no oil pressure

[620man]

:confused:I have a 1978 datsun 620 pickup with a new l20b engine and a good oil pump but I have no oil Pressure how do I fix this.

[datzenmike]

How do you know that there is no oil pressure.

[620man]

How do you know that there is no oil pressure.

The oil light is on and its not getting any oil in the top end

[datzenmike]

Check oil level on dip stick.

 

Unplug the sender (Yellow/Blue stripe) wire it's just to the left of the oil filter. If the light does not go out the wire is rubbing against a ground and that is why the light is on. If it goes out then there may be a problem with the sender ... or worse.

 

Unscrew the oil filter and crank the motor with the coil wire off. Be warned this could be messy. If there is oil pressure to the filter it will spray all over so have a pan to catch it and hold a rag over it.

[banzai510(hainz)]

If oil squirts out as DatzenMike said for where the oil filter comes from

try another brand filter. Im just winging this one here!!!!!!!!!!!!!!!!!

 

maybe the oil pick up fell off.

 

you can always pull the oil pump and turn it and see if it moves oil but remember to set motor to TDC and install pump /distributor correctly

http://www.guba.com/general/search?query=hainz&set=5&x=0&y=0

[banzai510(hainz)]

http://www.olddatsuns.com/620tech.htm

[620man]

Check oil level on dip stick.

 

Unplug the sender (Yellow/Blue stripe) wire it's just to the left of the oil filter. If the light does not go out the wire is rubbing against a ground and that is why the light is on. If it goes out then there may be a problem with the sender ... or worse.

 

Unscrew the oil filter and crank the motor with the coil wire off. Be warned this could be messy. If there is oil pressure to the filter it will spray all over so have a pan to catch it and hold a rag over it.

I already unplugged the sender and the light went out, the pump is brand new and I already checked it. I also put an old pump on that I had and new was good and still nothing. my dad and rebuilt the engine it fires right and purrs just no oil pressure.thanks for the help

Edited November 8, 2008 by 620man
mispelled word add a sentence

[datzenmike]

Did you fill the pump with oil to prime it? It will have trouble sucking the oil up from the pan if it's empty.

[620man]

Did you fill the pump with oil to prime it? It will have trouble sucking the oil up from the pan if it's empty.

 

yup did that just like the book says

[Fineline]

Before you started it did you pull the plugs and crank it over untill you had pressure? When I put the new motor in my truck I had to crank it like that for 30 seconds or so untill it had oil to the top end.

[620man]

Before you started it did you pull the plugs and crank it over untill you had pressure? When I put the new motor in my truck I had to crank it like that for 30 seconds or so untill it had oil to the top end.

no i did not do that I'll try that. thanks

[420n620]

I bought a 74 620 w/L18 that has been sitting for 4 yrs. All I did was put 5 qts of 30w in it, then pulled the plugs out, took vavle cover off, applied sum lube on lobes. cranked it over for about 10 second intervals so not to burn up starter, I could hear the motor turn easy at the start then it started to slow down just a little, about the forth time turning it over I got oil to the top coming out of all the oiling holes.

very ezzze japaneeze :D

[620man]

I bought a 74 620 w/L18 that has been sitting for 4 yrs. All I did was put 5 qts of 30w in it, then pulled the plugs out, took vavle cover off, applied sum lube on lobes. cranked it over for about 10 second intervals so not to burn up starter, I could hear the motor turn easy at the start then it started to slow down just a little, about the forth time turning it over I got oil to the top coming out of all the oiling holes.

very ezzze japaneeze :D

thanks I'll try that the truck is at my parents house about 45min away and I'm goning down next weekend i'll let you know how it turns out

[banzai510(hainz)]

head gasket oil holes blocked?

aftermarket cam and the Back of the cam is open(made for a spraybar set up)

 

is that ball valve stuck? I dont know what it does but i make sure its not stuck

 

 

I have no more ideas!!!!!!!

[620man]

head gasket oil holes blocked?

aftermarket cam and the Back of the cam is open(made for a spraybar set up)

 

is that ball valve stuck? I dont know what it does but i make sure its not stuck

 

 

I have no more ideas!!!!!!!

 

the cam is stock i'll check the ball valve. I had the block burned out and honed before I built the engine, I don't know how they burn out the block but thats how they do it at the shop I took it to instead of hottanking it I don't know if that could have done something.

[420n620]

heres what I would do first, take the oil sending unit out and see if you got oil coming out(while cranking injun), if you don't then go check the regulator valve and the regulator spring - which is external. Something might be lodged in there and keeping it open or sring is weak or broken, if everything looks good then maybe like what hainz says, maybe the pickup tube had falling out/off, I'm not sure if there bolted on or pressed in. well anyway, I guess we will have to wait and see what you have done.

Edited November 10, 2008 by 420n620
bcause i can ???

[620man]

So where is the regulator valve? and the pickup tubes are bolted I'll pull the oil sending unit out and try that two thank for the ideas

[datzenmike]

is that ball valve stuck? I dont know what it does but i make sure its not stuck

 

 

The ball valve only operates if the filter should clog-up and there is no oil flow to the motor. UNFILTERED Oil under pump pressure will push past the valve so the engine does not go dry.

 

The oil pressure regulating valve is on the side of the pump at the bottom. There is a large thin nut with copper washer facing the rear of the motor. Under the nut is a spring and a small piston that is pushed by pressure against the spring exposing an opening for the oil to re-cycle back to the inlet of the pump and regulate the pressure dependent on the spring stiffness.

 

I actually had a piece of casting jam the piston so it couldn't regulate properly. At low speed in town it was fine but on the highway, the high revs split the oil filter around it's base.

Edited November 10, 2008 by datzenmike

[Bugeye]

normally what i do is take an old dizzy apart, use the shaft in my electric drill, and with the trucks dizzy removed use the drill and spin the oil pump manually with out cranking the engine, just to see if oil is getting to the top end

[datzenmike]

Here's mine:

 

http://i138.photobucket.com/albums/q251/datzenmike/motor720preoiling9Large.jpg[/img]"]

 

The stiff rubber tube acts like a U joint.

[620man]

thats a good idea with the dizzy i'll give that a try thanks:)

[datzenmike]

To get the drive gear off heat with a torch and pound off with hammer.

[racerx]

Squirt some oil inside spark plug holes and squirt around timing chain, valve train area...it takes awhile for oil to come up and get reading. Several months ago, I replaced my tired L16 with rebuilt L18 and took a while for oilt to read.

[620man]

cool thanks for the input

[620man]

Problem fixed when my dad and I put the engine togther he made a gasket for the pick up tube. he made the bolt holes but forgot to make the center hole for the oil to flow through thanks to every body the who gave input:D