| Author | Message | ||
| '75 308 GT4 (Peter)
Intermediate Member Username: Peter Post Number: 1710 Registered: 12-2000 |
Congrats William!  | ||
| magoo (Magoo)
Intermediate Member Username: Magoo Post Number: 2151 Registered: 2-2001 |
Great Bill, Glad you found it. You'll sleep better tonight. | ||
| Bill Sebestyen (Bill308)
Junior Member Username: Bill308 Post Number: 126 Registered: 5-2001 |
Bill, What was the source of the rubber? | ||
| William Badurski (Billb)
New member Username: Billb Post Number: 37 Registered: 6-2001 |
Problem solved. Found the suction line from the bottom of the oil tank to the pressure pump was obstructed with a piece of rubber. Dropped some rod bearing caps and everything was fine. Engine runs with 75-90 psi now. | ||
| Bob Campen (Bob308gts)
Junior Member Username: Bob308gts Post Number: 78 Registered: 9-2001 |
Another thought, is there a strainer screen after the supply hose? If so junk from the new hose could be cutting the flow down enough so the pump is not getting enough oil to operate correctly | ||
| Mike Dawson (Miked)
New member Username: Miked Post Number: 15 Registered: 2-2001 |
I am not familar with how the Daytona's dry sump system is set up, but this may be worth checking. When the PO of my BSA 650 motorcycle had some engine work done, the mechanic hooked up the supply and return lines to the oil reservoir backwards. The oil pump was sucking air from the top of the oil tank and the scavenge pump was blowing air bubbles back into the bottom of the reservoir. A new BSA crankshaft was not cheap even way back then! | ||
| Bob Campen (Bob308gts)
Junior Member Username: Bob308gts Post Number: 77 Registered: 9-2001 |
Bill I hope I am wrong, but from expierence with hydraulic systems if you had a supply line sucking that much air the pump would cavatate causing the oil to foam. Is this a 2 or 3 section pump? If a multi section pump, mabey a body was turned 180 causing a free flow. I do hope it is just the supply line | ||
| William Badurski (Billb)
New member Username: Billb Post Number: 34 Registered: 6-2001 |
Magoo & Peter, Thanks for the suggestions. My next experiment will be to drop the sump cover again, connect the pump suction line to a separate oil source using a heater hose, and crank without plugs. This eliminates the aeroquip line from the bottom of the tank to the sump. I'm doing this because this was the only line I replaced during the overhaul, so it is suspect as being a source of a suction leak. Seems to me that after a week of pumping and purging, I should not still be getting air bubbles from the pump discharge during crankover. If this eliminates the bubbles, I'll have to remove the aeorquip line for testing. If not, I'm going to have to remove the engine and pull the front cover to gain access to the oil pump. Wish the pump was as accessible as the one in your Vette Magoo. I've got a '67 big block and the pump and pan can be off in minutes. Sounds like you may have the answer. | ||
| magoo (Magoo)
Intermediate Member Username: Magoo Post Number: 2138 Registered: 2-2001 |
Bill, maybe the old pump was okay with the worn tolerances. Now it can't push enough with the tighter engine. I had a vette that had the same problem after overhauling it. I put new gears in the pump and that corrected it. | ||
| '75 308 GT4 (Peter)
Intermediate Member Username: Peter Post Number: 1689 Registered: 12-2000 |
Well, that idea checked out okay (thankfully, as something that would stick the pres. relief open would be a serious problem). Do you think it may be sucking up air, in addition to the oil (now with you seeing air bubbles in the filter. Which could also add, or, be from that air-purging difficulties you explained earlier)? | ||
| William Badurski (Billb)
New member Username: Billb Post Number: 33 Registered: 6-2001 |
Update: Took the pressure regulator valve apart. No problem. It wasn't stuck. Turned screw in 5 turns from prior setting just to test, but no oil pressure after starting engine again. Did find that you can prelube the engine using a 1/2" pipe coupling on the oil filter mount and an external pump. Got 40 psi on the car's gauge doing this, so no blockage in the engine. Cut top off an oil filter and gutted it. Cranking on the starter for one minute produced 1/2 quart of oil from the main pump into the cannister. Don't know if this is normal delivery rate for cranking speed, but saw air bubbles the whole time. Beginning to suspect a suction leak in the lines leading to the pressure pump. Any comments? | ||
| magoo (Magoo)
Intermediate Member Username: Magoo Post Number: 2136 Registered: 2-2001 |
I think Peters suggestion of the valve being stuck open makes good sense rather than a blockage. You are getting some circulation but none under pressure. Just a thought. | ||
| William Badurski (Billb)
New member Username: Billb Post Number: 31 Registered: 6-2001 |
Peter, We're thinking the same thing. Next step is to take it apart to check. We're also planning to pressurize the oil gallery by connecting an external pump to one oil filter mount and watch for gauge movement. This should qualify all passages within the engine downstream of the filters. Since I've seen oil delivery from the pressure pump up to the hole adjacent to the filter mount, the step described above should complete the determination that no blockages exist. After that, it must be an air purge problem. Any other ideas would be appreciated. | ||
| '75 308 GT4 (Peter)
Intermediate Member Username: Peter Post Number: 1688 Registered: 12-2000 |
Could it be that the pressure relief is stuck open (resulting in some oil circulating, which you've seen running to the filters and to the dry-sump tank, etc..., but, not enough volume to fill the passageway to act on the gauge fitting)? | ||
| William Badurski (Billb)
New member Username: Billb Post Number: 30 Registered: 6-2001 |
Qualified the gauge using low air pressure, about 10 psi, and it responds immediately. This is a mechanical gauge, no sender. Yes, started the engine after a prelube and ran for three 20 second intervals. After that, dropped a couple of rod bearing caps to make sure all was well. Next tried cranking on starter without sparkplugs to minimize load. An independent Ferrari repair shop owner said he'd seen this and had to crank for a total of three minutes to purge air, but this hasn't worked either. | ||
| C. Smith (Italianauto)
Junior Member Username: Italianauto Post Number: 60 Registered: 10-2001 |
Did you actually start the car or are you just cranking it over to look for oil pressure? | ||
| Richelson (Richelson)
Member Username: Richelson Post Number: 610 Registered: 12-2001 |
That would scare me too. I would check the sending unit and make sure it is alright, all connections, etc. I would think it would be in the sending unit. Hope this helps. | ||
| TomD (Tifosi)
Member Username: Tifosi Post Number: 377 Registered: 9-2001 |
no movement on the gauge at all? How did you test the gauge sensor? | ||
| William Badurski (Billb)
New member Username: Billb Post Number: 29 Registered: 6-2001 |
Help! I have just installed the engine in my Daytona after a rebuild. I did not disturb the oil pumps as they were fine. After prelubing the engine through the gauge fitting at the rear of the block, I have no oil pressure register on the gauge. The gauge has been checked and is OK. While cranking the engine with sparkplugs and oil filters removed, oil is seen coming up hole adjacent to filter mounts, so the pressure pump is working. Also removed sump cover to verify all pumps turn with crank. Oil also circulates through scavenge system and back into tank. Anyone have an idea? |