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Old 08-31-2014, 10:44 AM   #1
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Default Leakdown test leads to decision time

Since I bought my 94 with 140K engine back in May, I knew that the engine was down on power. A compression test showed 180, 135, 125, 155. In 5K miles since, I have burned no oil, no overheating, nothing obvious that the compression is low except for lower power than I would expect, especially above 5K RPM.

This weekend I finally performed a leak down test, and quickly confirmed that Cyl 2 & 3 are just bleeding compression past the rings. I was seeing 70%+ leakage with air coming out the oil fill. Yes, engine was hot, I was TDC with valves closed, no air escaping to intake, exhaust, cooling, or adjacent cylinders. Damn, was hoping for a bad head gasket...

So, my plan was going turbo as my next step, however now I am at a decision point.

1) Continue with plan to go FM w/o electrical (already running MS3). Run until something breaks.
2) Swap in 94-97 long block (tough to find around here with <100K)
3) Swap in 99+ long block. I have a lead on a 2003 VVT with 60K for $750, including all sensors.
This will involve more work with electrical, which should not be much of an issue with the MS3, and I would need to decide how to handle the intake, will the 94 intake work on the VVT? I usually just see folks modding the fuel rail.

Interested in any insight.
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Old 08-31-2014, 01:25 PM   #2
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While my experience isn't quite the same...I'd say don't install a turbo if you are waiting for it to fail. You will just double the work you put in in dis-assembly and reassembly.

I built a motor on the side for the good part of a year and then just swapped it all in, trouble shot (which took a long while for other reasons) and then threw it on the dyno after breakin. Whatever you think your tune will be will likely change once you have refreshed piston rings.

would you plan on building or refreshing a stock motor?

The electrical work is not bad if you still run batch OR if you retain all the STOCK trigger systems for the 99.

I ended up with a 36-1 wheel in batch since there is no code yet for sequential using the 1-2 pulse from the oem cam gear. In all honesty, it runs. I'm happy.
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Old 09-01-2014, 10:22 AM   #3
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Thanks for your insight. I may be a bit confused however, in my readings yesterday, the MS3 will handle VVT and do sequential using the stock NB cam and crank sensor. That part looks pretty clean. The mods to the fuel rail concern me a bit more than the sensors.

If I refreshed I would have some down-time with the car. If I go that route, I would probably hold off to winter time.
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Old 09-01-2014, 10:37 AM   #4
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There is another option. You could just rebuild what you have.
You may just need a hone and some new rings. That would be your cheapest option, but if it's up to a new 94-97 block or VVT, go VVT. Your MSRx will handle it just fine.
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Old 09-01-2014, 12:14 PM   #5
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Quote:
Originally Posted by gjsmith66 View Post
Thanks for your insight. I may be a bit confused however, in my readings yesterday, the MS3 will handle VVT and do sequential using the stock NB cam and crank sensor. That part looks pretty clean. The mods to the fuel rail concern me a bit more than the sensors.

If I refreshed I would have some down-time with the car. If I go that route, I would probably hold off to winter time.

It will work. I am using a 36-1 wheel, hence it's not working for me. Just use a stock configuration trigger wheel
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Old 09-05-2014, 05:50 PM   #6
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Pulled the trigger on a 2004 VVT and 6-speed. Will keep old engine and open it up to see how bad those rings really look... Thanks for the input.
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