Leave the pcv valve on or take it out pros and cons

Automotive powered airboat discussion.
Basin_Runner355
Southern Airboat Member
Posts: 166
Joined: Sun Nov 13, 2016 7:16 am
Location: St.martinville , Louisiana

Re: Leave the pcv valve on or take it out pros and cons

Postby Basin_Runner355 » Tue Feb 06, 2018 5:47 am

Well two weeks ago i got in touch with a guy that suposed to know his shit has his own shop and does 90% airboat Work. He went through my carb and retuned it. While we were sitting there letting it run when i went get it it was still doing the same thing after idling for a few mins it starts to load up and puff smoke out the exhaust not bad but it’s smoke comming out he said it looked white to him. But it smelt more like gas he is the third person i brung it to. I haven’t got to go run it yet to see how it does but if it’s still not right idk who to go to next cause every mechanic does things a diffrent way and days the one before him don’t know anyting. Four ppl i know of bring theirs to the guy i brung it to this last final time hopefully. The problem i am having is i think it’s loasing up and when you go to start it sometimes it takes a while to start up again gota let it sit there and turn over
14ft diamond back mild zz4 355sbc pushin 410 hp 430 TQ 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200

swamper2
Southern Airboat Member
Posts: 409
Joined: Mon Apr 12, 2010 8:05 pm
Location: harsens island michigan

Re: Leave the pcv valve on or take it out pros and cons

Postby swamper2 » Tue Feb 06, 2018 8:46 am

make sure your rubber cap on the pvc tube at the base of the carb isn't cracked or rotten. If it leaks your carb will be difficult to tune. I put a 2 in piece 3/8 of rubber airhose with a bolt siliconed in it to replace the rubber cap.
16ft alumitech/406sbc/2.38w/3-80in.R's

swamper2
Southern Airboat Member
Posts: 409
Joined: Mon Apr 12, 2010 8:05 pm
Location: harsens island michigan

Re: Leave the pcv valve on or take it out pros and cons

Postby swamper2 » Tue Feb 06, 2018 8:47 am

make sure your rubber cap on the pvc tube at the base of the carb isn't cracked or rotten. If it leaks your carb will be difficult to tune. I put a 2 in piece 3/8 of rubber airhose with a bolt siliconed in it to replace the rubber cap.
16ft alumitech/406sbc/2.38w/3-80in.R's

SWAMPHUNTER45
Site Supporter - III
Site Supporter - III
Posts: 2517
Joined: Thu Nov 21, 2013 11:38 am
Location: Naturecoast, Florida

Re: Leave the pcv valve on or take it out pros and cons

Postby SWAMPHUNTER45 » Tue Feb 06, 2018 8:59 am

There have been several people who have been on Southern Airboat who suffered fatal lean conditions due to defective vacuum caps on their carburetor base.

loudmouse
Southern Airboat Member
Posts: 479
Joined: Tue Jan 22, 2013 3:20 pm
Location: Ocala Fl

Re: Leave the pcv valve on or take it out pros and cons

Postby loudmouse » Tue Feb 06, 2018 9:01 am

If there was a vacuum leak the engine would be lean at idle not rich unless it was flooding
15' Alumitech deckover LSX TT Oxbox 84" JX 4-blade
Gas required Water optional :dontknow:
Built and Tuned by Me
14'X8' JW, Chevrolet 122CID LNF Turbo Engine, Ox box, 80" NGR 3 blade

Life is short, eat your dessert first! :downtown:

Basin_Runner355
Southern Airboat Member
Posts: 166
Joined: Sun Nov 13, 2016 7:16 am
Location: St.martinville , Louisiana

Re: Leave the pcv valve on or take it out pros and cons

Postby Basin_Runner355 » Tue Feb 06, 2018 9:29 am

All my vacuum caps are good and brand new the carb was just rebuilt
14ft diamond back mild zz4 355sbc pushin 410 hp 430 TQ 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200

Basin_Runner355
Southern Airboat Member
Posts: 166
Joined: Sun Nov 13, 2016 7:16 am
Location: St.martinville , Louisiana

Re: Leave the pcv valve on or take it out pros and cons

Postby Basin_Runner355 » Tue Feb 06, 2018 9:33 am

I’ll take some pics today

Also the guy that put the Holley on put primary on the back side of the engine toward the distributor idk if that makes a difference or not.
14ft diamond back mild zz4 355sbc pushin 410 hp 430 TQ 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200

Basin_Runner355
Southern Airboat Member
Posts: 166
Joined: Sun Nov 13, 2016 7:16 am
Location: St.martinville , Louisiana

Re: Leave the pcv valve on or take it out pros and cons

Postby Basin_Runner355 » Tue Feb 06, 2018 9:34 am

Like i said it may be good now i haven’t ran it ima change my plugs also. So everything good and new
14ft diamond back mild zz4 355sbc pushin 410 hp 430 TQ 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200

SWAMPHUNTER45
Site Supporter - III
Site Supporter - III
Posts: 2517
Joined: Thu Nov 21, 2013 11:38 am
Location: Naturecoast, Florida

Re: Leave the pcv valve on or take it out pros and cons

Postby SWAMPHUNTER45 » Tue Feb 06, 2018 10:26 am

I was not implying HIS situation was a lean condition....anyways

Good luck with it

SWAMPHUNTER45
Site Supporter - III
Site Supporter - III
Posts: 2517
Joined: Thu Nov 21, 2013 11:38 am
Location: Naturecoast, Florida

Re: Leave the pcv valve on or take it out pros and cons

Postby SWAMPHUNTER45 » Tue Feb 06, 2018 4:15 pm

ZZ4 is 355hp @ 5250
Drive is 2:1 belt spinning WW Falcons

User avatar
kwanjangnihm
Site Supporter - IV
Site Supporter - IV
Posts: 1736
Joined: Sat Mar 30, 2013 8:23 pm
Location: Bartow FL

Re: Leave the pcv valve on or take it out pros and cons

Postby kwanjangnihm » Tue Feb 06, 2018 7:37 pm

I had to read this thread a few times, but finally have a visual of how a CM pcv valve works!! :toothy7: :stirpot:

Image
" I don't care who you are back in the world, you give away our position one more time, I'll bleed ya, real quiet. Leave ya here. Got that? "

One Eyed Gator
Southern Airboat Member
Posts: 1202
Joined: Wed May 30, 2007 11:33 am
Location: Ocala,Fl

Re: Leave the pcv valve on or take it out pros and cons

Postby One Eyed Gator » Wed Feb 07, 2018 8:37 am

FYI on the vacuum cap use the silicon caps. The black rubber caps will not last. I also put a small zip-tie around the cap.

BTW Loudmouse what is the name of your shop?

Basin_Runner355
Southern Airboat Member
Posts: 166
Joined: Sun Nov 13, 2016 7:16 am
Location: St.martinville , Louisiana

Re: Leave the pcv valve on or take it out pros and cons

Postby Basin_Runner355 » Wed Feb 07, 2018 10:29 am

Well upon checking other things yesterday i come to learn that i have a head gasket leak and I’m getting fluid on my #3 cylinder so I’ll be tearing it all down and getting my heads Reworked and fixing that issue before i make any adjustments. Always someting with a airboat.
14ft diamond back mild zz4 355sbc pushin 410 hp 430 TQ 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200

Basin_Runner355
Southern Airboat Member
Posts: 166
Joined: Sun Nov 13, 2016 7:16 am
Location: St.martinville , Louisiana

Re: Leave the pcv valve on or take it out pros and cons

Postby Basin_Runner355 » Wed Feb 07, 2018 10:30 am

358E02BC-47CD-4896-959C-7D81CA6DAFDA.jpeg
Spark plugs
14ft diamond back mild zz4 355sbc pushin 410 hp 430 TQ 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200

loudmouse
Southern Airboat Member
Posts: 479
Joined: Tue Jan 22, 2013 3:20 pm
Location: Ocala Fl

Re: Leave the pcv valve on or take it out pros and cons

Postby loudmouse » Wed Feb 07, 2018 11:19 am

@kwan, there is another 50+ pics of a pcv setup but they do not depict GM's way after the late 80's. Nor did the sbc come with a aftermarket holley carb.

Looking at ur plugs that engine has some severe tune issues that need to be corrected.

The Holley carb was NEVER designed to operate with a vacuum leak (vented pcv) as it's design is for performance use no pcv. The large port on the back of the base plate, (intended for the brake booster) SEALED, can be used for pcv if the system is sealed! If it's used in a vented pcv, the metering of the fuel must be reprogrammed by changing the air bleeds and corrected jetting. This I also do but not for a pcv but for a carb operating on an engine with very little vacuum(high overlap cams) to achieve a linear afr throughout the rpm.

Now to the head gasket, its very unfortunate that this had to happen but I see it all too often. 4 causes of blown head gaskets are operating the engine out of tune with a high load (prop), operating the engine hot, electrolysis from improper grounding and not maintaining a proper mixture of anifreeze to stop the corrosion inside the engine. Good luck with the repair and remember if the engine is allowed to operate under the same paramiters again the end result will also be the same!
15' Alumitech deckover LSX TT Oxbox 84" JX 4-blade
Gas required Water optional :dontknow:
Built and Tuned by Me
14'X8' JW, Chevrolet 122CID LNF Turbo Engine, Ox box, 80" NGR 3 blade

Life is short, eat your dessert first! :downtown:

Basin_Runner355
Southern Airboat Member
Posts: 166
Joined: Sun Nov 13, 2016 7:16 am
Location: St.martinville , Louisiana

Re: Leave the pcv valve on or take it out pros and cons

Postby Basin_Runner355 » Wed Feb 07, 2018 11:43 am

I wil try my best to get it right so it doesn’t happen again. When i got motor it had the green coolant i put the orange dexcool since that is suposed to be for engines with Aluminum head. I will get with about the tuning of the carb once i get the head gasket squared away and i know I’ll have a fresh set of valves that are seating properly. Hope I’m not down to long got a big ride in a few weeks.
14ft diamond back mild zz4 355sbc pushin 410 hp 430 TQ 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200

Basin_Runner355
Southern Airboat Member
Posts: 166
Joined: Sun Nov 13, 2016 7:16 am
Location: St.martinville , Louisiana

Re: Leave the pcv valve on or take it out pros and cons

Postby Basin_Runner355 » Wed Feb 07, 2018 11:50 am

I have to get the head gasket and all that fixed before i worry about the carb i haven’t rsnnit since that last guy i told you about put his touches on it but loudmouse i will be intouch oncd i get the internsls right again
14ft diamond back mild zz4 355sbc pushin 410 hp 430 TQ 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200

Basin_Runner355
Southern Airboat Member
Posts: 166
Joined: Sun Nov 13, 2016 7:16 am
Location: St.martinville , Louisiana

Re: Leave the pcv valve on or take it out pros and cons

Postby Basin_Runner355 » Tue Feb 27, 2018 12:32 pm

Well come to find out i fried the #3 piston and rings. My plan of attack right now it to just short block the motor out it back stock and use my old block to build a new one for later on down the road gonna get it bored and all that good stuff and build it bullet proof from the ground up. All forged internals the whole 9 yards so I’ll be asking for parts and what not in the near future.
14ft diamond back mild zz4 355sbc pushin 410 hp 430 TQ 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200

Striker543
Site Supporter - I
Site Supporter - I
Posts: 990
Joined: Wed Oct 13, 2010 11:03 pm
Location: Miami/Orlando, Fl

Re: Leave the pcv valve on or take it out pros and cons

Postby Striker543 » Mon Jul 02, 2018 1:49 pm

Do you guys have a catch can system you recommend? I just bought a boat with a 406 sbc that is building pressure and forcing the dipstick to pop up a little. It currently has a line from one valve cover going to the base of the carb and the other valve cover has a breather with a line going to a mount that faces the mouth of the hose against the carb air filter.

Striker543
Site Supporter - I
Site Supporter - I
Posts: 990
Joined: Wed Oct 13, 2010 11:03 pm
Location: Miami/Orlando, Fl

Re: Leave the pcv valve on or take it out pros and cons

Postby Striker543 » Mon Jul 02, 2018 2:43 pm

My setup is the same as the diagram posted above

User avatar
JAMES
Site Supporter - II
Site Supporter - II
Posts: 8569
Joined: Wed Aug 22, 2007 10:31 pm
Location: cocoa
Contact:

Re: Leave the pcv valve on or take it out pros and cons

Postby JAMES » Mon Jul 02, 2018 5:50 pm

I like them the motor needs and has to vent some way this is the cheapest source jmo . No vent u will develop leaks
https://m.facebook.com/321ccc/?ref=bookmarks Wp383 268 rotator 3 bld WT/EX 14.4 perdator

Hotdog
Southern Airboat Member
Posts: 36
Joined: Mon Nov 27, 2017 6:31 pm

Re: Leave the pcv valve on or take it out pros and cons

Postby Hotdog » Mon Jul 02, 2018 5:55 pm

I have a 434 with 13.2 compression. I run open breathers one on each side about 6 inches tall and I have no problems with oil seeping out of them


Return to “Automotive Power Only”

Who is online

Users browsing this forum: No registered users and 21 guests