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Mpec2 Samba Member
Joined: May 24, 2015 Posts: 49 Location: Chicago, IL
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Posted: Sat Mar 09, 2024 5:20 pm Post subject: 1972 Baywindow Idling and Brake Issue |
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I'm having some trouble with idling on my bus. I purchased it in November with word that it ran somehwat recently, didnt run when i purchased as it had a very gunked up fuel tank. I pulled the motor to clean out the fuel tank over the winter and got it all back in the car now.
I have statically timed the bus for now, will dynamically once i can get it to idle. Compression is good.
The bus can start and run if i feather the throttle, but once i release it the car just sputters out.
It is a stock 1700 engine, with the dual vacuum dizzy and single 32/36 DFEV weber carb. I know this carb isn't great, is what it is for now though.
One of the dizzy vacuum lines is routed to a three way splitter in the brake booster vacuum line. i've traced the brake booster hoses and they look okay, one of them just behind the tins was iffy so i replaced it. Despite that though, the brake pedal is EXTREMELY stiff, as in I can barely press it down.
Any advice on how to address the idling issue? Can the stiff breaks(potentially bad booster?) be related to the rough idling in any way?
I did clean the carbs thoroughly. Running 150/160 idle jets, float level checked; idle mixture screw and idle speed screw at 2 turns.
Any help would be greatly appreciated. |
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dodger tom Samba Member
Joined: March 25, 2013 Posts: 1272 Location: Central Coast, CA, but we're all still Ukrainian
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Posted: Sat Mar 09, 2024 5:41 pm Post subject: Re: 1972 Baywindow Idling and Brake Issue |
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not sure about the brakes.
as i'm sure you know the idling can be so many things from basic tune-up stuff (dirty plugs, old ignition wires, pitted points) to dying coil, carb issues, etc, etc.
one of the first things i'd do (besides checking the basics) is a smoke test for vacuum leaks. _________________ 1978 Champaign Edition 2 Westfalia
Would never find the time to keep up another classic air-cooled. |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16976 Location: San Diego, California
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Posted: Sat Mar 09, 2024 10:37 pm Post subject: Re: 1972 Baywindow Idling and Brake Issue |
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Why is it such a secret where members live. Just put your location in so we can better help you _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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Abscate Samba Member
Joined: October 05, 2014 Posts: 22677 Location: NYC/Upstate/ROW
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Posted: Sun Mar 10, 2024 2:18 am Post subject: Re: 1972 Baywindow Idling and Brake Issue |
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The carb indeed is what it is, and likely will never run and idle well if you are in any kind of area with climate. In SoCal with 75F +-2 degrees, maybe
That hard brake pedal is probably a disconnected or leaking vacuum hose, which will also kill your idle _________________ .ssS! |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50360
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Posted: Sun Mar 10, 2024 3:28 am Post subject: Re: 1972 Baywindow Idling and Brake Issue |
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Disconnect the hose going to the retard can (the nipple pointing towards the distributor body), plug it off, and let us know how it idles. |
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Mpec2 Samba Member
Joined: May 24, 2015 Posts: 49 Location: Chicago, IL
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Posted: Sun Mar 10, 2024 6:00 am Post subject: Re: 1972 Baywindow Idling and Brake Issue |
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Never got around to updating that part of my profile, but i see how location can be relevant here.
I'm just outside of Chicago, pretty cold here still low/mid 40's.
I didnt do the smoke test, but i bought some hoses this morning and just replaced all the ones that run to the booster; they were all pretty old lookin anyways.
I removed the hose on the retard can, plugged it off, but no real difference still wont hold the idle.
As a reply to Tom, the coil, points, ignition wires, and plugs have been replaced since i bought the bus. Point gap was measured and re-checked.
Can this be an issue with the choke? It appears that the weber does not have the standard weber choke, but rather some holley replacement? It almost seems like the first start of the day it'll hold idle for just a second or two (vs never otherwise), but any subsequent starts it doesnt do that.
Photos of carb below for reference.
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16976 Location: San Diego, California
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Posted: Sun Mar 10, 2024 7:53 am Post subject: Re: 1972 Baywindow Idling and Brake Issue |
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Can we see a pic of your booster vacuum source? _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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Mpec2 Samba Member
Joined: May 24, 2015 Posts: 49 Location: Chicago, IL
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Posted: Sun Mar 10, 2024 8:25 am Post subject: Re: 1972 Baywindow Idling and Brake Issue |
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Ah just stepped out of the house, I’ll be back in a few hours.
Do you mean essentially a picture of the booster?
If it helps in the mean time; There is a hose coming off the booster that connects to the metal line, that travels along the bus. And then connects to
another hose that essentially just connects to basically a hose adapter with small circle in between(picture of what it looks that I found online below). And then a hose continues to the three-way split inside the engine bay where I one hose connects to the intake and the other to the dizzy vacuum canister.
I’ve also noticed, when reading online, that people have check valves at some point along the series of vacuum hoses. It didn’t look like mine had one at any point.
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16976 Location: San Diego, California
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Posted: Sun Mar 10, 2024 9:08 am Post subject: Re: 1972 Baywindow Idling and Brake Issue |
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That hose connector is actually a check valve allowing flow in only one direction. You need to remove it , blow through it verifying that it works, and reinstall with the arrow pointing towards the engine. _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16976 Location: San Diego, California
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Posted: Sun Mar 10, 2024 9:16 am Post subject: Re: 1972 Baywindow Idling and Brake Issue |
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Edit: the one side of the check valve has very old hose. I’d replace that. The new hose you show may or may not be suitable for brake vacuum. Just because it fits doesn’t mean it won’t collapse. I use Gates power brake vacuum hose in 15/32 inside diameter. It’s widely available PN 27231.
Lastly, with all the hose removed I’d clean out the metal tube using shop air first, then fish a wire through, and pull a cloth patch soaked in solvent. _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51173 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Sun Mar 10, 2024 9:17 am Post subject: Re: 1972 Baywindow Idling and Brake Issue |
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I wonder about that new looking hose on that, it looks like 12mm smog hose since I don't think the reinforced stuff is available in braided. It could be collapsing when warm and shutting off the boost vacuum. _________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!
Слава Україні! |
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Mpec2 Samba Member
Joined: May 24, 2015 Posts: 49 Location: Chicago, IL
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Posted: Sun Mar 10, 2024 9:22 am Post subject: Re: 1972 Baywindow Idling and Brake Issue |
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Just to remphasise the image of the adapter/check valve above is just a similar one I found online since I won’t be home for a while, that is not from my bus.
But I will remove that valve in my bus then and check if it’s functional and installed in the correct direction. |
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mikedjames Samba Member
Joined: July 02, 2012 Posts: 2746 Location: Hamble, Hampshire, UK
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Posted: Sun Mar 10, 2024 10:23 am Post subject: Re: 1972 Baywindow Idling and Brake Issue |
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The choke heater may be an unusual Holley thing, but if it is working -
there is a cold idle throttle linkage going to a second adjustment screw sitting under the choke heater.
The screw points roughly towards the throttle cable connection.
That screw sits on a stepped cam. When the choke is cold, the stepped cam rotates and presents a large diameter to the screw. That screw then causes the throttle to be lifted off the idle end stop via the wire linkage that comes out from behind the choke heater.
As the choke heats up the cam rotates . Unlike the 34PICT-3 it doesnt lock while your foot is off the gas, so the idle drops all by itself back to using just the warm idle screw after maybe 3 to 5 minutes.
On my progressive, that cam moves fairly fast, but on initial startup I can adjust that screw to get maybe 1500rpm idle for a short time. _________________ Ancient vehicles and vessels
1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.
1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy |
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Abscate Samba Member
Joined: October 05, 2014 Posts: 22677 Location: NYC/Upstate/ROW
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Posted: Sun Mar 10, 2024 11:09 am Post subject: Re: 1972 Baywindow Idling and Brake Issue |
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That splitting of the vacuums between distributor and brake booster isn’t right. The brake booster needs a fat vacuum hose off the manifold.
Don’t say dizzy unless it’s a Gillespie or Dean, Shirley. _________________ .ssS! |
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Mpec2 Samba Member
Joined: May 24, 2015 Posts: 49 Location: Chicago, IL
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Posted: Sun Mar 10, 2024 11:30 am Post subject: Re: 1972 Baywindow Idling and Brake Issue |
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The split does get a big one, it’s got the reduced nipple for the smaller hose coming off the vacuum canister.
If you zoom in on the top there near the intake manifolds you’ll maybe be able to see the splitter.
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50360
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Posted: Sun Mar 10, 2024 12:48 pm Post subject: Re: 1972 Baywindow Idling and Brake Issue |
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Your carb is not designed to work with a vacuum retard dizzy, so just eliminate the "splitter" as you call it and run the brake vacuum hose straight to the fitting on the manifold. No use trying to fix something that needs to be eliminated. If retard function is actually working (note: they don't age well) it will cause your timing to retard an extra 12° at idle, while if it doesn't work (which is very likely) it will cause a sizable vacuum leak. Unless you want to get out the drill motor and start drilling holes in your carb, the carb can not be adapted to work well with a vacuum retard distributor. |
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Mpec2 Samba Member
Joined: May 24, 2015 Posts: 49 Location: Chicago, IL
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Posted: Sun Mar 10, 2024 3:15 pm Post subject: Re: 1972 Baywindow Idling and Brake Issue |
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I did try that.
Blocked off the input on the vacuum canister and on the splitter. No improvements in the idle. But i didn't mess around with any timing after closing them off. Would closing this vacuum port off and the splitter require some timing adjustments? For now i just have the timing set using the standard static timing method. |
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