Got Oil... won't prime.

[Binder]

When you try to prime it with a drill ( right direction?) is there resistance or does it just spin easy? It should put quite a bit of resistance on the drill. Also what are you going by to assume it's not priming other than the gage? The gage may just be full of air in the oil passage leading to it. Sometimes it helps to turn the crank to a different position to align the oil passage holes while running the drill.

 

[TreeClimber]

:corn:

 

[FiFo]

Ok, well we found that the oil pressure relief valve was stuck open, which we fixed. We where then able to prime the pump and get the engine running, we drove it out of the shop in order to start the cam shaft brake in, however the oil pressure quickly fell from 45-50 PSI to about 16-18 PSI and then plummeted to 0 PSI. I shut off the motor at that point and noticed that the coolant in the radiator was boiling, though the temperature gauge read fine. However it's a 30+ year old gauge so who knows if it's accurate.

We've removed the oil filter adaptor and made sure the valve is still closed, it is. Repacked the gears with Vaseline while we where their. Checked the oil pressure gauge, it's a new mechanical one and seams to work fine. We changed the oil and oil filter just for the heck of it. Running off the drill we can get about 4-5 PSI of pressure. It got to 40-45 last time off the drill.

Any idea?

 

[TreeClimber]

Some ideas

Total (poor mans) rebuild. New RV camshaft. New accessories (oil pump, timing gears and chain, new lifters, new water pump, etc).

Oil pressure was at ZERO when we picked the truck up from the previous owner. We drove it over the pass and it lost 2 quarts in the process.

You never said anything about crank bearings as part of the rebuild or why this engine had low pressure to begin with. The assumption is that it's a bad pump. But what if it's not the pump.

The drill won't provide near the oil pressure as the actual engine does. Plus, the vasoline trick is thick. That's why it primes good. But the thicker (than oil) vasoline should give an artificially high oil pressure reading. So once the vasoline is melted/absorbed into the oil itself, I'd expect the pressure will drop. And drop even more as the motor warms up and the oil thins out. So, at idle, maybe 10 to 15 psi, warm, is OK based upon old bearings, rings, etc etc etc...

Regarding why it ran hot, or if it's hot at all.

It could be that you've got a bad thermostat. I've had engines with stuck shut thermostats that'll boil the coolant in the radiator in no time at all due to the motor not 'flowing' the coolant thru it. Could be something simple like this

It could be that you've got a bad headgasket / and-or / a cracked head causing compression leakage into the coolant jacket, causing a 'boiling' type effect

It could be that you pieced together the cooling system with old parts and the clutch fan isn't locking shut and the fan is spinning too slow to cool.

It could be that you've pieced together the cooling system and the fan is a reverse direction fan (been there-done that) and not pulling air thru the radiator but instead just making a lot of noise and moving no air.

It could be an old radiator that just doesn't flow.

 

[TreeClimber]

this is far fetched, but whattheheck

And you also said it "lost 2 qts" while driving for an hour....

Where'd the oil go? If you have a major leak, that could be where you pressure is bleading off. Something that opens as the motor is hot and the metal expands and then shrinks together (holds pressure) when the motor is cold.

 

[skrause]

And you also said it "lost 2 qts" while driving for an hour....

Where'd the oil go?

maybe it's in the filter? ....just a thought... :redneck:

 

[FiFo]

The 2 qts of oil that it "lost" I believe you are referring too are when I drove it home from Wildman

 

[KarlVP]

Yeah, this motor has been kicking our butts.

Just when we get everything right, it breaks one of the rocker arm bolts.

No biggie. Anyone got any tricks to retrieve a lifter out of there? Once we get that done it should go pretty smooth.

The engine sounded great for the 15 minutes it ran while we were breaking in the cam.

 

[Binder]

Is your thermostat upside down or stuck closed? Is your lower rad hose the wrong one with no spring inside?
Why did the rocker bolt break? How big is the cam and is it too big for the stock rocker assy?

 

[TreeClimber]

Throwing a lifter is NOT something I would have thought of.

Try a magnet on one of those extendable pointer like thingies.

 

[TreeClimber]

Is your thermostat upside down or stuck closed? Is your lower rad hose the wrong one with no spring inside?

I also thought of stuck shut, but upside down is a good thing to check! And a collapsed hose will overheat you right quick too. Both good ideas

Why did the rocker bolt break? How big is the cam and is it too big for the stock rocker assy?

I'd guess that this was assembly error. The assemblers didn't torque the bolts down uniformly and AMCs have those aluminum bridge things inside the rockers - connecting two rockers together - which can easily get cocked during assembly and cause a similar event to what they described. I've put together a couple of AMCs with custom cams and never found a manufacturer that grinds big BIG cams for AMCs. So I doubt it's too big. Anyhow, I sure guessed wrong on the thrown lifter, so whadaIknow anyway?

 

[FiFo]

I know the assembler torqued all those bolts down to spec, since I did it myself. Course, the assembler also has no clue what he is doing, since again I did it myself. :eeek:

And ya, it has those little bridge things; I take it that's not normal? This is the first engine I have ever taken apart.

 

[KarlVP]

Is your thermostat upside down or stuck closed? Is your lower rad hose the wrong one with no spring inside?
Why did the rocker bolt break? How big is the cam and is it too big for the stock rocker assy?

Nope, the coolant was working. We do have a big ass fan we can use for the cam break in now. I don't think it was overheating anyway. The gauge is old, but no reason to think it doesn't work. The boiling coolant is a mystery though. But it could be because the brand new radiator came with a "coolant recovery hose" at the cap and it was allowing a little bit of the pressure to escape. The old rad didn't have that.


The cam isn't too big lots of the 401 guys run them on the stock valves.

Brand:COMP CamsProduct Line:COMP Cams Xtreme Energy CamshaftsPart Type:CamshaftsCam Style:Hydraulic flat tappetBasic Operating RPM Range:1,200-5,200Intake Duration at 050 inch Lift:212Exhaust Duration at 050 inch Lift:218Duration at 050 inch Lift:212 int./218 exh.Advertised Intake Duration:256Advertised Exhaust Duration:268Advertised Duration:256 int./268 exh.Intake Valve Lift with Factory Rocker Arm Ratio:0.477 in.Exhaust Valve Lift with Factory Rocker Arm Ratio:0.484 in.Valve Lift with Factory Rocker Arm Ratio:0.477 int./0.484 exh. liftLobe Separation (degrees):110Intake Valve Lash:0.000 in.Exhaust Valve Lash:0.000 in.Computer Controlled Compatible:NoGrind Number:XE256HQuantity:Sold individually.

from here. http://store.summitracing.com/partdetail.asp?part=CCA%2D10%2D214%2D5&autoview=sku

I also thought of stuck shut, but upside down is a good thing to check! And a collapsed hose will overheat you right quick too. Both good ideas

I'd guess that this was assembly error. The assemblers didn't torque the bolts down uniformly and AMCs have those aluminum bridge things inside the rockers - connecting two rockers together - which can easily get cocked during assembly and cause a similar event to what they described. I've put together a couple of AMCs with custom cams and never found a manufacturer that grinds big BIG cams for AMCs. So I doubt it's too big. Anyhow, I sure guessed wrong on the thrown lifter, so whadaIknow anyway?

The bolts were torqued uniformly and to spec. Also the radiator hose does have a spring in it. I think the reason for the coolant boiling was described above. We shall see when we get this bitch put back together.

 

[crash2]

:awesomework: :awesomework: :awesomework: :awesomework:

 

[jeepster72]

Bad cam berrings will also make a drop in oil pres.and wont make any noise.:eeek:

 

[TreeClimber]

I don't think it's the coolant recovery hose issue. As the radiator builds pressure, it forces the radiator cap up thereby venting pressure. As this pressure vents (depending on the psi of the cap) it forces coolant thru the coolant recovery hose into a storage tank, and later on will suck it back into the radiator. I cannot think of how that would ever cause you to overheat.

 

[KarlVP]

I don't think it's the coolant recovery hose issue. As the radiator builds pressure, it forces the radiator cap up thereby venting pressure. As this pressure vents (depending on the psi of the cap) it forces coolant thru the coolant recovery hose into a storage tank, and later on will suck it back into the radiator. I cannot think of how that would ever cause you to overheat.

I really don't think it overheated. Just a guess really. We are off of the old gauge so we don't know for sure. But that is good info to know.

Anywho, there is no recovery bottle (yet) because we haven't hooked one up. For now we just capped that line.

 

[Binder]

Do you need to retorque the heads while your in there working on the rockers?:;

 

[TreeClimber]

Do you need to retorque the heads while your in there working on the rockers?:;

(I'm wondering about the exhaust valves myself. All the old AMCs I played with had burnt #8 exhausts)

 

[KarlVP]

Do you need to retorque the heads while your in there working on the rockers?:;

Might not be a bad idea. We also need to retorque the headers when they are warm too.