Oil pressure drop thru 1/4 mile

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Oil pressure drop thru 1/4 mile Empty Oil pressure drop thru 1/4 mile

Post  Derek Wood on June 5th 2012, 3:09 am

Any ideas why the oil pressure would drop from 80psi to 50 psi during a 1/4 mile run ? Jeff Johnson pan Titan pump lots of oil in pan Acusump for backup. 50wt Lucas, System1 filter, A460 block, aluminum rods, restrictors to top end.
Thanks for the input. Derek
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Post  cturk1010 on June 5th 2012, 6:05 am

how hot do you start run at and temp at shut down

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Oil pressure drop thru 1/4 mile Empty oil filter

Post  slurm on June 5th 2012, 9:51 am

I am having the same problem with a supercharged 540 a-block, kaase pump, but with a canton remote filter. Took the filter off my funny car and placed on my fathers imca mod and burned up two 347 engines. Now running stock style filters with no problems. Is there a cavitation problem?
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Post  Derek Wood on June 5th 2012, 10:54 am

cturk1010 wrote:how hot do you start run at and temp at shut down

around 160 at the line and 180is at the finish.
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Post  bruno on June 5th 2012, 12:13 pm

just curious on what kind of times are you guys running ?
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Post  the Coug on June 5th 2012, 2:28 pm

do you have a windage tray in this engine?
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Post  Derek Wood on June 6th 2012, 2:46 am

the Coug wrote:do you have a windage tray in this engine?

Yes it is a short louverd tray between the rather large Titan pump and the dual tube pickup. Nice pan, big kickout, lotsa baffles and the pump looks good all round. Any bad experiance with System 1 filters?Thanks for any input. Goin racing Thursday.
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Post  Derek Wood on June 6th 2012, 2:55 am

bruno wrote:just curious on what kind of times are you guys running ?


First race outa the box was an 8.93@154 finished that weekend with an 8.89@150. The second weekend with a full scale 4 link readjustment an 8.80@153. 60 foots not all there yet. Trying to tighten the converter with synthetic for this weekend. Next step out it comes for a change.
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Post  the Coug on June 6th 2012, 6:11 am

ok Derek remember are your lifters are the link bars to the valley or to the cylinders? and you say it is restricted oil to the top end did you restrict it front? back? or both? what size restrictor holes? are you sure the drain back holes are lined up with the gaskets and block? how much main and rod clearances? what weight oil? how far is the oil pick up from the oil pan?
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Post  LivermoreDave on June 6th 2012, 6:51 am

Derek Wood wrote:
the Coug wrote:do you have a windage tray in this engine?

Yes it is a short louverd tray between the rather large Titan pump and the dual tube pickup. Nice pan, big kickout, lotsa baffles and the pump looks good all round. Any bad experiance with System 1 filters?Thanks for any input. Goin racing Thursday.

Could the style of oil pump pickup you incorporate within your engine be the problem? I assume the pickup's intakes are fore and aft. If this is the position of the two, could the fore located pickup become uncovered during acceleration and after being uncovered, become a "leak"? With the oiling system equipment you mention, I can't imagine an oiling problem with delivery or supply during acceleration!

Just another opinion,
Dave.

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Post  rmcomprandy on June 6th 2012, 9:27 am

IF ... rod bearing clearance is not to wide then the oil is not acting correctly in the pan around the pick-up(s) while RPM rises.

Figure out that cause and you will most likely fix your problem.

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Oil pressure drop thru 1/4 mile Empty A Couple of Thoughts

Post  mkopmani on June 6th 2012, 8:01 pm

Unless the oil has been heated before you run, I might guess that you may be starving a bearing and opening up clearances. Pop a main cap off if it's a chassis car.

Although the screen type filter should be pretty unrestrictive, it's a possibility that you may have a restriction there either from debris (bearings) or from the heavy oil which starves the motor at high rpm.

As the pump is not load sensitive, you might free rev the engine at a speed that's high but safe and see if the pressure drops. This would tell you if it's related to the acceleration.

With the difference in temp that you indicate, clearances would not increase that much to result in such a pressure drop.

Are you sure that your system capacity is correct between the pan and Accusump? If not, you might be pumping the pan dry into the Accusump.

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Post  Derek Wood on June 7th 2012, 2:40 am

mkopmani wrote:Unless the oil has been heated before you run, I might guess that you may be starving a bearing and opening up clearances. Pop a main cap off if it's a chassis car.

Although the screen type filter should be pretty unrestrictive, it's a possibility that you may have a restriction there either from debris (bearings) or from the heavy oil which starves the motor at high rpm.

I like the heavy oil theory, the filter gets regular inpections and hasn't indicated bearings as yet, alittle cast a little lint and some indication of aluminum chips from the incorect clearance on the valve cover flange...although the oil pressure should stay low if it was a filter restriction due to oil weight, but when you factor oil speed through the filter during the run it could definately be a factor.

As the pump is not load sensitive, you might free rev the engine at a speed that's high but safe and see if the pressure drops. This would tell you if it's related to the acceleration.

Going to the track tommorow, made some changes, will post results. I will take some lighter oil and already have a filter replacement in stock, and I will try to get in that free rev, could provide usefull data.

With the difference in temp that you indicate, clearances would not increase that much to result in such a pressure drop.

Are you sure that your system capacity is correct between the pan and Accusump? If not, you might be pumping the pan dry into the Accusump.

And yet another good question. Ive put up to 18 ltrs into the pan so 1 in the filter and approx 2 in the accusump 15 in the pan. At 45psi I get about 2 ltrs from the accusump. at 80-90psi do I get double?


Cheers and thanks for the great perspective.
Derek

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Post  Derek Wood on June 7th 2012, 2:46 am

rmcomprandy wrote:IF ... rod bearing clearance is not to wide then the oil is not acting correctly in the pan around the pick-up(s) while RPM rises.
Has 1 pickup with 2 tubes Titan pump, Billet fab pan with baffles and balls for decel. Rod bearing clearance is top limit plus a half, aluminum rods. Found a couple of possible causes and am heading to the track tomorrow. Thanks for the great input, Cheers Derek

Figure out that cause and you will most likely fix your problem.
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Post  Derek Wood on June 7th 2012, 2:59 am

LivermoreDave wrote:
Derek Wood wrote:
the Coug wrote:do you have a windage tray in this engine?

Yes it is a short louverd tray between the rather large Titan pump and the dual tube pickup. Nice pan, big kickout, lotsa baffles and the pump looks good all round. Any bad experiance with System 1 filters?Thanks for any input. Goin racing Thursday.

Could the style of oil pump pickup you incorporate within your engine be the problem? I assume the pickup's intakes are fore and aft. If this is the position of the two, could the fore located pickup become uncovered during acceleration and after being uncovered, become a "leak"? With the oiling system equipment you mention, I can't imagine an oiling problem with delivery or supply during acceleration!

Just another opinion,
Dave.

Has 1 pickup with 2 tubes to the back of the pan Titan pump, Billet fab pan with baffles and balls for decel. Wish I could figure out photoshop to post pictures as they say a thousand words. Thanks ror the great input, Cheers Derek
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Post  Derek Wood on June 7th 2012, 3:10 am

the Coug wrote:ok Derek remember are your lifters are the link bars to the valley or to the cylinders? and you say it is restricted oil to the top end did you restrict it front? back? or both? what size restrictor holes? are you sure the drain back holes are lined up with the gaskets and block? how much main and rod clearances? what weight oil? how far is the oil pick up from the oil pan?
Its late and I'm outa steam loading first thing so I gotta go. I'll get back to this when I get back.... lifters to the valley, plugs and restrictor size as per instructions from this site's links and A460 instructions...only thing not done was the distributer gear oiling mod as the cam bearings were in when I read about it. Off to the track, Cheers Derek
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Oil pressure drop thru 1/4 mile Empty Pump Pickup

Post  mkopmani on June 7th 2012, 8:07 am

Derek,
Have you checked the oil pump pickup clearance to the pan? If it's high, you might be pumping the pan dry if it's higher than 5/8" from the bottom of the sump.

Oil recommendation - if you have loose clearances, you'll not want to go to a light oil, but certainly a multi-viscosity oil. Assuming that you're changing because of fuel contamination and don't want to leave synthetic in there, I'd recommend Pennzoil 25w-50 race oil. Don't confuse this with many of the 20w-50 oils, it's specially formulated for race motors. Don't hear much about it, but it also comes in a 70wt that most of the nitro guys use. Dee Keaton (former Dale Pulde, Jack Chrisman, SWC crew chief, turned me onto it. Dee's still sharp as a tack at 76)

Mike

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Post  dfree383 on June 10th 2012, 7:34 am

have you tried running less oil, could be a windage problem.

My last motor had issues running capacity in the pan, when we dropped a quart and a half everything stablized. That was a 9 qt system, no accusump.
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Oil pressure drop thru 1/4 mile Empty KINDING of the same

Post  dave d on June 13th 2012, 9:18 pm

Sorry to jump a thread ,but I"ve got kind of same problem, new motor,same oil pump and pan as prior motor I'm only getting 35lbs at 3000rpm down to 20 at idle-----old motor was running 50--70 lbs.I don't have the specs in front of me for clearences and its 10--30 oil..Will this get better with heavier oil and break in time THANKS Dave champered drain backs on block and drilled dist oil hole.any input greatly appreciated
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Post  bosshoss on June 14th 2012, 12:45 am

Dave, 35lbs with a new motor at 3000 rpm would have me checking to make sure the bearings are not the wrong size or else a missing gallery plug somewhere.

dkp
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Post  cool40 on June 14th 2012, 12:55 am

dave d wrote:Sorry to jump a thread ,but I"ve got kind of same problem, new motor,same oil pump and pan as prior motor I'm only getting 35lbs at 3000rpm down to 20 at idle-----old motor was running 50--70 lbs.I don't have the specs in front of me for clearences and its 10--30 oil..Will this get better with heavier oil and break in time THANKS Dave champered drain backs on block and drilled dist oil hole.any input greatly appreciated
drilled what dist hole? it dont take much drilled hole to kill psi. Shocked
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Post  dave d on June 14th 2012, 9:12 pm

Forgot to tell you it's a solid roller cam,put 50 weight oil in still 35lbs.of pressure,HOW big of shim on to the spring makes how much more pressure.Thanks -----This is a high volume pump, not high pressure Dave Arrow dist hole is to oil cam gear
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Post  cool40 on June 14th 2012, 9:51 pm

dave d wrote:Forgot to tell you it's a solid roller cam,put 50 weight oil in still 35lbs.of pressure,HOW big of shim on to the spring makes how much more pressure.Thanks -----This is a high volume pump, not high pressure Dave Arrow dist hole is to oil cam gear
i've drilled a hole in the plug behind the dist gear and noticed a loss of psi but only after the oil was hot.i'd be looking for the problem cuz you have one. i use 15/40 oil and get 75cold,50hot @ idle with kaase pump.are the lifters in with the bars down? Idea
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Oil pressure drop thru 1/4 mile Empty Re: Oil pressure drop thru 1/4 mile

Post  Derek Wood on June 20th 2012, 2:46 am

mkopmani wrote:Derek,
Have you checked the oil pump pickup clearance to the pan? If it's high, you might be pumping the pan dry if it's higher than 5/8" from the bottom of the sump.

Oil recommendation - if you have loose clearances, you'll not want to go to a light oil, but certainly a multi-viscosity oil. Assuming that you're changing because of fuel contamination and don't want to leave synthetic in there, I'd recommend Pennzoil 25w-50 race oil. Don't confuse this with many of the 20w-50 oils, it's specially formulated for race motors. Don't hear much about it, but it also comes in a 70wt that most of the nitro guys use. Dee Keaton (former Dale Pulde, Jack Chrisman, SWC crew chief, turned me onto it. Dee's still sharp as a tack at 76)

Mike
Pick up clearance is 1/2" currently running 50wt brad Penn. Reducing vacuum pump helps. Still waiting for reply from Billet fab re pickup design. When launched at 3000 pressure is 80psi through whole run launch at 5800 oilpress drops slowly to 55psi.I think the pick up has been modified from it's original design (bought used) and moved forward in the pan. Thanks for the input. Cheers Derek
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Post  Derek Wood on June 20th 2012, 2:50 am

dfree383 wrote:have you tried running less oil, could be a windage problem.

My last motor had issues running capacity in the pan, when we dropped a quart and a half everything stablized. That was a 9 qt system, no accusump.

Tried from 15 to 18 which translates to 12 to 15 in the pan. Will update as we learn. Thanks for the input ,Derek
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