The Ford Barn

31forder · 10-27-2015, 04:43 PM

Does anyone have a method to lap a 1931 Model A Ford carburetor side bowl casting where the drain valve "petcock" seats? I have an original casting with a new drain valve petcock and it leaks just a little bit.. I was thinking maybe there was a Dremel grinding stone bit, but not sure if one exists.. Checked Steve Pargeter's restoration book and didn't see anything..

briphaeton · 10-27-2015, 06:18 PM

Is this what you need?
http://www.model-a.org/dremel_911.html

Gary WA · 10-27-2015, 09:04 PM

Lap with tooth paste

31forder · 10-28-2015, 04:35 PM

Thanx for your response.. I have the Dremel 911 grinding stones already and they work great for the fuel line ferrule seat.. The petcock drain valve is smaller and has a point..

31forder · 10-28-2015, 04:38 PM

Good idea toothpaste is gritty.. The only problem is the petcock is threaded once it seats I can't lap it in with a spinning motion.. Do I need to get a another new petcock drain valve, grind the thread's off and make it into a lapping tool?? Thanx for your suggestion

Tom Wesenberg · 10-28-2015, 04:56 PM

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Get a drill bit that just fits through the threads, put some valve lapping compound on the tip, then spin it BACKWARDS to lap the seat.

31forder · 10-29-2015, 04:09 PM

Thanx for the tip!! I'll try it this weekend

Jason in TX · 10-30-2015, 09:47 AM

Great tips here! Thanks for sharing!

Carb Guy · 10-30-2015, 04:04 PM

The 911 stone works good on the gas inlet, but is to big for the drain valve on the sidebowl. Clean it up real good and place a drop of silver solder on the tip and then fit to seat.

31forder · 10-30-2015, 05:41 PM

Thanx Carb Guy, briphaeton, Gary WA and Tom Wesenberg.. I agree with Jason in Texas that these are all great tips in this thread!! I have been rebuilding original Model A carburetors (obviously all with no side bowl's)!! for about 20 years as a hobby and thought I had all the carburetor rebuilding problems solved until my Dad gave me his indented firewall 1931 coupe last year (which he finished restoring in 1968 the year I was born).. I don't know how far back the Ford Barn Forum search goes, but was surprised that no one else had this question or problem.. Thanx again, Joe

10-27-2015, 04:43 PM	#1
31forder Junior Member Join Date: Apr 2014 Location: Fayetteville, PA. Posts: 8	1931 Carburetor Side bowl Drain Valve Seat Does anyone have a method to lap a 1931 Model A Ford carburetor side bowl casting where the drain valve "petcock" seats? I have an original casting with a new drain valve petcock and it leaks just a little bit.. I was thinking maybe there was a Dremel grinding stone bit, but not sure if one exists.. Checked Steve Pargeter's restoration book and didn't see anything..

10-27-2015, 06:18 PM	#2
briphaeton Senior Member Join Date: Jan 2012 Posts: 241	Re: 1931 Carburetor Side bowl Drain Valve Seat Is this what you need? http://www.model-a.org/dremel_911.html

10-27-2015, 09:04 PM	#3
Gary WA Senior Member Join Date: May 2010 Location: Clinton,WA/Whidbey Island Posts: 4,105	Re: 1931 Carburetor Side bowl Drain Valve Seat Lap with tooth paste __________________ www.whidbeymodelaclub.com

10-28-2015, 04:35 PM	#4
31forder Junior Member Join Date: Apr 2014 Location: Fayetteville, PA. Posts: 8	Re: 1931 Carburetor Side bowl Drain Valve Seat Thanx for your response.. I have the Dremel 911 grinding stones already and they work great for the fuel line ferrule seat.. The petcock drain valve is smaller and has a point..

10-28-2015, 04:38 PM	#5
31forder Junior Member Join Date: Apr 2014 Location: Fayetteville, PA. Posts: 8	Re: 1931 Carburetor Side bowl Drain Valve Seat Good idea toothpaste is gritty.. The only problem is the petcock is threaded once it seats I can't lap it in with a spinning motion.. Do I need to get a another new petcock drain valve, grind the thread's off and make it into a lapping tool?? Thanx for your suggestion

10-28-2015, 04:56 PM	#6
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: 1931 Carburetor Side bowl Drain Valve Seat Sponsored Links (Register now to hide all advertisements) Get a drill bit that just fits through the threads, put some valve lapping compound on the tip, then spin it BACKWARDS to lap the seat.

10-29-2015, 04:09 PM	#7
31forder Junior Member Join Date: Apr 2014 Location: Fayetteville, PA. Posts: 8	Re: 1931 Carburetor Side bowl Drain Valve Seat Thanx for the tip!! I'll try it this weekend

10-30-2015, 09:47 AM	#8
Jason in TX Senior Member Join Date: May 2010 Location: ⓉⒺXⒶⓈ Posts: 2,047	Re: 1931 Carburetor Side bowl Drain Valve Seat Great tips here! Thanks for sharing! __________________ -------------- Drive it like you know how to fix it! DMAFC / OILERS CC-MC

10-30-2015, 04:04 PM	#9
Carb Guy Senior Member Join Date: May 2010 Location: Wisconsin Posts: 186	Re: 1931 Carburetor Side bowl Drain Valve Seat The 911 stone works good on the gas inlet, but is to big for the drain valve on the sidebowl. Clean it up real good and place a drop of silver solder on the tip and then fit to seat.

10-30-2015, 05:41 PM	#10
31forder Junior Member Join Date: Apr 2014 Location: Fayetteville, PA. Posts: 8	Re: 1931 Carburetor Side bowl Drain Valve Seat Thanx Carb Guy, briphaeton, Gary WA and Tom Wesenberg.. I agree with Jason in Texas that these are all great tips in this thread!! I have been rebuilding original Model A carburetors (obviously all with no side bowl's)!! for about 20 years as a hobby and thought I had all the carburetor rebuilding problems solved until my Dad gave me his indented firewall 1931 coupe last year (which he finished restoring in 1968 the year I was born).. I don't know how far back the Ford Barn Forum search goes, but was surprised that no one else had this question or problem.. Thanx again, Joe