Carb insulators (1 Viewer)

[Degnol]

I've got an F('74) carb mounted on a 2f manifold, so I can run the 2F aircleaner, because I needed room for the PS pump. The 2f manifold is shaped a little different than the F and the carb is shorter than a 2F carb. I'd like to use a heatshield/carb spacer from a 2F, to keep as much heat from the header away from the carb, but that does not have a place for the PCV to vent into. Can I use both spacers and get the height I need. Looks like longer studs will be necessary, but NBD. I assume if I get everything tight and sealed there should be no problem.
Hey, does the pcv vent into the aircleaner on a 2F????
Thanks,
Ed

 

[IDave]

I asked about this once and was told that it might cool the carb too much, resulting in poor running.

 

[Degnol]

^^^^

 

[Poser]

In a perfect, controlled environment, I am sure that you could create the required air density/moisture content to get the carburetor to ice up, and cause a poor running condition. I have watched the base of a carburetor get frosty on the outside, but it has not affected the performance of the engine. I run a Weber 38mm on the Red truck with headers and no fluid heat riser to the intake manifold, and have not ever had an issue, hot/cold/dry/damp or any combo of the above, and that thing runs a spacer/adapter that is thicker than the stock thermospacer. I have the stock Aisins on everything else, and not ever had any problems with carburetor icing. There is a fair amount of heat under the hood of these trucks, and I really do not think that creating a spacer to get the air cleaner to mate up is going to cause you any adverse operating conditions.

Finding metric studs long enough to thread into the manifold, pass through the spacer, and leave enough for you to work with on top is probably going to be the real trick of the mix. Make sure that the threads in the intake manifold are not marginal, as I have had to heli-coil many a carburetor stud hole over the years. People seem to think that aping on the fasteners will cure those vacuum leaks, instead of replacing the base gasket, and simply tightening things up. Cutting new gaskets from gasket paper that can be picked up at any decent parts house is not that difficult.

If you can, post up a picture of your intake. I bet that there is another port on the intake manifold that the PCV valve hose could be routed to.

Post up some pictures of what you end up using!

Good luck!

-Steve

 

[IDave]

Somehow that doesn't surprise me, Steve. I thought that, especially with headers, carb running would be unaffected, except maybe during warmup. That's a big part of driving for me during the 9 months of winter we have here, but unlikely to be an issue for most of you.

 

[Poser]

Nine-months of winter...

That is funny...seems like it is that way here in Minnesota too...


-Steve

 

[IDave]

I lived in Minnesota for 4 years. I know what you mean, but I'm not exaggerating about 9 months. The only month I haven't seen snow here is.....well, come to think of it, there isn't one.

 

[Degnol]

Well, the only reason I wanted to use both is to raise the carb to the 2F Aircleaner, and to still have a place to suck the crankcase. I did install a fluid heatriser for those cold Missouri mornings. HaH!
Does the 2F aircleaner normally have the PCV vented into it?
There are two large hose connections into the aircleaner, one is pretty obviously for the smog pump, which I don't have and the other I can't figger out. Would that be an OK place to put the PCV hose?
I bought a 2F side plate( with the PCV vent toward the rear) from Freight Dog and I'm hoping I can vent into the aircleaner.
Whaddya think???
Ed

 

[IDave]

My gut feeling is you don't want engine oil going directly into your carb, so I wouldn't be putting it onto the aircleaner. Maybe someone knows better.

 

[Poser]

Ed,

On the rear of the 2F aluminum valve/rocker cover on the top of the engine, there is a spot that had a hose that went into the side of the air cleaner, on the rear of the air cleaner housing, a simple breather hose, nothing too fancy. The PCV hose coming from the PCV valve, should hook to engine vacuum, below the throttle plate, so, if you connect it to the intake manifold someplace, preferably in the most centralized location, you should be fine.

Do you have the ability to take a picture of your intake set up, and post that? You may have a pipe plug of some sort installed in the intake manifold that could be removed, and a hose barb installed there, to attach the PCV hose.

Good luck!

-Steve

 

[Toyoland66]

How important is it to have the crank case under vacuum?

I replaced the aircleaner on my 79 40 with a custom made plenium, connected to 3" tubing and a K&N cone filter

I just stuffed a clamp on crank case breather into that hose that comes out of the Valve Cover

well, it has been like this for over a year, but could it be a problem?

 

[Degnol]

Poser, there is a plug right underneath the carb on the intake. If I decide to go with the spacer/heatshield, I'll use that port for the PCV. I think the additional height I'd get from using both would put me right in the 2F aircleaner. But I think I'll make an extension for the airhorn to get it to attach to the aircleaner. You're right about the avaiabilty of longer studs, at least locally. Does anyone know of metric allthread??
Thanks, Steve.
I'll get some pics tomorrow.
Ed

 

[Landpimp]

my 45 truck 1 barrel aisin ices up sometimes....kinda cool........seems to effect nothing.

 

[IDave]

Ed wanted me to post this for him: having trouble. So this is Degnol's carb: