Upgraded Starter For VMC Speedster

Hey Dave,

Starter: IMI is recommended by several members, Carey says he changed to uses WOSP.  Several discussions over the years.  Here is a recent thread.

Jon

Thanks Jon

WOSP is good stuff...have their high output alternator in a 911 and it is quality.  I have IMI starters in the 911 and Spyder and they work great too.  Can't go wrong.  Not sure of the price differences...

Why the upgrade?
-=theron

Upgrading to give me a better startup. The new Optima Battery made a help some what, but I'm hopeful adding a high torque starter, distributor, and coil I would be set from the one that came with the car.

Do you have a mechanical or electric fuel pump?

A better starter and distributor are good ideas, but describe what is happening that you want a "better startup"? Vapor-lock is a thing.

I am looking to try and achieve the same consistency, (instant start) like our other Porsche's we have owned. I typically have to try and start the car 2-3 times. Hope that makes sense. Open for other options.

“Instant start” is an EFI thing. Carbs don’t work that way.

Carbs have float bowls that need to be full for the fuel to be drawn up through the jets and into the intake. The fuel in those float bowls can evaporate if the car sits for days or weeks between starts.

If you have a mechanical fuel pump, you’ll need to crank a good long while to refill the bowls. It might take 2 or 3 tries.  

Starting hard a few minutes after shutdown is a different (but related) problem. Vapor lock is when fuel in the mechanical pump or fuel lines begins to boil. Both can be greatly improved with an electric fuel pump.

Stan, I really appreciate your advice and clear direction on my best option to help clear up my issue. My only only question is , do you have a clear choice in fuel pumps for my Speedster?

https://www.cbperformance.com/product-p/3193.htm

It makes a difference what kind of carbs you have. If they’re Webers or Dellortos, you won’t need a fuel pressure regulator. If they’re Solex/Kadrons you can only run about 1-1/2 psi fuel pressure and will need one.

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Another problem with our cars is that the ECU isn’t located in those little black boxes that house it in modern cars.

It sits in the driver’s seat.

It’s easy to forget how many things (besides just the EFI) the computers on modern cars are constantly adjusting (often many times per second) to give the kind of smooth, effortless response we now take for granted in all conditions.

And, too, even most carbureted cars had at least an automatic choke to help with cold starts. My ‘68 BMW had a manual choke, something that was more common on European cars at the time, but which had disappeared from American iron a decade before. The 356 didn’t have a choke, but it did have a knob on the dash that helped with cold starts in a similar way by holding the throttle open until the engine had warmed enough to run smoothly.

Our cars can be tuned to start easier, but they will always run differently when cold, or when started after sitting for a week or after being run hot and shut down. Part of the drill is learning to program our own computers to compensate for the various conditions.

That said, properly tuned, they should start in a predictable way and without too much fuss. One thing some of us do is set the ‘warm idle’ higher than what would be normal in most cars (maybe around 1000 or 1100 rpm) so that it will idle for those first 30 seconds or so after a stone cold start without having to keep your foot on the gas.

Computer controlled EFI took over the industry when emission regs made it the only practical way to go, but it’s also pretty much erased from our memories the joys of dealing with carburetion.

https://www.speedsterowners.co...1#718536004273125091

Stan, Webber 40's. Have you anyone use the Facet Electronic Fuel pump. Rated 2-4 PSI.

I would second the motion to use an electric fuel pump.

Cold starting: You can usually hear an electric pump working when you activate the ignition.  It's running noise will be louder if the float bowls are empty or low.  So just turn it on for a few seconds, wait, then try the starter.  I have Webers 44IDF and an electric fuel pump and have never had any real trouble starting.  Gotta pump the pedal a couple of times to shoot some gas in there from the accelerator jets, but that's pretty much it.   I recently upgraded to a Maganspark system and it seems to have made things even better.  One touch on the starter and she fires right up. 

Hot starting: usually no big deal, but you don't need the initial pedal pumps.  If its a really hot and has been sitting and wont go right off, it might be a little flooded or has a case of the vapors. Just push the pedal all the way down and leave it there while you crank.

That's all I got. Seems to work for me.

@Techdave posted:

https://www.speedsterowners.co...1#718536004273125091

Stan, Webber 40's. Have you anyone use the Facet Electronic Fuel pump. Rated 2-4 PSI.

The Facet pumps are ridiculously loud. Not "cool sounding loud" -- they sound like a buzzer or electric hair clippers. The rotary pump I linked sounds like a pump. I like it because you can tell by the difference in the sound it makes when the float-bowls have filled and the needle valves closed and the car is ready for "two pumps (to squirt some fuel down the throats) and a crank".

Buy what you want, but I always liked the Carter P60504 pump that CBP repackaged and sold for years. That pump is NLA, but the replacement (a Carter 90091) is available on Amazon for $45 and is also rated for 2-4 psi. I've never used one, but it's probably what CBP is using now, and Amazon is half the price.

@Stan Galat posted:

“Instant start” is an EFI thing. Carbs don’t work that way.

Carbs have float bowls that need to be full for the fuel to be drawn up through the jets and into the intake. The fuel in those float bowls can evaporate if the car sits for days or weeks between starts.

If you have a mechanical fuel pump, you’ll need to crank a good long while to refill the bowls. It might take 2 or 3 tries.  

Starting hard a few minutes after shutdown is a different (but related) problem. Vapor lock is when fuel in the mechanical pump or fuel lines begins to boil. Both can be greatly improved with an electric fuel pump.

All EXCELLENT points. Another thing that can help is careful routing of fuel lines away from heat sources.

So, @Techdave, you have Weber 40 IDFs, I'm guessing? 99% chance of no cold-start system of any kind. Without a cold-start system(either enrichment or mechanical choke) your car will burp, fart, and generally be cantankerous until it warms. Usually only takes a minute or two.

The only way to make one of these run like a modern car is to install EFI and tune it, including cold-start and warm-up settings. This can take a considerable amount of time and effort. I installed EFI, but have yet to tackle the cold-start stuff. I will say, after the first 30 seconds it runs every bit as good as any modern car.

Fuel pump: the Facet "shaker" pump works, but it really makes a racket. Which of course, you won't hear once the car starts. I prefer a rotary pump, like a Carter. The self-regulating 3 to 3.5 psi kind are PERFECT for Webers.

Kelly is correct as to cold-start procedure. However, hot-starts are NEVER floored. I usually just very slightly crack the throttle open then crank it. Once it starts running, you can let off the throttle and let it idle.

To all, great information you provided and educated me. I now have a clear direction to move forward. Thank you again!

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@Techdave , you can see that electric fuel pumps are favored here, with pretty good reasons. There are some starting issues they will definitely help. But some they won't.

With electric pumps, you don't need to crank the engine nearly as long if it hasn't been run for more than a few days. They fill the carb float bowls with gas before you even turn the key.

But once it does turn over, it should keep running equally well with either kind of fuel pump. When you say you usually have to 'try two or three times' does that mean it turns over and immediately stalls? If so, the problem might well be carb tune or even something as simple as idle setting.

I'm a big fan of starting troubleshooting slow and methodically, without swapping in a bunch of new stuff you may not need. And OK, I'm also a big fan of not spending money I don't have to.

Another thing you mention is that a new battery seemed to help. This raises the possibility that the trouble could be spark related. Much has been written here of the evils of demon spark and how he's always trying to shift the blame to those hapless Weber carburetors. So, maybe a good question to ask is how does your car idle and run up through the revs once it is warmed up?

I've been running a stock VW mechanical fuel pump with Weber IDF 40's for nearly 50,000 miles now. The car always starts first try, hot or cold. But this involves some of the driver-sourced computing I mentioned above, and which @El Frazoo explains in greater detail. It's amazing how the engine always needs those simple 'two pumps' when cold, but doesn't like them at all when warm. And there are some subtle variations required depending on outside air temperature. My dad did this in his '52 Buick. I did it in our '62 Corvair. Carburetors. And this applies no matter what kind of fuel pump you've got.

Tuning these carbs is not as harrowing as legend says. There are a few basic things to get right in the beginning, but once that is done, maintaining tune is pretty simple and easily done by someone as clumsy as me. A really (really) important thing is to do the tuning when the engine is warmed up all the way after some real driving (not just idling in the driveway after a cold start). If the engine idles smoothly then, if both sides of the engine are truly in synch, it will probably be a little rough for 30 seconds or so after a cold start, but should gradually grow smoother as it warms up.

If you tune it cold, all bets are off.

One other thing, tangentially related: fuel filter.  There is wisdom in what Sacto observes about changing one thing at a time vs throwing a bunch of changes against the wall and seeing what sticks.  I understand this philosophy, but when tied to the chair with a bright light in my face, I'll admit to not following it all the time.  Short rendition: I was having some "issues" with my Webers, and I was doing lots of things.  clogged idle jets was among one of several things that were not quite right.  Along the way I ditched the little plastic and paper fuel filter that came with the car, and found a low micron stainless steel filter (not expensive) and installed that.  Seems to have helped, but as I said, I was fussing with a few other things at that time so whether or not that was a real improvement, or just something that did not hurt, I can't say for sure.  One of the other things I changed was to install ethanol approved fuel lines: The ones I could reach in the engine compartment that were rubber/neoprene.  There is an SAE standard spec for fuel line that resists ethanol erosion (whose exact name I do not off hand recall) . Often these lines are also suited for high pressure FI systems. These changes , plus several others, including getting a proper tune/balance of the carb settings and linkage did finally fix my carb issues.  And FWIW, through it all, I'm going to say that I never really had much trouble getting the car started -- except when I might have left the lights on and the battery went flat.  But that is another story, with a happy fix. . It was how well/smooth it ran after it got going that was giving me fits.

I believe that when the engine has sat a  while after running hard and is hot on a hot day, fuel in the float chamber can bubble up and flood the engine.  My advice to floor it (open the throttle wide open and keep it there while cranking) is how to overcome this situation.  When the engine is hot, I do not do that first thing.  I Just turn the key, no pedal pumping and let it turn over and start.  works 19 out of 20 times. If it wont catch and there is a goodly smell of gas, maybe it flooded??

Happy hunting!!

@Techdave lets talk starters..here is the lump of "CHI COM" junk that Dr.Jekyll installed installed in my $40K 2018 JPS coupe...it didn't last 6 months...just his way of 'cutting corners" to save $$$...i get that, sort of....in the 5 + years of ownership i have made this car better than delivered by 10 fold...which included a BOSCH starter which IMHO a brand you can't go wrong with...and a beyond easy nut & bolt upgrade dave...if you are listening

The new Bosch starters are significantly lighter than the older models as well...