Author Topic: Advance mechanism (Read 2505 times)

autoholic · « **on:** October 17, 2008, 07:26:20 pm »

The advance mechanism on the bottom of pump: is that only for the advance cable function? or does it function as an advance throughout the RPM range?
I searched this, but do not fully understand how it works. I read up on the pink spring, so I am assuming that it does function as an advance proportional to RPM, and it's not just there for the cable?

This can explain a wierd problem my friend is having.

autoholic · « **Reply #1 on:** October 17, 2008, 07:33:28 pm »

OK, again I did not search thoroughly enough. It does function as an advance proportional to RPM. I understand how it works with the cable, but need to look at an open pump to determine how it works with out cable actuation. I think I remeber having a pink spring around, cool.

jimfoo · « **Reply #2 on:** October 17, 2008, 08:05:31 pm »

It works on internal pump pressure

autoholic · « **Reply #3 on:** October 17, 2008, 08:14:13 pm »

interesting, I do not understand how, but that is good to know. maybe it's time I break down and buy a damn Bently!

autoholic · « **Reply #4 on:** October 17, 2008, 08:43:13 pm »

Great, thanks. And I thought that this was only for use with the cable, it's all making sence now - the cable is doing nothing, something is not right, I just hope I can fix this externally, I know the pin from that rotating cage thing is in (if you know what I mean), I think something is not right in the bottom portion.
I'll find out tomorrow.

autoholic · « **Reply #5 on:** October 19, 2008, 10:17:59 pm »

I pulled the pump yet again and looked at the advance mechanism, nothing wrong there that I can see, at first is was kind of hard to move compare to another pump so I thought maybe this was the problem. The spring was shimmed a bit less than my pump, but still had preload against the cover and seemed fine. When i moved the piston in and out, I could see that the shaft rotated a tiny bit, just like my pump, so i think everything is fine with the advance. I see how it works now, I never noticed the small hole that passes fuel pressure into the advance cyl, never really thought about it.
I reinstalled the pump, timed it and got it running. It ran the exact same way.
One thing I noticed is that when I adjusted the fuel screw, it had a drastic effect on idle speed, one way it would stall right out and the other way would increase RPM's indefinitely. I must have something wrong with the throttle arm or linkage or governor. I don't know what it can be, it all seemed to go together fine and appeared to be right.

Anyway, I'm gonna give my friend my IP since the Samurai is down for a while and then go back into his and fix it, I'll have to remove that damn throttle return spring again, my least favorite thing about working on these!

vanbcguy · « **Reply #6 on:** October 20, 2008, 03:44:19 am »

Quote from: "autoholic"

One thing I noticed is that when I adjusted the fuel screw, it had a drastic effect on idle speed, one way it would stall right out and the other way would increase RPM's indefinitely. I must have something wrong with the throttle arm or linkage or governor. I don't know what it can be, it all seemed to go together fine and appeared to be right.

That's normal... The max fuel screw shifts the throttle map one way or the other. Once you move it you need to reset the idle back where you want it.

autoholic · « **Reply #7 on:** October 20, 2008, 03:48:43 pm »

I've adjusted them before and have noticed idle speed fluctuation, but not this extreme, I can't even turn it 1/2 turn from no idle to high revs, maybe I have the throttle lever on shaft wrong, I don't know, its lined up with one of the hatch marks and the idle stop was close to where it was originally. I'll tear back into this pump and straighten it out for my motor, I'm gonna give Ken my pump and get that ratty Golf out of my door yard!
I've spent 3 precious Saturdays on it now!

autoholic · « **Reply #8 on:** October 23, 2008, 03:39:44 pm »

Installed my Samurai rebuilt IP on my friends car; runs perfect now, very little smoke and great power.
I'm gonna figure out what's wrong with his and go all through it again, When I get the pump done, I'm gonna bring it to the local injection shop so they can put it on the test bench for calibration. I'll put it on my Samurai motor when it's done.

zukgod1 · « **Reply #9 on:** October 23, 2008, 05:00:47 pm »

If your any type of wrench your self and it sounds like you are I wouldn't take it to the shop.. $$$ down the drain sir.

I mean if you are going to have them tear it down and reassemble then sure but if you are taking it apart and find the problem then I wouldn't.

If you take it apart and find nothing then take it down I guess.
Every pump I've built has been easy to tune once back on the car.

I guess I just have a bad taste in my mouth from paying my Shop $100+ to bench test mine when I still had to adjust about everything once it was on the car.

autoholic · « **Reply #10 on:** October 23, 2008, 05:31:21 pm »

I was thinking I would just take it to the shop to calibrate it on the bench after I rebuild it. Do you have to shim the delivery valves after replacing the rotor head? I thought maybe this was best done on the bench?.
If there is no reason to have it bench tested, great, I'll skip it.
The 1st pump I did for my Samurai (now on Kens car) works well and that never went on a test bench.
The FAQ section has some great info, I found some nice exploded view diagrams, pics, etc. When i did the Samurai pump, I had another pump to look at which was helpful, but did not have any diagrams or pics. I had to do the governor mod twice to get it right.
Now I have an old IP mount in my vice which is very helpful for working on these, someone on here mentioned that, what a great idea, can't believe i did not think of that.

zukgod1 · « **Reply #11 on:** October 23, 2008, 06:20:10 pm »

I feel (and I could be wrong) that if you are using the same delivery valves and new copper washers they should be the same. If you change out he DV springs or shims I can see having them checked.

autoholic · « **Reply #12 on:** October 23, 2008, 07:31:26 pm »

This pump has a new rotor head, not sure about the DV's or washers. These washers are not just for sealing are they? they shim the DV to spec as well? I'll have to readup on this more.
Thanks