Yellow Bullet Forums banner

1 - 20 of 32 Posts

·
Registered
Joined
·
4,202 Posts
Discussion Starter #1
I have just noticed that on a full 1/4 mile pass that when I let off the gas my guage goes to 0 and doesn't start to climb back up for about 2-3 seconds.. When I put this motor together I measured everything and have the right pickup and pump for my pan.. Its a 6 quart pan.. I put 7 quarts in it and went again and it still does it.. I have over 100 passes on it and im betting its did it the whole time.. Any tips on how to fix this issue.
 

·
Registered
Joined
·
4,202 Posts
Discussion Starter #2
I should also say it is just a hv pump.. my oil pressure is on the low side 60psi cold and then at idle it is very low.. Going to freshen up this winter. may only run it 1-2 more times this yr and then take it apart. There are no mods to the block as far as the return holes or lifter valley painted for faster return
 

·
Registered
Joined
·
1,229 Posts
Either the pump is filling the top of the engine with oil and it's not returning to the pan in a timely fashion, or your pan isn't baffled / restricted enough around the pick up point and it's sloshing away when your on the brakes.

If the oil is moving away from the pick up point occasionally you can add a quart or so and get the issue to subside but it's just a bandaid for poor pan design. I've got a cheapy stef's pan on my car and it will do it if I run less than 9 qt's in the system with my external pump set up. If i have 9-10 in the system I have 40 in the shut down, even on real short shutdown tracks. I'll be getting a nice pan as soon as my bank account allows.
 

·
Registered
Joined
·
2,761 Posts
Very unlikely that all of the oil is being pumped to the top of the engine . . . . .
Look closely at the clearance between the oil pump pickup and the floor of the pan. Too little clearance will cause the oil flow to be restricted at higher RPM, resulting in low oil pressure.
If there is oil pressure at the end of the run and pressure drops only after you lift or apply the brakes, then the oil is being forced away from the pickup, as noted in post #3.
 

·
Registered
Joined
·
4,202 Posts
Discussion Starter #5
Very unlikely that all of the oil is being pumped to the top of the engine . . . . .
Look closely at the clearance between the oil pump pickup and the floor of the pan. Too little clearance will cause the oil flow to be restricted at higher RPM, resulting in low oil pressure.
If there is oil pressure at the end of the run and pressure drops only after you lift or apply the brakes, then the oil is being forced away from the pickup, as noted in post #3.
so if thats the case what do i do about it. meaning oil being forced away
 

·
Registered
Joined
·
4,164 Posts
We used a pan with one way trap door in front of pick up...oil would flow to pick up under power and was trapped to the pick up under brakes.
 

·
Registered
Joined
·
3,339 Posts
Pretty common for the oil to rush away from the pick up during shutdown with a mass produced store bought pan. I had a Moroso pan that would loose 1/2 the oil pressure in shutdown... it did any damage to the engine.

As George said really good pans have a trap door to prevent this... my new Kevko pan has a V shaped diverter and doors infront of the pick up and oil pressure is rock solid even when slowing from 155+mph.
Will
 

·
Registered
Joined
·
1,239 Posts
When you get your clearances correct and a good pan, this is the oil pump you will need, Melling 10552C 10% over pump. No need for the HV pump.
 

·
Registered
Joined
·
4,256 Posts
One thing I found on my digger before I changed pans was if I ran 20w50, oil pressure in the shutdown would always go to zero, then climb back up....I switched to 10w30 and with no other changes it would maintain about 20 lbs in the shutdown area. Same amount of oil, same pan. New combo is getting a different pan and more work on oil returns, but still going to run the lighter oil.....
 

·
Registered
Joined
·
4,202 Posts
Discussion Starter #14
One thing I found on my digger before I changed pans was if I ran 20w50, oil pressure in the shutdown would always go to zero, then climb back up....I switched to 10w30 and with no other changes it would maintain about 20 lbs in the shutdown area. Same amount of oil, same pan. New combo is getting a different pan and more work on oil returns, but still going to run the lighter oil.....
I do run 20w50. I don't have the best oil pressure with it as my bearings are about shot I think. That's why I run thick oil. Cold psi is about 50 at idle and it can be as low as 15 hot.
 

·
Registered
Joined
·
4,256 Posts
I do run 20w50. I don't have the best oil pressure with it as my bearings are about shot I think. That's why I run thick oil. Cold psi is about 50 at idle and it can be as low as 15 hot.
thicker oil is slower to circulate. Heavier oil also doesn't mean better lubrication. It's all about oil flow to the bearings. I'd take more flow at a lower pressure than less flow at a higher pressure anytime..... I'm at about 20-25 hot, 1000-1100ish idle rpm, about 60-70ish down track......Actually going to turn it down just a bit.
 

·
Registered
Joined
·
1,239 Posts
I will look into that with my new pan and pickup.. Is that a high pressure pump.
Here is a little info on it.



10552
  • High volume performance oil pump.
  • 10% increase in volume over stock oil pump.
  • The 10552 is manufactured with the drive and idler shafts extended to allow for additional support in the cover eliminating dynamic shaft deflection at increased RPM levels.
  • The cover is doweled to the pump housing to assure alignment of the shaft bores.
  • Screw in plug retains relief valve spring instead of pin.
  • Relief hole in cover uses screw in plug instead of pressed cup plug.
  • All bolts are self locking socket heads, with the wrench supplied.
  • The housing and cover are CNC machined and phosphate coated.
  • Includes intermediate shaft with steel guide. Uses both 3/4” bolt on or press in screen.
  • The lower pressure spring is included to reduce pressure if desired.


10552C (Anti-Cavitation)
  • High volume performance oil pump.
  • 10% increase in volume over stock oil pump.
  • Same as the 10552 with the addition of grooves machined in the body and cover. The grooves reduce cavitation effects in high RPM applications.
  • Includes intermediate shaft with steel guide.
  • Uses both 3/4” bolt on or press in screen.
  • Using this oil pump will reduce pressure at idle.
  • The 10552C uses the high pressure spring only.
  • Racing Applications Only.
 

·
Registered
Joined
·
1,239 Posts

·
Registered
Joined
·
2,117 Posts
I had one of the Moroso step type pans and every time I hit the brakes oil pressure would go to zero for a long time! I put a full length Milodon dragster pan with baffles on it and no problem at all now.
If the problem is due to much of the oil ending up on top of motor a thinner oil will drain back faster but lower pressure a little. You need to try to figure out if it is bad oil pan design or too much oil up on top.
 
1 - 20 of 32 Posts
Top