flathead v8 crankcase ventilation ??

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May 18, 2010 | 06:19 PM

r_reed

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Laughing Gas

Joined: Jul 2003

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From: scotia. NY 12302

flathead v8 crankcase ventilation ??

i know the ultimate answer to this is engine rebuild, but that is off until next year. i have a good running eab, 110 Lbs. compression on 7 cylinders, 85Lbs. on 1 cylinder. it starts easily, idles smooth, Oil pressure 44LBS, start up, 18 cruising and drops to 10 at fast idle. i have a "ross" version pcv set up and have eliminated the draft tube, that seems to work fine. my question is about the oil filler cap (breather?). is that supposed to let air into the crankcase? i get puffs of smoke out of the filler cap and see evidence of oil blowing out when i'm hauling up hills at 45mph. i assume it's blowby, is there anything i can do to manage it? can i "t" it into my pcv line? does the draft tube area vent the valve chest ? is air supposed to come up from crankcase to the valve chest and out?? if so, does that passage sometimes get blocked? love the eab but the oily mist hits my engine/exhaust manifold and makes unnec. smoke. apologize for the length of the post. dick r

May 18, 2010 | 06:34 PM

ALBUQ F-1

Fleet Owner

Joined: Jul 2004

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From: NM

Modern OEM PCV systems have that tube that goes to the air cleaner housing, outside of the filter, to eliminate exactly what you're seeing. You can certainly do the same, it will at least contain the vapors. It's normal for the PCV to reduce the amount it draws when under load (low vacuum).

May 18, 2010 | 07:22 PM

r_reed

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Laughing Gas

Joined: Jul 2003

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From: scotia. NY 12302

thanks ross, i'm going to try that. right now i'm running the teeny/tiny hot rod chrome air cleaner. will have to look for something different to incorporate a vent tube. happy motoring. dick r

May 19, 2010 | 05:53 AM

joedellcarter

Senior User

Joined: Aug 2007

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From: Enfield Connecticut

Sounds a lot like my Flatty. Smokestack Lightnin'

May 19, 2010 | 07:51 AM

ALBUQ F-1

Fleet Owner

Joined: Jul 2004

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From: NM

Quote:

Originally Posted by r_reed

thanks ross, i'm going to try that. right now i'm running the teeny/tiny hot rod chrome air cleaner. will have to look for something different to incorporate a vent tube. happy motoring. dick r

It's hard to find something larger for these, but it's worth it. The little ones have a lot of pressure drop and the small filters also get plugged quickly. If you do run a tube for the vapors, try to incorporate a shield so oily vapor doesn't get right on the paper element. One thought is to use one of those typical Ford plastic "filter" elements that clips into the air filter housing, the ones with a coarse white mesh in them.

May 19, 2010 | 01:35 PM

r_reed

Thread Starter

Laughing Gas

Joined: Jul 2003

Posts: 1,224

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From: scotia. NY 12302

got the idea, ross, will go to the junkyard tomorrow on a scouting trip. when i ran my f-1 in the 1970's i used a carb clamp from and old oil bath cleaner and used two paint can lids for my upper and lower housing. hoping to avoid that this time around. maybe i can cut the clamp off my little cleaner and attach it to a larger cleaner with bigger paper element and vent hook up as you suggested. dick r.

May 19, 2010 | 01:38 PM

BlueOvalRage

Cargo Master

Joined: Jun 2001

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From: Oxford, Indiana

On a slightly different note, 110 lbs. of compression is pretty darn good on a flatty and your oil pressure numbers are good, too. Rather than a full rebuild, you might consider jerking the head off the bank with the 85 lb. jug and checking the valves. If you can get the compression back up in that cylinder with just a little valve work, then a rebuild might not be necessary.