melling high volume oil pump?

[ejholmgren]

It was something about about the higher pressure pumps shearing/twisting the hex drive as I recall.

 

[AlvinsRanger90]

What about a tired 2.9 with cam bearings in question? Has50 psi cold startup but falls fast as temp increases. It is nothing to have maybe 5psi running thru town and maybe 10 on freeway with the higher rpm. Seems like hv pump would help here. Any knowledge on this out there?

 

[bobbywalter]

For the effort of opening a 12 year old thread.....you should be rewarded because you are searching.




How do you know it's cam bearings?


The pump swap can work temporarily.

These engines run like this for many moons. I run a heavier oil in summer for this case....but putting fresh bearings in may be better longer if compression is ok.

 

[pjtoledo]

yep, old thread.
for worn out engines 20-50w oil is a hellava lot cheaper than new parts.
only for temps above freezing of course.

are you sure the readings are accurate?

 

[19Walt93]

I never get away with band aid type repairs. If you're tearing it apart to replace the pump you should overhaul the engine and get the clearances back where they belong instead of just pumping more oil. I've always run a stock pump in the Mustang I drag raced, too, and I drive it 90 miles to and from the track.

 

[PetroleumJunkie412]

Ran a melling high volume in my 2.9 before rebuild. Helped lifter chatter a bit.

I did half spin one cam bearing at 288k.

Lifter clatter was due to one bad and two more meh lifters.

They went dead from clattering against my cam.

My cam side by side with a melling stock grind.

Walt makes a point. So does Bobby and pj.

I changed lifters a year ago and started seeing weird crap happen in the upper rpm bands on my engine as I built it up before rebuild (engine is modified, have standalone ecm).

Should have done a rebuild or sent mine out for it when I swapped heads. Or at the very least shoved a cheap stock cam back in to buy a year or two.

I'm currently in full rebuild.

Complete gamble option I picked up from the UK cologne forums:

Flush engine with oil change. 10w30 conventional with Liqui moly ceratec, run for 1k MI, change oil and spark plugs (yes plugs, it's boron nitrate, it'll coat your electrodes, you have blow by), refill with high zddp whatever brand (super tech high mileage used to be its favorite) oil and a can of mos2

They swear by it to kick one back into acceptable order and breathe some life back into bearings.

Kicked one of our gm 4.8 fleet trucks right in the ass...

 

[19Walt93]

The magic words are " high zddp".

 

[PetroleumJunkie412]

Just another footnote, nowadays the only off the shelf oils that have a ZDDP count above 900 (I think) ppm are ones specifically sold as racing oils.

Valvoline and liqui moly both offer synthetics with zddp counts above 1100. Someone more knowledgeable can comment on what's necessary for flat tappet engines, but as of now, I won't run anything with a count below 1300 in my pushrod engines

I think Valvoline racing synthetic is 1350 - 1550 ppm if memory serves...