I looked into what micron I had put in and the primary is a 2 micron and the secondary on the motor is a 10 that is a real pain the butt to change. I think now this is backwards. the 30 year old perkins runs like a top but I was thinking to leave the 10 on motor so I dont have to change often leave the 2 micron in the racor 2000 and add a new racor 500 before that. I do have an electronic pump before the racor now will this be to many filters? is it going to be hard on the perkins? I dont always run the electronic pump it is a cheapy that helps me prime and start engine the first time of the day. I have lots to do no the boat but I want to get this right. thanks. Cliff
Allow me to help you here. I was deeply involved in filtration engineering (~35 years) and was indirectly involved with Parker/Racor (but other more critical 'super high tech' filtration divisions than Racor) for over 15 years.
For a
4-108, the typical 'best' is Tank---> 30µM----> 10µM----> 2µM ---->
10µM (small
engine mounted 'guard' filter) ..... Primary ----> Secondary----> Final----> 'Guard'
OR on typical small boat installations Primary---> Secondary----> "Guard".
The
ABSOLUTE MINIMUM should be
tank----> 10µM Racor---> 10µM (engine mounted guard).
The 10µM Racor is the
most important, followed by the engine 'guard' at ~10µM ... these two are all you need for safe operation, The use of a 2µM on a 4-108 is UNNECESSARY and will only cause the filtration set to
prematurely 'choke' / FAIL with debris (but OK to use, youll just have to change more often). The use of a 2µM will put an undue strain on the engine's lift pump and may cause future 'premature' lift pump failure .... long term.
The 30µM is a prefilter and reduces the amount of fine particulate going to the 10µM Racor. If you dont have the 30µM, the 10µM Racor will simply more rapidly plug as its function is solely to 'extend the in-service life' of the 10µM. When there is a 10µM preceding a 2µM, the 10µM acts as a 'prefilter' to the 2µM. Prefilters are there only to extend the service life of the next 'downstream' filter (not including the 'last chance or guard').
The 'engine guard' is there simply to protect the engine if the Racors (10µM or 2µM) fail (filter pleats break, etc.) or begin extrude very small soft/deformable particles. The engine 'guard' should ALWAYS have a 'prefilter' upstream protecting it, and the prefilter for the 'guard' should alway be SMALLER in µM retention than the 'guard'. You 'guard' is probably rated at 10µM (95%-97%)
Pressure/Vacuum Considerations.
(Simple Speak ... if you are running your filters in PRESSURE MODE, and you cant find the pressure rating of YOUR EXACT filter mod. in the below listed catalogue .... DO NOT EXCEED 15 psi pressure -- the lowest possible pressure rating possible for ALL 'Racors' . Some Racors used on small boats can operate as high as 30 psi, (some as high as 60 ... but you better be accurate when reading the confusing catalogue data and you MUST have a pressure gage mounted in the filter piping ...
if you dont find the data in the catalogue assume 15 psi MAX pressure
On small system as found in 'rec. boats', the 'pump' can be anywhere along the filter set;
best location is between the tank and the first filter in series with the pump 'pushing' oil into the filters - boat manufacturers use the engine lift pump as a vacuum source .... probably the 'worst' / 'cheapest' method vis a vie 'filtration'. So, in your case it really doesnt matter where the 'extra' pump is (and it doesnt have to even be 'on' .... the ONLY consideration is that the system pressure does not exceed 15 psi (pressure) for the small racors sets (30 psi for the 'larger' type sets) when that 'little
extra pump is ON' ..... You need to correlate the EXACT part number vs. system max. pressure.
Search out your EXACT Racor Housing part number and cross reference the MAX. OPERATING pressure in:
http://www.parker.com/literature/Racor/7501_Rev_H_Marine_Filtration_Systems.pdf .... and install or use a pressure gage to VERIFY the pressure if you plan to have this 'extra' pump continuously 'on'.
Note - If this is a pump only used for
bleeding air out of the filters and injection system ..... it doesnt have to be 'on' when the engine is running !!!!!, so just 'ignore' it and use it only to bleed and as a 'reserve' pump in case the engine lift pump fails.
Note: if your system is only a Single Racor preceding the engine 'guard', I suggest (next time you change out) that you use a 10µM instead of a 2µM .... as you will (properly) filter 5 TIMES the amount of oil before the Racor 'plugs' AND will cause less 'load' on the engine's lift pump.
hope this helps.