Ring Failure w/pics

[turbodave231]

If you plan on reusing your block, follow Nick's advice and have the main webs magna-fluxed. I have found blocks cracked in this area.

 

[jhanson1750]

I didn't even think about it but now I'm going to have it magged. I will bring it to work and have it magged and let y'all know the outcome.
Most of the carbon was from the pcv pumping oil into the intake. If you look at the pcv entry point into the intake it would get flowed to the rear of the intake cruding up #5 & 6. Which were the worst ones. They all had some but the rear of the motor it got worse.

It is nice working at a turbine machine shop as we have all the abilities to check out my projects without going to an "engine" shop. I have a hard time with my trust issues and built motors. Hell when I did this one years ago I had them machine it but give it back in pieces so I could verify EVERYTHING with my own mics.
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[BEATAV8]

I didn't even think about it but now I'm going to have it magged. I will bring it to work and have it magged and let y'all know the outcome.
Most of the carbon was from the pcv pumping oil into the intake. If you look at the pcv entry point into the intake it would get flowed to the rear of the intake cruding up #5 & 6. Which were the worst ones. They all had some but the rear of the motor it got worse.

Ditch the PCV system on the rebuild. Just run a couple of vertical free flowing open breathers one on each valve cover and block off the PCV.

Granted the cracked rings were increasing the blowby and causing extra oil carry over into the PCV, but still it's just an emmission control device. One less mess to worry about if it's gone.

 

[bryesh]

Well, SOB (that's an exclamation, not an adjective), you are correct. I do have it backwards. So the steel crank is over twice a stiff as the cast iron crank.

RemoveBeforeFlight

Just to clarify this issue, I believe that Buick turbo cranks are actually made from nodular iron which has a much higher modulus than gray iron.
http://www.engineersedge.com/manufacturing_spec/properties_of_metals_strength.htm.

According to this site, a forged steel crank will "only" have a 30% higher elastic modulus when compared with a nodular iron (23 compared with 30 msi) crank.

 

[TexasT]

Not to get too far off subject but I do have a question.

The extra stiffness of the forged crank reduces flex. Does this in turn reduce the need for girdle and/or caps in a lower hp situation? I'm not really planning on more than 525-575 hp. Goal is 6.99 in the eighth mile in a stock appearing car.

I have been following the 4.1 build Mr. Licht is assembling. I am going to put one together on a budget. I was thinking main caps, but if I could get away with a forged crank instead I think that would be better. I am excited that there will be forged pistons though I am planning on stock two dot rods.

Was there an answer to the chuck l question about the ring ends on the unbroken rings?

TIA

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[jhanson1750]

Well guys, I got the mains in and was checking the oil clearances..... Found the mains to not be round anymore. Pulled the bearing shells out and rechecked. Out of round by 0.0018 on 1,2,4 but 3 was out of round by 0.002 so I'm thinking about billet center mains and a line hone. Don't really want to spend the $700 for a steel crank right now. I'm going out to find the rings and will get some picks of the ends for you guys. Jon