Dk46 Posted October 24, 2019 Share Posted October 24, 2019 I’ve gotten a lot of great help here and now I definitely need some. Newly rebuilt engine. First fire up, I use a rod on the pump to pre-oil the engine and it builds some pressure. Not a lot, but up off the L on the gauge and I also have a manual gauge I added and I can see the oil pushing in the clear tube. Finally, after setting the timing several times, I fire it up. Once the oil pressure needle moves we run it up to around 2000 rpm and the pressure goes to about 1/4 gauge. After about five minutes i notice the engine noise increasing and look in at the gauges. The oil pressure has gone to almost zero. Scared I’m fixing to ruin it I shut it down. So....I pull the distributor and put the drill back on the pump and it will not pump any pressure on the gauge. When I stop I can hear oil running back down in the pan. I also took off the hose at the sending unit and it does pump out of there but not enough to even make the gauge wiggle. Any advice is very much appreciated. I’m about ready to throw in the towel. Thanks This is a 351w Link to comment Share on other sites More sharing options...
Rembrant Posted October 24, 2019 Share Posted October 24, 2019 It doesn't sound good... Can you tell us more about the rebuild and what work was done? And what oil you used? On a new cold engine with cold oil (By cold, ambient temps) you should have had oil pressure that pushed the gauge past the middle, up between 50-60 psi, maybe even a bit higher. Just past the "L" on the gauge wouldn't be enough pressure to do a 2000RPM break-in. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted October 24, 2019 Share Posted October 24, 2019 Danny, I agree with Cory that that doesn't sound good. What kind of assembly lube did you use? I usually spin the pump until I see oil pouring from all rockers before I put on the valve covers and fire it up to break in the cam. Link to comment Share on other sites More sharing options...
Dk46 Posted October 24, 2019 Author Share Posted October 24, 2019 Danny, I agree with Cory that that doesn't sound good. What kind of assembly lube did you use? I usually spin the pump until I see oil pouring from all rockers before I put on the valve covers and fire it up to break in the cam. I had the block went through at machine shop, valve job with new valve seals. Reused pistons and rods, new rings, rod bearings, cam bearings, can, lifters, reused push rods. Used comp can lubu on the can and Lucas assembly lube very liberaly on everything else. Napa 30w oil with a bottle of Lucas zinc break in oil. Link to comment Share on other sites More sharing options...
Ray Cecil Posted October 24, 2019 Share Posted October 24, 2019 I had the block went through at machine shop, valve job with new valve seals. Reused pistons and rods, new rings, rod bearings, cam bearings, can, lifters, reused push rods. Used comp can lubu on the can and Lucas assembly lube very liberaly on everything else. Napa 30w oil with a bottle of Lucas zinc break in oil. No oil pressure on a rebuild? Not good. I'd be calling the machine shop. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted October 24, 2019 Share Posted October 24, 2019 I had the block went through at machine shop, valve job with new valve seals. Reused pistons and rods, new rings, rod bearings, cam bearings, can, lifters, reused push rods. Used comp can lubu on the can and Lucas assembly lube very liberaly on everything else. Napa 30w oil with a bottle of Lucas zinc break in oil. That all sounds good 👍 So did they assemble the short block? If you did, did you throughly clean out all the oil and coolant passages? I use Brad Penn for breakin oil, but that shouldn't make a difference if you added ZDDP. Link to comment Share on other sites More sharing options...
Dk46 Posted October 24, 2019 Author Share Posted October 24, 2019 That all sounds good 👍 So did they assemble the short block? If you did, did you throughly clean out all the oil and coolant passages? I use Brad Penn for breakin oil, but that shouldn't make a difference if you added ZDDP. Machine shop cleaned, inspected, miked, and chased all bolt holes. I picked it up in a engine bag. I built it and did no extra cleaning. Link to comment Share on other sites More sharing options...
FuzzFace2 Posted October 24, 2019 Share Posted October 24, 2019 Machine shop cleaned, inspected, miked, and chased all bolt holes. I picked it up in a engine bag. I built it and did no extra cleaning. I bet that is where the issue is and it may not be all that bad. IIRC there is a oil galley that should have a plug in it that I would say was not put back in after the cleaning. For the life of me I cant remember were this plug is? Maybe under the intake manifold or behind the timing cover, just cant remember now as it was like 40 years ago. Had the same thing happen on a hot little 302 with 351 heads I built for one of our off road 4x4 race trucks. Maybe ask the machine shop if they would know? Dave ---- Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted October 24, 2019 Share Posted October 24, 2019 Machine shop cleaned, inspected, miked, and chased all bolt holes. I picked it up in a engine bag. I built it and did no extra cleaning. I bet that is where the issue is and it may not be all that bad. IIRC there is a oil galley that should have a plug in it that I would say was not put back in after the cleaning. For the life of me I cant remember were this plug is? Maybe under the intake manifold or behind the timing cover, just cant remember now as it was like 40 years ago. Had the same thing happen on a hot little 302 with 351 heads I built for one of our off road 4x4 race trucks. Maybe ask the machine shop if they would know? Dave ---- Inside the bellhousing, at the back of the cam? At least that's one that gets forgotten on 385's Link to comment Share on other sites More sharing options...
FuzzFace2 Posted October 24, 2019 Share Posted October 24, 2019 Inside the bellhousing, at the back of the cam? At least that's one that gets forgotten on 385's From what I remember it is internal and why he does not have a oil slick under the truck. I think on the 385's you get oil coming out the bell housing and most likely all over the new clutch disc if a stick. Wish I could remember where it was on the motor I built Dave ---- Link to comment Share on other sites More sharing options...
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