[70RAlll]

Originally Posted by Bentwheelbob

So the air cleaner project is finished. I switched out air cleaners and am using one I restored previously. I'll go through the one I removed and ultimately reunite it with the Black Car. Thanks to a lot of assistance from the forum, I think I have it plumbed correctly. I know that it is working correctly. It's pretty cool to watch the flappers close up and then several minutes later reopen. I also have the new correct air cleaner decal in place, and of course PB's correct lid decal. Thanks to everyone for your assistance.

You still have me lost on your setup.. one of your flappers ,using this plumbing, will always be exposed to vacuum. The thermo switch only has a chance to regulate one of the flappers with this plumbing. everyone can shoot me down on this, but I still think you have it wrong. I think the clips on the underside of the snorkel only hold the hoses to the flappers, the vacuum hose went directly from the intake manifold vacuum source to one of the ports on the thermo switch. I think you have gotten tied up with trying to make everything sit nice and neat under the snorkel, when it didn't. How does the thermo switch regulate the flapper that is right next to your "t"?? when the engine warms up, what is going to interrupt the flow of vacuum to the 1st flapper??nothing as I see it..
This is how I think the vacuum hoses ran:
1st Thermo Switch Port:vacuum directly from intake to one port of thermo switch
2nd Thermo Switch Port: other port of the thermo switch to the "t"
Both Flappers: "T" to each flapper.

That is the only way the thermo regulates both flappers.

[Norwood]

I have to agree

[Bentwheelbob]

Originally Posted by 70RAlll

Rustoleum makes a semi-flat paint that seems to be just enough above flat without looking too shiny.. Try that, NAPA sells it, or I'm sure an online search will produce retailers..

Thanks Bill. I was more concerned about what type of finish is currently on the master cylinder as it relates to determining the best way to recoat it. I am worried about adhesion since it is so glossy, and even more so if it were an epoxy type paint like POR-15. However, after poking around tonight I find that the existing paint is already crinkling and lifting around the top from the brake fluid. Looks like I will need to figure a way to get the existing paint stripped off. With respect to recoating it, I know it is a bit hare brained, but I have this evening ordered some stove black that I am going to experiment with. It is basically black pigments and wax. While it isn't permanent, it can be renewed without stripping.

[70RAlll]

Originally Posted by Bentwheelbob

Thanks Bill. I was more concerned about what type of finish is currently on the master cylinder as it relates to determining the best way to recoat it. I am worried about adhesion since it is so glossy, and even more so if it were an epoxy type paint like POR-15. However, after poking around tonight I find that the existing paint is already crinkling and lifting around the top from the brake fluid. Looks like I will need to figure a way to get the existing paint stripped off. With respect to recoating it, I know it is a bit hare brained, but I have this evening ordered some stove black that I am going to experiment with. It is basically black pigments and wax. While it isn't permanent, it can be renewed without stripping.

I always just either blast or use heavy body paint stripper, wash down real good with lacquer thinner to get surface good and clean,dry and then I put a single coat of lacquer-pretty sure that is what GM's suppliers used in the 1970's.Thick coats end up nopt looking right. Seen many who prime then paint, still my opinion you loose the original look by applying too much/thick paint... As far as keeping it fresh, if your master is not leaking and you keep the top on, there is no reason you should have any problems with the paint. I commented cause I misread this thread, thought you guys were talking about the sheen. 70-71's were not flat, they were semi lacquer.can't say for sure on 72's.. Then again.. each to their own I guess.

[Bentwheelbob]

Originally Posted by 70RAlll

You still have me lost on your setup.. one of your flappers ,using this plumbing, will always be exposed to vacuum. The thermo switch only has a chance to regulate one of the flappers with this plumbing. everyone can shoot me down on this, but I still think you have it wrong. I think the clips on the underside of the snorkel only hold the hoses to the flappers, the vacuum hose went directly from the intake manifold vacuum source to one of the ports on the thermo switch. I think you have gotten tied up with trying to make everything sit nice and neat under the snorkel, when it didn't. How does the thermo switch regulate the flapper that is right next to your "t"?? when the engine warms up, what is going to interrupt the flow of vacuum to the 1st flapper??nothing as I see it..
This is how I think the vacuum hoses ran:
1st Thermo Switch Port:vacuum directly from intake to one port of thermo switch
2nd Thermo Switch Port: other port of the thermo switch to the "t"
Both Flappers: "T" to each flapper.

That is the only way the thermo regulates both flappers.

That's what I thought too until I broke out the vacuum pump and heat gun, and actually tried it. As it turns out, both nipples on the sensor are plumbed in series. Pull a vacuum on one nipple and it transfers to the other nipple. In other words, both nipples are on the same side of the switch - not on different sides. The switch is normally closed until it heats up. You have a closed system when the car is cold and the engine vacuum activates both vacuum actuators upon start up, thereby closing the flappers. Once the sensor reaches operating temperature (or the preset intake air temperature of the sensor/switch) it opens and creates a controlled vacuum leak on the internal air cleaner side of the switch. This controlled leak allows enough vacuum bleed off that the vacuum actuators return to their normal position and the flapper doors open, and enough of a leak to keep vacuum from forming as long as it is open. This was a surprise to me, but it functioned perfectly in this fashion both in bench testing and once installed on the car. My thermac sensor may be faulty, but I don't think so. Actually both the old AC logo sensor and the new Delco unit functioned exactly the same.

I am open to being wrong - it happens a lot and I may very well be wrong here. However, spend a little time first with a vacuum pump and a heat gun and see if you don't come to a different viewpoint than you currently have. I've got two NOS sensors coming in the mail that I will also check. I'll be interested in hearing the results of your effort.

BTW - the part about doing it a certain way just so it was nice and neat was an unnecessary cheap shot. I may have thick skin, but that suggestion added nothing to your post that was pertinent in determining the correct technical way to do something. I may not have 10,000 posts, but there should be enough for the reasonable person to ascertain that I am not lazy and looking for the easy way out.

[Formulabruce]

On the master cyl. I posted this earlier, take it for what it is.
Quote>"You are right, it wasnt phosphate, but it was semi gloss (60% roughly) when new. It was cheap black Alkyd enamel paint which fades fast ( like all cheap alkyd enamels do). The durability of that original crap paint is slightly better than horrible. After 2 years they looked nearly flat. Only "masters" shipped bulk in crates for sub assembly got the paint, brand new ones over the counter in 72 were unpainted like they are today." < End Quote
pic was taken with a flash ( hence the booster look) on a very very low mileage F body. Car was around 37 years old at time of picture

[70RAlll]

Bob.. no cheap shot meant, not at all. If I only had enough space to list all the ,what I now know as, stupid sh!t I have done in attempts to make my engine bay's look nice and neat..well it is a long list. I think we have all done things like this. And yes that comment did add to my post. Often we all try and have things look nice and neat when in fact original design often didn't care about nice and neat. I am guilty ..without a doubt.. You know.. I started adding a disclaimer"this is just my opinion" to many of my posts because readers get bent sideways at some of my comments. Guess I will start adding a new one" please do not take my comments personally, they are not meant that way".. for the love of God.... good 'nite bob

[Judge273]

Originally Posted by Bentwheelbob

Well as it turns out the thermal switch I installed was the new AC Delco version, not a cheap repop. They no longer produce the original version with the AC logo and the metal hose clip. From what I have read the guts are the same, and if you are talented you can switch them out so that you can retain the original look. I believe the AC Delco PN is 213-4400 and GM's PN is 6484244. If you have an original - hang onto it. Here are pictures of the original and the replacement.









I think a lot of folks use a very short section of heater hose also. That is what is on the Black Car.

Now I have looked at mine. I have a Black one, and a Tan one? Makes me thirsty so early....



Is the Black one anyone has seen before? The one Bob has "AC" faces opposite of the black one too?

[blue71ta]

...they also come in green, Mike

Is that a "Trans Am" pen being used to prop them up?

[transam1972]

Bob...I see you have a bracket that mounts to the water neck outlet on the intake manifold...it looks as though it helps the upper radiator hose stay in place...I have never had this...is this a part the 455 H.O.s all had?... or a Formula only item?...am I missing mine?...thanks!!

[70RAlll]

Originally Posted by Judge273

Now I have looked at mine. I have a Black one, and a Tan one? Makes me thirsty so early....



Is the Black one anyone has seen before? The one Bob has "AC" faces opposite of the black one too?

Black was the original ones on 70 and 71's, don't know about 72's..

[unruhjonny]

Originally Posted by transam1972

Bob...I see you have a bracket that mounts to the water neck outlet on the intake manifold...it looks as though it helps the upper radiator hose stay in place...I have never had this...is this a part the 455 H.O.s all had?... or a Formula only item?...am I missing mine?...thanks!!

(I am just following/lurking here now)

Do you mean the rear alternator bracket?

[transam1972]

yes...is that not an 80 amp. alt.?..my T/A has 80 amp. but no rear bracket? thanks

[unruhjonny]

I know the early cars got them, I have one;

(old pic)

[Judge273]

Good stuff here:

http://forums.maxperformanceinc.com/...mp+alt+bracket

[transam1972]

the one threaded hole on the back of my alt. appears never have to been used...certainly does not need it...I will have to check other 72 T/As....thanks

[Formulabruce]

Originally Posted by transam1972

the one threaded hole on the back of my alt. appears never have to been used...certainly does not need it...I will have to check other 72 T/As....thanks

that rear bracket is different than other rear brackets used on smaller alternators and it curves away from the alternator at the top.

[Formulabruce]

Originally Posted by unruhjonny

I know the early cars got them, I have one;

(old pic)

The bracket above picture is for a NON 80 amp set up and that bracket will not line up to the Boss hole on the back of the 80 amp alternator
To illustrate, the picture below the bracket on left is the more common one for the 55 amp alt. The one on the right is for the fixed position 80 amp Alternator. Its like a mirror image of the other one.

Sorry for the short hijack...

[transam1972]

I am confused..did 80 amp get a rear holding bracket or not...sorry about this

[njsteve]

The 80 Amp alternator, which is the one that is mounted in a non-adjustable position (the idler pulley sets the adjustment) has a large bracket in the rear with a spacer. If you ordered A/C and the rear defogger - the glass with the electric grid, you got the 80 Amp alternator. Here is a shot of the bracket and spacer and bolt from my 73 SD. Both of my 72's had the same set up as well.

BTW, the bracket is actually grey phosphate and not painted.