Oil cooler back pressure

[cavy1]

Does anyone know of any problems with oil cooler back pressure. We have a customer that is suggesting that they have 20 psi pressure differential across the oil cooiler and it calls for 10 psi in the book. Has anyone had any experience in these problems. Problem is across the pond.

Thanks in advance

Mark

[pjvr99]

Filter 8psi

FHS 12psi

Cooler 10psi

Filter outlet also should not exceed 30psi

Now: older type oil coolers (full oval face) below 75°C give a differential of +-8psi, but

happily rise to 18psi above 75°C. Newer type (square face) seldom have a differential

of more than 8psi, but often have trouble keeping the oil temp below 85°C on very hot

days. The question becomes 'do you go by the book, and reject cooler after cooler for

high back pressure', or, 'get the back pressure right, but have high oil temp problems

in ground range on hot days'?

Bearing in mind, that high back pressure can lead to oil dumping at altitude. What I would

suggest is get the engine onto the test cell, and check out the scavenge system; i.e. is

the RGB and power section scavenging all the oil back from the various sections. Check the

indicated difference in qty between running at 900°C and immediately after shutdown. Also

check indicated qty at LSGI and NGI with the oil temp at normal running temperature. Check

residual quantities in RGB and PS by draining and measuring immediately after shutdown. Make

your decision from there ......