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Discussion Starter · #1 ·
its been a while since i've posted here but here is the new problem

im just putting this 355 into my corvette, its been switched from fuel injection to carburated system. there is excess pressure being built up in the motor, to the point that it is smoking out of the valve cover holes. I tried running a PCV on one side and a breather on the other, and still building up alot of pressure. any other ideas on how to fix this?

and here a a pic of whats coming along

 

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sounds like the rings are leaking pressure, not keeping all the cylinder pressure in the cylinders
 

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maybe they failed to seat fully? try running it fairly hard for a few miles while varying the loads and rpms rapidly :thumbsup:
theres only one MAJOR source of blowbye pressure and thats cylinder pressure past the rings
 

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Discussion Starter · #5 ·
maybe they failed to seat fully? try running it fairly hard for a few miles while varying the loads and rpms rapidly :thumbsup:

i should have put it a little different though, the motor has less than 100 miles on it, but its been sitting here and there from about 4 years now... but is been started up every 2-3 months its a project i've been working very slow on.
 

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if your really curious as to the cause.... do a LEAK DOWN TEST

read this

http://www.xs11.com/tips/misc/misc3.shtml

http://www.goodvibesracing.com/leakdown%20Tester.htm

http://www.globaltoolsupply.com/cgi-local/SoftCart.exe/online-store/scstore/p-P1-275.html?E+scstore

http://www.tavia.com/cat8.html#3



http://www.motorcycleproject.com/motorcycle/text/leakdown.html

http://www.xs11.com/tips/misc/misc3.shtml


http://goodvibesracing.com/Leakdown%20Tester.htm
1) For most accurate results, engine should be up to operating temperture.

2) Remove all spark plugs.

3) Rotate crankshaft until piston being tested is at top dead center of compression stroke.

4) Screw the spark plug adaptor hose into spark plug hole making the sure the o-ring is seated properly.

5) Connect the spark plug adaptor hose to the coupler of the leakdown tester.

6) Connect leakdown tester to a good source of compressed air, preferably a filtered and water trapped source.

7) Adjust the regulator on the leakdown tester so the the LEFT HAND GAUGE indicates at least 10 pounds less than your sorce pressure. The leakdown percentage conversion table shown below is based on regulated pressures of 100, 90, or 75 psi.

8) Read the RIGHT HAND GAUGE (differential gauge), then look up gauge reading on the conversion table below to get actual leakdown percentage. After noting percentage of leakage, turn the regulator knob counter-clockwise to relieve the pressure. This reduces the shock to the gauges. If you ever get an unrealistically low pressure reading on the right hand gauge, there is a finite possibilty that something is blocking the small orfice located within the hex tube located between the regulator and the main body of the leakdown tester.

9)To remove any obstruction that may be lodged in the metering orfice, unscrew the hose coupling assembly from the aluminum body. Ultilizing a 1" wrench, remove the knob assembly from the regulator. Blow compressed air in the opposite direction (from the coupling end) to clear the orfice. Re-assemble the regulator and the coupling.

NOTE: DO NOT ATTEMPT TO REMOVE THE BRASS HEX NIPPLE BETWEEN THE REGULATOR AND THE ALUMINUM BODY. DAMAGE MAY RESULT.

 

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Cleaner than Stock, Faster than Phock
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sounds like the rings are leaking pressure, not keeping all the cylinder pressure in the cylinders
:agree: Been ther done that.

Take the Valve Cover cap off and rev the engine and see if it blows more smoke, or no change.
 

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:agree: The cylinder leak-down test is a good idea. Good luck.
 
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