going to buy my tune up stuff

[usetaboost]

was gonna go with stock plugs, autolite wires, a k@n filter maybe, and all the other normal stuff. One thing I have in question is the fuel filter. I read somewhere that the stock one tends to clog easily and some of the turbo guys like rich are running an aftermarket clear on and doing away with the stocker completely. Would this be something I should do on my n/a? Any other suggestions appreciated, only wanna do it once!

 

[usetaboost]

Oh, and of course, a motor mount Didn't know the na had enough torque to break one

 

[TURBOELKY]

Oh, and of course, a motor mount Didn't know the na had enough torque to break one

I think I need one too, they are just crap period. and I also read to do away with the stock filter, makes sense. they are little paper pos's.

 

[Freddie's Buick]

.....and I also read to do away with the stock filter, makes sense. they are little paper pos's.

Not really. It's ok to put a clear after-market in addition to the stocker. On some, (I experianced this), you will flood the carb if you run w/o the paper filter.

The flow rate pressure seems to be controled by a small valve in the paper filter. Too much pressure will push the carb's internal flow valve open.

It may not happen to all but it happened to me. I've often wonderd about the max limit of fuel pressure on these cars, (3-4 gpm). Too much may cause problems like the one I experianced.

I read Doug Roe's book and it does not mention this problem. In it he suggest that for drag racing the removal of the OEM filter is a good idea. More flow.
But I think that this has more to do with the bronze filter not the paper one.

The bronze one has no valve in it and came mostly on the older Rochesters.

 

[b4black]

The paper filter starve my motor at high rpm's. I went with a larger inline filter and two years of porblems went away.

The valve in the stock filter is a check valve to keep fuel up at the carb when not running. I sometimes have to crank a little longer becuase of this.

 

[Freddie's Buick]

....The paper filter starve my motor at high rpm's.

Doug Roe gives high marks to the paper filter. The mesh type fuel filter has less restriction so less starvation. However, more than 4-psi and you're getting into possible flooding issues. Some can go as far as 6-psi before flooding conditions can occur.

As for the check valve in the filter, it's main purpose is to prevent fuel from flowing into the carb in the event of a roll-over accident.

See Pic:

 

[b4black]

A check valve stops reverse flow. Without it, I can watch the fuel drain back down the line through my clear in-line filter.

This style check valve uses a spring therefore acts as a pressure relief valve as well. The pressure is small and easily overcome by the fuel pump, but high enough to stop fuel flow by gravity in a rollover.


Doug Roe can like the OEM paper filters all he wants. I'm not using them I my car. At WOT, fuel pressure drops to 1-2 psi. With the small in-line filter, there isn't enough flow. Maybe it's the filter media, or maybe it's the new flanged check valve thingy.

 

[Freddie's Buick]

Yeah..... I 've wondered about that valve since one failed on me and I ended up getting a fuel pump misdiagnosing the problem. My concern is more about the flooding which is more detrimental.

I tried this twice with two differant Q-Jets. I ran w/o the paper filter and installed a Russel inline filter. I think it was meshed to within 5-microns and they flooded miserably. Great flow though.:biggrin:

So in my case it was'nt a good idea. I still use the inline filter but with the paper element. My pressure runs at about 4-psi at the fuel inlet.

The earlier carbs with the long paper filters did not come with the valve. So I may try that next.

Having a limited knowledge on plumbing I also noticed that the flow constricts at the opening of the carb's filter canister, (the flared opening).

One should have a uniform even flow straight to the carb. So why they're made this way makes no sense.

I think that if one drills the opening to 5/16-3/8" that maintains an even flow. The OEM opening at the flare is less then a 1/4" and all the fuel lines are 5/16" I.D.

Just an idea.

 

[usetaboost]

Aftermarket ones made to just be "another filter" to be put in on top of the factory style filter? I've seen these filters put on many cars, including my friends camaro with a regular quadrajet. I never remember him having any trouble starting it. What makes newer carbs different from older carbs that they need the filter with the check valve in it? Is the only reason for the in-carb filter is to stop fuel on a roll over? As far as gravity pulling fuel back down the line away from the carb, does it really make it that much harder to start when its cold?

 

[Freddie's Buick]

......What makes newer carbs different from older carbs that they need the filter with the check valve in it? Is the only reason for the in-carb filter is to stop fuel on a roll over? As far as gravity pulling fuel back down the line away from the carb, does it really make it that much harder to start when its cold?

I believe that the check valve in the paper filter was also a federal emissions requirement for the time period. The earlier carbs paper filter, (pre 1980's), did not have this check valve. So you really can do without it.

One really only needs an after-market filter if your tank is really dirty from many years of cheap gas. The advantage on the newer mesh ones are the flow rate.

I don't know what the cold start issue is. I never experianced this.

Rich mentioned his problem was with WOT. (He likes to go fast at the strip:biggrin: ).

At higher rev's the fuel pump seems to drop pressure in his case. (Some kind of restriction)? I don't know what may have caused that. But he believes he solved it by removing the paper filter and using just an inline.

 

[usetaboost]

Damn! Price of some of this stuff has went up in the 6 years! Cost almost 100 bucks for everything. Well so far the cap and rotor was half shot, plugs were lookin pretty brown and 5 thousanths out, 2 bad plug wires that I've found so far, carb dirty as hell, thermac valve not working so it was stuck shut at op temp, noticed that last night. I'm sure the fuel filters nasty too beings everything else is almost garbage. Car ran alright before but should be kick ass when I get done, hopefully I get a little more power and mileage increase.