4.0 oil system improvements?

[Dunk67]

Rebuilding a '94 4.0, my first time into one of these. I got a Melling high volume oil pump. Looking at the pump outlet and the block passage to the oil filter adapter there is a large difference in the size of these ports and the gasket is more square shaped around them. The oil pump has a much larger outlet than the inlet on the block. The oil filter adapter does not seem to have such severe restrictions, though a couple areas could use some smoothing of hard edges at bends.

On the FE a common and easy improvement is the drill this passage larger and chamfer/radius the inlet to gasket match to the pump. I'm thinking I should cut out a gasket to match the oil pump and use that to match the block, at least put a smooth radius to the edges to funnel down to the small block passage. Not sure at a glance how much meat is in the block but it doesn't look super thin, though is tight at the filter side to the filter adapter sealing surface. Might be able to drill it larger? just like the FE, shame to have such a large restriction right off the pump. Particularly given the top end oiling/wear issues on these engines as well as the rods. Not sure if that's common but the rod journals on this one were pretty badly worn after 260k+ miles. I notice there are oil squirters built into the rods, which probably doesn't help with wear to bleed off so much oil after the bearings starts to wear a bit.

I could do similar and radius/enlarge the inlet passage to the main oil gallery out of the oil filter adapter. Small passage and hard edges from the factory.

Seems there is already a NPT plug at the rear of the main oil gallery, and the front is sealed with the cam thrust plate. Some plugs in a few other places, though I think they're steel balls rather than cup plugs as on the FE. On the FE I drilled and tapped most of the plugs for NPT plugs though that may not be needed for the 4.0?

Is restricting oil to the top end required or prudent in these engines? Common of FEs to restrict top end oiling at the oil passage in the head where the rockers mount, as they tend to just flood the valve covers promoting leaks and more importantly starve the bottom end with excess oil at the top end. Not sure that's a big concern with the 4.0 given the reputation for pushrod and rocker wear.

Anyone do these or other oiling system improvements on the 4.0 OHV? What do you guys recommend? Now is the time for any improvements to the bock, after disassembly and before I take it to the machine shop for boring and crank work.

 

[franklin2]

I looked in the "book", the Sven Pruett "How to rebuild and modify Ford V6 engines, and all he talks about as far as the oiling system is taking a high volume oil pump apart and deburring it and then reassembling it.

 

[Dunk67]

I acquired a copy of the Sven Pruett book. Some good information in there. unfortunately a good chunk of the performance stuff is products offered by companies that are no longer in business or no longer make the parts.

Cleaned some parts today, rocker assemblies and disassembled one. Several of the lower oil holes were plugged with crusty hardened sludge. Unsure of what plug size for the ends of the shafts to clean them proper... Minor wear on the shaft that I'd be tempted to flip it over to have a fresh wear surface for the next 260k miles but in the book Sven says always use new rocker shafts, though that was when Ford still made them as he gives Ford part numbers. I have all new rockers so will order new Melling shafts rather then finishing cleaning the old ones. In the book he mentions chamfering the oil holes for the rockers, I'll do that to the new shafts. Probably grind a slight groove just past the lower oiling holes as is common on FE shafts.

Block is power washed and brushed through all the oil passages I could get to. Cleaned up the oil pump to filter gallery inlet, quick and dirty but matched to approx size of the oil pump outlet. Used a small cone carbide burr, minor oops and apprentice mark well inside where the gasket seals but better than it was. Can't hurt, might help. I'll probably smooth it out a bit with a stone. Probably won't bother with radiusing the inlet from filter adapter to the main oil gallery, or maybe I will. I didn't enlarge the passage from oil pump to filter adapter. The entrance at oil pump fits a 3/8" drill bit and it necks down to slightly less in the drilled passage. Tempting to just run the 3/8" bit all the way through, or increase to 7/16". Walls don't look real thin or anything, but it's probably not necessary.




I'm guessing oiling on these engines is mostly adequate for the relatively low RPM they turn. Interesting the notable wear on the crank was all on rod journals, and these rods have oil squirters bleeding off oil to hit the pistons and cylinder walls. Nice design feature but maybe bleeding too out of the rod bearings... Or just a high mile engine driven by a young driver who beat on it and may not have had the best oil choice or change interval... Given the level of sludge and crustiness. Lots of hard crud came out of all the oil passages including in the crank.

The only major wear I found from lack of lubrication was the upper pushrod ball and rocker sockets, which seems more of a fundamental design issue than anything. I'd like to do spacers for free floating rockers and associated better top end oiling which may help with that wear, but unsure if I'll bother since nobody makes those parts and it would be a one off thing I'd have to outsource. Maybe with a high volume oil pump and synthetic oil the rocker and pushrod ball/cup lubrication issues will be less.

 

[franklin2]

If you think about it, you have very little problems on a 260k mile engine. I think you are on to something about oil changes and heat breaking down the oil into crusty carbon, which from your description sounds like the major oiling problems. I have read that it is pretty much mandatory to take the plugs out of the rocker shafts and clean them out.

 

[superj]

260k on it before you rebuilding it seems like you will have a good amount of time before it needing to be redone. i like your port matching on the oil pump mount surface. good idea there.

i will follow your build. i have not had to tear into any engine because of lack of lubrication except on a vw bug engine i was so excited to finish rebuilding that i drove it around the block without putting oil in the sump. this led to a second rebuild starting about 5 minutes after leaving hte driveway

 

[bobbywalter]

If you are using a high volume pump..then cleaning up the block is a given on any engine. Blueprinting the entire critter when changing oil scenario is sop where I am from. Especially with mel or fe.