View original topic: Couple of (possibly stupid) q's about cranking for oil pressure
richierich Sun Jun 26, 2016 11:40 am

Ok - just about to install motor that sat on stand for 6 months. Have filled the motor and external filter with oil, put a little oil into each cylinder and then will install the motor into the car, pull the plugs, coil middle and oil pressure switch.

Question 1 - (possibly stupid!) Can i crank for pressure without the inlets/carbs bolted up? - just to ease the pain of replacement of spark plugs with carbs (48's) in.

Question 2 - once oil comes out of the oil pressure switcn the motor is primed right?[/i]

the2ndcashboy Sun Jun 26, 2016 11:44 am

#1: probably the best way to do it, since you don't want to be sucking fuel into the engine unless it's getting burned. I usually build oil pressure and break the cam in on the ground before I put the motor in, but if you don't have a run stand or spare tranny that won't work for you.

#2: yes, more or less. I'd put the switch back in and crank another 5-10 seconds so you know it's made it to the bearings too.

I will add that I've had good results packing the oil pump with grease. Helps create a good suction, especially if your pump is on the loose side.

richierich Sun Jun 26, 2016 1:48 pm

Makes sense on the carbs thing. What type of grease do you pack the pump with?

stan_tichomirov Sun Jun 26, 2016 2:02 pm

I stopped putting grease in the pump a while ago (assembly moly grease). I just use thick oil on the gears when putting them in, or the red assembly lube. Primes just fine.

Last time I did it with plugs installed, and dual springs. Starter was weak (dying), but still primed fine.


richierich Sun Jun 26, 2016 2:22 pm

Thanks for the advice Stan and excuse me here but I thought I was supposed to have plugs out? The motor is not a fresh build but has been on the stand for 6 months. Do I still need to oil the gears?

vwracerdave Sun Jun 26, 2016 3:10 pm

richierich wrote: The motor is not a fresh build but has been on the stand for 6 months.

Forget about all the witchcraft VooDoo magic. Put everything together and start the engine up.

jfats808 Sun Jun 26, 2016 3:20 pm

All you need is the pump and lines to be air bound and have a pocket of air that limits pressure. Do what is necessary and not make your money burn to guarantee that engine doesn't sieze.

In fact air bounding happened on an engine I broke in yesterday when I took off the oil pump mating surface leak from casting flash.

richierich Sun Jun 26, 2016 3:29 pm

Dave - i tend to take that view but i dont want to **** this up!

Jfats - I'm not 100% sure what is necessary.......that's why I am asking.......

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