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Discussion Starter #1
I thought I would check my PCV valve so I pulled the elbow out of the L/H rocker cover. Well I got it out in a couple of pieces and no valve, just a hollow elbow. Where did they hide the PCV on the 97 4.6L T Bird or does it even have one?

Thanks, Phil Swanson
 

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The pistons moving downward in the cylinder cause a pressure to build in the crankcase. Has anyone ever upgraded breathers or used a vacuum pump on a MN-12 to lower that resistance?

On some smog motor v8 from the 80's hooking up the smog pump to the crankcase was talked about. Instead of blowing air it was used to cause a vacuum in the crankcase that made the piston travel easier down.

These kinds of things probably come into play at high rpms, and lookin' to squeeze out another tenths.

anyway, just to chat about car stuff...
 

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Thanks, got it. My stupid book showed it on the other side.

Phil Swanson
97Bluebird
I think it's important to be pro-active about maintenance.

There are a lot of threads to replace similar components on TCCoA about not only the pcv, but egr valve, vacuum hoses, etc...the are sometimes neglected.

Do you have any pics to post of your car?
 

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WOT Junkie and avid corn burner
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The pistons moving downward in the cylinder cause a pressure to build in the crankcase. Has anyone ever upgraded breathers or used a vacuum pump on a MN-12 to lower that resistance?

On some smog motor v8 from the 80's hooking up the smog pump to the crankcase was talked about. Instead of blowing air it was used to cause a vacuum in the crankcase that made the piston travel easier down.

These kinds of things probably come into play at high rpms, and lookin' to squeeze out another tenths.

anyway, just to chat about car stuff...
I imagine that if staying N/A, just using the stock style PCV valve would work best. Maybe an open breather on the driver's side valve cover if running forced induction.
 

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The pistons moving downward in the cylinder cause a pressure to build in the crankcase. Has anyone ever ...
anyway, just to chat about car stuff...

Some issues with that... :)

As far as swept volume goes, there is no change in crankcase volume as the pistons move.

For every piston going up, there is one going down at the same rate. :)

4 pairs or three pairs, it's the same.


The only current engine this is Not true of is a 72° V-Twin Harley.


On the 96 and 97, at least, the drivers' valvecover is connected to a tube that comes off the inlet tube. (metered air)

It passes thru the engine, and out the passenger VC, where it connects directly to a large vacuum port on the front of the manifold.

So it sees hard vacuum at idle when there is little force on the rings and they don't seal well; but at wot there's no real vacuum, and the rings are held down by the charge in the cylinder pretty well. :)

Our pcv system likes to run oil thru it at WOT, thus the market in oil separators. :)
 

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Discussion Starter #9
I think it's important to be pro-active about maintenance.

There are a lot of threads to replace similar components on TCCoA about not only the pcv, but egr valve, vacuum hoses, etc...the are sometimes neglected.

Do you have any pics to post of your car?
I now have two 1997 T Birds. I had 3 but just sold the one with over 200k on it. I just bought one from a little old lady from Pasadena, just like the song, but for real. It has 23k original miles and has always been garaged. Still has the new car smell. Great find but not cheap at 5k. All of my 97s have had the 4.6l motor. Before these 3, I had a 91 with the 3.8. No pictures but all great cars. My newest is Pearl White with gray leather interior.

Phil Swanson
97Bluebird
 

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The pistons moving downward in the cylinder cause a pressure to build in the crankcase. Has anyone ever upgraded breathers or used a vacuum pump on a MN-12 to lower that resistance?

On some smog motor v8 from the 80's hooking up the smog pump to the crankcase was talked about. Instead of blowing air it was used to cause a vacuum in the crankcase that made the piston travel easier down.

These kinds of things probably come into play at high rpms, and lookin' to squeeze out another tenths.

anyway, just to chat about car stuff...
Yup unless you're turning some serious rpm looking to eek out every last 1/2 HP, the cylinder moving up at the same time as the one going down more or less equalizes the pressures. Any blow by getting past the rings travels up to the heads via the huge cavity that is the timing chain cover, and then "evacuated" via the PCV valve.
 

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I've got two Mark VIII smog pumps buried in my crawl space for that very project. I plan to run them in tandem eventually but I can't say I'm super motivated to lol
 

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I now have two 1997 T Birds. I had 3 but just sold the one with over 200k on it. I just bought one from a little old lady from Pasadena, just like the song, but for real. It has 23k original miles and has always been garaged. Still has the new car smell. Great find but not cheap at 5k. All of my 97s have had the 4.6l motor. Before these 3, I had a 91 with the 3.8. No pictures but all great cars. My newest is Pearl White with gray leather interior.

Phil Swanson
97Bluebird
@#$&_batman! 23K!!!

That's almost still whiskers still on the tires.

Am I to understand you correctly? There were no '97 3.8 'birds?
 

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I've got two Mark VIII smog pumps buried in my crawl space for that very project. I plan to run them in tandem eventually but I can't say I'm super motivated to lol

That's probably because there is not a lot to gain on a street car. The pump(s) take power to run, and on a street car that can be self-defeating. There'd be some plumbing/bracket work to do also to get it work. It might help lower et's through the traps tho'..combating the law of diminishing returns.

That's cool you have some pumps saved. Neat, you've heard of crankcase pressure relief tricks. lol
 

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Discussion Starter #14
@#$&_batman! 23K!!!

That's almost still whiskers still on the tires.

Am I to understand you correctly? There were no '97 3.8 'birds?
NOT True!! I never said that! Just not in my stable. I prefer the 4.6. The tires were original but 17 years old which are unsafe to drive on, so I took the car directly to Discount Tire and got it re-skinned with a set of Michelins.

Phil Swanson
97Bluebird
 

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NOT True!! I never said that! Just not in my stable. I prefer the 4.6. The tires were original but 17 years old which are unsafe to drive on, so I took the car directly to Discount Tire and got it re-skinned with a set of Michelins.

Phil Swanson
97Bluebird
I gotcha, "...not in my stable". Yup, the 4.6 is the way to go. I guess I miss read your comment. Many apologizes.

Michelins ride smooth. They balance the best. I bought bfgoodrich radial ta's. rwl out. lol 215/70r15's on fanblades. For 70's series tires they handle pretty good with the stiff sidewall. They're not as quite on the interstate as the Mich' tho'.
 

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Discussion Starter #16
I gotcha, "...not in my stable". Yup, the 4.6 is the way to go. I guess I miss read your comment. Many apologizes.

Michelins ride smooth. They balance the best. I bought bfgoodrich radial ta's. rwl out. lol 215/70r15's on fanblades. For 70's series tires they handle pretty good with the stiff sidewall. They're not as quite on the interstate as the Mich' tho'.

They are the same thing now and made in the same plants. BFG sold their tire business to Michelin a few years back. The are strictly in the aerospace business now. Shop for the best price. BFGs tend to be a little cheaper. I have had trouble with other brands with seperation. And shop for the latest manufacturing dates you can find, especially if you dont drive the car much. Also my front end guy says to run 40 pounds on the T Bird. He has over 50 years experience. I follow his advise to the letter. Harder ride but better MPGs and longer lasting tread life.

Phil Swanson
97Bluebird
 

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50 years of Mercury Cougar 1967/2017
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The pan-vac pumps that are being referred to are mainly
For Forced induction engines.
To stop the build up of explosive gasses that are forced by
The piston rings.
With an errant ignition source, bang you need a new
Engine.
 

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97Bluebird said:
Also my front end guy says to run 40 pounds on the T Bird. He has over 50 years experience.
Thanks for the skinny on the tires I usually run 35psi. I'll try 40 see how they feel.

The pan-vac pumps that are being referred to are mainly
Forced induction engines.
To stop the build up of explosive gasses that are forced by
The piston rings.
With an errant ignition source, bang you need a new
Engine.
Interesting.

E-vac volatile explosives. Dang!
 

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The pistons moving downward in the cylinder cause a pressure to build in the crankcase. Has anyone ever upgraded breathers or used a vacuum pump on a MN-12 to lower that resistance?

On some smog motor v8 from the 80's hooking up the smog pump to the crankcase was talked about. Instead of blowing air it was used to cause a vacuum in the crankcase that made the piston travel easier down.

These kinds of things probably come into play at high rpms, and lookin' to squeeze out another tenths.

anyway, just to chat about car stuff...


If someone wants to play with using some smog pumps for this idea, I have two from my 93 tbird 5.0 donor cars.

Just pay me a few bucks ($5 is plenty) + shipping (might even be able to do flat rate) and you can have both of them.

-g
 

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If someone wants to play with using some smog pumps for this idea, I have two from my 93 tbird 5.0 donor cars.

Just pay me a few bucks ($5 is plenty) + shipping (might even be able to do flat rate) and you can have both of them.

-g
Thanks for the cool offer. I plain to keep my 95 stock because, I'm in the market for a low mileage, rust free 97 thunderbird 4.6, and build performance in a 97 that looks like a 95. So in otherwords, I'm a long way off to adding crankcase pumps.

Thanks for the reply. Neat that other peeps know about the smog pump trick.

I think I'd use, perhaps, an electrical motor instead of running one off the belt.

...now where again is that pcv
 
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