Posted by Jon Richard  8/23/2013 7:56 PM | #1 |
This is a cut and paste from a post I made on TFFN a couple years back that I received no response to. The spacer is now installed on the car and running but I always felt left wanting feedback on this so I hope this sparks someones interest here:
Years back I purchased a Professional Products crosswind intake manifold which is similar to an Edelbrock Air Gap http://www.summitracing.com/parts/PFS-54025/?rtype=10
My carburetor is a Pony Carbs spreedbore Autolite 4100. The above manifold has the same narrow mounting flange as the Edelbrock. I've read many folks have issues with vacuum leaks when trying to run this combo, but that manifold has been sitting around unused for years and I want to give this a shot so I made a spacer.
I purchased a Moroso 1" phenolic spacer intended for a Holley 4150 390 cfm carb. The holes are 1.467". I bored the holes out on the spacer .030" larger than that of the venturies on the Autolite to allow for misalignment as the carb has a littlt wiggle room on the carb studs.
So this is where I went a little off the reservation and decided to hawg out the bottom side to make a blended spacer similar to a Super Sucker but I wanted to keep the left and right side separated to maintain the 180 deg. characteristics of the dual plane intake.
Heres a better shot
I don't know what to expect as far as performance or efficiency as I know little about fluid dynamics. It's possible I could need to change jets as this may affect the signal strength generated, but I cannot see any reason this should not make a seal and allow the Autolite to function as normal on the intake.
One thing I was curious about is that the factory spacer has a stepped ridge on the primary side.
Does anyone have an idea why? I plan on running timed vacuum to the distributor and wonder if that ridge has anything to do with when that port delivers vacuum.
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Posted by Tubo 8/23/2013 8:07 PM | #2 |
Nice blend job Jon.
So, now that it's been a couple of years how did it work with the intake and carb??
Tubo
If it ain't broke, I haven't modified it Yet
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Posted by Jon Richard 8/23/2013 9:23 PM | #3 |
Tubo wrote:
Nice blend job Jon.
So, now that it's been a couple of years how did it work with the intake and carb??
Tubo
Thank you
Well, it seals and she runs. I haven't had time to tune the car so it's hard to judge if this has any merit. She idles rough but when you stab the gas or raise the RPM it sounds very good, I get all goose bumpy.
I drilled a port on the back of the spacer to plumb into the secondary venturi's for PCV. I wanted to get all fancy and copy the factory spacer for that, but it was too much like work 
. I'm hoping this won,t be a problem and scavenge the crankcase pressure normally, I mean will it only scavenge when the secondaries open? I'm pretty sure because the primaries and secondaries are blended it should work fine but I just kind of did it without knowing how to know for sure.
The manifold vacuum was a little low at idle last I checked, around 16hg. Also, I need to verify at what RPM the timed vacuum port opens up as last time I ran this carb it wouldn't deliver a signal to the distributor till 2100 RPM and was causing a drivability issue for me. I had a lame aftermarket carb spacer at the time that I believe was the cause but I still need to follow up and verify.
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Posted by Jon Richard 9/11/2013 9:33 PM | #4 |
I've been running the Falcon setting up the throttle linkage and what not and even tooled around the neighborhood a bit and noticed that the spacer is fuel soaked all around the perimeter about half way up from the base.
I don't see fuel around the manifold and suspect the fuel is just leeching through the phenolic material rather than a leaky gasket. This can't be normal, at least it seems to me to be an under hood fire waiting to happen. This spacer started life as a Moroso unit and I'm curious if anyone has used a phenolic spacer before and if so noticed a similar trait.
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Posted by boomyal 9/11/2013 10:34 PM | #5 |
All Jon Richard needed to do was to turn the factory spacer upside down. The flat top of the spacer would have sealed on the intake and the webbed bottom woud seal on the flange of the 4100. Budda Bing!
