please read my comp. test - Team Camaro Tech
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post #1 of 6 (permalink) Old Apr 6th, 03, 10:28 AM Thread Starter
 
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have a 305 engine brord 30 w/400 crank and rods.
edel.manifold w/750 carb. i have been trying to determine why burnig so much oil. bought this car about 6 months ago and engine had abut 5000 miles.
car smoke on start up after setting a week or so and quits soon after. does not smoke going down road but can let it idle for 15 minutes or so then rev up hard and will blow blue smoke pretty good. put new seals in heads with no change. new plugs put it 3 weeks ago and driven about 200 miles. pulled them today to do comp test and all plugs were dry and black except #6. rich? comp test showed
dry wet
1 175 180 2 162 190
3 175 185 4 170 185
5 175 185 6 170 180
7 170 190 8 165 170

does this look like ring job? or running too rich cause my problem. burning about 1 quart in 300miles
thaks terry
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post #2 of 6 (permalink) Old Apr 7th, 03, 06:39 AM
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Jim
 
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From what I've read, I would say your oil problem is coming past the seals and valve guides. What you may want to try is another compression test. Do the first one dry then on the second, shoot a little oil in the cylinder. This will seal the rings. Check the difference between the two test results. If very little difference, the valves are leaking. If there is a lot of difference, it's coming past the rings. Another method is a leakdown test, but this requires more expensive testing equipment.

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post #3 of 6 (permalink) Old Apr 7th, 03, 07:31 AM
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Eric
 
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When you say "wet" I am assuming you squirt a little oil in the cylinder before doing the test. If that is the case here is what I get out of the test.

Cylinder #2 looks like you might have some blow-by past the rings, it is on the low side to begin with then there is a big jump up when you do the "wet test".

Cylinder #8 starts low and stays low when you try the wet test. Looks to me like maybe a valve isn't sealing very good. A little oil added to a cylinder will help rings seal, but not valves.

I don't really see anything terribly wrong that indicates there is something that must be repaired right now, but it does look like an engine that has some wear on it. It should be fine if your intention for the car is just transportation, but I think it might be a little lacking if you are intending this car for any real high perf use.

Might be a good time to start building a 355 for it

PS. Another thought - if your plugs are black (light fluffy carbon) the carb may be running rich (burning oil shows as dark oily crust and looks different than a rich carb). If it is running REAL rich excess fuel in the cylinders can contribute to poor ring seal.

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68 Camaro, E85 powered 427" small block. 9.96 @ 133 MPH, 1.319 sixty foot on motor. 5.92 eighth @ 116 with a 1.42 sixty breaking beams with back tire on the bottle
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post #4 of 6 (permalink) Old Apr 7th, 03, 08:52 AM Thread Starter
 
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i did the comp test dry and then put oil in each cyl for the wet test. the plugs were black like running very rich. this is a new edel 750. last nite i went 2 stages lean with the carb and will see if this helps. does the small increase in cyl pressure on wet test indicate enough change to mean rings are bad or not seated? engine has a hi-po oil pump and runs 80# pressure. could this be to much pressure causing oil by the valve?
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post #5 of 6 (permalink) Old Apr 7th, 03, 10:23 AM
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Eric
 
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A 5# increase sounds roughly right IMO. A cylinder that jumps a lot more than the others indicates a ring problem with that cylinder.

80 psi is an aweful lot of oil pressure. You could be pumping a lot of oil up into the heads causing your valve seals to get overwhelmed with oil. Instead oif getting splashed, maybe they are getting submerged . . .

its tough to tell for sure - just an idea.

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68 Camaro, E85 powered 427" small block. 9.96 @ 133 MPH, 1.319 sixty foot on motor. 5.92 eighth @ 116 with a 1.42 sixty breaking beams with back tire on the bottle
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post #6 of 6 (permalink) Old Apr 7th, 03, 02:02 PM Thread Starter
 
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any engine additives worth putting in the oil to try and make rings seal:
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