Volvo tamd60 pressure drop puzzle

[tinkicker0]

Was the problem resolved?

Interested because I am having the same problem on a D7C that was converted from truck to bus spec.
When warm the oil pressure is 8psi at low idle which is allowable according to book, but EDC is putting the motor into limp home mode.

Also when hot and the RPM is set to 1500 (no load) or so on the cruise control stalk it will get 5 bar pressure for about 20 minutes then suddenly nosedive to 3 bar.

Stopping and restarting the motor restores the pressure for another 20 minutes.

New oil pump fitted as a matter of course due to build spec, so cooling jet and top end supply valves are also new.
Cooling jet press reg valve was cleaned out and inspected thoroughly and passed fit for reuse.

Main reg valve in the filter head was replaced with new as part of build spec.

Filter blockage bypass valve in filter head cleaned and inspected.

Suspecting a sensor problem, a new pressure sensor was fitted with no change.
A pressure gauge tapped into the main gallery confirms the pressure drop is as the sensor is reporting.

The only fly in the ointment is that due to 2 yearly oil changes now specified (7000+ hours ), the bus company has fitted non standard spinners to all the D7s, getting the oil feed from the bypass filter valve housing and doing away with the bypass valve and bypass filter altogether.

Thought the spinner was bleeding static pressure at idle so sent our service engineers out to remove the spinner takeoff union and refit the OE bypass valve and cap to see if it made a difference.

Apparently not. However getting the same information out of our service lads on 2 days running is very difficult so we have to read between the lines as to what they are actually telling us.

I'm now at the point of thinking a vortex forming in the sump or a wrongly calibrated dipstick meaning the sump is overfilled.

Changing spec on these things is always a minefield with many timebombs ticking away esp when you are dealing with specialist parts supplied by both Volvo and the bus manufacturer on the same motor.

Sick of hearing about the damn thing.

 

[volvopaul]

Some of the early d 6 435hp motors suffered from low oil pressure. The system has a valve in the timing case at the front outside of engine. It turned out after stripping the motors that the builders fitted two valves instead of one. The valve is a one piece cartridge assembly.

 

[Latestarter1]

Was the problem resolved?

Interested because I am having the same problem on a D7C that was converted from truck to bus spec.
When warm the oil pressure is 8psi at low idle which is allowable according to book, but EDC is putting the motor into limp home mode.

Also when hot and the RPM is set to 1500 (no load) or so on the cruise control stalk it will get 5 bar pressure for about 20 minutes then suddenly nosedive to 3 bar.

Stopping and restarting the motor restores the pressure for another 20 minutes.

New oil pump fitted as a matter of course due to build spec, so cooling jet and top end supply valves are also new.
Cooling jet press reg valve was cleaned out and inspected thoroughly and passed fit for reuse.

Main reg valve in the filter head was replaced with new as part of build spec.

Filter blockage bypass valve in filter head cleaned and inspected.

Suspecting a sensor problem, a new pressure sensor was fitted with no change.
A pressure gauge tapped into the main gallery confirms the pressure drop is as the sensor is reporting.

The only fly in the ointment is that due to 2 yearly oil changes now specified (7000+ hours ), the bus company has fitted non standard spinners to all the D7s, getting the oil feed from the bypass filter valve housing and doing away with the bypass valve and bypass filter altogether.

Thought the spinner was bleeding static pressure at idle so sent our service engineers out to remove the spinner takeoff union and refit the OE bypass valve and cap to see if it made a difference.

Apparently not. However getting the same information out of our service lads on 2 days running is very difficult so we have to read between the lines as to what they are actually telling us.

I'm now at the point of thinking a vortex forming in the sump or a wrongly calibrated dipstick meaning the sump is overfilled.

Changing spec on these things is always a minefield with many timebombs ticking away esp when you are dealing with specialist parts supplied by both Volvo and the bus manufacturer on the same motor.

Sick of hearing about the damn thing.

Suspect your thoughts re lube cooler are closing in on possibe cause, what type of cooler does Volvo employ?

Not very helpful I know but personally the loons that re-designed the lube system have to be held accountable. Your company is never going to make a Dime out of these re-builds as and meet the bus company requirements, time to say NO THANKS.

Think I may have mentioned it, but bus company started using compressors from gypo parts supplier and they have been siezing up. Just purchased a 2007 ReCon 6BT as scrapper, bus was fully loaded pulling up a hill, suspect torque converter was in lock up with engine screaming away at rated when compressor locked up solid.....Turned the gear on the crank shearing the key which sure takes some doing, then pistons hit the valves.

The actions of financial directors are simply loony. Had a call from a fitter who had been instructed to weld a patch on brake reservoir as his garage had run out of budget for the month. Sorry for thread drift, but it is a matter of lighting blue touch paper!

 

[tinkicker0]

This particular motor was getting coolant in the oil when first fitted. Bus company supplied the compressor as we will not supply them or even fit them unless supplied by the bus company at the time of build

Turned out the compressor head was the culprit, leaking coolant down the bore and out into the timing chest when it was stood overnight.


You should see the state of some of the motors we get. I think ethylene glycol is rarer than hen's teeth in a bus garage judging by the corroded blocks; as for DCA......judging by the liner cavitation pitting they get a new cartridge when the engine is new and that's it.

 

[david_bagshaw]

What is DCA?

 

[Latestarter1]

What is DCA?

Fleetguard supplimentary coolant additive, requirement on all Cummins engines with wet liners, C Series and above. Works like a dream on ANY wet liner motor, keep up concentration and liner cavitation will never be an issue.