Air filter on M35B

Jim Lucas · March 14, 2020, 02:44:55 PM

After some recent service work I was looking at the (I assume) original air filter on my M35B with the wire wool filter. It appears to be fairly oil soaked and the blow-by hose is simply sitting beside the air filter with some bilge pad underneath to catch drips. It doesn't seem to be a big problem with oily residue in the engine compartment but I should be able to improve on this...
Is there a good replacement air filter option for these that is an improvement? Also, is the best idea to have the blow-by hose empty into some kind of container?

KWKloeber · March 14, 2020, 04:22:39 PM

Jim

Yeah the westerbeke solution of cutting off the hose at a 45 and zip tying it to the intake is, well, typical westerbeke. Not the most elegant.

I'm familiar with the m25xpb intake which should look much like the 35b. There should be a knockout on the intake manifold, just adjacent to the air cleaner/silencer. On some Kubota engines (tractors?) the knockout is replaced with a hose nipple that accepts the crankcase breather hose. I can look up the Kubota part number we used for the intake hose nipple if you want that route.
Of course another option is to just drill and tap a hole in the throat just behind the silencer (for a threaded hose barb.)

Or, although this wasn't for the B series, maybe it will give you some ideas to run directly into the silencer on the 35b.
http://c34.org/wiki/images/1/13/Example.pdf

Jim Hardesty · March 15, 2020, 04:45:01 AM

Jim,
May I suggest you do a search on "oil breather" and "air filter". Been lots of discussion and many ideas. I went with a filter in the oil breather line, added a barb to the air filter box and routed the hose there. No oil smell. The little added filter traps about a teaspoon of oil between oil changes.
Jim

Jim Lucas · March 15, 2020, 03:27:59 PM

Thanks all,
I've been searching the topic and see a lot of notes of changes for the M25 engines. I haven't had time to look to see what differences there might be with the M35B. But, maybe easier to just take the existing air cleaner to my auto parts store for a replacement K&N version. I like the idea of a air/oil separator and plumbing back to the air intake. Looks much more professional and reduced smells is always a good thing.

ewengstrom · March 16, 2020, 04:05:54 AM

On our M25XP we had that nasty smell when we bought it last year and you could feel a draft out of that vent hose along with some drips of oil just aimed into the bilge....not pretty.
That filter folks are mentioning is called a "catch can" and I installed one on Ohana. Pretty sure I picked it up new from Ebay or Amazon, it was only about $12.00 delivered. It appears to be eliminating the oil drip but part of my winter work is to route that vent line back into the intake to eliminate any further smell issues. I see where others have done this with good results.

Good luck!!!!

Jim Hardesty · March 16, 2020, 05:25:39 AM

Here is a thread that shows the oil separator filter. The picture is show a similar installation to mine. But I retained the original air filter.

https://c34.org/bbs/index.php/topic,5650.msg35344.html#msg35344

Jim

Jim Lucas · March 16, 2020, 04:47:39 PM

Thanks again. I did pull the existing air filter and see that the flange diameter is 1.75". When I searched K&N Filters, it looks like the smallest flange available is a 2". I'm guessing I need to get a reduction fitting made?

Breakin Away · March 21, 2020, 08:08:20 PM

Quote from: Jim Lucas on March 16, 2020, 04:47:39 PM
Thanks again. I did pull the existing air filter and see that the flange diameter is 1.75". When I searched K&N Filters, it looks like the smallest flange available is a 2". I'm guessing I need to get a reduction fitting made?

You could consider just getting the genuine Westebeke part. Not everything they sell is outrageously priced - you should check first to see if it's really worth your effort to custom make something. I think it's part #301049. Verify in the parts manual first, in case I've misunderstood what you're looking for.

KWKloeber · March 22, 2020, 08:26:58 AM

<<< You could consider just getting the genuine Westebeke part. >>>

Jim
I'm confused. Why are you looking to replace the unit with a KN? Don't you (correct me) have a perfectly good intake? A KN doesn't solve what you want - to get rid of the crankcase breather hose being divorced from the air intake.

Others -
enlighten me. What's the benefit of an oil catcher? I've seen pop bottles, coffee cans, and bought filter units. But why introduce that when just routing the breather hose to the intake works? It's the same principle as the PCV valved hose that we all used to have that on our auto engines that ran to the carburetor and sucked fumes from a hole in the valve cover. (And as I said Kubota does on some of those engine configurations.)

Stu Jackson · March 22, 2020, 09:47:00 AM

Quote from: KWKloeber on March 22, 2020, 08:26:58 AM>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>

Others -
enlighten me. What's the benefit of an oil catcher? I've seen pop bottles, coffee cans, and bought filter units. But why introduce that when just routing the breather hose to the intake works? >>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>

I agree. I just routed mine to the top of the air intake with a barb, no oil filter, after years of having it run down into a peanut butter jar!:D

I've always felt the oil filter was a waste and could eventually get clogged and make matters worse, not better.

Ron Hill · March 22, 2020, 03:00:26 PM

I agree with Stu - I vented my oil pan breather in to a cut off Budweiser can filled with foam - for over 20 years. Cleaned it out twice a season! Kept the engine compartment almost spotless !!

A thought

Jim Lucas · March 22, 2020, 03:04:29 PM

I haven't done anything yet. I was considering keeping the current intake and plumbing the breather through an air/oil separator back to the air intake. So, I guess we're on the same page. But, are you suggesting the oil separator isn't necessary?

Jim Hardesty · March 22, 2020, 03:49:32 PM

QuoteBut, are you suggesting the oil separator isn't necessary?

I don't believe it's necessary. But, by my unscientific testing it does keep the engine area cleaner and more important to me totally eliminates the smell.
Jim

Stu Jackson · March 22, 2020, 03:54:08 PM

Quote from: Jim Lucas on March 22, 2020, 03:04:29 PM
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
But, are you suggesting the oil separator isn't necessary?

Jim, yes I am. Based on Ron's experience, which he shared over 20 years ago, I went that route for decades and just last year routed it directly to the intake, as discussed in the 101 Topics, no separator. My reasoning: separator traps oil and could get blocked, or in any event requires service, so why add something else that is not essential.

Breakin Away · March 22, 2020, 04:46:48 PM

Quote from: Stu Jackson on March 22, 2020, 09:47:00 AM
...I've always felt the oil filter was a waste and could eventually get clogged and make matters worse, not better.

Hi all, I'm having a hard time picturing some of these suggestions. Could Stu or Ron please post a picture of how you're eliminating the oil filter? I haven't seen this anywhere on the site.