Originally Posted By: onion
Quote:
I've been Jeep'n for many years and never had any issues at all with installing Melling high volume oil pumps in my Jeeps.
Yet.
Well, I guess we'll just have to see what happens in the next 20+ years of wheel'n.
Originally Posted By: onion
The extra oil pressure from high volume oil pumps is NOT good for the bearings... this is not a 'more is better' situation. In fact, I've read that bearings can be
damaged by excessive oil pressure (never seen this personally, but it's generally referred to as the bearings being "washed"- it's covered in most engine manuals). HV oil pumps also tend to wear out the gears on both camshafts and distributors (seen this several times). They unnecessarily rob power. I've even seen them pop oil filter cans on a cold morning.
So I've seen them cause lots of problems, and I can't name a single benefit. Except maybe if you want to run your engine while your jeep is laying on its side? That's gotta be great for the engine.
You can't name a single benefit because you probably don't have a Jeep. We're only talking 20%-25% more volume. The UOA's of my 2.5L, with a high volume oil pump, have been stellar for the amount of beatings it sees. Wear metals are excellent. So, maybe a high volume pump could be damaging to another car, who knows. Maybe the vehicle you saw had a bad relief valve. I know Jeeps, and this guys 193K mile 4.0L will be perfectly fine, if not better off, with a high volume oil pump. IMO, the factory oil pump in a Jeep 2.5L or 4.0L(especially Renix) is only marginally up to the task of lubricating the upper end. It also has a typical life expectancy of 100-150K miles. How many "my Jeep ticks" threads are on this forum? I've been there myself with an old Renix 4.0L that had periodic lifter tick (and no, the engine wasn't dirty). I changed the leaking rear main (another 4.0L issue) and installed a high volume oil pump. Guess what? No more tick, ever. I've done 8-9 rear mains/oil pumps/pan gaskets on mine and friends Jeeps (some with a periodic lifter tick) with a 100% success rate. No blown out filters or stripped cam/dist. gears. No noticeable effect on HP on these tractor engines either.
In the end, this guy can go any route he chooses and listen to any advice we offer. I live, breathe, and eat Jeeps. It's a Jeep thing that most wouldn't understand.