing order is the same. I took my specs down to the machinist today and he said that they were a little bit high on the end gaps but nothing to cause that much blowby. We looked at the rings I pulled out and they showed even wear all around so he really didn't offer much help other than to suggest that maybe the hatch I put in when I honed those 2 cylinders wasn't deep enough. I have rehoned the cylinders and put the new rings on and put the pistons back in the motor. The head is back on and I'll hopefully get finished tomorrow. If it is still the same I'll pull the motor and send the block away to get bored out.
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  #51 (permalink)  
Old 07-12-2012, 01:18 AM
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From your measurements of 3.999 to 4.008 you have .009 clearance and .006 there. That would indicate the piston has been rocking in the bore. A piston to cylinder clearance should be about .0025 new so you have a clue there as to why you have blow by as the rings would expand half way down the bore and then contract at the bottom. If it were mine i would go to the next oversize piston and look for some decent clearances. If you hone again and take out another .001 you will increase that clearance.
Hope it works for you , good luck.
Al.
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  #52 (permalink)  
Old 07-12-2012, 04:01 AM
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Cobalt 327

I agree totally with Cobalt 327 . His comments are the same as you would find from the engine builders here as well. The piston going up and down in a tapered bore rocks from side to side which prevents the edge of the rings sealing against the cylinder wall. That is likely the cause of your low compression. What did your engine builder say about the .009 and .006 clearance you have there. "Tapered bore." The rings will show edge contact for sure just looking at them but imo the edges of the rings running out of parallel with the cylinder walls is something you should talk to the tech dept from the supplier of your rings.
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  #53 (permalink)  
Old 07-12-2012, 07:53 AM
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Al and Cobalt

You have both been extremely helpful helping me diagnose this problem. I realize that what I'm doing may not be the correct way to deal with it but I am really wanting to try it and see if it is any better just so I can drive it this summer. I know if I have to pull the motor I won't be driving it again until next year. As I said earlier, if it does run without the blowby this time, lucky for me but if it doesn't, it'll come out and I'll pull it apart. Either way I'll start saving for a bore and new pistons and rings in the near future. I'm away on vacation for a week or so but I'll keep you posted on how thing s go ..Thanks again and don't think I'm not hearing what you're saying, I do , but I just gotta try it one more time ....Thanks again
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  #54 (permalink)  
Old 07-12-2012, 06:11 PM
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My Worst Day

Okay, I worked like a dog in the heat to get the engine back together so I could try it before I leave on vacation. I got it together and filled it with fresh oil and antifreeze and turned the key and it's not moving. I can see the fan move about an inch whenever I engage the starter. I even tried putting a bar on the nut on the front of the pulley and I can't turn it. So it looks like I have to pull it apart again and see if I can find out WTF is wrong now. I am about ready to drag it behind a barn and leave it there. I have no idea what the hell I did wrong but I can't see it being anything easy ....Any thoughts?
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  #55 (permalink)  
Old 07-12-2012, 07:57 PM
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Which way did you bolt the rod caps up, bearing notches on the same side or opposite. Rods and caps are made as a matched pair and the caps are only fitted one way. V8 rods that run side by side have chamfers to clear the radius ground into each side of the journal. If you reverse the caps then they will not clear the side of the crank, locking up.
Did you turn it over by hand before you fitted the sump.
Most important thing is to double -check as you go, and when pulling rod caps off, mark them so reassembly is easy.
This thing has nearly beaten you so maybe you should walk away for a while, write down what you need to do to make a good engine and go from there.
Experience is going to be your teacher here.
Keep on.........
Al.
You may be able to reuse your head gaskets if you have not started it this time.
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  #56 (permalink)  
Old 07-12-2012, 09:55 PM
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I Believe

that I put the caps on correctly as the cylinder # was stamped on the outside of the connecting rods. I did turn it over by hand when I was moving the crank to so I could get the rods in properly. You said the same thing my neighbor told me .....walk away from it for a while so I'm off to the lake for a couple of weeks and hopefully when I come back, I will have a new enthusiasm to get it right . Thanks again for all your help and advice ...
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  #57 (permalink)  
Old 07-15-2012, 07:33 AM
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Quote:
Originally Posted by ssmonty View Post
Is this a new build? If so, the rings need to get so time on them to seal/break-in and the blow-by will decrease unless one or more are broken(hope thats not the case).
If its an older engine you may need to perform a leak-down test to see if the rings are wore out.
If its new keep an eye on the oil level.
FWIW
ssmonty
This is just what I was going to say..and was always the problem for me ...the compression from the cylinders is get into the crankcase ,it has to go somewhere so it goes out the PCV but when it comes out the dip stick also it sounds like a broken ring. Do a compression check. This is how I learnd about using a ridge reemer when I built my first engine just about the same problem ,when the ring hit that ridge it snapped and I got blow by the same thing can happen with an older engine if it gets reved to high the rod streches and the top ring hits the ridge ...
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  #58 (permalink)  
Old 07-24-2012, 03:55 PM
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Okay

I'm back from vacation for a couple of days so I was able to pull the pan off enough to se that when I put the 2 pistons back in, I put the wrong caps on them. I know , they're marked and I would still swear that I looked at them and had them right but apparently not. I'm hoping I will have enough time tomorrow to switch them back to where they belong. That being said, I hope I didn't do any damage to the journals . Hopefully this will be the end to my summer of frustration and I'll start it up and have none of the previous crankcase problems .....
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  #59 (permalink)  
Old 07-24-2012, 04:03 PM
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Quote:
Originally Posted by LBL View Post
I'm back from vacation for a couple of days so I was able to pull the pan off enough to se that when I put the 2 pistons back in, I put the wrong caps on them. I know , they're marked and I would still swear that I looked at them and had them right but apparently not. I'm hoping I will have enough time tomorrow to switch them back to where they belong. That being said, I hope I didn't do any damage to the journals . Hopefully this will be the end to my summer of frustration and I'll start it up and have none of the previous crankcase problems .....
Be glad it was too tight to crank up, else the entire bottom end could have been trashed! Hopefully this'll end your trial by fire.
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  #60 (permalink)  
Old 07-24-2012, 06:48 PM
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x2............... What co says. Carpenters will tell you measure twice ,cut once. If it saves you its a good thing.
Goodluck.
Al.
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