[Vwdiesel] rebuild? RE: GTD Spec/ My Quantum Spec

[James Hansen]

Just a thought as I was reading Mark.   You may want to take it cool with the slow idle speeds- camshafts don't react well to poor oiling, which you can get easily with low idle speeds on these, unless you know for sure you have plenty of oil up top.
That extended injection event timing is really all that these fancy new ones are accomplishing with so very much computer participation, and not all of them very well at that.
-james

-----Original Message-----
From: vwdiesel-bounces at vwfans.com [mailto:vwdiesel-bounces at vwfans.com] On Behalf Of Mark Shepherd
Sent: May-16-13 9:51 AM
To: Brian and Ruth Decker; vwdiesel at vwfans.com
Subject: Re: [Vwdiesel] rebuild?    RE: GTD Spec/ My Quantum Spec

Hi Brian,
So now you know what technique I used for this engine...

Let me just say I do not recommend using my method. After all, it's not as if I've done it many times, and my score of 100% is based on one attempt. It is merely a practical demonstration of what can be achieved in these times of poverty, or merely because I like to repair things others like to throw away. With that record, I personally will certainly do it again. WRT the head skim, definitely repeatable, definitely improvable with immediate use of counterweight, and definitely not do something like 60 pushes 'n' pulls. 

Concerning 'radical' timing, I wouldn't recommend it, unless you are running similar break pressures, and I've not ruled out the timing being a quirk of the injectors. The bodies and probably more significant, the springs being for TD 155bar. N/a springs were different, but both types can be shimmed across the standard working range.Be aware that N/a nozzle ends, caps and springs i/d are smaller gauge than TD so some bit don't combine...

I've forgotten if these are the nozzles out of some old Ford or not. I should have checked when I searched for the mismatched injector last month. My aim was to spread the burn time of the fuel, lower peak pressures, but increase the average pressure after TDC...A kind of plateau (seems to be my favourite word at the moment) well that's the napkin jottings of this mad-man :o)

Concerning my pump, it's a standard TD pump for a 1985 Quantum. I have upped the internal pressure of the pump so that it mirrors the SAE graphed average as of 1982 issue [I think that's the date]. The pump had been at 20psi for 1000rpm (crank), and I upped it to 40+ 

I have the engine idling @ 750rpm, which is well under the 900 recommended for the Quantum, despite this; it doesn't shake too much, and a goal is to get it down to 500rpm. This if successful, would I'm sure up the urban mileage to something in the mid 50's which has been my goal all along. The engine will actually run at 250rpm! 

The cold start advance can be pushed with a finger tip at this idle speed into advance position, and stiff with engine off.[It's not connected to the cable] This tells me that the advance has mostly taken place once engine has started, so perhaps the correct internal pressure should be a little less for the 1985 pump...

Having said that, if there is indeed a magic timing point, this particular pump would follow it's correct advance with or without the advance pulled, but again, this would be contrary to the theorists including those who wrote the SAE paper who think advance should only become ineffectual @2000rpm or I guess a weakening advance spring!
Mark

When I used to run veg oil, I used the Quantum GL5's headlight washer bottle that held something like 20 pints of oil within 1ft of the pump, so no pump pull-up issues. 
Just coil a pipe round the upper rad hose...




Subject: RE: rebuild?    RE: [Vwdiesel] GTD Spec/ My Quantum

HI Mark;

My TD pump on my 1.6 Turbo engine in my 1990 VW Fox Wagon is set at about 1.0 so a .57 is a lot of difference. For a hone did you use one with rectangular stones or did you use the one that looks like a chimney brush with stone balls on the ends. I can easily try a .57 pump timing but I’m pretty sure I will have to move the fuel screw in or out.

Thanks for the tips. I build and rebuild my diesel engines so I am not afraid to try something new or different or both. At the present time I have a two tank setup with a plate heater and a fuel filter heater on my second line. I switch from diesel to alternative fuel when the engine gets to operating tempatures and back to diesel before I park. It is basically like a waste vegetable oil system except that I use waste motor oil that I have cleaned and de-watered by running through a hot water heater and a centrifuge that is supposed to clean to one micron. I recently did a 2100 mile trip in my 1983 Mitsubishi Mighty Max 2.3 turbo diesel pickup that used just 12 US gallons of pump diesel the rest was used motor oil. I usually don’t post my oil adventures on the list for fear the Gov might complain about my fuel.

Brian Decker











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