Perkins Air Filter
Date: December 20, 1999
From: John Witanowski slipf18@atl.mindspring.com
Dear Paul,
I need some advice on my engine...a Perkins 4-108. Could you please pass my request on to the forum membership?
- Air Cleaner question. Just dawned on me...I have been servicing the air cleaner without thinking too much about its design. On the underside of the "mushroom" type cover is an attached plastic mesh filter cup which I inspect and clean regularly. It appears to be the only filtering the air receives. I have never thought about whether there should be additional filtering for the engine. The engine manual is unclear on this point. Should there be a separate finer filter here? (perhaps a fine wire mesh or fabric element?) Does anybody know? Do you think I have done harm to the engine?
- Aside from the air cleaner, the engine has always been well maintained. Does anybody have any information on the expected lifespan of this engine (in terms of engine hours) and when might I expect to add an engine overhaul into my maintainence schedule. Are the any particular items I should attend to when this is done?
Thank you so much,
John Witanowski (aboard "Obsession"...E37 #437)
Date: December 21, 1999
From: Carl Hibbard Chgypsy@aol.com
1. Air Cleaner question. On the underside of the mushroom" type cover is an attached plastic mesh filter cup which I inspect and clean regularly. It appears to be the only filtering the air receives.
This is correct.
Do you think I have done harm to the engine? Do to the way the air ducting is placed
NO
REPLY: You should have a 2 or 3 inch flex hose coming in from the port rear clam shell air intake. This is normally routed to the left side of your engine and terminates roughly hanging down from your electrical panel perhaps with the end 1 to 1.5 ft. from the air "intake" mushroom. This is your suction (if you will) air supply for the engine, it shold be intact (no splits or holes) and try to have gentle bends. Any dirt coming in would tend to waft down and not into the engine. The mushroom and screen is to keep the big boulders, rags, nuts bolts insulation etc., out. The starboard rear clam shell should have a blower (12v) that pulls the hot air out of the engine compartment while pulling the engine source air. Same suggestions for the air flex tube. Without the blower it is still an air supply.
You will find that with the blower on your engine will run cooler, and your berth and or lockers, will be considerably cooler. (mine is relatively loud) This during hot weather and particularly if you are in warm engine cooling water.
Diesels, even as small as ours use a ton of air. This system is one that is easily checked first if you suddenly have lots of black smoke (running rich--or lack of air).
2. the engine has always been well maintained.
Does anybody have any information on the expected lifespan of this engine (in terms of engine hours) and when might I expect to add an engine overhaul into my maintainence schedule.
REPLY: Assuming that maintainance includes clean fuel, probably 95% of the problems that I have seen with engine stoppages with pumps injectors etc have been dirty fuel related.
Assuming;
That you change oil and filter regularly and with the correct grades of oil. That if you are in a cold storage climate you change the O & F prior to and after storage (acids). That when you start your engine you give it a warm up before applying working loads and pressures, and after heavy use you give it say 5 minutes before shutting down. That you haven't run it with a restricted cooling system (salt water deposits, perhaps caused by the incorrect thermostat), causing overheats. IE Impellers, water/oil coolers, and/or an intact exhaust manifold. No rusted hole or restrictions (in the outlet neck particularly- on the restriction);
Note: a rusted out exhaust manifold or water coming back in from the exhaust will probably blow the engine.
The actual answer based on the above:
Your engine should conceivably run well for literally thousands of hours. The highest hours that I have seen was 12,000 plus. This was an original owner, live aboard cruiser 1971 model boat (yes it was a 4-107). Have seen several with 8-10,000 hours. If it would help to have a comparison : One hour of running time is the equivelent of about 35 miles when related to stationary gasoline engines.(I can go to court with this one) When do you have to overhaul a cars engine if you do all of the maintainance?
Hope this helps a little.
