Mopar AVS help

05-09-2007, 09:43 PM

I need a little help in getting my AVS to work right.
I am running a 70 340 in Pure Stock. I have a stumble / bog on the launch that I can't fugure out how to get rid of. I am not an expert on carbs, so any help would be appreciated.

I have tried different accelerator pump linkage positions, larger and smaller squirters, larger jets and adjusting to the air valve. None seem to completely cure the problem. The air valve seems to help best, if I put enough preload on the spring, but the stumble is still there.

Any suggestions would be appreciated.

Thanks
Mike Coates

IHRA 3914 D/PS swinger

Mike Coates

SSDiv6 · 05-09-2007, 10:44 PM

Call Dean Oliver:

http://www.retunedmusic.com/deano/

MFR440 · 05-10-2007, 01:12 PM

Quote:

I need a little help in getting my AVS to work right.
I am running a 70 340 in Pure Stock. I have a stumble / bog on the launch that I can't fugure out how to get rid of. I am not an expert on carbs, so any help would be appreciated.

I have tried different accelerator pump linkage positions, larger and smaller squirters, larger jets and adjusting to the air valve. None seem to completely cure the problem. The air valve seems to help best, if I put enough preload on the spring, but the stumble is still there.

Any suggestions would be appreciated.

Thanks
Mike Coates

IHRA 3914 D/PS swinger

Mike Coates

Been a while since we ran the AVS's, but you might try closing up the oval-shaped holes in the flappers, if it's legal of course. This helped throttle repsonse with our Max Wedge. We used duct tape at first, then epoxied wire mesh over the holes.

Meyer Family Racing
'64 Plymouth Max Wedge
'65 Dodge - rebuilding for ??
N/SS S/ST & H/R 3426

John Dinkel · 05-10-2007, 03:24 PM

Make sure the air valve is tight enough. 1 1/2 to 2 turns should help.

George Mirza · 05-10-2007, 09:24 PM

Try a new spring on the air valve, sometimes when they are weak the door will snap open and not open gradually. I chased that problem on a TQ, new spring stumble was gone. AVS's can be tricky, they don't have a vacuum diaphram to delay the air valve opening.

Also the carb may be to lean, try jetting up the secondary side.

Make sure the primnary's are open 1/2 - 3/4's before the secondaries. I had one that must have been a marine unit and the primary's would open about 1/4 and the sec. would start to open. I tried everything and could not get the stumble out. It was the only AVS I ever saw that did that.

Chuck Beach is the guy to talk to about AVS's.

When you get one right it will work great.

Paul Precht · 05-10-2007, 11:45 PM

Hey George, Whats cookin

05-11-2007, 12:33 PM

Thanks everyone for the input!!
I will try out the suggestions and determine where to go from there.

Thanks again!
Mike

Mike Coates

George Mirza · 05-11-2007, 10:39 PM

Hey Paulie, long time no see!

I don't get out as much as I used to. Hows life in PA? I still see Lenny once in a while and Howard and I still run quite a bit up here. The only race we go to down your way is the Dutch. I miss the Mopar Nats.

How about yourself, your in the thick of it now, when are you going to get out.

George

Chuck Beach · 05-12-2007, 07:34 PM

I have worked on these carbs for about 30 years, part of the problem is the accerator pump, I make my own. I can send you one for about $30.00. I run a '68 340 cuda in G/SA, have gone 11.0's, but I leave on a 2 step, but can still go back to foot braking. The secondary air valve needs to be tight, if it binds up, replace it with another one. If you want me to go thru it I charge $350.00. good luck

Glenn Person · 05-14-2007, 07:28 PM

Chuck , Would you send your email to me at aaaltd@sasktel.net Would like to talk about an AVS. Thanks Glenn Person

05-09-2007, 09:43 PM	#1
Mike Coates Guest Posts: n/a	Mopar AVS help I need a little help in getting my AVS to work right. I am running a 70 340 in Pure Stock. I have a stumble / bog on the launch that I can't fugure out how to get rid of. I am not an expert on carbs, so any help would be appreciated. I have tried different accelerator pump linkage positions, larger and smaller squirters, larger jets and adjusting to the air valve. None seem to completely cure the problem. The air valve seems to help best, if I put enough preload on the spring, but the stumble is still there. Any suggestions would be appreciated. Thanks Mike Coates IHRA 3914 D/PS swinger Mike Coates

05-10-2007, 03:24 PM	#4
John Dinkel Senior Member Join Date: Nov 2005 Location: Pinckney, Michigan Posts: 507 Likes: 399 Liked 263 Times in 68 Posts	Make sure the air valve is tight enough. 1 1/2 to 2 turns should help. __________________ John Dinkel 3295 STK

05-10-2007, 09:24 PM	#5
George Mirza Senior Member Join Date: Jan 2002 Location: North Attleborough Ma. Posts: 522 Likes: 0 Liked 0 Times in 0 Posts	Try a new spring on the air valve, sometimes when they are weak the door will snap open and not open gradually. I chased that problem on a TQ, new spring stumble was gone. AVS's can be tricky, they don't have a vacuum diaphram to delay the air valve opening. Also the carb may be to lean, try jetting up the secondary side. Make sure the primnary's are open 1/2 - 3/4's before the secondaries. I had one that must have been a marine unit and the primary's would open about 1/4 and the sec. would start to open. I tried everything and could not get the stumble out. It was the only AVS I ever saw that did that. Chuck Beach is the guy to talk to about AVS's. When you get one right it will work great. __________________ GEORGE MIRZA STK 1236

05-11-2007, 10:39 PM	#8
George Mirza Senior Member Join Date: Jan 2002 Location: North Attleborough Ma. Posts: 522 Likes: 0 Liked 0 Times in 0 Posts	Hey Paulie, long time no see! I don't get out as much as I used to. Hows life in PA? I still see Lenny once in a while and Howard and I still run quite a bit up here. The only race we go to down your way is the Dutch. I miss the Mopar Nats. How about yourself, your in the thick of it now, when are you going to get out. George __________________ GEORGE MIRZA STK 1236

05-12-2007, 07:34 PM	#9
Chuck Beach Senior Member Join Date: Jun 2006 Location: Delaware, Ohio Posts: 664 Likes: 12 Liked 58 Times in 13 Posts	I have worked on these carbs for about 30 years, part of the problem is the accerator pump, I make my own. I can send you one for about $30.00. I run a '68 340 cuda in G/SA, have gone 11.0's, but I leave on a 2 step, but can still go back to foot braking. The secondary air valve needs to be tight, if it binds up, replace it with another one. If you want me to go thru it I charge $350.00. good luck __________________ Chuck Beach 3340 STK

05-09-2007, 10:44 PM	#2
SSDiv6 VIP Member Join Date: Feb 2003 Location: Glendale, Arizona Posts: 3,043 Likes: 712 Liked 1,577 Times in 581 Posts	Call Dean Oliver: http://www.retunedmusic.com/deano/

05-10-2007, 11:45 PM	#6
Paul Precht Senior Member Join Date: Dec 2001 Location: Elysburg, Pa Posts: 731 Likes: 355 Liked 317 Times in 119 Posts	Hey George, Whats cookin

05-11-2007, 12:33 PM	#7
Mike Coates Guest Posts: n/a	Thanks everyone for the input!! I will try out the suggestions and determine where to go from there. Thanks again! Mike Mike Coates

05-14-2007, 07:28 PM	#10
Glenn Person Junior Member Join Date: Jul 2004 Location: Regina, Canada Posts: 29 Likes: 0 Liked 0 Times in 0 Posts	Chuck , Would you send your email to me at aaaltd@sasktel.net Would like to talk about an AVS. Thanks Glenn Person __________________ Glenn Person 5356 STK

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