Guys, Here is the deal, Fresh big block rebuilds, Dyno'ed, Sheets show oil pressuer 49.5 @ 3000 rpm, 51.8 @ 5500 rpm, only change from dyno pulls are dressed out motors , have stock remote oil coolers, and remote oil filter set up with 1/2" lines.. problem is on start up oil pressure is good on both . after warm up @ idle my port oil gauge reads close to 10 psi to 0 psi !! Full roller valve train. Engine is not ticking or knocking, not over heating, start fine.after running hard.. pressure on both motors read 40-50 crusing, tried mechanical gauge reads identical ? On my second oil change less than 20 hrs, cut filters they are clean?? talked to my builder he said not to worry ?..I plan on installing larger coolers this winter.. using Castrol 15 w 40 oil..

Put a new sending unit on.

Mechanical guages are reading the same as his electric, so this won't change anything.

Run some straight 40 weight Valvoline Racing oil or M1 15-50 and retest.

You probably need a bigger oil cooler.

There could be an issue with the oil bypass as well.

I agree with Griff, mechanical gauge is correct!

How about an oil temp gauge?

If not, you can get an infrared temp gun and shoot several areas of the engine oil pan, cooler and lines.

Should be somewhere between 210 and 330 degrees after a real hard run.

Just a thought.

Dave

330? is this a typo? I would not run it higher than 280. Over 300 you are risking an oil related bearing failure. Oil temp gauges are just as important as water temp gauges on hi perf. engines. I'm still amazed at the number of people that don't have them.

anyone have the line drawing of oil path flow on a gen VI ?..where is the bypass ?

bypass is under the filter adapter pad.

It should be removed in my opinion

Dave,,,,you need to get an oil temp of whats in your pan.

Give me a call

Thanks Dennis..I'll call ya..Can you get me a decient price on some correct size coolers ?I'm doing a dash up grade adding temp oil temp gauges.. I hook some up temporally to check..Shoot me your number again..

Yep typo...Meant 300 TOPS. Only a spike to 300 though after a real long WOT run. Thanks for the catch!

Dave

What generation engine block are you running ?
If you are running a gen 5 or 6 there are two bypass valves installed in the engine block one for the filter bypass and the other one is for the gm factory remote oil cooler witch is up inside the block where the threads for the remote adapter would bolt up to the block remove the one in the middle. where the adapter is and the one offset needs to be changed to a 30 psi or plugged so all the oil will go throught the filter and cooler.
Do a search here on bypass valves
dont run until you get your problem sorted out with the right bypass valve or you will be removing the engines due to you buring them up like a lot of other guys have done. I spent a lot of research on my set up with the right bypass valve install I still have not fired up my engine but for right now I'm only running a filter on the block and will be motioring the oil temp then going from there I hope I can run just a larger filter and no cooler my set up is pretty light 24 foot boat, and make sure you run a good filter like napa wix do not run fram they are junk.


GM (General Motors) 25161284



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25161284 - 1991-2000 & 454 - 502 GM Performance Crate Engines Big Block Chevy Oil Filter Bypass Valve - 30 LB Bypass Pressure Used With Sandwich Adapter For External Oil Cooler Only 25161284


Pace Price Qty
$7.95



Detailed Description
Used on Gen V & VI engines when running an external oil cooler with a sandwich adapter between the block & oil filter. The 30 Lb valve compensates for the restriction caused by running an external cooler. Used in the location adjacent to the oil filter nipple on the oil filter pad. For standard non-sanwich adapter applications use GM # 25013759

25013759 - 1991-2000 (And GM Performance Parts 454 & 502 Engines) Big Block Chevy Oil Cooler / Oil Filter Bypass Valve 25013759
Gen V & Gen VI Engines Use 2 Of These

Pace Price Qty
$6.95



Detailed Description
Gen V & Gen VI Big Block Chevy Engines & All GM Performance Parts 454 & 502 crate engines use two of these bypass valves. Location for oil filter bypass valve is adjacent to oil filter nipple on oil filter mounting pad, Location for second valve (For oil cooler bypass) is above oil filter nipple in block on filter mounting pad. If a cooler is not connected to the oil cooler ports on the oil pan rail, the second valve is not needed. Engines using a sandwich adapter between the block and oil filter to connect a remote oil cooler must use GM # 25161284 oil filter bypass valve (in the location adjacent to oil filter nipple) to compensate for higher system backpressure






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