• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Air filter securing mod

Share this page

P

Pete3000

Member
Country flag
Offline
Hello. Hoping someone has the info on how to secure the air filters using helicoils instead of the nut and bolt set up. I think I read it here but cannot find it. I have 3 carbs and this would make it much easier to remove and replace. Thanks.
 
Well Ed, maybe I did not see it here. However I looked through some of my Moss catalogs where in the back of the catalog there are a few Tech tips and I found the tip I was looking for. It is from the Fall/Winter 2008 catalog. It states that simplifying the problem of removal and replacement of the nut, bolt, washer, while contorting our hands to do so can be eliminated and simplified. It states that the holes in the carb flanges that the 1/4" air cleaner anchoring bolts go through on "H" carbs are .257" plus and this just happens to be the recommended hole size to install 5/16" x 18 t.p.i. helicoils. Run the 5/16" x 18 t.p.i. tap in a helicoil kit into these holes with the tool and screw a 1/4" x 18 tpi bolt through to break of the small tang and set them. Now removal and replacement of the air cleaners is from the outside, and washers/nuts under the carb are not required. Wonder if anyone has done this?
 
Their must be an error in either the article or the sizes miscopied. A 5/16 inch bore measures .3125 inch and bore size indicated on the carburetor flange is .257 inch. One would assume the article meant to indicate using a ÂĽ inch helicoil tap. The next is indicated using a ÂĽ - 18 tpi bolt. The US standard ÂĽ inch bolt is either 20 tpi UNC or 28 tpi UNF.

So reading between the lines if a ¼ - 28 helicoil is inserted in the carburetor air filter mounting bore and then secure the air filter housing with a ¼ - 28 inch UNF bolt will eliminate the washers and nut…

The US standard UNC for a 5/16 bolt is 18 tpi. Maybe the bore size listing is not correct. It has been a while since looking at the air filter mounting flange of an “H” SU carburetor but I believe the bolts are 5/16 - 18. I could be wrong but I will look later today to verify.
 
I am going to order a couple of 2 inch ram pipes with gauze from
Cape int. and then install the helicoil modification.
 
Hi Ed,
Probably one of those crankcase vent filters from K&N.
crank_rubberbasesteeltop.jpg
 
Ed_K said:
I want to order a couple of these from Cape International,

https://www.cape-international.com/capeshop.php?parttypes=19&thepart=RP3

But where does one connect the crankcase vent hose when using
these ram pipes ? Does anyone use these and if so, where did you connect the crankcase vent hose ?
:savewave:
Just reverse it and let it hang down this way you can produce a negative pressure at its end.

It is always good to have a COMPLETE plan before purchasing parts for a Healey modification .
:square:

Thanks !
FWIW---Keoke

Ed
Click to expand...
 
OH The air rushing past the end of the exposed vent draws air out of the crank case. If you cut it on a slant it will work even better.---Keoke
 
On early cars before PCV valves they were called draft tubes. Keoke is correct they work by creating a suction when air blows by the tube.

Doug
 
dougsmarkIII said:
On early cars before PCV valves they were called draft tubes. Keoke is correct they work by creating a suction when air blows by the tube.

Yes Dough, early engines where vented by the use of a
Draft Tube :thumbsup:-----Keoke
Doug
Click to expand...
 
Back
Top