rob75383

I need to create a THICK seal between my holley carb and my air cleaner base... it needs to be about 3/16" or so.

I purchased the Adjust-a-jet kit this spring, and didn't install them until I moved into my new home. I bought two kits, and installed them about 2 months ago.
I had to use an adjustable summit dual feed fuel line with filter and gauge, and had an extra drop base air cleaner I had to beat up to get it to fit.

Each kit is about 1/2" thick, so with kits on both the primary and secondary side, I had some real fun beating the base of the air cleaner with a ball peen hammer for a couple of days. I also had to do a tiny bit of grinding on the outsides of the bowls.
I almost had fitting perfectly, except for the fact that the air cleaner base is about 1/4"-1/8" up from the gasket surface. There really is no way I can get it any lower, the needle adjustment screws and the fuel inlets are butting aganist the air cleaner base already.

I am currently compensating by using a bead of rope seal, and a home made air cleaner gasket I cut out of some extra thick gasket material I bought at the hardware store.
I am considering an idea- I can just make a nice thick bead of silicone around the gasket surface, let it cure without the air cleaner, then use that like a kinda makeshift o-ring to seal the air cleaner to the carb. My only fear is that the sharp edges of the air cleaner base will cut pieces off the silicone and send them into the engine.
I have the K&N x-treme lid, and a drop base, and I have only about 1/4" gap between the lid and the hood, so I can't get a flat base air cleaner, unless its like a 14" x 1.5" filter element.
What would you folks recommend I do to fill the gap between the air cleaner base and the carb??

I can post pics after midnight, once I get off of work.

Jvette73

Mr. gasket makes plastic spacers that go between the carb and air cleaner. They come 1" height. I have one on mine but trimmed it down to 3/4". So they can be trimmed to desired height. I just picked it up from the performance section of a discount auto parts store.

rob75383

Jvette73-
How thick is the spacer??
My air cleaner base may not be perfectly round anymore due to the pounding I did to it, so it might be tricky to get a plastic spacer to work, but I bet it's cheap though!

Jvette73

1" thick out of the package. Its easy to trim down to desired size and notch to fit if needed. i cut mine down to 3/4" by wrapping tape around it to use as a guide and zipping it off with a cutoff wheel on the dremmel.

Jvette73

Another idea would be to stack a number of standard carb to air cleaner gaskets untill you reached the thickness you wanted. You could glue them togeather with silicone so they would become one.

Smokehouse69

I used some 3/8 half round weather stripping. Just ran a strip of it around the air horn and held it in place with a drop of silicon in 4 places. It conforms to variations in the roundness of the carb or aircleaner opening.

rob75383

As you can see, the air cleaner base is pretty beat up!! :smash:
...well, I had to kinda pound it all over to get it to seal the k&n filter again after I had stretched the metal in some areas.
Its barely noticeable once its all assembled, though.

Thanks for the ideas fellas!!
I figure I might combine the ideas and try to glue a spacer, or something, to the air horn to reduce the gap, then use a gasket or two along with some more silicone to seal it all together.
Someone in the engine mods section suggested that I use a vacuum hose and run that around the air horn... that's a good one too.

I'll hafta run down to the parts store and see what I can whip up this coming week!

Matt Gruber

i guess now you will be tuning with oxygen sensors? http://community.webtv.net/MATTGRU/AFtesting

rob75383

Matt, I like your article that you linked... thanks! :seeya
Plus, I do have an O2 sensor and gauge. Problem is, I purchased a pair of 3"-2.5" reducers with bungs. You state that that might not be enough accuracy to get a good tune out of the carb.
The adj-a-jets are REAL easy to install and its a simple turn of the screw to change the "virtual" jet size.
To get a real accurate tune job, like you did for your '61, I'd have to:
>remove the headers... piece of cake
>unwrap my headers... hate to do it after all the work I put into wrapping
>buy a set of 8 bungs... can't be too $$$
>pay someone to weld the bungs/ drill primaries... again, not too much $$$
>tap the bungs... another easy one
>wire up the O2 sensor and gauge for easy tuning use/ repeatability... not too hard
>buy some high temp paint to dress up the headers... probably por-15
>and slap it all back together.

I guess I could just put a bung into the "lean" cylinder only, but I don't trust myself that much.
The way I look at it, I've been real lucky with all the work I've done to the car myself, and have only oil leaks and an untraceable rear end clunk going in/out of gear, to show as side effects.

When I asked for the C3 forum members' opinion of the adj-a-jet kits, a racer said that he didn't like the lack of repeatability... he wants to be able to quantify going up or down X number of jet sizes to compensate for temp., barometer, etc. I can clearly see his point.
Even though I had gotten jet swapping down to a 3 minute job start to finish, I really wished for an easier way to get the trial and error factor out of the picture.
I also realize that I no longer have the option of putting a mismatched set of jets in to compensate for a lean/rich cylinder (for example: 72on the left 73 on the right) the adj-a-jets are equal flow to both sides (so they claim), controlled by a single needle and orifice setup much like an enlarged version of the idle screws.
I have quite a to-do list already, and its already slow going on the existing projects.
I need to patch in a panel on the passenger floor (man, it gets REAL hot with that panel off, hence my lack of driving her this summer).
I need to finish working on the front and rear bumpers- not the skins, but the real metal bumpers that are behind the plastic.
I need to buy me some bumpers once the prep work is done.
Then, I'll need a paintjob.
Then, I can start working on tuning my motor, or even better, get the AFR heads and XE282 roller cam I want.
Whatever I decide to do, engine-wise, I could always use a sure fire way to tune her up.

I'll probably get my bumpers sometime in 2005, get her painted by 2010, and get the cam/heads I want in my retirement years, at my current rate.

Matt Gruber

you can get a very good tune with a heated sensor.
since you can't stagger jet with the adjust-a-jet
i can't see the need for 8 bungs.
with 1 on the left you will only need to pull the leaner plugs and check for a too lean condition.
i did not know the adjust-a-jet were non-adjustable left to right :rolleyes:
and with the air cleaner mods you had to make, for most people i will advise against them.

rob75383

I forgot to mention that the O2 sensor, gauge, and a pair of reducers had been ordered almost 2 yrs ago AND NEVER BEEN INSTALLED! :bb

The air cleaner mods are a side effect to my using the edelbrock performer RPM versus the plain performer.
Combine the RPM manifold with a holley, and with a stock hood, and you're pretty much left with about 1/2" of gap between the air cleaner and hood (well, I guess it really does vary with all the differant hood types over the years).

I had 2 sets of drop base air cleaners, a perfectly good 14"x3" K&N filter, plus the K&N extreme lid.
If my hammer job wouldn't work, I was planning on getting a 14" flat base air cleaner, with the filter being as low as possible, (I'm guessing a 14"x1.5" would be enough to clear the choke tower), and the extreme flow lid SHOULD provide me enough flow.
I decided to go cheap and hammer away at my old stuff, seeing that I already had an extra drop base lying around, along with the 14"x3" reusable filter... just so happens that I got it to work.

About the heated sensor: would I be able to get away with using it in the collector reducers, and get decent results? Again, I'd like to use as much of what I already have on hand, versus buying more stuff that might be likely to just gather dust (packrat alert!)
What about using the non heated sensor as close to the head as possible?
It'd be cheaper to drill, weld, and tap the bung, compared to buying a decent heated sensor.
As for staggering the jet sizes left-right, I've read about it, but never have tried it personally, so I don't miss being able to do that.

I was hoping to get to do another mustang dyno pull at Bloomington Gold, like I did last year. I was counting on being able to tweak the jet sizes between pulls, in the hope that I'd be able to beat my disappointing numbers from last year.
But, Breathless Perf. from FLA, decided to go to another show, (where the crowd was mostly C5's) and I was VERY angry that they did this last minute and even their road schedule on the website listed Bloomington Gold as their destination for the weekend :confused: :mad :cuss :boxing :cry

There was a considerable investment in $$ in getting the jet kits, not to mention the air cleaner mods, and fuel line mods that need to be done.

So I will agree with you for the time being and not recommend these kits.
It would've been cheaper to just stick to my original box of jets and jar of gasoline to drain the bowls, along with a little time and patience. But noooo, I HAD to go and order some new fancy stuff. :banghead:

Matt Gruber

i firmly believe that once it is jetted with 02 sensors, it wont need changes to jets. perhaps timing or other tuning but not jets. That is the whole point of 02 tuning, to get the best power without a dyno, g-tech, or drag testing.
for my money i would put 2 sensors 6" from the head. With 2, you can compare, looking for cyl variation AND keep an eye out for a faulty sensor.