M

moll780

Well Known Member
Hi yall.
Im looking at replacing the K&N filter and was wondering how you did the carb cutout/hole.
I was thinking I would use my drill press and eat as much away as possible and use RTV to create the right size and seal.
anyway.
any advice would be awesome.

thanks
 
What are you "replacing" and what hole are you trying to cut?
If your question is misworded and you are fabricating the top plate to the airbox, I used a fly cutter.
It is not a good idea to seal anything in the airbox with RTV. It is known to peel away and can get ingested.
 
I believe the instructions for this are part of the filtered air box instructions. You'd mangle it up pretty good with a drill press. I used a rasor blade to notch the filter. Then put a wad of RTV in the notch and reassemble, let cure, trim as needed.

(Jonjay on some carb setups the a part on the bottom of carb protrudes beneath the alum plate and into the rubber ring around the K&N filter, you need to notch the ring and sort of seal it to the bottom of the carb. True, special care should be taken when fabricating this so RTV is not ingested, recommend follow Vans instructions)
 
Yes I used a razor blade to get it close and filled gaps with RTV, from the outside, so that it would be pretty hard for any to get sucked in. Most pictures I have seen of these modified filters don't look pretty; it just has to work. It isn't an ideal situation but the Van's way seems to work fine.

Chris
 
This is what I was looking for. So, notch filter with razor blade, use RTV to seal gaps and re-assemble. Then disassemble when cured and trim to fit.

Anyone have the vans instructions handy?

thanks!


Dbro172 said:
I believe the instructions for this are part of the filtered air box instructions. You'd mangle it up pretty good with a drill press. I used a rasor blade to notch the filter. Then put a wad of RTV in the notch and reassemble, let cure, trim as needed.

(Jonjay on some carb setups the a part on the bottom of carb protrudes beneath the alum plate and into the rubber ring around the K&N filter, you need to notch the ring and sort of seal it to the bottom of the carb. True, special care should be taken when fabricating this so RTV is not ingested, recommend follow Vans instructions)
Click to expand...
 
moll780 said:
Hi yall.
Im looking at replacing the K&N filter and was wondering how you did the carb cutout/hole.
I was thinking I would use my drill press and eat as much away as possible and use RTV to create the right size and seal.
anyway.
any advice would be awesome.

thanks
Click to expand...

Dbro172 said:
I believe the instructions for this are part of the filtered air box instructions. You'd mangle it up pretty good with a drill press. I used a rasor blade to notch the filter. Then put a wad of RTV in the notch and reassemble, let cure, trim as needed.

(Jonjay on some carb setups the a part on the bottom of carb protrudes beneath the alum plate and into the rubber ring around the K&N filter, you need to notch the ring and sort of seal it to the bottom of the carb. True, special care should be taken when fabricating this so RTV is not ingested, recommend follow Vans instructions)
Click to expand...

moll780 said:
This is what I was looking for. So, notch filter with razor blade, use RTV to seal gaps and re-assemble. Then disassemble when cured and trim to fit.

Anyone have the vans instructions handy?

thanks!
Click to expand...

I used my "tin snips" that I cut aluminum with to cut the filter for the accelerator pump bowl that is on the 320 carb engine. (360 does not need to do this.) The instructions did say to use RTV to seal the cutout.
 
Copy / Paste from Instructions

From FAB-320 Instructions MSPUB FAB-320 9/16/97 (There may be newer instructions out there but this is what I used.) [email me directly if you would like the document in PDF]

2. To allow the filter to sit flush on the mount
plate the filter must be trimmed to fit over the
accelerator pump. Any gaps between the filter
and bump are then filled with silicone rubber
(RTV) sealant. The silicone rubber effectively
replaces the rubber edge flange that was cut
away (Fig. 7). The filter is first marked to help
locate the proper place to cut the clearance hole.
The filter is first marked to help
locate the proper place to cut the clearance hole.
Bolt the filter between the mount plate and the
filter plate. The five bolts and the drain plug hold
the filter to its oval shape. When the filter is
aligned flush with the five bolts and the drain plug
cutout, mark it through the accelerator pump
cutout. Remove the filter and care- fully cut it
with metal cutting snips to fit over the accelerator
pump. Use the marks and carburetor bottom as a
guide. Make the hole slightly larger than the
pump. Install the mount plate to the carburetor.
Coat the accelerator pump, and any areas of the
mount plate which may contact the silicone
sealant, with a thin layer of parting agent. he
parting agent (a coat of automotive wax or grease
works well) keeps the silicone from sticking to the
carburetor, pulling apart, and leaving a mess each
time the filter is removed. Fill the cutout on the
filter with enough silicone to completely fill any
gaps between the accelerator pump and the filter.
Also apply a little silicone rubber to the bottom of
the accelerator pump to assure complete filling of any gap prone areas. Making certain everything is aligned correctly install the filter and filter plate to the mount plate. Wipe off any excess silicone rubber and allow at least 24 hours for drying. When dry,the filter can carefully be removed from the mount plate. Be certain the silicone is well cured; a large mass of silicone can cure slowly. Use a knife point or screwdriver blade to help lift the silicone from the carburetor. Wipe off any left over grease or wax and cut away any excess silicone rubber left on the filter. During final assembly fill all gaps that would allow unfiltered air to. enter between the carburetor and mount plate (especially around the drain plug) with silicone rubber sealant.
 
Dbro172 said:
(Jonjay on some carb setups the a part on the bottom of carb protrudes beneath the alum plate and into the rubber ring around the K&N filter, you need to notch the ring and sort of seal it to the bottom of the carb. True, special care should be taken when fabricating this so RTV is not ingested, recommend follow Vans instructions)
Click to expand...

Got it. Thanks for the explanation.
 
If you use a K&N E-3322 filter from Amazon $30, it will fit without any alterations.

This is for an O320 only.
 
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