7670 Kit on stock Block - Compression and Leak Down - Opinions Wanted

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Apr 20, 2017 | 01:38 PM
  #1  
So i did my semi annual check on the motor after beating the **** out of it for a week at VIR and down in deals gap NC and the numbers are as follows:

1 - C 135 L6% 2- C138 L3% 3- C134 L17% 4-C137 L18%

Last year the compression was about the same and the leak down was the same on 1 and 2 and 3 and 4 were both at around 10 or 11%. It looks like the motor is slowly letting go. The question is do i try to finish the season with a couple more track days and weekends in the mountains as is or do i shut it down and put in a built motor now. Thoughts?

Is this a complete time bomb at this point or would there be further warnings signs so i could shut it down before it blows and costs me a block or turbo?
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Apr 20, 2017 | 02:21 PM
  #2  
On th eleak down test, where are cylinder 3 and 4 leaking from?
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Apr 20, 2017 | 06:40 PM
  #3  
Couldn't hear it out of a valve or exhaust, they think it's likely the rings.
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Apr 20, 2017 | 07:55 PM
  #4  
did you do the ol' oil in the cylinder trick?
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Apr 21, 2017 | 06:19 AM
  #5  
No, what trick is that?
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Apr 21, 2017 | 01:14 PM
  #6  
Quote: No, what trick is that?
If compression increases with added oil, your rings are sub-par. If it doesn't , then it's the valves?
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Apr 21, 2017 | 01:30 PM
  #7  
They "think" its the rings? All that tells me is you got an incomplete report on your leak down test. Take it back, and tell them to tell you where it's leaking down from, not where they "think" it's leaking down from.
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Apr 24, 2017 | 07:20 AM
  #8  
spoke to the shop again and it was my selective hearing. They said they could clearly tell where it was coming from and it was the rings.
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Apr 25, 2017 | 10:15 AM
  #9  
Well, its not going to "blow up" per se just from excessive leak down at the rings. That being said, it's only going to get worse and I would say it's time to start saving your pesos to at least refresh/replace/build the short block.
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Apr 25, 2017 | 01:13 PM
  #10  
When you dump a lot of power into an engine is this just a byproduct (quicker wear/death) of that or did something have to go wrong to cause it?
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Apr 25, 2017 | 01:32 PM
  #11  
That would require an autopsy to see what happened. But, generally, the same 2 engines, but one with more power, and driven in a similar manner (amount of time spent in boost/at WOT, or whatever); the higher power setup will wear faster. Keep in mind, on a our turbo cars, you're only making big power when in boost. So, in theory, a high HP setup driven easy could last longer than a stock turbo setup that gets the **** kicked out of it every day.
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Apr 26, 2017 | 11:10 AM
  #12  
so i decided to pull the trigger on a built 2.0 block. Moore is going to be doing it using their machine shop (AR Fabrication in Windsor VA). AR Fab seems to have great experience and reviews and they are the Darton east rep. Doing a fully coated, sleeved 2.0 with the usual suspects manley I and wiseco pistons. Hopefully I don't run into any problems that delays it too much, would love to get the car back by late July for some late summer and fall driving.
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Apr 26, 2017 | 11:24 AM
  #13  
If you still have the option, I would go with a lighter weight connecting rod. Carillo Pro-H would be a good choice at a touch over 70 grams lighter.
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Apr 26, 2017 | 12:16 PM
  #14  
thanks for the advice. I'm amazed at how light that is, should be much better for the life of the bearings and revving with that weight. Looks like i'm going to use those. Any negatives I should know about? I don't plan to make more than 600WHP (but I would love the option of turning it up if i felt like it haha), are these weak like the manley H beams, online reviews seem to imply they are very strong but carrillo doesn't have a HP rating on their website.
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Apr 26, 2017 | 12:25 PM
  #15  
Yes, much easier on parts, solid choice to ditch the manley's.


I know in the 4g63, the manley ibeams actually weigh more than OEM rods. Blows my mind people use them. Not much engineering behind them, just a bunch of high strength material in the shape of a connecting rod, which obviously makes them strong, but far from light.
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