Plenum Pull Advice, Starter Rebuild, MAP Sensor Info

[mgbrv8]

I am debating if i should put a newer style condenser or add a fan to my system while I have it open during my a/c compressor rebuild, besides new orings and Orfic tube and accumulator. I live in south tx and we hit well in to the 100s for long periods. I've hear the r134 systems have more fins per inch.

Dave

[mgbrv8]

Okay I was mounting my Water pump pulley when I noticed there was more resistance in the water pump then when I spun it on the bench. So I pulled it back off just to find that the impeller was touching the casting in two spots. So I put it on my lathe and cut 8 Thousands of a inch off. That brought the back of the impeller distance to the Water pump casting to exactly the same tolerance As the factory unit I should have checked that before I assembled the pump. I should never have assumed a new pump would be perfect. And I'm going to add a surprise that I think the members might like while I have the pump off.

Dave

[mgbrv8]

From what people have said its hard to purge the air out of the water pump between the inlet and outlet of the pump. So it eliviate any unwanted air I drilled a and tapped a pipe plug in the water pump so I dont have any air pockets.

[Dynomite]

Originally Posted by mgbrv8

From what people have said its hard to purge the air out of the water pump between the inlet and outlet of the pump. So it eliviate any unwanted air I drilled a and tapped a pipe plug in the water pump so I dont have any air pockets.

That actually will work

An extreme measure but a good one as there is no other way to be sure you get that air out of an air locked water pump other than blowing it out (actually blowing coolant into the water pump area) from drivers side with long radiator hose connected to Drivers side Injector Housing Manifold. With your modification we know we got the air out and we did not blow that water pump air into the passenger side Injector Housing

See Filling With Coolant and the Air Locked Water Pump

[mgbrv8]

Ya it's not a nos pump and the Z isn't a NCRS candidate so I figure what the heck.

Dave

[scottfab]

Originally Posted by Hib Halverson

"scottfab"...Please, cite the source of your information about early LT5 development and TB ice being ingested into the engine.

Ok I spent a few minutes searching the archive. One thing I learned was the the posted archives on the ZR1netregistry.com page don't seem to be complete. Some dates don't show up.
I have some posts in my own archive that don't appear in the official one.
Having said that. I have not found specifically what I was looking for.
I found stuff close to it but not it.

Over the years the subject of ice in the TB/plenum has come up multiple times. I don't think it's in doubt that the TB receives coolant water as a counter measure for same but only how often or how likely it would be to occur.

Below is a snipped parts of a thread. To do your own looking search for either "icing" or "ice formation".

__________________________________________________ __
Message-ID: <33426637.2FE4@pacbell.net>
Date: Wed, 2 Apr 1997 13:59:21 +0000
Reply-To: Gary Livick <glivick@PACBELL.NET>
Sender: "ZR-1 Corvette enthusiast list." <ZR1NET@HOME.EASE.LSOFT.COM>
From: Gary Livick <glivick@PACBELL.NET>
Subject: Re: TECH: MAT sensor relocating
To: ZR1NET@HOME.EASE.LSOFT.COM
X-Lines: 27
Content-Type: text/plain; charset="iso-8859-1"
Content-Length: 1327
Status: RO
X-Status: $$$$
X-UID: 0000000389

Hi again Jim:

Yesterday, we were talking about ice formation in venturi flow. I
talked to a flight instructor, and he states as follows: Carb ice can
form at temperatures as high as 72° F as long as atmospheric conditions
are supportive. He states however that it is more typically seen at
between 40 and 55°.

I just gotta say this here--- there were a bunch of highly-skilled and
well-funded engineers and technicians put to the task of developing the
LT5. Engine specialists like Callaway, Lingenfelter and Rippie can make
improvements to performance in part because they do not have all of the
limitations imposed on their work that Lotus did, such as noise, overall
streetability, reliability, and specific fuel consumption. It is my
considered opinion, with the usual qualifications, that unless a ZR1
owner who uses his or her car for pleasure driving is willing to spend
the money to send his or her car over to DRM for the whole package, he
or she should leave the thing cold, dead stock and live with the 400
HP. If you just have to mess with it, only do bolt-on, reversible
changes that are developed by engine builders like Rippie or guys on the
net whom you trust, and who know what they are talking about.

[Dynomite]

My ZR-1 is not an airplane but close
I fly airplanes and use carb heat on long approaches to landing when throttle is pulled way back to prevent icing. Under full power no carb heat.
My ZR-1 does full power landings

Any one that suggests I should not mess around with modifications (only do bolt ons) on my LT5 are crazy folks and I think mgbrv8 will agree with me here

Maybe Scott should just delete this post Scottfab suggests to keep the plenum from developing ice never bypass the TB as well as the post above if he cannot nail down the facts rather than tell you to chase the facts down for him

Originally Posted by mgbrv8

Ya it's not a nos pump and the Z isn't a NCRS candidate so I figure what the heck.
Dave

[Hib Halverson]

TB ice in an LT5 occurring under the same atmospheric conditions as carb ice in an aircraft engine?

Holy What an amazing analogy!

Who'd a thunk it?

Fact is TB icing can occur but under a very set group of atmospheric conditions. Also, a carburetor has a far more pronounced venturi shape than does an LT5 TB so the possibility of TB ice in an LT5 is less than carb ice in an aircraft engine.

That said, again I remind everyone under a specific set of atmospheric conditions and an LT5 after a cold start and during early warm up, TB ice can happen.

I've had my TB coolant bypassed for about 17 years and have never had a problem with TB icing, but I suppose if I operated my LT5 during the winter in a place north of the "freeze line" and in damp weather, I'd reconnect it.

[scottfab]

Originally Posted by Hib Halverson

TB ice in an LT5 occurring under the same atmospheric conditions as carb ice in an aircraft engine?

Holy What an amazing analogy!

Who'd a thunk it?

Hey, it is what it is. I did not say it but makes sense to me. Some on the list may think the coolant running through the TB is to keep it cooler than without (which it does in certain circumstances).

Originally Posted by Hib Halverson

Fact is TB icing can occur but under a very set group of atmospheric conditions. Also, a carburetor has a far more pronounced venturi shape than does an LT5 TB so the possibility of TB ice in an LT5 is less than carb ice in an aircraft engine.

Ah, so it can happen you say? And that it's less than in a carb or say maybe a deep freeze refrig? OK, I buy that. I bet there's less on a plane hanging in a museum too.

Originally Posted by Hib Halverson

That said, again I remind everyone under a specific set of atmospheric conditions and an LT5 after a cold start and during early warm up, TB ice can happen.

But I bet less often in southern Cal than say the Northwest?

Originally Posted by Hib Halverson

I've had my TB coolant bypassed for about 17 years and have never had a problem with TB icing, but I suppose if I operated my LT5 during the winter in a place north of the "freeze line" and in damp weather, I'd reconnect it.

I don't doubt that and I won't ask for proof of the statement.
Exactly right though, Yanking the TB coolant is NOT a universally good idea and EVERY TIME I see it suggested on any forum of same I'll remind those being hood winked to to think it through. We each have a right to put bailing wire on our ZR-1 but alternatives should be made clear if there are any even if you are a farmer and have lots of bailing wire.

[scottfab]

Originally Posted by Dynomite

My ZR-1 is not an airplane but close
I fly airplanes and use carb heat on long approaches to landing when throttle is pulled way back to prevent icing. Under full power no carb heat.
My ZR-1 does full power landings

Why not just disconnect the carb heater? Icing doesn't happen every landing in every weather condition. Oh, maybe it will? And maybe you'd then wish you had left the design alone? oh, ok.

Originally Posted by Dynomite

Any one that suggests I should not mess around with modifications (only do bolt ons) on my LT5 are crazy folks

Originally Posted by Dynomite

and I think mgbrv8 will agree with me here

Well, first off to be clear, I did not write that. It was pasted from email from many years ago from an intelligent individual whom I respect. Any one reading this thread can see that it was pasted by reading the posts.

While I think it narrow minded to say such a thing as what was pasted, I certainly do not think it "crazy" but saying someone is crazy for stating their opinion is certainly mentally suspect.

Originally Posted by Dynomite

Maybe Scott should just delete this post Scottfab suggests to keep the plenum from developing ice never bypass the TB as well as the post above if he cannot nail down the facts rather than tell you to chase the facts down for him

I respect your opinion but while I disagree with your suggestion that I remove my post I will not claim you to be crazy for suggesting it. I maintain that it is a reasonable thing for me to suggest to wit:
Removing coolant going to the TB is NOT for everyone.
Leaving it in place WILL "keep the plenum form developing ice".

Time to go for a drive. Sunny out but cool and humid. Not to worry. I have my TB coolant path in place.