Oil Pressue Concern

[UNC017]

Originally Posted By: SteveSRT8

When you changed the cam was the timing gear set and chain done too? Many of my Mopar 318/360's in my fleet back in the day would puke bits of plastic that would clog the screen of the oil pickup. Oil pressure drop was obvious.


FYI, Steve, the Magnum version of the 318/360 never used a nylon coated cam gear. Its got a steel chain (non-roller) and steel gears. It'll get loose enough to make the cam timing sloppy (crank-triggered ignition keeps the spark stable, at least) but in my experience its like a Ford Modular- at multi 100k miles the chain will get so loose that the engine will barely start due to retarded valve timing, but it'll never jump like the old plastic covered cam gears would.

 

[rslifkin]

Yep, it's a steel cam gear. I replaced the chain with a double roller setup when I did the cam swap. I also added the Mopar Performance chain tensioner (which is nylon coated, so it could theoretically puke plastic). I guess at ths point, I'll wait until I finish up this OCI and do a used oil analysis on it to determine if the low pressure is actually an issue as far as wear.

 

[SteveSRT8]

Originally Posted By: 440Magnum
Originally Posted By: SteveSRT8

When you changed the cam was the timing gear set and chain done too? Many of my Mopar 318/360's in my fleet back in the day would puke bits of plastic that would clog the screen of the oil pickup. Oil pressure drop was obvious.


FYI, Steve, the Magnum version of the 318/360 never used a nylon coated cam gear. Its got a steel chain (non-roller) and steel gears. It'll get loose enough to make the cam timing sloppy (crank-triggered ignition keeps the spark stable, at least) but in my experience its like a Ford Modular- at multi 100k miles the chain will get so loose that the engine will barely start due to retarded valve timing, but it'll never jump like the old plastic covered cam gears would.


Thanks for the clarification. ALL of our trucks had nylon gears in the 80's, and would routinely fail before 200k miles even with good maintenance. With todays oils it may not even be applicable anymore, but the improvement is a good one.

 

[SteveSRT8]

Originally Posted By: rslifkin
Yep, it's a steel cam gear. I replaced the chain with a double roller setup when I did the cam swap. I also added the Mopar Performance chain tensioner (which is nylon coated, so it could theoretically puke plastic). I guess at ths point, I'll wait until I finish up this OCI and do a used oil analysis on it to determine if the low pressure is actually an issue as far as wear.


Note that in the SRT8 6.1 motor many of the cam swaps have had timing set issues. Despite the fact that OEM appears quite robust from the factory.

There are 'downstream' events that cause variations 'upstream' in any valvetrain. And no one sweats that detail like OEM does.

 

[rslifkin]

So I finally hit on a resolution to this: poor block ground causing a low gauge reading.

I noticed this morning that the Jeep was cranking a bit slow, so I decided to check things out. Sure enough, the block ground was looking kinda corroded. Cleaned it up and it starts better now, and the oil pressure shows about 8 psi higher at any given point (it almost hit 60 on a slightly lukewarm restart!). Oil pressure at hot idle appears to be just a little below 20 now, which is plenty for me not to worry.