K10 350 Oil Pan replacement, what fits?

[dyeager535]

Not sure what others opinions are, but IMO if you are digging into this thing, as you obviously already have, if that oil pump is original and/or who knows how old, it may not be a bad idea to throw a new one in there. They aren't that much.

That pan is deeper than stock apparently, if you are worried about clearance that's the wrong pan. FWIW, if you aren't doing anything but logging/fire roads, you'll never have an issue with pan clearance. The transfer case needs a skid IMO.

 

[KeyBlazer]

Thanks for the input guys.
Let’s see how this pan I ordered fits.
Maybe, just maybe it’s a win.
I resealed this pan in 2008, and while I had it off I popped a few main caps and rod caps and the bearings were like perfect, and 10 under confining the motor was rebuilt. Wish it was a 383, but tbh, if I was pulling it out, it would not go back it because I’d do an LS or BT4…
I actually have 2x Cummins BT6’s and a Big Block 454 that I bought over the years… one is destined for my Airstream Motorhome, and the other maybe will end up in my k5, but I will have to box the chassis first.
But I digress, this small block appears to be good.
I agree with the oil pump change tho… and with good reason. I think the pickup is welded to the pump anyway, so if the pan looks ok, I’ll prob change it.
Next question is smelling?… high pressure or high volume?

TC case has its OEM skid plate… I just have not put it back on yet.

 

[dyeager535]

I think for standard usage, a standard oil pump will be fine.

I went direct to Melling and spoke with one of their engineers on the topic. He recommended HVHP for my application, but I've got a manual and I end up lugging the engine, which drives oil pressure down. With an automatic I'd expect that to not be an issue.

Digressing a bit, my suspicion is that if an oil pump starts to "lose pressure" the spring is likely the issue (losing tension). The pump, unless abused, is submerged in oil, pretty much nothing in the engine should be as well lubricated as the pump. Again from limited experience, the oil pumps I've disassembled from engines that I know weren't abused, had no appreciable wear. but for the cost of a new motor vs. a pump, or even the hassle of replacing one in the vehicle later...

Most of what I've seen anymore in regards to oil pumps is that you won't suck the pan dry, and they don't really impart a huge load on the distributor nor suck a ton of power up. So theoretically I suppose you could run the most expensive HVHP pump you like on there (heck, there are even better designs now, just $$), it just wouldn't make much difference. But part of my thinking is that if I start with a 30PSI standard pump, and over time pressure is cut in half, I end up with 15PSI (granted, still considered "enough" pressure). If I start at 60, 30 is halfway. Pressure is easily modified via the spring.

 

[1-ton]

My new GM small block crate engine came stock with a High Volume / Standard Pressure pump. If GM thinks that is the right pump for it then that is what I went with. If you do not already have one you should install a steel sleeve oil pump shaft as well.

 

[KeyBlazer]

Good advice.
I will do that.

 

[1-ton]

Most of what I've seen anymore in regards to oil pumps is that you won't suck the pan dry, and they don't really impart a huge load on the distributor nor suck a ton of power up. So theoretically I suppose you could run the most expensive HVHP pump you like on there (heck, there are even better designs now, just $$), it just wouldn't make much difference. But part of my thinking is that if I start with a 30PSI standard pump, and over time pressure is cut in half, I end up with 15PSI (granted, still considered "enough" pressure). If I start at 60, 30 is halfway. Pressure is easily modified via the spring.

I would have to agree with you on that. My new crate engine with about 15,000 miles on it, and a HVSP oil pump starts out at 60-PSI at idle when the engine is cold, but drops down to about 25-30 PSI at idle when the engine oil warms up.

 

[dyeager535]

Even with my HVHP pump, while I did put a 50PSI spring in (wanted to see the results), pressure drops to the 30 PSI range once warmed up even with a minimal mileage motor. Initially it was definitely higher.

If I can get my hands on a diesel 80PSI oil pressure gauge, I'll at some point swap back to the 70PSI spring.

 

[KeyBlazer]

Oil pan arrived.
Looks sweet.






Will do visual side by side with the OEM pan first, and then some measurements, so I know what the loss of ground clearance will be.
If that looks good, a test fit will follow.
I am concerned if the pan wings will be an issue with oil filter clearance too, but hope it won’t.

Confirmed my original pump is welded to the pickup…


I ordered a Melling HV oil
Pump and ARP drive shaft too.
Read that the best option for my needs which is low speed with oil coolers!
Anything else suggested?

 

[KeyBlazer]

Looks good!
Looks to me like the height difference between old 5q and new 7q is about 5/8”

 

[KeyBlazer]

So that done, it was the moment of truth…
Had to pull the original oil pump, as the pickup fouled the new baffle.
Confirmed it’s a std volume, std pressure Melling M55 unit.

That out of the way, the new pan slotted straight in, and I secured it with a couple of bolts.

Pan is theoretically only 5/8" or so lower than the original 5q pan, so not much and it still above the line of the headers and spring hangers...
I think it will be fine, and the extra safety margin of + 2 quarts and baffles and wings will keep the oil level in the pickup tube area constant on inclines.

I was worried about oil filter clearance but its easy to get at and can be removed just fine!

 

[TJ1978]

..my '78 K case Th350 bell housing support bars.
@Wes Harden

 

[Wes Harden]

Yeap those are them

 

[KeyBlazer]

Def missing from my truck

 

[KeyBlazer]

I also bought one of these oil pump pick-up tube retainers as well for cheap insurance.

View attachment 419976

I bought one too as I didn’t want to weld the pickup on…
Hasn’t arrived yet…
But when I went and looked at the pickup tube that came with the pan…. It has 2 legs…. Does the same thing, right?



Decided to buy the correct tool to drive the tube into the pump body… not arrived yet so I’m in limbo..
Interesting quote in the Melling instructions….


So I got this… right thing?

 

[KeyBlazer]

Wes, thanks for the photos.
My truck is an early 1973 I think, and I see no sign of the bars, and brackets, and I have a normal tin convertor cover.

 

[1-ton]

Yes, that pick up does come with a retaining bracket...Cool!