I do not know how the carb. will not work. The engine creates the vacuum.
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Getting the ‘57 beetle back on the road in 2024
- Thread starter bosco659
- Start date
just bug porn...
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Pat D
XS650 Addict
So help me out here- is my understanding correct that your motor has a stand-alone vacuum pump? My diesels also had a stand alone pump for the power assist brakes, since diesels don't make much intake vacuum. But distributor/spark advance/retard is dependent on engine/intake vacuum- more load=less vacuum=less advance. I'm curious how the stand alone vac pump works with the distributor spark advance? Vacuum from the pump should be relatively constant- it isn't going to vary with throttle the way intake vacuum will. I'm gonna assume you are much more steeped in late 50's air cooled VW theory than I am, but I've got questions now! Our old Nash/AMC cars use an auxiliary vac pump built into the fuel pump, but that's for the vacuum operated wipers. Are you 100% certain the vac pump is related to/part of the advance system? Maybe save some grief?
^^^^ This. I'm pretty sure the vacuum your distributor advance diaphragm wants to see is intake manifold - generated.
Yep, manifold vac. is indirectly related to engine load.
More load=less vac.=less spark advance.
Mechanical advance is tailored to limit advance at maximum load RPM to avoid detonation(at peak torque)
This is RPM sensitive.
Vacuum advance is Load sensitive.
Advancing at lighter loads for better fuel economy.
Really, it's more of a vacuum retard.
anyways, the diaphragm can be replaced or sealed to work
I always use manifold vacuum instead or ported vacuum.
The vacuum for the advance is supplied from the carb body. When I rebuild the carb I’ll try to see where is coming from.
Pat D
XS650 Addict
OK, cool, I got off track somewhere. "They say it happens in the autumn years." Fat Tony
From my experience, the tap on the carb body presents manifold vacuum.
And as has been contributed by @AUTOMAN , most run better on manifold vacuum. Most later engines that had the option of ported (timed) vacuum from their carburetors, ran better with manifold vacuum...if you are looking for best performance. Sorry, my experience in this area is SBC.
What you want to use if available is ported vacuum, second best is manifold vacuum.
I think the differences are somewhat subtle but distinct, and you are obviously welcome to choose either approach as per your own feelings. And...if you use the nominated port on the stock carburetor, VW's engineers will have picked for you!
That said, my lore has always contributed that, for most street applications, manifold vacuum is preferred for better idle quality, cooler running temperatures, and crisper throttle response. I believe ported vacuum was designed for emissions control to reduce emissions at idle but can run hotter and offers little to no advance until the throttle is opened.
That said, my lore has always contributed that, for most street applications, manifold vacuum is preferred for better idle quality, cooler running temperatures, and crisper throttle response. I believe ported vacuum was designed for emissions control to reduce emissions at idle but can run hotter and offers little to no advance until the throttle is opened.
Correct. Ported is for minimal advance to get exhaust hot for emissions.I think the differences are somewhat subtle but distinct, and you are obviously welcome to choose either approach as per your own feelings. And...if you use the nominated port on the stock carburetor, VW's engineers will have picked for you!
That said, my lore has always contributed that, for most street applications, manifold vacuum is preferred for better idle quality, cooler running temperatures, and crisper throttle response. I believe ported vacuum was designed for emissions control to reduce emissions at idle but can run hotter and offers little to no advance until the throttle is opened.
As for the heater, ported, helps warm interior at idle.
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Test fit rear seats and one recovered side panel. I’m happy with the colours (flash changes shades). Battery hold down mod - I still need to put a rubber cover over the positive terminal. Carb and fuel pump are now rebuilt. Getting ready for rest fire #2 (probably Saturday). Attempting to save a beat up old running board.
Jim did you use any sound deadening material on the doors or side panels of the van? I need to replace some factory stuff that’s fallen off the doors of the beetle.
I used this stuff, Vic.
https://www.amazon.com/dp/B09MCSZ6G7?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_4&th=1
https://www.amazon.com/dp/B09MCSZ6G7?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_4&th=1
Well the passengers side is done. I may put a second coat on the rusty areas. I have to wait about 3 hours to do that.
Paint prep - nothing extreme since most of the floor pan will never see the light of day. Scraper, wire brush, sand surfaces, vacuum, wash down with 70% alcohol. The paint is POR15. Love that stuff.
The spots in the “after paint” pics are light reflections. Everything is well coated. Only a few spots showed through a bit. I’ll try to do the drivers side this week.
Paint prep - nothing extreme since most of the floor pan will never see the light of day. Scraper, wire brush, sand surfaces, vacuum, wash down with 70% alcohol. The paint is POR15. Love that stuff.
The spots in the “after paint” pics are light reflections. Everything is well coated. Only a few spots showed through a bit. I’ll try to do the drivers side this week.
It's the thick rubber foam used for sound insulation. Glue on one side with a paper cover you peel off as you go. It's sticky as all hell. make sure it's in the right place before you push it down... 'cause it ain't coming back off.
When I rebuilt my carb, the mixture screw that was removed from the carb had a hole in it. The replacement screw is solid with no hole. I found out why the hole was there. Anyone care yo guess why? I can post the reason later. Looks like previous mechanics really rammed the screw into the carb body.
to create an emulsion?
