When to worry about engine noises?
My engine is running great and pulling hard but it makes some noises that I don't like so I would appreciate any input on this.
I have about 1500 miles on my Blueprint engines 408 stroker. This is a hydraulic/roller engine, Magnum block with Edelbrock aluminum heads and 10:1 compression. It does have forged pistons (which may be relevant to the noise issue...).
I ran their recommended/branded break-in oil for the first ~700 miles or so, and I have run their recommended version of Shell Rotella dinosaur oil ever since. I am on my second change with that stuff...so the thing has never been low on oil nor has it ever had old oil in it. It has seen nothing but Shell 93 octane gas. Timing is set as recommended (all in at 34*). The engine has yet to be flogged, largely because the Radial T/A tires won't let that happen. :D
The oil pressure runs lower than my old Magnum 5.9. When fully warm, it hovers around 40psi while cruising. At idle, it drops down to close to 20.
When running, especially at idle, the engine makes some clattering/clacking noises. It almost sounds like it has solid lifters. It's noticeable from inside or outside of the car.
I called Blueprint engines last summer to ask them about this and they said that their Chrysler motors tend to be mechanically noisy and not to worry about it. They also said that the oil pressure was normal.
Would you be worried about this noise? When do you know it's time for a tear down?
The engine has a warranty but the last thing I want to do is actually use it.
The old standard was 10PSI per 1,000 RPM. 20 PSI at idle seems OK to me as there is no load on the engine. 40 PSI at cruise, well what RPM. My guess would be 2300 to 2700 RPM.
Oil pressure is a balncing act, a dance to speak of. The oil pump creates flow with a volume at any given RPM, remembering the oil pump is turning 1/2 crankshaft RPM. Then there is a relief valve designed to limit the maximum pressure in the system. The oil is restricted in flow rate by the internal "leaks" in the engine. What "leaks" you ask? Main and con rod bearings, camshaft bearings, lifter bore clearance, lifter plunger clearance on hydraulic lifters and rocker arms should cover pretty much all. The tighter the clearances the higher oil pressure can be, bit oil flow is reduced. If oil flow is reduced too much, bearings can heat up. Cylinder walls and camshaft lobes are lubricated with oil thrown off the con rod journals between the rod side clearances.
Loose clearances let oil spill out causing low oil pressures. Loose or worn rod bearings with rod side clearances on the wide side of specs flings too much oil on the cylinder walls for the oil rings to control.
So oil flow, pressure and control in an engine is like a dance with your partner, must be co ordinated and in sync.
Unfortunately oil pressure is not controlled by throttle opening or load. On a medium or heavy duty engine that operates much of its time at say 2500 or 3000 RPM and fairly wide throttle openings, that 40PSI may be a little low. In that situation I would like to see 60 PSI to ensure a good oil film keeping metal surfaces from contacting.
A tidbit to consider; where does camshaft bearing supply enter between the bearing and camshaft journal. Of course if that oil hole is below the camshaft, the valvesprings push through the valve train and tend to block the oil flow. Conversely if that supply hole is directly on top of the camshaft, the cam being pushed down tends to open up the clearance at the top, allowing oil to spill out the sides of the bearing. Looking at camshaft rotation from the engine front with chain or belt drive, the camshaft tends to rotate clockwise. The best place to enable a good oil film for the camshaft bearings and restrict oil flow properly, is to have the oil hole in the bearing about the 2:30 to 3:00 position. The oil can flow into the bearing where it can be carried around to float the camshaft off the bearing and properly cool the bearing and journal.
People tend to forget camshaft bearing clearance as a possible oil pressure problem source.
In this instance a person must trust Blueprint Engines to have installed the cam bearings properly.
The Buick/Olds aluminium 215 V8 had the cam bearing oil holes directly above the cam. To correct this a small diameter carbide burr can be used to machine a groove off to the right side as viewed from the front. Then the oil hole is installed rotated 45° to 60°from vertical , to the right. Better oil pressure control and longer cam bearings life. I can not be sure whether Rover corrected that when they bought the rights and tooling from the General. Included as a point to consider.
