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Life in the fast lane - - again!
https://www.slantsix.org/forum/viewtopic.php?t=39002		 Page 2 of 3
Author:  Pierre [ Sun Feb 14, 2010 11:13 pm ]
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Quote:
and spark plugs showed - black - like too much fuel
Or too much oil :( All the plugs the same though? Compression gauges are relatively cheap.

I say broken ring - I have a hard time believing it would have went from nothing to billowing smoke instantly if it was a seating issue. Something catastrophic must have happened suddenly.
Author:  dakight [ Mon Feb 15, 2010 3:53 am ]
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Have you run a compression test? Oil being pushed out of the breather cap indicates excessive crankcase pressure. There are only a few things that can cause it; worn or broken rings, a hole in a piston, clogged PCV valve, etc. Good luck!
Author:  WhaleMstr [ Mon Feb 15, 2010 12:38 pm ]
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When it was down last month I did a compression test on it - all were at or really close to 115 each. I think only one was off by maybe 10 pounds or so.

Just got finished getting it towed back here and slowly getting ready to tear into it.

I had even bought new seat covers and had just put them on a few minutes before this happened!! I was that happy with the old girl - now she's acting like a typical spoiled b*&^$ !!! lol

Will let ya'll know what I find with the latest compression test.
Later,
Dan


Oh - never has it burned or lost any oil between changes since the rebuild.
Author:  Pierre [ Mon Feb 15, 2010 5:16 pm ]
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You said 5 years at less then 5000 miles a year... so you have less then 25k miles and your already at 115 compression? While that may not be bad for a worn engine that is a bit low for one this fresh. This is starting to look more and more like a ring / wall wear issue. I'll keep my fingers crossed for ya on the compression test but its one of those "hope for the best but expect the worst" situations.
Author:  volaredon [ Mon Feb 15, 2010 7:50 pm ]
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those compression numbers might not be so bad; there are factors involved that can give different readings on the same engine.
I have a (gag) SBChevy on my stand right now. what can I say... it's a favor/side job for a buddy. I have the manifolds off and plugs out.
I put the batt charger on the starter and jumped the "S" terminal with a screwdriver. Not the best way to do this job but I was wanting to do a compression test on it and oil pressure test to see if this unknown-history engine would be a "worthy" replacement for the tired original.

I oiled the cylinders and turned the engine over by hand a few revs before putting the power to the starter. 1st cylinder I struggled to get 90. 2nd one I got ~100. Batt charger on "BOOST".

I then went and got my jumper cables. put them on the battery that's still in the truck and "piggy backed" the battery charger onto those. Hooked the other end of the jumpers to the starter and did the same test. Same 2 cylinders I started with, now put out 175 PSI. and I proceeded to complete the compression test on the engine.

Point is, if the OP didn't have the throttle open on the carb or if his battery/starter/cables are weak, his compression might very well seem "low";
Cam selection, overall comp ratio, etc., can alter readings too.

That is why; (1) some people advise to do the comp. test with the engine running on the rest of the cylinders while testing each cylinder
and (2) it is also said that "overall readings" and comparison between all cylinders on a given engine, and percentage of allowable variation among cylinders is more important than actual numbers achieved.
also; warm/cold engine can be a factor
and; here in "computer space" we don't know the accuracy of "that" particular compression gauge. I have 2 myself and sometimes double check one against the other if something does not seem as it should be.

that is why many techs won't even go by a compression test, but instead (or in addition to) go by a "cylinder leakdown test", running that pistion to TDC on compression, and putting regulated air to that hole. Air out the carb; intake valve problem. Air out tailpipe? Exh valve. Bubbles from radiator? Head gasket/cracked casting. out oil fill/dipstick tube? rings/cracked piston.
Author:  Pierre [ Tue Feb 16, 2010 12:04 am ]
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Ok, let me qualify that - 115 is a little low assuming your not trying to run your starter off a battery charger, have a healthy electrical system, stockish build, and the moons gravity didn't suddenly increase so much that it sucked all the air out of your cylinders.

The throttle being closed - maybe a couple points, but from 140-150-160 to 115? Didn't make a noticeable difference when I did my compression test with the throttle open or closed.

I kid, I kid. My sincere apologies for being so cynical. Sure, if you have a leakdown tester go for it. But a compression test will be plenty to narrow it down to the "rip the engine apart" or "look elsewhere" stage of this adventure.
Author:  WhaleMstr [ Tue Feb 16, 2010 10:41 am ]
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A month or so ago I did a compression test and all were within a few points on 150 - with one being at or about 115

Now, running the same thing - twice - these are what it is showing
6 - 50
5 - 135
4 - 150
3 - 100
2 - 145
1 - 145
Author:  Pierre [ Tue Feb 16, 2010 12:28 pm ]
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6 is way low, 3 is suspicious.

Don't yank everything out yet. Start by taking the head off and inspect the valves to see if they have become egg-shaped or sunk and check for any cracks. Then look at the cylinder walls - I'm guessing the fault will be fairly easy to spot.

I don't mean to harp, but you should have done this before when you found out one was at 115 and the others 150. If the valves are adjusted, the difference shouldn't be nearly that large. Now the repair is gonna be more costly.
Author:  WhaleMstr [ Tue Feb 16, 2010 12:56 pm ]
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hahahahaha - yea - just pop the head an take a peak!
nothin to this silly game

actually - aside from the carb - I have been unbelievably happy with this thing since I built it - it has been all over northern CA and a couple of you have seen it at the drag strip - (and again - the damn carb and throttle linkage was the only problem I ever had with it!), it's raced into and out of San Fran in the hammer lane at an extrememly high rate of go on more occassions than I can remember, it's been run from this area to Santa Rosa and back - empty there and fully loaded back - 4 times during the heat of the summer, it's been up to Mt.s Lassen and Shasta a bunch, this thing has been so reliable - EXCEPT the damn carb! for so long!

guess that after 5 years of hammerin the crap outta her - she was gonna throw a little fit??

well, as i mentioned once before, i was always suspicious of the stock springs - with a cam with the lift this thing supposedly has? hahahaha - no memory and can't find the cam card! - but for some reason i have always remembered it as being "up there" 400's+ - Isky - auto etc.

guess that I can toss another 35 worth of oil
i have a feeling that i am not gonna worry about putting this back together with this carb after all this - time to stop frettin over it and shoot the sumbeach with the automatics!!!!!!!!!!!!!

guess once i get the thing apart i'll let ya'll know

later
dan
Author:  Aggressive Ted [ Tue Feb 16, 2010 1:15 pm ]
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What carb are you running?
Author:  WhaleMstr [ Tue Feb 16, 2010 2:00 pm ]
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if memory serves me correctly (HAHAHAHAHAH - yeah right!!!)
it's a Holley 4412 500cfm
Author:  WhaleMstr [ Tue Feb 16, 2010 2:04 pm ]
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man i hate having to tear crap apart that looks so clean and shiny!
Author:  Aggressive Ted [ Tue Feb 16, 2010 2:17 pm ]
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Power valve stuck?

It will be interesting to see what you find....broken ring on #6????
Author:  WhaleMstr [ Tue Feb 16, 2010 3:52 pm ]
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Black Diamond rings a bell???

I lived in Fife, Tacoma, Goldendale and Elk WA. - '76 to '98 - then ended up stuck here in the land of the californicators!
Author:  Aggressive Ted [ Sun Feb 21, 2010 10:09 pm ]
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So on #6 it was a blown head gasket?
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