BB exhaust Manifold removal with A/C

[Ken C.]

Sorry a little long.
Car info. 72 BB with a/c
Just ordered a AIR system from Bill Hodel. Thanks guys for the recommendation. Great guy to deal with
Well, the plugs in the manifolds arent budging. I've followed some previous threads for soaking in PB Blaster. But after a week dont move and dont want to take the chance of breaking, so going to remove the exhaust manifolds to try the heat method.
1st i have a Kwik Lift system so access to under car is fine.
I dont see a problem with the drivers side. removed alt/brackets and spark plug heat shields for a little more room.
But with the a/c unit on passenger side i'm wondering if i'll be able to move the compressor enough without disconnectng anything but a few bolts. Or should i have the system purged. So i can take compressor out?i I know i'll be removing the manifolds from bottom. Any hints for making passenger side a little more bearable.
Also to Joe L. I just found out my water pump u responded to in past thread isnt correct numbers, so going to contact Bill Mock? regarding correct one.
again thanks in advance to all

[Joe L.]

Re: BB exhaust Manifold removal with A/C

Sorry a little long.
Car info. 72 BB with a/c
Just ordered a AIR system from Bill Hodel. Thanks guys for the recommendation. Great guy to deal with
Well, the plugs in the manifolds arent budging. I've followed some previous threads for soaking in PB Blaster. But after a week dont move and dont want to take the chance of breaking, so going to remove the exhaust manifolds to try the heat method.
1st i have a Kwik Lift system so access to under car is fine.
I dont see a problem with the drivers side. removed alt/brackets and spark plug heat shields for a little more room.
But with the a/c unit on passenger side i'm wondering if i'll be able to move the compressor enough without disconnectng anything but a few bolts. Or should i have the system purged. So i can take compressor out?i I know i'll be removing the manifolds from bottom. Any hints for making passenger side a little more bearable.
Also to Joe L. I just found out my water pump u responded to in past thread isnt correct numbers, so going to contact Bill Mock? regarding correct one.
again thanks in advance to all

Ken-----

What kind of plugs are in the manifolds? Are they external hex head, external square head, or internal square or hex head?

I can't help with the manifold with A/C removal for a big block; I've never done it.

Your waterpump should be 3992077 casting. Bill Mock would be a good source for a rebuilt unit with this casting.

[Ken C.]

Re: BB exhaust Manifold removal with A/C

plugs in the air hose are external square heads. I'm pretty much comfortaboe with the drivers side. The a'c side had me a little "what it" .
But as we talked about earlier if i take out the water pump for a correct one, will give more space for hand work. I'm giong slow and easy. But if u think of anything check out the future threads and see how we run.
thanks
Joe.
Looking for the parts to arrive and start putting them in. Will be luck all.
Thanks again,
ken

[Joe L.]

Re: BB exhaust Manifold removal with A/C

plugs in the air hose are external square heads. I'm pretty much comfortaboe with the drivers side. The a'c side had me a little "what it" .
But as we talked about earlier if i take out the water pump for a correct one, will give more space for hand work. I'm giong slow and easy. But if u think of anything check out the future threads and see how we run.
thanks
Joe.
Looking for the parts to arrive and start putting them in. Will be luck all.
Thanks again,
ken

ken-----


Well, you're out of luck here. I've had some success removing the hex head plugs after repeated soakings with GM Heat Valve Lubricant and, subsequently, using an air impact gun to twist them out. However, with the external square head plugs, you'll almost always break off the head of the plugs if you try this.

In general, I have found most "penetrants" (i.e. GM Heat Riser Lube, Kroil, PB Blaster, etc.) to be rather useless in loosening stuck fittings or bolts.

[Bill C.]

Re: BB exhaust Manifold removal with A/C

The lower bracket that bolts to the manifold on the pass side can be removed without taking the compressor out. It has two lock nut holding on to the studs in the head. You will have to loosen the front bolts - on the front bracket - so that the compressor can be rotated, but that is all.

Also remove the starter - makes it MUCH easier.

The only exhaust manifold bolt that will give you some grief is the one next to the AC unit.

Suggestion - change the spark plugs while you are at it

You will have to put the AIR trees in after the manifold is installed, the dvr side is a breeze, pass side PITA. With the spark plug wires out of the way - the tree is okay to deal with.

- Just a note -
do not reuse the self locking nuts, they were made to use one time only.


Hope this helps some.


PS: I have some really good pics of the AIR system on my car all hooked up, be happy to email them to you if needed.

[Ken C.]

Re: BB exhaust Manifold removal with A/C

Thanks Bill and Joe

Bill, sent u email

Got the starter off already, and going to tackle pass side this afternoon. Also tackling the water pump. See other thread.
What size is your a/c, smog fan belt? Does 49.5 sound right?

[Dick W.]

Re: BB exhaust Manifold removal with A/C

Since you have the manifolds off, try heat. Heat the plugs and then immediately attempt to remove.

[Jack H.]

Re: BB exhaust Manifold removal with A/C

There may be a 'rate buster' method to pulling the RH exhaust mani without completely unbolting the A6 compressor, but if there is one, the mechanics in our shop (+25 years) don't know it....

There is one big CAUTION on unbolting your compressor though...

The compressor and its factory original rear manifold were unique to Corvette. The A6 is HEAVY. You don't have to disconnect it (loose your Freon) and it WILL move enough on its hoses to give you freedom to work.

BUT, you need to jury rig a method to hold it in an adjacent position (against the inner fender, strapped down so it can't move) to prevent it falling down and breaking the rather fragile aluminum in/out tubes that are integral to the manifold assy. I've seen more than one novice 'drop' the AC compressor and wind up ruining a factory original manifold that's HARD to replace as well as kissing his refrigerant load bye-bye....

[Ken C.]

Re: BB exhaust Manifold removal with A/C

Thanks Jack, I'm looking at ways to secure it before i attempt to remove the manifold. Too bad it wasnt as easy as drivers side. Just dont want a freon shower while working on car.

[Doug M.]

Re: BB exhaust Manifold removal with A/C

Ken,
The way Jack described, was the way I changed a pass. side ex. manifold on a 71 BB with AC. Loaded up the fender and inner fender , plenty of towels and padding. Separated comp. from brackets but left the plumbing part hooked up. Then tied the comp. as far as possible away from manifold. I actually had the comp. sitting on the fender. This method worked for me.

Doug McClure

[Ken C.]

Re: BB exhaust Manifold removal with A/C

thanks guys, i got the driver side out easy enough. going to attempted the pass side today. I also forget to add i have an auto. so looking at the lines in way of removing starter. Funny how much u forget. I think 1989 was the last time i did this on vette.

[Ken C.]

Re: BB exhaust Manifold removal with A/C

thanks to all for all the info on this procedure. I was a bit nervous about the a/c.
I completed removing the exhaust manifolds this afternoon. I did notice a hairline crack about an inch long in the passenger side along the runners. Hadnt noticed any leaks. but when i put a flashlight into manifold i could faintly see the light come through. Going to take to shop tomorrow and have them remove plugs and fix crack.
Again thanks.
Now i can sit and look at system bill hodel sent me today. And wait for waterpump to arrive from mr. mock. If that wont be torture enough waiting. Spring in Florida.
Thanks to all i've gotten help from since i've joined.