Chad Hicks: 3/23/2000 - 7:33:06 PM
Priming a rebuilt Flathead?
Hi, I have just rebuilt a 40-48 flathead and I have no clue on how to prime it to get oil pressure, could anyone tell me?? regchamp@hotmail.com

rodnut: : 3/23/2000 - 8:07:48 PM
CHAD: Unfortunately, the oil pump on a flathead is driven directly from the camshaft, which means you must rotate the engine to turn the pump. Remove the spark plugs, disconnect the ignition coil and the fuel line to your fuel pump and hold the carb throttle plate wide open with a piece of wire. Squirt a little oil down each s.plug hole and crank the engine for about 10 seconds with about 20 seconds between each cranking period. Watch your pressure gauge and when you see pressure, you've got it! If you assembled the motor with oil or assembly lube, all you really need to do is prime the pump. It's a little late know, but a good trick is to pack the oil pump with light grease or vaseline on assembly and it will pick up your oil right away. Don't forget to put oil in the c/case - seems like a no-brainer, but experienced rebuilders have done so! When you get 'er running, quickly check for oil pressure, leaks, etc., then, if you've installed a new or reground cam, run the engine at about 1500-2000 rpm for 10-15 minutes to work harden the camshaft lobes, otherwise you can easily ruin your cam. Don't let it idle for more than a minute or two before doing this Good luck! Jim Marlett: 3/23/2000 - 8:46:55 PM
I recently read of a trick I haven't tried. Replace the oil pressure switch with a hose to a pressurized oil source and prelube from there. Probably doesn't get everything, but ought to get oil into the system. Wish I could remember who to credit for this, but I can't.

Arrowsmith: 3/23/2000 - 10:43:46 PM
Does the cam realy need to be broken in new cars don't get it done to them

paul.selfe@marconimed.com: 3/24/2000 - 6:39:16 AM
Chad; The method Jim suggested is the way I have primed my engine several times (each spring). I simply made up a primer pump in a scrub bucket, driven with a drill motor. I think I saw this in 'Thunder Road Flathead', or one of my other flathead books. It works fine, you just have to keep track of the amount of oil you are dumping into the pan as you top off, I change oil each spring.

Waly Dupont: 3/24/2000 - 4:38:50 PM
I made a oil pressure tank out of an old freon bottle, put 5 qt. of oil in it, hose to the sender unit, force oil thru the engine

rodnut: 3/23/2000 - 8:07:48 PM
CHAD: Unfortunately, the oil pump on a flathead is driven directly from the camshaft, which means you must rotate the engine to turn the pump. Remove the spark plugs, disconnect the ignition coil and the fuel line to your fuel pump and hold the carb throttle plate wide open with a piece of wire. Squirt a little oil down each s.plug hole and crank the engine for about 10 seconds with about 20 seconds between each cranking period. Watch your pressure gauge and when you see pressure, you've got it! If you assembled the motor with oil or assembly lube, all you really need to do is prime the pump. It's a little late know, but a good trick is to pack the oil pump with light grease or vaseline on assembly and it will pick up your oil right away. Don't forget to put oil in the c/case - seems like a no-brainer, but experienced rebuilders have done so! When you get 'er running, quickly check for oil pressure, leaks, etc., then, if you've installed a new or reground cam, run the engine at about 1500-2000 rpm for 10-15 minutes to work harden the camshaft lobes, otherwise you can easily ruin your cam. Don't let it idle for more than a minute or two before doing this Good luck!

rodnut: 3/23/2000 - 11:07:41 PM
It is my understanding that OEM camshafts are usually case hardened, where aftermarket camshafts generally are not. Keeping the idle speed up until the engine reaches operating temp assures proper lubrication of the cam and cyl walls, from the oil thrown off of the crankshaft, during this critical initial break-in time. Also, most aftermarket cam manufacturers recommend this method also. I have seen new cams that were wiped after just a short time due to not being properly broken in. Plus, all of the material that is scuffed off of the cam lobes ends up in your bearings, piston skirts, oil pump, etc. Not good!

rodnut: 3/25/2000 - 12:18:44 AM
Ya! I like the freon bottle trick. I'm lookin' for one tomorrow

rodnut: : 3/25/2000 - 12:42:15 AM
Along this same vain, I am building a pre-lube accumulator for my flatmotor. A friend did one of these and it works slick. Make a container with sealed, screw of lid (from a piece of large diameter tubing?) that will hold 100psi and about 1/2 qt of oil. Put a shraeder (sp?) valve in the lid and a line fitting at the bottom. Plumb it to a tee between the oil sending unit and block, with a solinoid valve in the line, wired 'open' with ignition on. Put oil in container, charge with air to same as running oil pressure. When you turn on ignition, valve admits pressurized oil to engine. When you start the engine, the oil is forced back into container, and when you shut engine off, valve closes, trapping pressurized oil in container for next pre-lube! Neat! Make it from aluminum, polish it up - 'hey, what's that deal for?'

Tom: 3/25/2000 - 8:21:59 AM
rodnut.With a roller cam is the break in necessary?

rodnut: 3/25/2000 - 9:50:03 AM
Addendum to accumulator: I was going over this in my alpha state last night, and I'm thinking one could eliminate the air valve. Just hook the system up, start the engine and it would force oil into accumulator until pressure equalized, and trap it when ignition was shut off. Then check your oil level and add make-up oil. This way you would now how much oil is being held by the accumulator, and no worry about forcing air into your oil system!? Plus, you wouln't have to make a removable lid. Only question is how large it needs to be in order to hold enough (1/2 qt) oil before reaching equal pressure? Any physicist's out there? I understand Moroso sells an accumulator, but I hate to buy something I can make!

rodnut: 3/25/2000 - 9:33:21 AM
good question - I wouldn't think so, as there is no sliding friction between the cam lobes and the lifter. It is possible that the rolling of the lifter over the lobe and spring pressure would also tend to harden the lobe surface.

Matt: : 3/24/2000 - 6:10:30 PM
An oil burner pump attached to a variable speed drill will work when tapped into the oil filter line(to engine) Cam lube is what will make the cam break in instead of break down.

rumble seat: 3/25/2000 - 2:04:00 PM
Chad: I made a pre-oiler some years ago that works great. I use it to check for pressure leaks on the engine stand and, again, to pre-oil when it's ready to fire in the car. Used a 2 gallon bucket, a piece of strap iron, and a junk Falcon 6 or V8 oil pump with the oil pump drive shaft (most any late oil pump will work), a couple of fittings, and about 4 feet of clear plastic hose (you can watch the oil going through the clear hose). Mounted the oil pump on the strap iron so the pump pick up is just barely off the bottom of the bucket. I vise grip the strap to the bucket to stablize things. Took about 40 minutes to make everything form scrap parts. The oil pump shaft is turned by a reversible 1/2 inch drill. Connect the clear plastic line to the pressure side of the pump and route it up to where the flathead oil pressure sending unit is located. Dump in 4-5 quarts of oil and start the drill. When checking the engine on the stand, I leave the pan plug out and position the bucket under it so it will catch the circulated oil and recirculate it over and over. I hook a gauge to the block so I know it's getting pressure (about 40psi). After running it for about 5 minutes I let it drip for awhile before I install the pan plug. When in the car, I hook everything up the same way and pump the same 5 quarts used on the engine stand into the engine. I monitor the car's oil pressure gauge while I run the pump. After the bucket is empty, I pull the oil pan plug and let it drain. Then I refill the engine with fresh oil before starting the engine. I save the oil in a plastic jug that was recirculated and use it on the next engine. Several friends have borrowed it and are making their own. Incidentally, be SURE you fill the oil pump gear cavity with thick oil or light grease when you assembly the engine. Many times, the oil pump won't pick up a prime when they're dry and you get to pull the pan and do it later! rumble seat

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