Ram AIR

[71stagegs]

Cliff got my carb back from you for a 455 buick.WOW what a difference in performance and the carb idles at 800 before 1050 at best.I have a ram air set up I noticed when I put the Air cleaner on it did not run as well.I took it off and saw some gas around the acc pump, low end it is not as crisp.Runs great with ac off.Should I make some holes in the back of the ac too much pressure?I have read on v8 buick some have had the same trouble.Thanks for the great job on the carb.Steve
<a href="http://s38.photobucket.com/user/buickgrandsport/media/100_4967_zps7be1ae84.jpg.html" target="_blank"><img src="http://i38.photobucket.com/albums/e132/buickgrandsport

[Ethan1]

Cliff got my carb back from you for a 455 buick.WOW what a difference in performance and the carb idles at 800 before 1050 at best.I have a ram air set up I noticed when I put the Air cleaner on it did not run as well.I took it off and saw some gas around the acc pump, low end it is not as crisp.Runs great with ac off.Should I make some holes in the back of the ac too much pressure?I have read on v8 buick some have had the same trouble.Thanks for the great job on the carb.Steve
<a href="http://s38.photobucket.com/user/buickgrandsport/media/100_4967_zps7be1ae84.jpg.html" target="_blank"><img src="http://i38.photobucket.com/albums/e132/buickgrandsport

 Nice! BTW, I agree, Cliff does AMAZING work.

 

[71stagegs]

Hey Cliff any ideas too much pressure down the vent?

[Cliff Ruggles]

I've ran into some issues with air cleaners that place the lid too close to the carburetor.  With my own set-up, I was not able to use later T/A parts to run a taller intake on my 455.  The later parts have a shorter Shaker assembly, so use a shorter air filter.  My engine HATED that deal, and gave me all sorts of troubles.....Cliff

[71stagegs]

Thanks Cliff Do you think its the vent tube? shorter air cleaner will do what?

[Cliff Ruggles]

On my set up the shorter element put the lid too close to the carb.  It ran fine with the taller element and lid further away, and with no lid at all, but hated the lid being close to the carb.....Cliff

[motorvation2go]

  I had this very same problem when running a ram air system with the Q-jet.
In my case the filter element was ~ 5" tall allowing plenty of clearance above the air horn/vents etc.
After several attempts to locate the source of a raw gas smell (drive, stop quickly, pop hood, pull breather assy), it was seen that the casting area around the accelerator pump stem was soaking wet with fuel.
Only solution I could come up with was to vent the rear of the breather housing (side closest to firewall) with a few 1.5" holes.
Of course this pretty much defeated any positive pressure feature, however the biggest benefit of cooler air remained.
I vaguely(?) recollect having seen one Q-jet with a thin 'captured' wiper seal installed underside the top carb housing which/where the accelerator pump stem poked through.
Perhaps a  fix?
(If not just a figment of my imagination)... I wonder if these seals are still available?
       

             

[71stagegs]

Thanks for reply I wonder if you extented the vent tube past lid?

[v737d]

Not an expert by any means but I had this idea,

What if you used a tube vent similar to the type used on a rear axle with the check ball hooked up to the carb vent?


Cheers


Chris

[motorvation2go]

Yes this IS an old thread, but I thought it might be helpful to bring it back to the top.
The issue of fuel leakage around the accelerator pump stem (when using a 'ram air' box) is the case in point.
Likely(?) occurs due to higher than ambient pressure in the float bowl combined with normal spray/frothing fuel inlet activity.
Seems later M4ME-M4MC carbs had an accelerator pump single lip(?) upper stem seal w/retainer installed in the underside of the air horn where the stem passes through... emission requirements of the day?
Looks like a potential fix for liquid fuel leakage too.
Did some measuring on my carb # 17080213.
Pump stem Diameter .217"
Counter bore ID of [pump stem] boss underside air horn .346"
C/bore depth .110"
Are the upper stem seal and retainer piece still available?
Thank you in advance.

[Cliff Ruggles]

The later castings also used a divider between the float bowl and the accl pump well. 

I suspect most the fuel that chases the pump shaft comes from spray the needle/seat area and some splash from the float bowl. 

I use a 1977 carburetor with the divider in place and don't have this problem.  I also peened the material around the pump shaft down some, then drove an old pump thru the smaller hole to create a tighter fit.

I don't stock the seal and retainer for the late model carburetors that used them....Cliff

[motorvation2go]

Thanks for the reply Cliff
Good of you to be ever helpful.
Seems the seals are no longer available anywhere... at least within the limits of my present search.
I have full access to a vertical mill, lathe etc... was considering making a close tolerance bronze (press in) bushing.
However, your idea for peening the existing hole sounds like a better approach.
Simpler is always better!
Will keep looking for (or perhaps rigging) an appropriate seal.
Incidentally [my] carb experiences the fuel wetting problem even with the vertical well baffle in place.
Thanks again.