Andy J Posted February 25, 2023 Share Posted February 25, 2023 Andy J Members 189 Location: east central Mississippi Posted just now Today I'm trying to start my fresh Pontiac straight 8,engine completely rebuilt,bored,new pistons,crank turned,valve job.I spun it over for a couple of minutes and didn't get oil pressure at the gauge.Thinking the line to the gauge may be stopped up,I took it off and checked it and it was open.I left it off and continued to spin it over, watching for oil coming out of the oil galley.No oil yet,so I pulled the plugs out thinking it would spin faster,thus speeding up the oiling process. My question:how long should it take for oil to come from the pump into the engine? I called an old friend I know that is familiar with these engines and he said 10-12 minutes.Does this sound reasonable? I've never worked on a flathead before,so I'm somewhat in the dark about these engines.Any advice will be greatly appreciated. 1 Link to comment Share on other sites More sharing options...
OrtonvilleBob Posted February 25, 2023 Share Posted February 25, 2023 When I rebuilt my flathead I was super paranoid about getting oil to lubricate the engine during the initial startup. I wasn't sure if the internal oil cleaner had to fill up before the oil pump could built up pressure. I didn't take a chance and devised a relatively simple method to fill and prime the oil passages. I used a brake bleeder jug to force oil into one of the extra, unused oil passages on the side of the block. The line leading to the block is connected so it's under the fluid level. I set my air compressor to a low setting and pushed a quart of oil into the block. Was this necessary or maybe even silly? I don't know. But what I do know is that when I cranked the engine for the first time oil pressure came up in a matter of seconds. Hopefully someone with more experience with these flatheads gives you a definitive answer to your question. 3 Link to comment Share on other sites More sharing options...
PhilAndrews Posted February 26, 2023 Share Posted February 26, 2023 (edited) If the oil pump is completely dry it'll have a hard time drawing up the oil. I would say there is no harm at all with @OrtonvilleBob's method- last thing you want in a new build is a lack of lubrication. That should backfeed to the pump and prime it. Primed from everyday running mine will build at least 5lb (puts the pressure warning light out) on the starter in a couple of seconds, even hot. if you lack a method of pumping oil in, take the oil pump off and pack it full of petroleum jelly, reassemble and that'll help it pull the oil up. Phil Edited February 26, 2023 by PhilAndrews (see edit history) 2 Link to comment Share on other sites More sharing options...
Andy J Posted February 26, 2023 Author Share Posted February 26, 2023 That's a great idea,OrtonvilleBob. A fellow on the Technical forum,Gary F,said he packed his pump with vasoline and had nearly immediate pressure. Like an idiot,I put my pump on dry. I should know better than that.I was a fireman for 39 years and I know all about pumps and how they work.An oil pump is a gear pump,which is self priming provided there is fluid in the pump to displace air so it will create negative pressure within the pump.Atmospheric pressure then pushes the oil in the pump,then the oil is pressurized by the pump gears and away you go. I am pissed at myself for such a stupid move when I know better.(end of rant) I'm going to sleep on it and fix this after I get home from church tomorrow.I believe I'll get one of those brake bleeders and do the same thing you did. That will keep me from taking the pump off. 2 Link to comment Share on other sites More sharing options...
Andy J Posted February 26, 2023 Author Share Posted February 26, 2023 Thank you for your response Phil. Now I'm trying to figure out how I could be so stupid when I knew all the time what I should have done. I'm really mad at myself for overlooking the obvious. 1 Link to comment Share on other sites More sharing options...
PhilAndrews Posted February 26, 2023 Share Posted February 26, 2023 Happens to the best of us. You get in the mindset that the procedure "start engine, get oil pressure" is so normal and taken for granted it's easy to forget. 1 Link to comment Share on other sites More sharing options...
Andy J Posted February 26, 2023 Author Share Posted February 26, 2023 You know,you're right. When I was young,all I dealt with was small block Chevys. An old distributor shaft and a drill motor and you had oil pressure in a few seconds. I haven't work on cars since before I got married 44 years ago,other than changing oil,brakes,shocks,starters,alternators,and other minor repairs to keep my vehicles running to put bread on the table. When I retired 3 years ago,I started working on cars again,with this Pontiac I bought 6 years ago.This is like starting from scratch for me,being completely in the dark about these flatheads. I ain't giving up because I'm so close to the finish line. 2 Link to comment Share on other sites More sharing options...
OrtonvilleBob Posted February 26, 2023 Share Posted February 26, 2023 Wait, what? I could have just packed the pump with petroleum jelly instead spending a day creating my Rube Goldberg primer? 1 Link to comment Share on other sites More sharing options...
OrtonvilleBob Posted February 26, 2023 Share Posted February 26, 2023 Andy J, now that we both know the simple pump prime solution I don't believe there's any need to remove the oil pump from the engine to pack the gears with Vaseline. Just remove the four bolts that hold the cover on and the gears are exposed. 1 Link to comment Share on other sites More sharing options...
Andy J Posted February 26, 2023 Author Share Posted February 26, 2023 Ortonville Bob,I need ya'll to hang around me and wake me up! Not long ago,I had that pump apart checking it for wear. I can't believe that I didn't consider that. This proves that 3 or 4 heads are better than one! Thanks again! 2 Link to comment Share on other sites More sharing options...
PhilAndrews Posted February 26, 2023 Share Posted February 26, 2023 Don't give up on it. They're not fast but they are fun cars to drive about in. Once you have the kinks ironed out, they're great. Link to comment Share on other sites More sharing options...
Andy J Posted February 28, 2023 Author Share Posted February 28, 2023 Well,I finally got oil everywhere,so I'm going to start the motor tomorrow afternoon.I have church meetings tomorrow morning. Packing the pump with petroleum jelly didn't do it.I probably didn't spin it over long enough,as I hated grinding and grinding the thing. I next went with Ortonville Bob's method of injecting the oil in the oil galley. Spun it for 30-35 seconds and it primed up.I am just not patient enough I guess. Thanks,everyone,for the suggestions and encouragement.Maybe I can get this thing to the upholstery shop this week and get this jewel finished. 2 Link to comment Share on other sites More sharing options...
Andy J Posted February 28, 2023 Author Share Posted February 28, 2023 A friend of mine came over this afternoon and after a couple of tries we fired it up. The motor sounds really good,runs smooth and quiet. I've got a few problems to work out,the fuel pump isn't pumping enough and the generator isn't charging.I rebuilt the pump myself with a kit I got from Kurt Kelsey,although I certainly could have done something wrong.I know the generator is working,but I think the voltage regulator is bad.This car hasn't ran for at least 25 years and I'm using the old parts that were on it when I got it. Link to comment Share on other sites More sharing options...
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