351 valve cover breather
Printed From: CorrectCraftFan.com
Category: General Correct Craft Discussion
Forum Name: General Discussion
Forum Discription: Anything Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=47115
Printed Date: March-09-2025 at 10:21pm
Topic: 351 valve cover breather
Posted By: mmfarmer1
Subject: 351 valve cover breather
Date Posted: January-11-2019 at 10:37am
| I'm wondering about options for my 76 ski nautique with a 351w. On the starboard side valve cover I'm running a pcv valve with a hose going to the spark arrestor and on the port side cover I have a breather cap. I'm tired of the fume build up from the breather which only shelf vents since my carburetor wedge does not have a hose connector port??? Any advice or options to help with this? Thanks |
Replies:
Posted By: phatsat67
Date Posted: January-11-2019 at 10:56am
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The PCV valve should be hooked up to a vacuum source below the carburetor. The vent should just vent into the flame arrestor. The PCV will create some negative crankcase pressure in higher vacuum situations thus getting rid of your excess underhood fumes. You can pipe the PCV into an intake runner that has a port. Some say that may make said cylinder run a little lean but you would have to trial and error it. To stay on the safe side you could get a base plate that has a port in it or a carburetor with a port in the throttle body. Pretty simple solutions. Also, if the valve hasn't been serviced lately I would pick up the correct stock PCV. https://www.amazon.com/gp/product/B000C5FJG8/ref=oh_aui_search_asin_title?ie=UTF8&psc=1%20" rel="nofollow - Correct Valve |
Posted By: Jonny Quest
Date Posted: January-12-2019 at 1:04pm
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A new PCV valve is an inexpensive part. Change it out and see if that clears up the oil. If the oil persists, there are oil/air separators that can be used. Many racer/gear-heads use the oil/air separator to keep oil ingestion through the PCV down. They aren't cheap, however. JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: KENO
Date Posted: January-12-2019 at 10:51pm
Here's a picture of what Zach is saying. It's a mid 70's PCM. from an old thread here on CCF The drivers side valve cover has a PCV valve in it with the black hose going from the PCV valve to the carburetor spacer or alternately a fitting on an intake runner right behind the carburetor. Normally the manifold has a pipe plug in it that you'd have to remove and put a fitting for the hose into the hole.. The oil fill cap has a right angle fitting in it with the reddish hose hooked to it and connecting to a fitting on the spark arrestor. That's the original setup on a 76 PCM 351. There were slightly different variations over the years on the oil fill cap/breather setup but the flow path was the same The red hose color isn't original but you get the idea 
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Posted By: DrCC
Date Posted: January-13-2019 at 12:52am
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And here's what Zack and Ken mentioned. Please excuse the old homelite chainsaw color combo on the 351.  ------------- Keep it....from sinkin' |
Posted By: rosconole
Date Posted: January-13-2019 at 3:55am
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Their should be no reason for a valve cover breather you do not have any positive crank case pressure ------------- 1989 ski nautique ,1991 barefoot nautique, 1993 Mustang Cobra 1998 5.0 Magazine shootout invitee |
Posted By: KENO
Date Posted: January-13-2019 at 9:21am
Good teamwork on the pictures Doc I like the Homelite color schemed 351, I think Roscoe needs to refresh himself on how a pcv system works |
DrCC wrote:Posted By: mmfarmer1
Date Posted: January-13-2019 at 10:22am
| Thanks for all the info! I've ordered a new carb spacer with port for the PCV and new breather with port for the arrestor. I've been running the boat for so long now with the breather just venting into the dog house that i'm hoping this set up really makes a difference. Thanks again for everyone's help! |