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

Automotive powered airboat discussion.
loudmouse
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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
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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 zz4 355sbc 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200

Basin_Runner355
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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 zz4 355sbc 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200

Basin_Runner355
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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 zz4 355sbc 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200

SWAMPHUNTER45
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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

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

Postby ladyblackwater » Tue Feb 06, 2018 3:20 pm

I see you have a 750DP Holley but what is your set-up? What motor, gearbox/belt box or is it direct drive? What HP is the motor at what rpm? What Holley 750DP do you have? With an Airboat to get the best tune you really need a carb that allows you to change the air bleeds. I'm willing to bet your idle circuit is drawing too much.
Greater love hath no man, than to lay his life down for a friend.

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I am that conservative republican your momma warned you about!

SWAMPHUNTER45
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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

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kwanjangnihm
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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? "

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

Postby ladyblackwater » Wed Feb 07, 2018 1:23 am

:o :scratch: :lol: :lol: ^^
Greater love hath no man, than to lay his life down for a friend.

Bitterly clinging to my guns and my religion!

I am that conservative republican your momma warned you about!

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

Postby ladyblackwater » Wed Feb 07, 2018 1:51 am

Thanks Swamphunter. Dummy me should have just looked at his signature :violent1: :lol: It sounds like he has the right size carb then. It definitely sounds like it's a problem in the idle circuit then. My next question would be if you have done a Vaccum check yet to see how much Vaccum you are pulling?
Greater love hath no man, than to lay his life down for a friend.

Bitterly clinging to my guns and my religion!

I am that conservative republican your momma warned you about!

One Eyed Gator
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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
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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 zz4 355sbc 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200

Basin_Runner355
Southern Airboat Member
Posts: 112
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 zz4 355sbc 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200

loudmouse
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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: 112
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 zz4 355sbc 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200

Basin_Runner355
Southern Airboat Member
Posts: 112
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 zz4 355sbc 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200

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

Postby ladyblackwater » Wed Feb 07, 2018 4:30 pm

Basin_Runner always remember you can NEVER mix the Green Coolant with the Orange Dexcol. They are made of 2 different chemicals that don't mix together. When you go from one to the other you have to do a complete flush of the cooling system. I can say personally I'm not a fan of the Dexcol. There is no need for me to repeat what Loudmouse said but he is 100% correct. I see this all the time in airboats. 99% of the time the carb tune and timing not being correct for your application will cause major problems and most of the time catastrophic failure. I hope you get everything figured out fast so you can get back on the water.
Greater love hath no man, than to lay his life down for a friend.

Bitterly clinging to my guns and my religion!

I am that conservative republican your momma warned you about!

Basin_Runner355
Southern Airboat Member
Posts: 112
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 zz4 355sbc 2:1 belt drive reduction with a 78 water walker falcons pitched at 5200


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