Help! High pressure at the Dyno

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LIME TWIST DART

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So, they fired it up and it hit 100psi at 3k. Builder, not original builder and did not assemble the bottom end, said we can pull it off and start by looking at the pump. Or, since we have it here, put in thinner oil and see if it holds steady or climbs very little up to 5k. I'm not there at the moment and am trying to make a decision on the fly. Thoughts? Anything constructive is welcome. Thanks

Here is the setup:
408 stroker
LA 360 Bored 30 over.
Full roller.
Eagle 4" Crank.
Ross Pistons.
MAKE BORE STROKE ROD LGTH DOMECC DOME HT. GRAM WT. C.H. PART NO.
360 4.030 4.000 6.123 3.0 11.5 479 1.459 99789^
Comp Cams 20-740-9 Xtreme Energy™ Mechanical Roller.
Edelbrock Performer RPM's. Surfaced and stage III ported.
Edelbrock Victor 340 Intake Manifold. Port matched.
Holley 4150 850 carb.
MSD dist/coil/wires.
3/8 pushrods.
ARP head bolts/main studs.
Isky Valve Springs 9265.
Billet Timing Set.
Melling High-Volume Oil Pump M72HV.
Milodon UP18346 Pick Up
POWER BOND BALANCERS PB1004-SS.
 
What weight is in it now? I would try a standard volume pump with a high pressure spring.
 
Baxter61 said:
What weight is in it now? I would try a standard volume pump with a high pressure spring.
Click to expand...

I am not well versed in this area, but I realize the existing pump may have an optional high pressure spring and think that may be the culprit. Don't know what weight they started with. Just got home and putting all the info together. Fixing to give them a call.
 
I would not call 100 psi on a new build "extreme"
 
Depending on the oil clearances, bearings, and expected rpm range - the HV pump is not needed. If I had that much I'd pull the pump and replace it with a stock pump with the HP spring. I aim for peak oil presure around 65-70psi and most will reach that by 3K. I think it's just too much pump volume.
 
I agree a stock pump with maybe the main feed whole drilled to 7/16:blob:
 
100psi is too much though. I had oil filter issues when I ran a hv pump & 20-50 oil on my previous small block. Since it's not in the car, I'd also put a stock volume pump in it.
 
I've had pressures start over 100 on a new, cold engine, reving it up, especially with higher viscosity break-in oil (15w-40). After many cycles of warm/cool break in, change to a lighter oil (5w-20) and some moderate passes, it's gone down and stabilized at reasonable pressures. I've been using stock oil pumps and, I believe, stock springs.

Being on the dyno is nice because you can run it through several cycles, load it several times and still have an easier time getting to the oil pump and bearings if still not comfortable with the pressures.

Not that I think clearances are too tight, but it may not hurt to cut open & check the filter, just for peace of mind. Oil pan drain magnet?
 
Hot versus cold really matters. 100 PSI with 40 wt. oil in a cold engine @ 3000 RPM might be fine, if it drops to 50 psi when hot. 100 PSI at 3000 RPM when hot is too high, you risk blowing the filter off the car and just as importantly you are giving away HP by moving that much oil.

10 PSI per 1000 is plenty.

Regards,

Joe Dokes
 
Yesterday it was 2 small pulls to 3k on 20-50 oil. PSI at 100. Today, dropped oil to a 5 and made 6 more pulls that rolled out around 30 PSI and settled in at 75 to 80. Took it to 6,200 RPM. I think the motor was coming in a little tight and now looks good. I will switch weight when I get it in the car and go from there. If I don't like what I see, then I will make a change to the pump and/or spring. Thanks for all the advice. I am going to update the Dyno thread here http://www.forabodiesonly.com/mopar/showthread.php?t=259906
 
Sounds better and might settle down after some other running. I forgot to mention for the most part I run 10-30.
 
moper said:
Sounds better and might settle down after some other running. I forgot to mention for the most part I run 10-30.
Click to expand...

Thats my plan. To run 10-30. Thinking I might run the lighter stuff for 100 miles since we already changed the oil after the first 2 pulls.
 
I've been told that the Melling high volume oil pumps were resulting in very high oil pressure numbers. You might want to check this out. Hope this helps.
 
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