Any sugestions will be apreciated... Sbc with fresh rebuilt standard block and rebuilt heads. This motor is for my wifes 51 mercury. Got everything hooked up, started the motor and right off the bat - smoke. Brought the engine up to running temp, gave it some fuel and smoke started poring out the tail pipe. Checked everything over. I ended up pulling the carb and finding oil in the intake. Changed out the intake and put new gaskets - still smoke. I pulled carb and have the same problem. WTF? A. Figure I have a broken ring B. Bad valve guides or no seals C. The hot rod gods have decided to kick me square in the balls. My house looked like it was on fire!
Man, no fun on an initial start up. Who did the "rebuild" with what parts? Sure it is oil smoke and not coolant smoke? Lots of things can cause oil consumption. Bad cylinder sealing, bad valve guides bad valve seals. Oil in the intake could be caused by a pcv valve sucking up oil. Maybe start by doing a compression check and go from there. Good luck and keep us posted.
Would help if I had more info on the "rebuild". Std bore on a used block is not a good start. What was done to the heads? any guide work? Was any measureing done on the bore or on the piston ring-grooves or even ring gap end clearance? Was the block ridge reamed before you re-assembled it? That much oil that fast to me indicates a serious error somewhere. I would like to help if I can but need more info.
You said rebuilt standard block. Does that mean no over bore? Did you check for taper? Did you remove the ridge? You can check for bad intake gaskets by disconnecting the pcv system and using an unlit propane torch in to the oil cap. If engine picks up you have a internal vacuum leak. Were the heads milled? If they were milled too much the intake needs milled too.
Mmmm oil in the intake? im thinking pcv too, as long as your gaskets are good..how else could it get inside the intake? PCV
As stated before PCV sucking oil. Is this a new build meaning new valve covers that have no baffles that type of thing. Is it oil or is it tranny fluid. If tranny fluid the modulater valve went out on trans. I'm assuming it's auto. Try pulling PCV out while its running to see if it clears.
I did all the work . Its not my first rebuild but I could have made a mistake. My friend thinks its bad valve guides but I had the heads rebuilt. It is oil for sure. Compression check is the next thing on the list. Totally stock motor turned crank rebuilt heads new rings = smoke machine
Standard low mileage block no ridge ring at all. I will try the propane trick and will try to get a picture of the smoke! Intake appears to be seated well for the third time! Thanks for the help
Just looking for solutions, did you install the rings properly, paying attention to how they lined up so as to get a proper seal. If you pull a few plugs what do they look like? Oil in the intake is just plain weird to me.
What rings did you use? If it was just a simple rering job the Molly or chrome ring quite often won't seal right. I've seen that a few times. Try a compression test and maybe a leakdown test before you go to far on it. If the guides are loose it should show up on a vacuum gauge. Just about every Motor manual and tune up manual has a vacuum gauge page.
Check the rings. I had that happen to me once, the guy at the parts house gave me rings for a 265 and I managed to install them on 283 pistons without breaking them. End result, large clouds of smoke.
Oil in the intake manifold has nothing to do with valve guides, rings, or anything else down stream from the intake manifold. Either you've got a pinhole in the bottom of the intake manufold or the pcv is drawing oil from the valve cover or wherever it's venting the crankcase from because of poor baffling. If you pulled the carb and see oil underneath, then I doubt the oil is coming from a leak at the joining of the heads and the intake manifold. I know you said that you disconnected the pcv system and it still smoked, but did you give it time to clear out the oil already there? A little oil can make a helluva lot of smoke. Dave
That's the roll up your sleeves and get the job done type of advice I'm sure he was looking for......
Yeah,must have alot of money,no tools,if you go out and buy a crate engine when one tears up,that the 1st sign of a goldchainer.
I would put my vote on a Cracked intake floor. It would not take much to pull oil in from the bottom. PVC would be the other issue that comes to mind but you think that might be eliminated. Try to wash out the intake with Brakleen, and let it sit a few hours open to dry it out. Leave the PVC port plugged, run it and pull carb to check for oil. If it is still under the carb, it would be the intake leaking. a bad area is under the heat sheild under the center near exhaust crossover. I have seen intakes on SBC that were hottanked and looked fine that pulled oil from the bottom in this area. CJO13
Crate motors are for people scared to try it themselves. I know for a fact not all of them are so great! If you want to waste your money go ahead and let the people that like to leave a little bit in the bank account for tires, paint, etc. decide for themselves... There are a helluva lot more "Home Rebuilds" out there than Crate engines, so I think that we are still within an acceptable margin of arror. CJO13
Checked that out put new gaskets still oil. No road draft tube. Nothing wrong with a crate motor but thats not my style. This motor will make my 10 motor build with no troubles shit happens and you figure it out. I picked up a compression tester from a friend I will check that out tomorrow see if I have a bad ring. Also thanks for all the ideas
Guides, broke ring putting in pistons, hone the cylinders?, use alot of oil on cylinder walls, intake doesnt fit right? break the rings in, etc........ No fun either way.
If you've rebuilt engines before as you say, and you paid attention to your P's and Q's, I would say intake is not sealing underneath or like was mentioned, cracked intake floor into a port. Has anything been milled that you know of? She's sure sucking oil from somewhere. Hang in there you'll get it. Lippy
After doing the compression test, u will hopefully have a better idea what is going on. I have done standard bore rebuilds on low mileage systems. First I ridge ream the ridge off all cylinders. Then remove all pistons and rods and number each of them. After measuring out of round and taper and if within tolerance comes the hone. Honing helps seal the rings. A good 60 degree crosshatch works well. Install new CAST IRON rings on each piston with each ring 120 degrees apart. Verify that all rings are free to move. Proceed with rebuild. I normally use non detergent oil for the first five hundred miles, then drain and replace with deterent oil. Thought I might give you my .02 cents worth.
Do yourself a favor and use a leakdown gauge, instead of the compression tester, you will get much more info
The Jalopy Journal
