fuel pump pushrod issues / questions

[dubstar]

'63 Kombi w/ '70 1600 single port w/ generator

this engine came with a cheap aftermarket fuel pump installed...possibly related to this, my carb has developed a slight leak at the throttle arm after it is shut down...after discussing this with ed fall, the long-term goal is to have the carb rebuilt, rebushed, and new throttle arm installed...we also discussed that it is very probable that the aftermarket pump is putting out way too high fuel pressure, which would cause even a rebuilt carb to leak

time (as always) is an issue, so in the short term, I purchased a rebuilt pierburg fuel pump from a samba member with a large amount of positive feedback similar to the ones ed periodically rebuilds (bottom pump):

http://vintagewerks.com/Fuel%20Pumps/fp_4sale.html#40hopierburgfuelpump

upon installing the new pump today, I encountered a possible issue with the pushrod...based on the bentley, idiot guide, and http://www.vw-resource.com/fuel_pump.html#replace , the generator pushrod should be 4.25"...so far, so good

next, all three sources indicate that the pushrod height should be measured at the top of its travel and that it should be approximately 0.25" or 4-5mm above the top gasket at its highest position...the web link also indicates it should be close to the gasket at the bottom of its travel

here is the problem...mine measures closer to 0.5" and is not particularly close to the gasket at the bottom of its travel

the new pump seems to run fine, but there is still a slight leak from the carb, possibly less than before, when the engine is shut down...fuel pressure will be measured shortly, but in the meantime:

* can I use multiple gaskets to decrease the stroke and hit proper specs?
* am I damaging the newly rebuilt pump with this much stroke?
* should I seek out a 4" alternator pushrod?
* what are the possible causes of this? what's going on inside my case? is it related to the distributer?

apologies for any misconceptions or misunderstandings I may have...please feel free to set me straight or offer any other thoughts

also, it is acceptable to pack the pump base with white lithium grease?

thanks
_________________
1963 Type II Kombi
1977 Type I Fuel Injection

http://instagram.com/john_aka_dubstar/
http://web.stagram.com/n/john_aka_dubstar/
http://dubstar.smugmug.com/Other

"you could transport really tall things too, like a giraffe"

[Stanagon]

I'd say measure the fuel pressure so you know if that is the issue. Likely it's not. Leaky throttle shaft bushings sound more possible to me.

The fuel pump pushrod is probably correct. Using an alternator rod with a generator pump will likely just cause the pump not to work. Using a generator rod with an aftermarket alternator-style fuel pump will damage the pump (I learned this from first hand experience ).

I don't know if white lithium grease is the correct grease, but yes you do want to grease the lower inside of the fuel pump where the operating lever is.
_________________
Stan's Classic Service, specializing in air-cooled VWs: http://www.thesamba.com/vw/classifieds/detail.php?id=614073

www.stanagon.com

[dubstar]

"The fuel pump pushrod is probably correct"

thanks, stan...we will, of course, measure the fuel pressure, and the carb will be sent to ed eventually

however, what might cause the extra stroke distance? if the pressure checks out, I won't be overly concerned, but I am wondering what is going on...
_________________
1963 Type II Kombi
1977 Type I Fuel Injection

http://instagram.com/john_aka_dubstar/
http://web.stagram.com/n/john_aka_dubstar/
http://dubstar.smugmug.com/Other

"you could transport really tall things too, like a giraffe"

[Glenn]

The pushrod should be 108mm. The 100mm pushrod is for the alternator pump.

Did you replace the base under the pump? The base should be 12.3mm tall. I've seen aftermarket ones of varying heights, all shorter and one 11.8mm which will raise your fuel pressure. I never measured travel but used a a fuel pressure gauge to see what the pump is putting out. Yes you can and should stack gaskets to adjust the fuel pressure.

You should use wheel bearing grease and not white lithium. The white lithium will breakdown from the fuel and oil where the wheel bearing grease will not.
_________________
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"
HBB/RW
www.DasVolks.com
Long Island's Aircooled Club

[dubstar]

"The pushrod should be 108mm"

that's what I have

"Did you replace the base under the pump? The base should be 12.3mm tall"

no, I didn't; it appears to be original, but I will measure the height tomorrow...that might be the answer

"Yes you can and should stack gaskets to adjust the fuel pressure."

I know you can add a few, but currently it seems I would need to add MANY

"You should use wheel bearing grease and not white lithium"

does wheel bearing grease go by another name at the auto parts store?

thanks
_________________
1963 Type II Kombi
1977 Type I Fuel Injection

http://instagram.com/john_aka_dubstar/
http://web.stagram.com/n/john_aka_dubstar/
http://dubstar.smugmug.com/Other

"you could transport really tall things too, like a giraffe"

[Stanagon]

Aftermarket base, good thought Glenn. I haven't used any of those yet, but I think I'm out of good original fuel pump bases.

And it's good to know wheel bearing grease is the right thing to use. I've been using that for years.
_________________
Stan's Classic Service, specializing in air-cooled VWs: http://www.thesamba.com/vw/classifieds/detail.php?id=614073

www.stanagon.com

[Eric&Barb]

Think you are reading it wrong.

Pump stroke should be 4 mm or .160", but can be as much as 5 mm or .200".

So top of push rod should travel from lowest about 8 mm or .310", to 13 mm or .510" at highest.

No on white lithium. Would use general purpose lithium grease instead.

Just because the carb leaks at the throttle shaft does not automatically mean it is worn there. Give it a wiggle and see if there is lots of wear. Wiggle you can not really see, but only feel should be fine and other causes are your trouble.
_________________
In Stereo, Where Available!

[dubstar]

no wiggle on the throttle arm at all...will switch grease asap

"So top of push rod should travel from lowest about 8 mm or .310", to 13 mm or .510" at highest."

I was getting a reading of 12-13mm above the gasket at top of travel...and 8mm for lowest seems about right, as well

I was reading this:

With the insulator block, pushrod and one gasket installed (see picture below) -

Fuel Pump Pushrod

Checking Pushrod Length

Rotate the engine until the fuel pump pushrod is at it's lowest point. At this point the top of the pushrod should be only slightly above the level of the gasket on the flange.
Next, rotate the engine until the pushrod is at its highest position.
Measure how much of the pushrod is sticking up past the gasket on the flange. This measurement should be between 4 and 5mm (1/4").


thanks, everyone
_________________
1963 Type II Kombi
1977 Type I Fuel Injection

http://instagram.com/john_aka_dubstar/
http://web.stagram.com/n/john_aka_dubstar/
http://dubstar.smugmug.com/Other

"you could transport really tall things too, like a giraffe"

[Glenn]

You're being too anal, get a pressure gauge and see what it's putting out. If its too high, add gaskets.
_________________
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"
HBB/RW
www.DasVolks.com
Long Island's Aircooled Club

[Eric&Barb]

[dubstar]

alright, thanks...

I'll go "mellow out" now
_________________
1963 Type II Kombi
1977 Type I Fuel Injection

http://instagram.com/john_aka_dubstar/
http://web.stagram.com/n/john_aka_dubstar/
http://dubstar.smugmug.com/Other

"you could transport really tall things too, like a giraffe"

[dubstar]

well, so much for that...went out this morning to find the newly rebuilt / installed pump leaking from the top four bolts (non-return valve cover)

the old pump is now reinstalled...best laid plans and all that
_________________
1963 Type II Kombi
1977 Type I Fuel Injection

http://instagram.com/john_aka_dubstar/
http://web.stagram.com/n/john_aka_dubstar/
http://dubstar.smugmug.com/Other

"you could transport really tall things too, like a giraffe"

[dubstar]

I found this thread:

http://www.thesamba.com/vw/forum/viewtopic.php?t=510753
_________________
1963 Type II Kombi
1977 Type I Fuel Injection

http://instagram.com/john_aka_dubstar/
http://web.stagram.com/n/john_aka_dubstar/
http://dubstar.smugmug.com/Other

"you could transport really tall things too, like a giraffe"

[Culito]

I have also rebuilt a Pierburg pump, the kit was kind of janky, and there were leaks everywhere, even though I took great pains to make sure every gasket surface was straight and true.
Now I use aftermarket pumps and keep the Pierburg as a spare.
Also, I've had to use 1/16" gasket material to get pressure down to acceptable levels with new pumps.
_________________
Copyright 2012-apocalypse, CJ Industries, Inc.
'62 Turkis fleet