Thread: black oil,smells like gas?

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Just got a nuther small block,but this 1 was just rebuilt and the guy said it just had gotten finished breakin it in.My question is the oil smells big time like gas and the exaust ports are real black,I have talked to a couple of people and it was said that this is normal on an engine when u break it in ,the rings need to seat and all,whats everyones take on that ?I have very little exp. on these things.Its outa the truck now is there sumthin I can look at without takin it apart,like compresion and so forth.Or is this normal?

If it smells like gasoline, and the soot is dry looking it was likely running way too rich. If the carbon is "shiney" black then it was probably oil. And if it ran too rich too long the rings could be more than "seated"

You didnt say what year .If its older couldn't the fuel pump also cause this?Or lend to the problem

Just crank it up with the starter on the ground for compression {not runnin} and just pull 1 plug that ur doin the comp check on right?And what would be a round about area the comp should be?Its a 305 basically stock. thnx all

It was a long block rebuild {luckily} and the kid bolted the rest on before I got it ,thats why I tore all the outer stuff off like water pump,valve covers and intake just to be sure there was nuthin funky.Theres no wear on the rockers or the valve tips ,no sludge or wear on the cam at all!!The pickup fer the oril pump was welded on and theres all kinda marks on the crank it was supposedly balanced and fresh machinin marks on the counterweights and what little u can see around the heads.His quote was just gettin the timing advance on the distributor and the carb set and was out takin it fer a run and blam right in the pass side totaled his 66 chevy truck.fired it up and ran fine before I pulled it sounded goooood..........but then the gassy oil when I started to clean it all up to be put in and I said hhhhhhhhhhmmmmmmnnnnnnnnnnn.Will check compression today!!!I am gunna hide in the garage outa the cali rain!!!!!!

Bob Parmenter is correct to ask about the soot.

1. How long have you run it?
2. What kind of carb is on it?
3. What has been changed on the fuel pressure system?
4. Were the floats set/checked?
5. Are the intake ports sooty too?
6. Is the intake manifold stock?
7. Who put the intake on?
8. What did the plugs look like?

mike in tucson

Still massive crosshatch on the cylinder walls and the plugs looked dark and a little oily except for 2 plugs looked a little fouled but was mostly coco brown,the exaust ports were sooty,and the intake runners are clean.edelbrock streetmaster intake ,single plane even runners,1405 edelbrock carb(600 cfm) ,mechanical fuel pump and I have never ran this engine myself.Still yet to do the compression check.Pistons have .030 stamped on the top.

I have had that happen to me twice, once with an electric fuel pump and a shot carb and the other time I had a bad pvc valve on a old motor. I would think that the soot would indicate not firing properly with a way to rich mixture. With all the crosshatching it sounds like it's barely seated in too, but that wouldn't cause the soot.