Author Topic: Lobe on intermediate shaft  (Read 7785 times)

December 16, 2024, 03:37:45 pm

chickenpot

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Lobe on intermediate shaft
« on: December 16, 2024, 03:37:45 pm »
Has anyone ever installed a mechanical lift pump for a gasser that rides on the intermediate shaft lobe? thinking of ways to do a lift/circulation pump for a waste oil system
1986 Jetta factory TD

Reply #1December 16, 2024, 08:39:51 pm

fatmobile

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Re: Lobe on intermediate shaft
« Reply #1 on: December 16, 2024, 08:39:51 pm »
I didn't even know that option was possible.
 I've seen the lobe on the I-shaft but didn't know the gassers used it for that.
 Usually see a warmup regulator covering it.
 Must be a Rabbit carbureted gasser thing.
Tornado red, '91 Golf 4 door, with M-TDI 12mm pump, south bend clutch, VNT-15 turbo, 02A trany
MK4s: 2000 TDI jetta, 2003 TDI wagon, 2000 golf 2.0 gasser.
'84 Rabbit with 1.7TD KY block pistons bored to 80mm, VNT-15
'84 GTI with stock 1.6TD starion intercooler.

Reply #2December 16, 2024, 11:14:32 pm

chickenpot

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Re: Lobe on intermediate shaft
« Reply #2 on: December 16, 2024, 11:14:32 pm »
I didn't even know that option was possible.
 I've seen the lobe on the I-shaft but didn't know the gassers used it for that.
 Usually see a warmup regulator covering it.
 Must be a Rabbit carbureted gasser thing.

Im guessing this forum doesnt have image hosting, but here is a link to one i found
heritagepartscentre.com/us/026127025a-fuel-pump-carburetor-model dot h t m l

(this is not spam?) im new to this forum, not new to IDI diesels, and about 1 year into VW IDI realm. it seems to have been plagued by spam and it's a pain in the ass to post. thousands of other forums out there got it figured out a long time ago but, whatever. anyway..

I had considered using my power steering pump, since i have converted to a manual rack, however uncomplicated belt drive is an ideal.. i have a 1.5 Block that i have been toying with and it doesnt have provisions for the power steering brackets. an eccentric driven lift pump would be pretty neat. I added a gear pump driven off the belt drive of my 7.3 IDI to power the waste oil system on there, works pretty decent. the VW IDI needs way less flow, really i just want something to circulate the oil/fuel through a heat exchanger. maybe someone has tried it..
1986 Jetta factory TD

Reply #3December 17, 2024, 04:53:42 pm

ORCoaster

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Re: Lobe on intermediate shaft
« Reply #3 on: December 17, 2024, 04:53:42 pm »
What is wrong with a small volume electric pump that pushes the fuel through the heater?  I used two heaters on my system and back when and just pulled the fuel through the heater with the IP.


Reply #4December 17, 2024, 05:04:36 pm

fatmobile

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Re: Lobe on intermediate shaft
« Reply #4 on: December 17, 2024, 05:04:36 pm »
 I bet it would work.
Since it usually pulls/pushes fuel.
 I wonder what would happen if the oil was too cold to move.

If you were planning to use it to pump veg oil through the injection pump,
my guess is it would create too much pressure at the front of the pump. But that's a pretty uninformed guess.
Tornado red, '91 Golf 4 door, with M-TDI 12mm pump, south bend clutch, VNT-15 turbo, 02A trany
MK4s: 2000 TDI jetta, 2003 TDI wagon, 2000 golf 2.0 gasser.
'84 Rabbit with 1.7TD KY block pistons bored to 80mm, VNT-15
'84 GTI with stock 1.6TD starion intercooler.

Reply #5December 17, 2024, 08:29:34 pm

chickenpot

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Re: Lobe on intermediate shaft
« Reply #5 on: December 17, 2024, 08:29:34 pm »
So my idea is to just create a circulation loop through a heat exchanger back to the tank, so there would never be any restriction or pressure on the system. then the tee off to go to the IP is just on the other side of the heat exchanger and a filter and the IP can pull in the fuel that has positive flow but no pressure behind it.

The reason i dont want a small electric pump is because i dont trust it to hold up to very cold or very hot uncut oil. the diaphragm pump might not hold up, maybe i will find a rabbit forum where people have carbed ones with the mechanical pumps
1986 Jetta factory TD

Reply #6December 18, 2024, 03:40:49 pm

fatmobile

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Re: Lobe on intermediate shaft
« Reply #6 on: December 18, 2024, 03:40:49 pm »
I still wonder what would happen if the oil was cold and the pump couldn't move it.
 What gives first? Would it break the lobe on the I-shaft?

 Might put a polishing filter in your heat exchanger setup too.
Tornado red, '91 Golf 4 door, with M-TDI 12mm pump, south bend clutch, VNT-15 turbo, 02A trany
MK4s: 2000 TDI jetta, 2003 TDI wagon, 2000 golf 2.0 gasser.
'84 Rabbit with 1.7TD KY block pistons bored to 80mm, VNT-15
'84 GTI with stock 1.6TD starion intercooler.

Reply #7March 28, 2025, 09:42:30 am

rabbitman

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Re: Lobe on intermediate shaft
« Reply #7 on: March 28, 2025, 09:42:30 am »
I didn't even know that option was possible.
 I've seen the lobe on the I-shaft but didn't know the gassers used it for that.
 Usually see a warmup regulator covering it.
 Must be a Rabbit carbureted gasser thing.

Correct, I had a 1.7L carbureted gasser that had a fuel pump on that lobe. Also somewhere on the web was an early rabbit diesel that had a lift pump installed there. Obviously it isn't necessary.

The early 90s cummins 5.9 has a VE pump and still uses a lift pump.

As far as what would break first, maybe nothing. My 96 dodge cummins has a lift pump that only pushes fuel on the return stroke. Some people install a heavier return spring in it to increase fuel pressure/flow to the injector pump.
'82 Rabbit, I put on a euro vnt-15, 2.25" DP, 2.5" exhaust, the result.....it whistled.

I removed the turbo, made a toilet bowl 2.5" DP, the result....it was deafening. Now it has a homemade muffler up front and a thrush in the rear, the result.....less loud.
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