B motor Oil pressure issues?

[BJ40ER]

I just finished my B engine rebuild for my 1978 BJ40. My oil pressure when i first start it sometimes doesnt rise for a few seconds and the low oil pressure switch will shut the motor down unless i rev the motor up a little and then gain oil pressure quicker. what could be the cause of this? i didnt rebuild the the oil pump because i couldnt find parts for it but didnt have this problem before i rebuilt the motor. also when first starting the newly rebuilt motor i had to prime the pump before i got any oil to pump through it. at idle it runs about 5 to 15psi and stays between 20 psi and 60 psi while driving. any ideas on why i have the problem when i first start it occasionally? any help would be great thanks

on another note it smokes black when i first start it up, could that just be that the injection timing is slightly off?

 

[Wedg3]

What was you pressure before the rebuild ?

The first time you start your engine after a rebuild, you need to put some oil in the pump. I don't do it when I do mine and it's was like you said. It's take about 5 sec to build pressure. After that your pump don't keep is oil inside and need to refill all the time.

If you have 5psi at idle (Hot oil) + 10 psi at each 1000rpm more... your good to go.

By the way, don't forget the change the little piston and spring that keep you oil pressure below 80psi on the side of the cover just after the pump. You can buy longer one for 10$-20$ with spring in your toyota dealer of do it for maybe 20$ in a machine shop with your old one... juste tell I'm to put 1/32'' more in diameter if you piston is slack and 1/4'' longer.. so the longer part sit were you don't have any wear.

It's easy to rebuild your pump since it's in the front cover. You buy a set of gears in your toyota dealer for 200$ and send your cover on a milling to remove all scrach on the bottom of it where the oil pump gears sit. Don't forget to remove the same amount of metal all around. Put your gears in the cover, mesure how mutch you need the remove on the top where the cover sit... after that you face the cover of the pump.

I do that for my B engine... pressure was 0 psi at idle, 19 at 3000rpm.. after my rebuild, 10 psi at idle and 40psi at 2500rpm. take 2 seconds to build pressure and have more then 80 psi with cold oil.

 

[seapotato]

Give this a read,

https://forum.ih8mud.com/diesel-tec...432-edic-relay-oil-pressure-timer-repair.html

might be worth checking how long it takes to build pressure with a stop watch...

cheers,
ryan

 

[BJ40ER]

Awesome information on what Psi everything is typically Wedg3

And the information on the EDIC Relay Oil Pressure Timer Repair thread was perfect, it seems very plausible that this is my problem seapotato! Thank you very much for leading me to this thread!!