gretchen/jason Posted April 6, 2008 Share Posted April 6, 2008 On my sbc there is a threaded plug just to the left " sitting in the car " of the oil pressure port is this a oil port of some sort or oil passage . I can just barley see it between the head and the block . Im asking because after the shop rebuilt my engine and assembled the entire block heads and all there is oil pissing out near that aera . Its not the intake gasket as i removed the intake and used a oil pump primer and still got a oil leak .Plus id like to know what it would be used for as i see nothing it could attach to . Pisses me off 2 times ive had this engine built within 6 months and it now leaks oil and seems to use 1 quart of oil every 200 miles .But i cant be for sure untill i fix the leak which im assuming im going to have to remove the head after only 500 miles of use on a new engine . Jason Quote Link to comment Share on other sites More sharing options...
SHO-Z Posted April 6, 2008 Share Posted April 6, 2008 It could be the Knock senor connection. It has been a long time since I was around a Chevy Small Block. Quote Link to comment Share on other sites More sharing options...
jnjdragracing Posted April 6, 2008 Share Posted April 6, 2008 I think I know the plug you are talking about, it is to the left of the normal oil line hook uo, the head at the rear barely covers it about half of it. If is an oil passage. It should have a 3/8 pipe plug in it. On my engine I always pack alot of silicone in that area all around the back. SBC are prone for oil leaks. You should be able to clean the area with some either / starting fluid and fill in area with silicone. Are you sure you sealed the rear of the intake? If oil leaks from the back it will flow downwards and will accumulate there. I use silicone, I form a bead for the front and rear of the intake and let it get tacky then put on the intake. I do not use the stock cork or rubber gasket. Hope this helps.... John Quote Link to comment Share on other sites More sharing options...
gretchen/jason Posted April 6, 2008 Author Share Posted April 6, 2008 Oh i even checked it with the intake off of the engine using the oil pump primer . I cleaned the heck out of it once with brake clean and dried it and filled it with silicone but it found a exit someplace and leaked . I then redid it with JB weld and 2 weeks latter it leaked . Thanks for the info though at least i know what the plug is for now . Jason Quote Link to comment Share on other sites More sharing options...
pparaska Posted April 8, 2008 Share Posted April 8, 2008 My experience with that leak is that you have to pull the head to be able to stop the leak. I know what plug you are talking about. The OLD SBCs had a cup plug in that hole, the newer blocks have a screw in plug. The hole is to cover up where an oil galley coming up from the filter was drilled into the block casting. Pull the head, remove plug (not always easy), clean the hole, and insert new or good plug with some non-hardening sealer. I had that happen once. It sucks to have everything in the car and have to pull the head to fix that leak. I now pressurize the oil system on the stand, and get oil coming out of each pushrod (cranking the engine over a bit) to see all the rockers get lube AND make sure that plug and the galley plugs in the rear of the block, and the one above the filter pad don't leak. Sorry to give you the bad news. Give the shop some grief over it. Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted April 8, 2008 Share Posted April 8, 2008 I hate to tell you this but whomever built your engine is a moron! AFAIK that has always been threaded, under the main cap there is a welch plug that if you don't get it in there your oil doesn't get filtered on gen 1 sbc's. IMO the order of building an engine is to install the cam bearings, wash it with soap and water using oil galley brushes, blow it dry, then install all the oil galley plugs correctly, etc, etc. Quote Link to comment Share on other sites More sharing options...
pparaska Posted April 8, 2008 Share Posted April 8, 2008 I hate to tell you this but whomever built your engine is a moron! AFAIK that has always been threaded, under the main cap there is a welch plug that if you don't get it in there your oil doesn't get filtered on gen 1 sbc's. IMO the order of building an engine is to install the cam bearings, wash it with soap and water using oil galley brushes, blow it dry, then install all the oil galley plugs correctly, etc, etc. The plug he's referring to is on th head deck or just behind that surface, near the back of the block on the odd numbered bank side. The 327 block I had in my car had just a cup plug hole there - no threads. Later blocks where threaded to use an NPT plug (hex key type). I had to fix that on the 327 when the shop just tapped a cup plug in there and it leaked just a bit. I put a new cup plug in with JB weld. That one under the rear main cap is important too - I agree! Easy to see its there too - it's just an inch or so below the cap mating surface. Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted April 8, 2008 Share Posted April 8, 2008 The plug he's referring to is on th head deck or just behind that surface, near the back of the block on the odd numbered bank side. The 327 block I had in my car had just a cup plug hole there - no threads. Later blocks where threaded to use an NPT plug (hex key type). I had to fix that on the 327 when the shop just tapped a cup plug in there and it leaked just a bit. I put a new cup plug in with JB weld. That one under the rear main cap is important too - I agree! Easy to see its there too - it's just an inch or so below the cap mating surface. Interesting find pete, I have a '67 327 sitting here in the floor of the shop and it's a threaded hole. Maybe yours is earlier than that or never got threaded for some reason. Quote Link to comment Share on other sites More sharing options...
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