Engine swap

[force11b]

Hi Everyone,
Just have a quick question. This past weekend I finally got my engine swap done. I pulled my rebuilt 350 from my 70 GM and replaced the worn out 305 in my 83 Chevy 4X4 4 speed. The trouble is now at idle my oil pressure sits at the bottom quarter (about 100-110 KPA) and at most slightly less than 200 KPA when cold. In the old truck the mechanical gauge would max out at cold starts and drop to only half gauge at warmed up idle. Any suggestions or am I just being paranoid?
Thanks for the help!

[force11b]

Also 110 KPA is about 16PSI.

[bobcooter]

200 KPA is roughly around 29 psi if my math is right. Is this at idle?  I think I would check it with a different gauge so I could sleep at night.

[force11b]

its just under 200 at cold high idle.....once warm it drops to just over 100 KPA. 

[jaredts]

I see more of a problem with the numbers from your old motor.  Same weight oil in both motors?  Have you checked your idle speed?  Idle speed a little low can bring pressure from a healthy 30psi down to your 16psi pretty quickly.  Even if your idle is correct I don't think 16 at idle is the end of the world.

[force11b]

Exact same oil as before. I know the motor was built with a HV oil pump. We did adjust the idle down greatly after the swap  because it was racing......could that caused this? We couldnt figure out why is was racing because it always idled low and smooth in the other truck.

[force11b]

But now when I rev the engine at a warm idle, the pressure doesn't jump up like it used to, instead it moves up just a little.

[jaredts]

I think it would be best if you could get a tach. hooked up to set your idle speed properly instead of what sounds right.  This will have an impact on your idle oil pressure.  Have you driven this thing yet?  What's the pressure when you're driving down the road?

[force11b]

Driving down the road at about 45 MPH is about 15-16 PSI.

[jaredts]

Driving down the road at about 45 MPH is about 15-16 PSI.

  Oh, that's not good.  Scrap my comments about idle speed, that's insignificant.  I agree with the previous comment about verifying the gage.  Have you looked at oil flow under the valve covers?  What weight oil are you using?  Have you heard the valves tapping?

[force11b]

the motor sounds good and I am using Esso 10-30 XD3 oil. How would I go about checking the heads through the valve covers?

[Lt.Del]

dont rule out a bad sender as well.  I had to replace one on my '91.

[force11b]

Is there anyway to test the sender or is it just a case of replace and see?

[bgctrading]

Make sure you verify the gauge is working. It kind of sounds like you may have knocked some sludge or silicone loose during the swap and maybe it is clogging the pickup tube slightly.

[force11b]

Well i just did more work on the truck. When I disconnected the wire going to the oil pressure switch the gauge when right to the top. This must mean that the gauge and wiring is good and must mean it is either the switch or the motor itself.....right? Its also odd to me that the new built 350 seems to sit at the same oil pressure as the tired old 305 with 275,000KMs used to sit.