Oil Pump

[FFRSpec72]

So last set of races I was running low oil pressure (running remote filter and oil cooler) and good oil and water temps, so I'm going to test oil pressure with manual gauge to make sure its not the electronic gauge.

So question is are folks still set on a normal volume/normal pressure oil pump, as if I have low pressure and bearings are OK, I was going to move to a high volume normal pressure pump so I can get the pressure up as I feel that 30-35PSI @ 5000 rpm is a little low. Engine is brand new at the start of last season with about 10 races on it.

[avgjoe]

In my shadetree opinion I would stay away from high volume or pressure pumps at this point. That would just be a bandaid to mask the problem. I would suspect that maybe the relief valve (bypass, ...) is hung open or the filter is clogged up a bit. Of course it could also mean that you wiped a bearing. The first thing I would do is pull the filter off and cut it open to see what it collected if anything.

I believe that you have to build an engine w/ the idea of using a HV or HP pump from the start. These pumps move a specific volume of oil per revolution and it has to go some where. That some where is through the filter, past the pressure sensor, to the bearings ( crank, cam, lifters, ...) then back to the pan. The tightness of the passages past those places will affect the pressure observed at the gauge. If any one of those tolerances open up, or there is more if a restriction in the filter you'll see a lower pressure.

You recently removed you PCV and went to a breather setup, yes? I'm not sure how much an affect the different crankcase pressure would affect the oil pressure; I would think it would be marginal.

Good luck and keep us posted,
Joe

[Mark Dougherty]

Tony
start with a filter check, as recomended. pick up a longacre filter cutter and that will make short work of the job.
second if all looks good in the filter.
check the oil psi sending unit. i have had atleast 6 sending units go bad over the years on different cars. I just replaced one 7 days ago on a car that had low idle oil psi., like 3 psi. after warming up.
as for the high volume oil pump I use them frequently on used engines. but remember the more oil you are pumping the more HP it takes.
Later
Mark D

[FFRSpec72]

So took off filter and cut it open and examined (engine shop also looked) and looks clean (so I don't suspect warn bearings), no issues. I'm running a Melling Select std volume/pressure pump now. I'm run a WIX racing filter, seems that pressure was higher when running the Ford Racing filter. I checked the pressure with a mechanical calibrated gauge and pressure with the electronic gauge was only about ~3-4 pounds less then the mechanical gauge. The pressure cold is about 45 lbs at idle and 20 lbs hot (after 30 min race), and runs about 35 lbs max during race. The pressure climbs as rpm increases.

If the oil pump bypass was stuck I don't think I would see the 45 lbs @ cold idle. I'm running Joe Gibbs XP7 (10-40 semi synthetic oil) and may switch to a 20-50 (Joe Gibbs or Royal Purple fully synthetic) to see if I'm getting viscosity breakdown at high temps, but engine temp is only 160-180 and oil temp is only 220-230 max during race. I did not check the pressure with a mechanical gauge after engine was hot.

If the change in oil does not make a difference then I will pull pan and check the bottom end and pump for issues.

I don't expect a change in pressure due to the ventilation since the 302 PCV does not really work at WOT anyway and that is where I am during most of the race.

[Doutie]

I was involved with a roundie round Camero running a 600 HP 455 Ponitac and experienced the same problem when we tried a remote filter set-up. The stock filer mounting had the headers wrapped around it, making a filter change very hard and impossible when hot off the track. I tried oversized hoses, porting of filter base, and adaptor plate, and still had flow problems. Finally put stock mount back on and oil pressure returned to normal. During all of this, we tried different oil filters and found that cheap filters had larger pores and flowed more oil than good filters. Makes sense, a good filter does more filtering.