MM85

Hi I’m new to the forum and needing some help, I fully deleted the afm/ dod and disabled the dod system with a handheld tuner (Diablo tuner). All stock parts and tune just non dod (cam, lifters, valley cover). Motor sounds great but oil pressure is having an issue. Oil pressure has always been low with this vehicle 30-35 on startup and 18-22 roughly when motor is warm. I took it for a drive around the block after idling in the driveway for 15-20 minutes and 5 minutes into the drive the oil pressure slowly dropped to nothing. I shut it of immediately and gave it a few minutes then restarted the motor and oil pressure was back up to “normal” so I drove it home then confused to let it idle with no issues. What could it be? The motor remained quiet throughout this entire time, not knocked like it was starving for oil.

thanks, Mike

grinder11

iTrader: (1)

First guess would be the junk GM oil sender. Replace it, and report back......

MM85

The oil pressure switch at the back of the valley cover? It’s a new ac delco switch

bbond105

I have had new parts be bad right out of the box. I always hook up a manual gauge to confirm oil pressure.

tech@WS6store

iTrader: (2)

Did you remove the screen in the valley when you replaced with new flat cover?

Also did you plug the oil pan bypass AND ALSO did you change the cam?

MM85

Yes I replaced the cam with a non dod cam, regular stock lifters, and the o ring style valley cover. I did not replace the cam retainer plate or oil pump, but I did replace the o ring with the correct o ring. I also installed a new screen with the new oil pressure switch.

MM85

I did not plug the oil bypass in the pan, I was told by a gm tech it wasn’t necessary.

MM85

I am going to replace the cam retainer plate, block the pressure relief in the pan, and a new oil pressure switch. Is it worth swapping the oil pump? I’ve heard issues with the stock milling pumps this is the only reason why I ask. Thanks

G Atsma

The stock pump in DOD/AFM/VVT engines is a high volume pump, which you don't need. Get a Melling high pressure pump. They are very good quality.

Che70velle

iTrader: (6)

Did you use a thick assembly lube when putting these parts in? A thick assembly lube will often clog the tiny LS oil filter element, sometimes briefly until it can dissolve…sometimes it won’t dissolve…depends on what you used. Maybe change the filter and see what the pressure looks like. I always recommend cutting the filter open with the correct tool, to see if the engine Is making metal. I’ve seen quite a few guys change a camshaft in these LS engines and mess up a cam bearing also.

MM85

I used the Lucas assembly lube and I’ll see what I can do about cutting the filter open with a pair of cold cutters (I don’t have a the tool).

Also, This engine is just afm/ dod with a plain timing gear no vvt. What would be a good model melling oil pump? I was going to put an m295 in with a new tube assembly and also plug the relief.

MM85

Ok I got the filter apart and it’s dirty but nothing unusual. No metal chunks In the new filter or the old filter. The old filter was removed after a Dod lifter failed but again no metal chunks in that filter as well

Che70velle

iTrader: (6)

Any change in pressures with new clean filter in place?

MM85

I installed a new 10295 melling pump, oil pickup tube, cam retainer plate, plugged the oil pan pressure relief and new ac delco switch today. I’ll prime the pump and start it up tomorrow and see what I got. Im hoping this gets it right. I wouldn’t doubt if the sudden pressure drop was the oil switch clogged or junk.

pdxmotorhead

What kind of shape is the ol pressure sender screen in? (If you have it) its in the hole the sender threads into, they can get fouled and block flow to the gage.

MM85

The screen looked clean. At start up I got 40 psi cold and right at 30 on the gauge on the dash after warm-up. Motor is running smooth, but I do have a very quiet tick on the passenger side. Definitely not a knock off. It almost sounds like a small exhaust leak, but does not get loud with an rpm increase. Sounds like it goes away

MM85

The screen looked clean. At start up I got 40 psi cold and right at 30 on the gauge on the dash after warm-up. Motor is running smooth, but I do have a very quiet tick on the passenger side. Definitely not a knock off. It almost sounds like a small exhaust leak, but does not get loud with an rpm increase. Sounds like it goes away

pdxmotorhead

FWIW I've had exhaust manifolds that would seal up with a little heat in them and get noisy when they cooled, foudn that loosening all the bolts, warming it up then torquing them down while war occasionally fixed the issue. I also use a MLS exhaust manifold gasket.. The manifolds may need a visit to a good machine chop for a light cut on the sealing side.

MM85

I’ll have to check if the manifolds are leaking and re-torque them

gilmoresalvage

How did your oil pressure ever get? Did it stay constant or fall again?