low oil pressure

[Grim 82]

I'm back on this rainy day project now. I have the motor out and upside down on a stand. I removed all of the caps and as you guys suspected, there is NOT a spun main bearing. However, the main bearings on the cap side are ground down pretty good and brass or copper material is showing through. There is also a little bit of scoring on the crankshaft surfaces. Pulling the caps and visually inspecting is as far as I have gotten. I tried to replicate the front to back travel and was unable to, so it may have been my imagination or I was drinking. From what I can see from the bottom, the cylinders still have a nice crosshatch pattern and smooth spots, and it looks like one cylinder has a sleeve pushed into it. A few of the cam lobes look a little discolored with minor chipping.

What's the next step as far as inpecting and/or replacing parts to get it going again? If I have to get any machine work done it's probably going to be a deal breaker.  Thanks

[VileZambonie]

I'm not sure what your skill level is so don't take offense but you did mark all of the bearing caps right? Make sure you mark the rods too. What's your goal? Sounds like the engine is tired and needs a rebuild. If the crank is scored you will need to have it ground. If there is no major cylinder wear you can hone and re-ring it.

[1980c10]

Maybe get some pricing from the local machine shops and know what the pricing and time frame would be; It may not be as bad as you think. Just ask around first to be sure you are going to the right place if you don't already know.

[Grim 82]

No offense taken, this is as far into a sbc as I have been. Everything was stamped from the previous rebuild, but I also used a 3' piece of 1x12 and drilled a bunch of screws into it and then set the caps over the screws to keep them from getting mixed up or turned around. I left the pistons in it and just pushed them to the top. I talked to a machinist and he estimated that I could have the crank ground and get new main and rod bearings for about $200.

I'll be dropping the crankshaft off at the shop later today, but I'm not sure if it can be ground now. The surface for one of the rod bearings looks horrible, like somebody drove the rod bolts into it when they installed the piston or rotated the crank and mashed the threads against it. It's chewed up pretty bad.

The cylinder bores look perfect, and my goal is to get the lower end put back together cheaply and see if that fixes the low oil pressure problem that I had. If everything checks out after that I would like to put a little bit more aggressive cam in it with some vortec heads and put it in a new project, or maybe swap it into my daily driver and use the 400 for something that's more of a toy since that 350 always used to get much better mileage.
Thanks

[1980c10]

This would be a great time to get the block bored if needed and put in some flat top pistons as well if your budget allows. Also check for a ring ridge at the top of the cylinder walls.

[1979C20]

I'll have too look at my machine shop receipt but I think my crank grind was only like 80 or 120. and main bearings were 30.

[slammed79]

I'll have too look at my machine shop receipt but I think my crank grind was only like 80 or 120. and main bearings were 30.

What shop did you use? I may pick up a 5.3 for the 74 after I pay the rent.

[1979C20]

It was B&B (BAKE AND BOIL) in mesa. Its on broadway and extension? I believe. I think on broadway between extension and country club. Vat, crank grind, magna flux, head check, head magnaflux, and hardened valve seats cost me 320.

[1979C20]

I posted this on the wrong subject.

[Grim 82]

My crank was toast, but he swapped it out for a good one and just charged me for the grind. Crank, main, rods, and cam bearings and borrowing the cam bearing installer for $170.

I left the pistons in it cause the bores look good with this motor only having 20-30k on it. It has flat top pistons stamped 030 with 4 relief areas.

I went to a builder to pick up a gasket set, double roller timing set, oil pump, cam, and lifters. IIRC my heads are stamped xxxx993? The guy said those are decent enough heads for my purpose and since I had an RV cam in it before my springs and everything should be good to go, and he recommended an Elgin E923p cam. He said it should be comparable to what I had before, which I liked.
http://shop.enginekits.com/osb/itemdetails.cfm?ID=60

He also borrowed me a spring compressor so I can clean the crap out of the heads. Should I plan on putting new seals in it? Any other suggestion on that task or opinions on that cam is welcome. Also, at this point is it a good idea to install a high volume or a high pressure oil pump, or will a stock replacement work? Thanks

[1980c10]

I run a stock replacement pump and have 60+ lbs all the time. If your budget allows maybe upgrade to a 63cc head, maybe the machine shop has some around(maybe some vortechs). This could be worth an easy 20-30 hp, pretty good bang for the buck and maybe see some better mpg as well.

[screamin86]

i agree with running a stock pump this truck of mine is the only motor ive ever ran a hv pump in and the only reason i am is the guy who originaly built the short block was building it for boost and set clerances to run the hv pump. honestly i hate it lol id rather run a standard pump.

[VileZambonie]

If you have more than .0025" clearance you may want to run a HV pump