Help!!!......Frustrated......

[myersjeremy]

Can not figure this truck out. I have went through as much as I know and the truck still runs like crap. Let me run through my equipment. I bought a short block 350 with standard flat-top pistons, x-rods, and LT-1 cam from a local guy off ebay. The block was honed and receipts included for the machine work.I checked over everything as far as torque specs before I put the motor together. I bought a set of double hump heads which I thoroughly regret the headache of the brackets and the other B/S that goes along with them. I got an edelbrock performer intake and edelbrock performer carb. Since the first time I started it the oil pressure has sucked and it totally runs like crap. How much oil pressure can be lost through the heads? I feel thats where my weakness is. I am getting blue smoke at start-up. What should be my order of elimination to find the problem? Pressure test the cylinders? Or throw the hump heads away and go with some standard heads?


Let me know.....

[Zoomad75]

There are no oil gallies in the heads. The only way oil gets up to the heads is through the pushrods and then it drains back to the pan. Low oil pressure could be from not setting up the main/rod/cam bearing clearance correctly. Or it could be a oil galley plug wasn't reinstalled (that would be pooring out oil though). The oil pump's pickup might be restricted somehow or it's just a bad pump.

I'd hate to say this, but it might be easier to investigate if you yank the engine back out. Then you can take the pan off and measure the main/rod bearing clearances, check out the pump/pickup and work your way up from there. If the pressure is really low and you keep running it, you are running the risk of wiping out the bearings. Then you got to pull it anyways.

Blue smoke on start up is typically oil leaking by the valve stem seals into the valve guides. That leak dosent result a loss in oil pressure as the valvetrain is only splash lubed from the pushrods. If the heads were just rebuilt the valve stem seals might not have been put on correctly (easy to screw up with the stock o-ring seals) or they did a crappy job on the valve guides.

[69BBsuburban]

Yeah, what he said^^^^^

But do not throw away the camel humps....they are good heads 461, 462.....some factory 2.02....

[knightlife]

I concur...

[myersjeremy]

If the problem turns out to be as minor as I think it is then I will feel really dumb. Is it possible the low oil pressure could be coming from the loose tee behind the intake that the oil pressure switch is screwed into? I had noticed an oil leak from a weird place but I had written it off to maybe splash from the distributor being loose. I can only pray......Next thing is how the heck to get to it to tighten it up. I am thinking of removing it all somehow and just screwing the oil sensor back in. Right now it has a pipe that goes into a tee then it has the oil and the choke sensors.

[ron350]

The first thing to do is verify your oil pressure with a second oil pressure gauge.

[knightlife]

pull your valve covers, start the motor...and see if the top end is recieving any oil if thats your worry...if its not...boom, new oil pump *shrugs*

[sick69]

is the oil pressure just low or does it have it when you rev it and nothing at idle? and what do you mean by low oil pressure?


Frank

[87 STEPPER]

What kind of oil pressure guage are we talking about here the unreliable stock Ele. one or a direct pressure one?

You really need a direct pressure one hooked up to really verify the true oil pressure being produced by your pump.

The leak your talking about isn't going to cause this problem your having but it needs to be fix.

Man it could be anything Zoomad75 mentionde or all of them it's hard to say.

You will need to start the process of elimination.

1 remove valve covers stars eng and see if oil is being pumped up to the valves the ones at the rear should flow more than the fronts closer to the pump press.

2 hook up a direct press oil guage and ck press.

3 pull distributor and visually inspect the bottem of the drive gear & the oil pump drive rod.

4 drop oil pan in vehicle visually inspect everything check oil pump pick up is installed in pump correctly or at all also check clearance of oil pump pick up to bottom of oil pan if it's too close to the pan the oil press will be down.

5 remove oil pump and visually inspect oil pick up screen for blockage you may want to even disassemble the pump and see if theres any foreign debris in the pump gears.

6 if you havn't found any thing obvious by now then yank the engine out and check all clearances of the rotating assembly.

[myersjeremy]

It has maybe 15lbs of pressure at idle after it has warmed up. It has oil pressure, just not what I think a fresh rebuild should have.

[myersjeremy]

Would pressure testing the cylinders eliminate the rings? What should I expect pressure wise at each cylinder?

[myersjeremy]

How else is there to check the oil pressure?

[myersjeremy]

Figured out one thing. After breaking down and finally getting out the timing light the timing was way too high. It was at 8 without vacuum advance hooked up so I set it back to 4 and hooked up the vacuum line and rechecked. Starts so much easier.....It jumped up to not quite 8 so is that close to what it should be? I hooked that line into the left port on the carburetor. Now if I can only get this carburetor tuned in. Thinking Holley seemed much easier to get right.

[jimfulco]

15psi warm & idling is not necessarily bad.

[Ivan D.]

Originally Posted by myersjeremy

Figured out one thing. After breaking down and finally getting out the timing light the timing was way too high. It was at 8 without vacuum advance hooked up so I set it back to 4 and hooked up the vacuum line and rechecked. Starts so much easier.....It jumped up to not quite 8 so is that close to what it should be? I hooked that line into the left port on the carburetor. Now if I can only get this carburetor tuned in. Thinking Holley seemed much easier to get right.

Advancing yer timing actually makes it easier to start, so you really want 8*BTDC, and not so much 4*. However make sure you're actually on the advanced side, and not on the retarded, cause the way you say you moved from 8 to 4 and it starts easier makes me think you started with 8 after TDC and by going to 4 you actually advanced it. But yeah, set yer timing with the vac line pulled, the carb port plugged, and the idle rpms dropped down to like 800 (so the mechanical advance in the disty don't engage). My timing this way is set to 8 before TDC, lotsa folks run up to 14 - here's a link about what you want yer timing and advances to do: http://www.73-87.com/7387garage/drivetrain/hei.htm

[Ivan D.]

Originally Posted by myersjeremy

It has maybe 15lbs of pressure at idle after it has warmed up. It has oil pressure, just not what I think a fresh rebuild should have.

A chevy small block wants at least 5psi before killing the bearings, so you're good. However, to make sure, warm up the engine, lay on the brakes, and throw it in gear, that'll bring the engine speed to as low as it can get, about 400rpms in case of my truck - if you still have 10+ pressure you'll be fine for a while.

Oh, and just as an idea - my 350 has a Melling high-volume (not high pressure) pump, runs on Rotella-T diesel oil (by recommendation from Melling), and normally pegs the gauge, the lowest I've seen the pressure is about 45-50psi while idling in gear at a looong red traffic light. Pump is supposed to crank out about 70psi so it all makes sense. On a fresh bottom end you should be seeing similar numbers, maybe a little lower but still over 30psi at warm idle in gear at a red light.