Oil Pump upgrades?

[Siekyre]

Any one rebuild their own 4.0? Are there any upgrade options (high Volume type) for the oil pump?

My motor currently has 155k on it. It does not have any upper end issues as of yet (valve clattering or timing chain clattering or oil burning). However I do have significant oil pressure drop once the motor warms up. Cold = 60psi at an idle, Warm = <20. When you give it gas it jumps up to over 40. I figure I'll be doing a rebuild here soon (Hopefully not until this winter) and was wondering if there was any options.

Thx

 

[Glacier991]

I am not aware of any upgrades. The stock pump is pretty good actually. Sounds to me like you have bearing issues. When you rebuild so us all a favor and plastigage a couple main bearings and let us know what you find! Thanks


Happy Exploring

Chris

 

[SteveVB]

No upgrades available in the pressure or volume department.

The stock pump is aluminum. I installed a Melling which is a cast iron replacement. A bit better than stock. Check 4.0 performane they have rebuild kits wiith good quality parts.

When I tore my 150k mile engine down the mains and rods were fine- specd right in the center of the range. So I doubt that any decently cared for engine will have bottom end problems for at least 250k miles.

The top end is another story. The rockers were worn badly on both the valve and the pushrod ends. The pushrods were off a bit also. So check and recheck the upper end carefully and replace everything- nothing should be reused in the valve train IMO. 4.0 performance can get the upgraded rockers . Smith Bros for the pushrods.

If the darn oil pan could be removed in the vehcile a pump change and a head job would all that I would have needed at 150.

Good Luck

 

[Glacier991]

Good info Steve, thanks!

Happy Exploring


Chris

ps. 92 with 200K on orig eng and trannie. Oil pressure low but not bad. Have a 93 trannie in garage to rebuild.

 

[Siekyre]

YES good info Steve. Thanks.

Do you happen to have a link for 4.0 performance? I did a search on the net and found nothing

 

[Slick Rick]

Hey Steve....

can you tell us how frequently you changed your oil? What kind of oil you used ( Brand name and grade ), your driving style ( hard driving or easy going ), and anything else that may have led to the upper portion of your engine having more damage than the lower ( other than the facts about the oil pump that we already know ). Thanks

 

[SteveVB]

Link:
http://www.4.0performance.com/products.html


As for oil changes:
I bought the vehicle new and changed it per the recommended interval for the first few years which was 7500 miles or so- maybe twice a year. A couple years I doubt I changed it- I had too much going on and vehicle maint wasnt at the top of the list so It may have gone 20k without a change. When it got to 100k miles I changed it more frequently every 5000 miles or so. Dino oil the entire life. I rebuilt the engine at 145 or so because the oil pickup was clogged- I was out on a trail and went through some really cold water and on the other side my oil pressure was down and the engine was noticably louder. A mechanic on the ride thought that the cold water or the rough,hard(frozen dirt) trail may have broken some junk loose. Previous to the ride I had the ticking lifter/ valve train problems that were so common on the earlier engines, so I pulled it apart and took a look.
The engine has poor rocker oiling, really poor. Interesting enough though the engine had little sludge in it. The intake was another story though- caked with carbon and residue. A couple of companies have come out with treated rocker cups and tips to address the rocker issue, and frequent intake cleaning and use of the throttle to clean out the intake is recommended for the carbon build up- there is a TSB somewhere about this(run 87 octane, hit 3500 rpms once a week etc. ).

Now with the new engine Im running Mobil 1 and change it every 10k and filters every 5k- probably a bit excessive, I may go to 15k changes and 7500 mile filters.

 

[FLYIN 5.0]

Melling is one of the best oil pumps on the market.
I have used their high volume pumps on a couple of rebuilds and was very happy with them.

 

[SteveVB]

Noticed some other questions I didnt address;

Brand of oil - I belive for most of the life it was Castrol regular 10w30 dino, may have tried a syn/dino blend at one point though.

Driving style- Im pretty easy on vehicles smooth acceleration, coast down to lights just enough pedal to get to where Im going. Some days I can drive all day without the tach hitting 3000. My wife drove the vehicle for the first few years - standard commute stop and go and some highway. Shes a bit hard on vehicles - you know foot is either pressing the gas or the brake.