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914World.com _ 914World Garage _ webber carb work
Posted by: william1764 Jul 27 2010, 10:02 AM
mechanic is saying that he needs to remove carbs to investigate/fix backfire issue (bad). He believes carb(s) are dumping fuel which is cause of the problem- maybe float stuck or something? There is a heavy fuel smell after running the car...heavy! How many labor hours should I expect for removal, tear down and rebuild of carbs?
Posted by: ME733 Jul 27 2010, 11:02 AM
mechanic is saying that he needs to remove carbs to investigate/fix backfire issue (bad). He believes carb(s) are dumping fuel which is cause of the problem- maybe float stuck or something? There is a heavy fuel smell after running the car...heavy! How many labor hours should I expect for removal, tear down and rebuild of carbs?
..........First of all , if you don't trust your mechanic to charge you fairly, AND maintain your car, or rebuild your carbs then ....find a mechanic you feel more confortable with.....the work you are talking about cannot be absolutely quantified here on "world". It,s a what sort of set up you got sort of thing., and how many OTHER related subsystems need attention...with that said ..$.400.00...+ bucks.as a wild ass quess.
Posted by: pin31 Jul 27 2010, 12:36 PM
Bill,
The last thing I would do is mess with the carbs (and if you do please read the Weber book I provided). The popping on deceleration has been there since day one when I purchased the car from Camp914. The car runs great in all gears and under all loads/RPMs.
As we discussed, if I was going to keep the car I was going to do 3 things.
1. I suspect there is an exhaust leak (most likely where the SS heat exchangers bolt to the engine). I included all the proper gaskets (and copper nuts) for that and also the gaskets where the HE bolts to the Triad exhaust.
2. Replace the stock fuel pump with a CB Performance 3.5 PSI Deluxe electric fuel pump (Pelican Parts, PEL-CB3193, $69.20). When the car came from Camp914 the fuel pump was dead (most likely the car carrier guy left the key on during transit). I replaced it with what was on it (stock fuel pump). Also get rid of the pressure gauge/regulator/tee that feeds the carbs (it came that way, I believe that’s how they reduced the pressure to 3-4 PSI). I would also replace the plastic fuel lines with the SS ones from Tangerine Racing (just for good measure).
3. Replace the Bosch 050 distributor (and the Pertronics II) with the Mallory unilight distributor (tweaked with the proper advance springs) that I provided to you with the car. Also, set the timing and for good measure, adjust the valves (I haven’t touched either since I bought the car (3,000 miles).
4. Then if it still pops on deceleration, I may consider a different exhaust (or live with the popping like I did). Even though I like it, I don’t think the dual-outlet Triad exhaust was properly designed (I don’t think it provides enough back pressure ….just a guess).
Tim
Posted by: Ericv1 Jul 27 2010, 02:09 PM
Bill,
The last thing I would do is mess with the carbs (and if you do please read the Weber book I provided). The popping on deceleration has been there since day one when I purchased the car from Camp914. The car runs great in all gears and under all loads/RPMs.
As we discussed, if I was going to keep the car I was going to do 3 things.
1. I suspect there is an exhaust leak (most likely where the SS heat exchangers bolt to the engine). I included all the proper gaskets (and copper nuts) for that and also the gaskets where the HE bolts to the Triad exhaust.
2. Replace the stock fuel pump with a CB Performance 3.5 PSI Deluxe electric fuel pump (Pelican Parts, PEL-CB3193, $69.20). When the car came from Camp914 the fuel pump was dead (most likely the car carrier guy left the key on during transit). I replaced it with what was on it (stock fuel pump). Also get rid of the pressure gauge/regulator/tee that feeds the carbs (it came that way, I believe that’s how they reduced the pressure to 3-4 PSI). I would also replace the plastic fuel lines with the SS ones from Tangerine Racing (just for good measure).
3. Replace the Bosch 050 distributor (and the Pertronics II) with the Mallory unilight distributor (tweaked with the proper advance springs) that I provided to you with the car. Also, set the timing and for good measure, adjust the valves (I haven’t touched either since I bought the car (3,000 miles).
4. Then if it still pops on deceleration, I may consider a different exhaust (or live with the popping like I did). Even though I like it, I don’t think the dual-outlet Triad exhaust was properly designed (I don’t think it provides enough back pressure ….just a guess).
Tim
Every time I've had popping on decel it's been an exhaust leak. Start there first as it's the easiest and cheapest solution up front.
Posted by: SUNAB914 Jul 27 2010, 02:11 PM
So I see you got yourself a car. Sure isn't white. Anyway, duel carbs may take awhile to adjust. Sounds like the PO owner has given you some good gouge, so try to use it. Can you describe when it pops? Is it on decel or during light rpm use? Good luck!
I just re-read the PO comments, if its on decel I would look to the exhaust. Probably just bad copper rings between heads and heat exchangers. Not a difficult or expensive job to rule that out.
Posted by: william1764 Jul 27 2010, 04:37 PM
Thanks all. I did go ahead and replace the exhaust gaskets...no change unfortunatley. Tim, the popping has gotten significantly worse from what I think you must have lived with. I'll even get intermittent backfire that is as loud as my 12 gauge! Something is cleary amiss as also evidenced with the thick fuel smell that surrounds the car for hours after she's shut down. I will replace the distributor with the Mallory now that she's in the shop. She will barely idle...lower than when I took delivery and occassionally will stall. She's now missing/sputtering 1/2 up the power curve in each gear...timing I assume? Anyway, the mechanic comes highly recommended and has significant webber experience according to friend who has his work performed there. No trust issues...just trying to anticipate my exposure. Thanks for everyones feedback. I'm expecting results of his inspection and accompanying estimate in the am - fill you in later.
** SS fuel lines on the wish list as well
Posted by: Kirmizi Jul 27 2010, 05:55 PM
You'll need to "massage" your engine tin in order for the Mallory to fit because the cap is much larger than the Bosch unit's. And SS fuel lines are a good thing!
Mike
Posted by: tornik550 Jul 27 2010, 07:59 PM
[/quote]
Every time I've had popping on decel it's been an exhaust leak. Start there first as it's the easiest and cheapest solution up front.
[/quote]
I'll second that. Sure sounds like an exhaust leak.
Posted by: pin31 Jul 28 2010, 06:41 AM
Bill,
Wow...I thought for sure replacing the exhaust gaskets would resolve the problem. From your description it does sound like something else is amiss.
I would still recommend replaceing the stock fuel pump and the gauge/regulator/tee unit that feeds the carbs with a 3.5 psi CB Performance unit (even if you dont do the SS fuel lines now). I never really liked this setup and it was on my to do list right after the gaskets.
Please keep us posted.
Thanks,
Tim
Posted by: Vacca Rabite Jul 28 2010, 07:16 AM
If you are getting loud backfires, you have an exhaust leak for sure.
figuring out if the pops are coming from the carbs or the tail pipe can be a challenge, but a backfire is a sure sign that it is coming from the tail pipe.
have the car smoked and see if they can locate the leak. Any exhaust shop can do it. They put a smoke machine on the tail pipe and look for smoke coming out of your pipes. if there isn't any, your exhaust is sealed. but if you are getting loud bangs, no way are you sealed.
If the pops are coming from the carb, that means you are running a little lean, or are out of balance. Once you have eliminated the exhaust leaking, then move to the carbs.
and read the weber tech book. So much good info in there.
Zach
Posted by: 9146986 Jul 28 2010, 07:26 AM
If your mechanic wants to take off the carbs to solve an exhaust leak, you need to find a new mechanic!
Posted by: Cap'n Krusty Jul 28 2010, 08:23 AM
Am I understanding you right? The ORIGINAL type fuel pump is still on the car? THERE'S a fire waiting to happen. Let's talk more about that, in detail, before you even consider what the backfiring issues are.
The Cap'n
Posted by: Cap'n Krusty Jul 28 2010, 08:23 AM
OOPS! Double post.
Posted by: Vacca Rabite Jul 28 2010, 08:53 AM
Am I understanding you right? The ORIGINAL type fuel pump is still on the car? THERE'S a fire waiting to happen. Let's talk more about that, in detail, before you even consider what the backfiring issues are.
The Cap'n
Wow. I missed that in the first post. The good rotary fuel pump for carbs is short money. You really don't want 30+ psi in the fuel lines if you are running carbs, even with a regulator in line.
I agree with CK. replace the fuel pump sooner then later.
Zach
Posted by: SUNAB914 Jul 28 2010, 09:29 AM
Loud backfires like you described could probably be something in the ignition.
Posted by: william1764 Jul 28 2010, 09:59 AM
this is all very helpful. going to discuss replacing the fuel pump with mech right now.
Posted by: william1764 Jul 28 2010, 10:00 AM
this is all very helpful. going to discuss replacing the fuel pump with mech right now.
Fuel pump recommendations?
Posted by: Racer Chris Jul 28 2010, 11:28 AM
Fuel pump recommendations?
Bill,
We have a fuel line kit for carbs that includes one of the rotary pumps:
http://www.tangerineracing.com/stainlessFuelLines.htm#Fuel%20Lines%20and%20Fuel%20Pump%20for%20Carburetors,%20Conversion%20Package
Chris
Posted by: Phoenix 914-6GT Jul 28 2010, 11:33 AM
Fuel pump recommendations?
Bill,
We have a fuel line kit for carbs that includes one of the rotary pumps:
http://www.tangerineracing.com/stainlessFuelLines.htm#Fuel%20Lines%20and%20Fuel%20Pump%20for%20Carburetors,%20Conversion%20Package
Chris
Posted by: william1764 Jul 28 2010, 01:37 PM
Fuel pump recommendations?
Bill,
We have a fuel line kit for carbs that includes one of the rotary pumps:
http://www.tangerineracing.com/stainlessFuelLines.htm#Fuel%20Lines%20and%20Fuel%20Pump%20for%20Carburetors,%20Conversion%20Package
Chris
Chris. Does this kit include everything I'd need to replace fuel pump and plastic lines with SS?
If it wasn't already evident to most of you, my ignornace as it relates to anything engine, mechanical related is clearly shining through - sorry guys
Posted by: Racer Chris Jul 28 2010, 05:24 PM
Chris. Does this kit include everything I'd need to replace fuel pump and plastic lines with SS?
Yes, everything from the tank to the right rear corner of the engine compartment is included. All you need (which you might already have) is a tee and hoses to each carb.
Posted by: Kirmizi Jul 28 2010, 06:16 PM
Chris and Bill, just a thought, is the existing fuel pump still in the original location?
If so, would you recommend relocating the new pump to the front, below the tank?
Mike
Posted by: william1764 Jul 29 2010, 07:18 AM
Chris and Bill, just a thought, is the existing fuel pump still in the original location?
If so, would you recommend relocating the new pump to the front, below the tank?
Mike
Mike - it was relocated to the front trunk.
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