PMD/FSD mounting

[guyina4x4]

ok, so everyone says remote mount the thing but I'm wondering about the mounting itself.

I have 2 PMD's, 1 that was on the pump and one on a heat sink.

I removed them both and
found the pump mounted one had a very thin layer of something greasy looking between it and the pump. also there was little pieces of plastic over the transistors? these plastic things fall right off

the heat sink mounted driver
had a rubber looking? pad between it and the heat sink. looks like it has the plastic things on the transistors also, they do not come off.

either way, it looks to me like the transistors never touch the heat sink, they are recessed into the PMD. even with the plastic things over them I don't think they touch the heat sink.

How are you guys mounting them? to the heatsink?

[guyina4x4]

OK after a closer look I see the Pmd is mostly aluminum and that mounting it to a heat sink should transfer the heat.

Ok

[sctrailrider]

The greasy stuff is a type of heat transfer stuff and should always be used..

[Kennedy]

ok, so everyone says remote mount the thing but I'm wondering about the mounting itself.

I have 2 PMD's, 1 that was on the pump and one on a heat sink.

I removed them both and
found the pump mounted one had a very thin layer of something greasy looking between it and the pump. also there was little pieces of plastic over the transistors? these plastic things fall right off

the heat sink mounted driver
had a rubber looking? pad between it and the heat sink. looks like it has the plastic things on the transistors also, they do not come off.

either way, it looks to me like the transistors never touch the heat sink, they are recessed into the PMD. even with the plastic things over them I don't think they touch the heat sink.

How are you guys mounting them? to the heatsink?


We do not use the transfer pads and have actually gone to removing them from the package ith the new PMD's. It seems that many that are replacing them and having early failures are using this pad.

Here are a few examples of how we mount them with our large cooler:

http://www.kennedydiesel.com/6265FSD.cfm

[john8662]

I think the biggest contributor to failures as we already know is heat, but specific places these things get mounted are hotter than the original place on a working system on the pump.

The heat transfer pad is actually a good idea as it serves as a gasket for compensating for the surface imperfections of the heat sync rather that be a plate or the side of the injection pump.

The side of the injection pump machining is very straight and very good, so a minimal gasket is fine. These aftermarket coolers are spotty on how true they are.

I have had my hands on just about every kind of cooler made out there and I can tell you from experience in measuring that many are not very true at all. They all start out as a slab of aluminum block, the fins are machined on one side, altering the flat surface on the other. Most manufacturer's are not resurfacing the flat side after the fins are machined onto the plate. So the end product is warped.

The Beta and DSG units I've inspected were very true, others I've seen are very untrue, and really need the heat transfer pad.

High failure rate of PMD Modules that are remote mounted?

The Grey Stanadyne module absolutely will not last when remote mounted on a cooler that is inside the engine bay. Been there done that. It isn't necessarily a bad module, but it's tolerance to heat is much less than the previous black versions it's replaced. It's a more stable unit electronically, but it must be mounted to an injection pump with a working lift pump and return circuit to stay within it's optimal operating range.

The aftermarket Flight Systems modules appear to be a way better module as they are more resistant to heat and last longer on coolers mounted all over the engine bay, even though those installations typically do not offer a cooler operation than on the pump itself.

My only recommendation for remote mounting a PMD is inside the factory bumper on a C/K truck where it has airflow.

http://www.uniquediesel.com/images/pmdcooler/photo-4.jpg

[guyina4x4]

I went to radio shack, they're going out of business, got $13 artic silver for $2.50 a tube.
I mounted it behind the front bumper, works fine.
Thanks for the replies