Author |
Message |
79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
|
Posted: Sun Oct 17, 2010 3:34 pm Post subject: Tracking down a backfire problem - SOLVED - Thank you all! |
|
|
Short version: poor seal between J-pipes and muffler. Solution, Permatex Copper High-Temp Gasket Maker, then metal or asbestos rings and clamps.
Long version:
I have to find the source of the backfiring when engine braking. I can reach all the exhaust nuts except the two top ones on number one and three cylinders. Can I get to those by removing some tin in the engine compartment or do I have to drop the engine? _________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt.
Last edited by 79SuperVert on Sat Nov 06, 2010 11:43 am; edited 3 times in total |
|
Back to top |
|
|
Glenn Mr. 010
Joined: December 25, 2001 Posts: 76760 Location: Sneaking up behind you
|
Posted: Sun Oct 17, 2010 3:35 pm Post subject: |
|
|
You should be able to get to them with a swivel socket. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare |
|
Back to top |
|
|
79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
|
Posted: Sun Oct 17, 2010 3:48 pm Post subject: |
|
|
You mean like one of these?
_________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt. |
|
Back to top |
|
|
Glenn Mr. 010
Joined: December 25, 2001 Posts: 76760 Location: Sneaking up behind you
|
Posted: Sun Oct 17, 2010 3:50 pm Post subject: |
|
|
79SuperVert wrote: |
You mean like one of these?
|
EGGzackly _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare |
|
Back to top |
|
|
79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
|
Posted: Sun Oct 17, 2010 3:51 pm Post subject: |
|
|
Thanks. _________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt. |
|
Back to top |
|
|
Cusser Samba Member
Joined: October 02, 2006 Posts: 31268 Location: Hot Arizona
|
|
Back to top |
|
|
Michael Fischer Samba Member
Joined: April 20, 2004 Posts: 1585 Location: Salem, OR
|
Posted: Sun Oct 17, 2010 6:30 pm Post subject: |
|
|
I use a half moon 13mm. |
|
Back to top |
|
|
79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
|
Posted: Mon Oct 18, 2010 6:01 am Post subject: |
|
|
Never heard of those. This kind?
[/url] _________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt. |
|
Back to top |
|
|
79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
|
Posted: Mon Oct 25, 2010 10:27 am Post subject: |
|
|
Swivel sockets worked nicely. Tightened the exhaust nuts and clamps all around. Had to loosen and move the heater boxes but that wasn't any trouble. Unfortunately, it still backfires. It may be that the gaskets are shot but I'm going to try other "easy" stuff first.
By the way, can the gaskets be changed out on the front exhaust ports easily? I suppose if I undo all the exhaust clamps the pipes can be moved forward enough to clear the studs.
The VW shop manual says that backfiring can also be addressed by turning the idle air mixture screw out 1/8 turn. I'm going to try that next. _________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt. |
|
Back to top |
|
|
Harris Samba Member
Joined: June 11, 2004 Posts: 1317 Location: Texas
|
Posted: Mon Oct 25, 2010 10:36 am Post subject: Top nuts on Exhaust |
|
|
If it's on your '62, make sure you have the the smaller 32mm asbestos looking gasket (muffler to J tube connection) I'm guessing here but I think the larger is 35mm and the smaller is 32mm. The 32 fits tight on the J tube. If the larger one is one there it could backfire. Mine did until I got the right one installed. |
|
Back to top |
|
|
79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
|
Posted: Mon Oct 25, 2010 11:15 am Post subject: |
|
|
This is the pic of the Wolfsburg West muffler installation kit for a 40hp stale air. Can you show me which one you are referring to? It looks like there's only one size gasket ring that would fit over the J tube.
_________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt. |
|
Back to top |
|
|
Michael Fischer Samba Member
Joined: April 20, 2004 Posts: 1585 Location: Salem, OR
|
Posted: Mon Oct 25, 2010 11:21 am Post subject: |
|
|
79SuperVert wrote: |
Never heard of those. This kind?
[/url] |
Yes. I have a complete set but the only one I have ever used is the 13mm. Very useful wrench. Works great for pulling the carb too. Every VW owner should have one. |
|
Back to top |
|
|
Harris Samba Member
Joined: June 11, 2004 Posts: 1317 Location: Texas
|
Posted: Mon Oct 25, 2010 11:28 am Post subject: Tracking Down a Backfire Problem |
|
|
It's the round gasket that looks like it's made of asbestos.
Joe, if the ones you have fit loose on the J tube, PM me with an address and I'll send you two that fit. Most kits have the larger gasket. The one you need fits tight on the J tube and most kits only include the larger gasket.
Lou |
|
Back to top |
|
|
Erik G Samba Member
Joined: October 16, 2002 Posts: 13247 Location: Tejas!
|
|
Back to top |
|
|
79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
|
Posted: Mon Oct 25, 2010 12:45 pm Post subject: |
|
|
I hope this doesn't sound stupid, but if I only hear it when I'm driving, I don't know how to tell whether it's through the carb or through the exhaust. It kind of sounds too loud to be coming from inside the engine compartment but I don't know if a carb backfire sounds different. Would there be some visual indication around the carb area?
Also, if it only happens during engine braking, would it backfire through the carb? Other than for the backfire it runs great, starts right away, no hesitation, smooth acceleration in all gears, no other indication of a problem.
Thanks for all the replies so far, by the way. _________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt. |
|
Back to top |
|
|
61SNRF Samba Member
Joined: March 29, 2009 Posts: 4657 Location: Whittier 90602
|
Posted: Mon Oct 25, 2010 12:48 pm Post subject: |
|
|
79SuperVert wrote: |
The VW shop manual says that backfiring can also be addressed by turning the idle air mixture screw out 1/8 turn. I'm going to try that next. |
Are you sure about this?
Backfiring on decell can be caused by exhaust leaks and/or too rich a mixture. I think I would try turning it in 1/8 turn. |
|
Back to top |
|
|
79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
|
Posted: Mon Oct 25, 2010 12:50 pm Post subject: |
|
|
61SNRF wrote: |
79SuperVert wrote: |
The VW shop manual says that backfiring can also be addressed by turning the idle air mixture screw out 1/8 turn. I'm going to try that next. |
Are you sure about this?
Backfiring on decell can be caused by exhaust leaks and/or too rich a mixture. I think I would try turning it in 1/8 turn. |
I will read it again before I actually turn the screw. But also note, it doesn't backfire on deceleration. It only backfires when I brake with the engine. The note in the shop manual specifically refers to turning the screw out when it backfires as the engine brakes the car. _________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt. |
|
Back to top |
|
|
61SNRF Samba Member
Joined: March 29, 2009 Posts: 4657 Location: Whittier 90602
|
Posted: Mon Oct 25, 2010 12:58 pm Post subject: |
|
|
I'm sorry if I wasn't clear, but by "decell" I meant engine braking. |
|
Back to top |
|
|
79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
|
Posted: Mon Oct 25, 2010 1:00 pm Post subject: |
|
|
61SNRF wrote: |
I'm sorry if I wasn't clear, but by "decell" I meant engine braking. |
OK. Because if it was also backfiring every time I took my foot off the gas it would be driving me nuts.
And I WILL check the wording in the manual before I turn the screw! It's running fine otherwise and I would like to keep it that way. _________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt. |
|
Back to top |
|
|
usrname Samba Member
Joined: September 12, 2008 Posts: 165 Location: Arizona but not Phoenix
|
Posted: Mon Oct 25, 2010 2:07 pm Post subject: |
|
|
I will be interested in hearing about this as I have the same problem with my '62. |
|
Back to top |
|
|
|