Low oil pressure at idle, pulling my hair out, looking for any and all options.

[kruznlow69]

One of the commonalities I see is that they are all using the 10355 pump (this and other threads across the internet) instead of the M365. It should not matter but it seems to.

What about that pressure relief valve in the pan? Anyone replace that with a plug and still have pressure issues?

We initially put a melling 355 pump in on the rebuild. Swapped that out last weekend B4 pulling. We also plugged the oil pan pressure relief valve this time.

Annnnnnd another Update. Drained a quart out, lil shimmer in the oil .. added a quart of Lucan Oil Stabilizer. Oil pressure did idle higher around 16psi once hot but now we're worried about the shiny shiny. F!!!! Lucas additive shows there's a pressure issue fixed by thicker oil but that's only temporary. We're now more worried about the metallic in the oil. We know it's a fresh rebuild so we will have some but this only ran for 30min or so on refresher.

 

[j91z28d1]

eh it's a fresh rebuild and you've run it on 6psi when warm. I wouldn't worry to much about the shimmer.

I got nothing for the rest thou. do you have a working vvt or did you put a non vvt cam in? just out of curiosity.

the 355 is a high volume pump and it still did it?

 

[kruznlow69]

eh it's a fresh rebuild and you've run it on 6psi when warm. I wouldn't worry to much about the shimmer.

I got nothing for the rest thou. do you have a working vvt or did you put a non vvt cam in? just out of curiosity.

the 355 is a high volume pump and it still did it?

Yeah that's our hope but worried, just doesn't make sense it drops almost 70PSI once warm.

We have noticed with cold start, a lotta lifter chatter, once warm, nice and quiet. Old motor was a diff block but both were 200k miles. Piston slap was terrible.

 

[Dustin Jackson]

I second the oil relief valve question. I've heard that when the oil pressure relief valve in the oil pan fails it can be a major source of oil pressure loss. Summit racing sells a plug for it

 

[swathdiver]

Barbel is new and not in backwards? Is there a way to put a mechanical oil pressure gauge in the various oil galleys to check pressure? Cam bearings were changed?

@Dustin Jackson He plugged that Dustin.

Aluminum engines don't need a lot of pressure, they need volume because of increased clearances once warmed up. The oil pump for aluminum engines pumps 1/3 more volume of oil per revolution than an iron block pump. The 10355 is supposed to have this wider gerotor for more volume but runs at a higher pressure. The M365 is the preferred pump for an aluminum engine, running a yellow 33 pound spring instead of the 43 pound red spring.

Speaking of which, have you taken it out and made sure it moves/operates freely? If not do so, it has caused low oil pressure issues before, even new ones.

 

[Geotrash]

Barbel is new and not in backwards? Is there a way to put a mechanical oil pressure gauge in the various oil galleys to check pressure? Cam bearings were changed?

@Dustin Jackson He plugged that Dustin.

Aluminum engines don't need a lot of pressure, they need volume because of increased clearances once warmed up. The oil pump for aluminum engines pumps 1/3 more volume of oil per revolution than an iron block pump. The 10355 is supposed to have this wider gerotor for more volume but runs at a higher pressure. The M365 is the preferred pump for an aluminum engine, running a yellow 33 pound spring instead of the 43 pound red spring.

Speaking of which, have you taken it out and made sure it moves/operates freely? If not do so, it has caused low oil pressure issues before, even new ones.

I’m running the M365HV in my L94. Had to replace the factory pump due to low oil pressure after my first cam swap. This is a good hypothesis.