Quieter engine on SVO is not better

For discussing the modifications needed for diesel vehicles to run with 2 tank veggie oil conversions.

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Postby SunWizard » Mon Jun 02, 2008 4:35 pm

Here is another good crossbones post on this same subject:
"a "quiet engine's" autoignition is taking place after piston dwell so you are not going to have a "KNOCK"
Cetane and Diesel Knock
YVORMV - Your veg. oil results may vary.
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Postby Welder » Tue Jun 03, 2008 2:52 pm

hheynow wrote:
David wrote:I was of the impression that computer controlled engines were easy to change timing on by just adding a chip and plugging into a laptop.


I really need to call the fellow who burned my chip and find out if he can re-burn it to give me an SVO setting.


Why not have two seperate timing chips and a simple selector switch?

The manual switch could even have a temp switch so a guy could just leave the manual switch set on SVO and when the motor warmed up, the thing would automatically switch over to SVO automatically. The manual switch would then only act as an over-ride switch in case the veggie tank was empty.
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Postby denson » Tue Jun 03, 2008 5:51 pm

I have heard somwhere that newer computer controlled engines can advance or retard timing based on fuel temp. sensors. Does anyone know if this is true?
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Postby coachgeo » Tue Jun 03, 2008 7:52 pm

denson wrote:I have heard somwhere that newer computer controlled engines can advance or retard timing based on fuel temp. sensors. Does anyone know if this is true?
I have heard this too. Think I've read some fool this sinsor on VW's to change timing.
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Postby canolafunola » Fri Jun 06, 2008 9:41 am

SunWizard wrote:
hheynow wrote: those of us with computers can't adjust our timing as easily as those with mechanical controls can.

Many of the mechanical pumps are not easy to adjust the timing either.


Interesting thread. Lots of good points and counterpoints. I agree mechanical pumps are not easy to adjust. My Bosch VE pump developed a leak last winter (a drip every second or so and made a mess of caked up poly, good rust proofing agent though). I bought a re-seal kit and pulled the IP about a month ago to replace the 2 advance piston o-rings (what I suspect was leaking). I marked the pump before pulling it and advanced the mark by approx 1/16" when re-installed. I can't say whether it got louder or more power since whatever changed was too subtle for me to tell, but one thing that was very noticeable was the big decrease in the amount of smoke and smell of VO from the tailpipe at idle. Anyone know how much 1/16" advance translates to degree BTDC on a Bosch VE pump? I wish I have the equipment to measure the timing. I was thinking of buying a piezo sensor, make a clamp for it for the injector line, hook it up to my old oscilloscope and use the scope to trigger an old zenon timing light. I think this is do-able. Now you got me interested I may look into it again.
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Postby coachgeo » Fri Jun 06, 2008 12:16 pm

We are getting into some detailed areas. Nothing wrong with that. Its GREAT. We just need to know we need to think detailed too.

For example it is my understanding that there are even on the mechanical IP's like the infamous MB 617 motor's IP, that in affect will adjust itself internaly according to viscocity while on the newer computerized motors there are sensors that are involved that will tell the computer to adjust timing to a degree.

So again we need to understand these points; per engine type, as we look into changing timing settings.
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Postby WD8CDH » Mon Jun 09, 2008 10:50 am

I have noticed quieter engine operation with very small amounts of WVO that would be too small to change the cetane enough to change the knock so I suspect that quieting the engine comes from not just ignition timing but also flame propagation (and of course lubrication).
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Postby Performance Plus WVO » Mon Jun 09, 2008 5:44 pm

I am under the impression that you advance a diesel engine by retarding the timing. Am I incorrect in this thinking? Could a guy run a hot lead to the cold start advance to get to the point where we need to be. Does any one know how many degrees that will get you?
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Postby coachgeo » Mon Jun 09, 2008 7:06 pm

Performance Plus WVO wrote:... Could a guy run a hot lead to the cold start advance to get to the point where we need to be. Does any one know how many degrees that will get you?
How many vehicles have electric cold start advance mechanisims?
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Postby denson » Mon Jun 09, 2008 7:31 pm

I think my 05 f-350 and 05 Excursion do. Thought it was a block heater at first but it doesn't stay on that long. When you first turn the key (not all the way to ignition) a little light comes on in the shape of a coil for about five seconds then goes off, then you start the engine. I could be totally wrong, anyone?
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Postby John Galt » Mon Jun 09, 2008 8:27 pm

That could be the glow plugs on an Indirect Injection diesel or the glowscreen on a Direct Injection Turbo diesel engine.

Engines with computerized controls can change the injection timing.
Last edited by John Galt on Mon Jun 09, 2008 10:00 pm, edited 1 time in total.
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Postby Performance Plus WVO » Mon Jun 09, 2008 9:16 pm

IDI Fords with DB2 IP as well as 6.2 and some 6.5 GMC products have cold start advances. Whether a guy can run them in advanced position for a long duration that remains to be seen. Whether they advance enough I dont know how to test it. My Ford has diesel knock all the time WVO or not. My Mercedes on the other hand does get quieter but I have a strange feeling some of that issue may be adjusted through the ALDA.
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Postby WD8CDH » Tue Jun 10, 2008 5:41 am

My '80 Audi had a mechanical cold start advance.
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Postby John Galt » Wed Jun 11, 2008 12:55 pm

There's a discussion on quieter running relative to biodiesel at
http://biodiesel.infopop.cc/eve/forums/ ... 4551080452

This message from "Johno" is very informative.

Near top dead center the piston doesn't move much relative to the crankshaft rotation. However, you're description of the extra fuel sprayed is right on. By the time petro-diesel ignites, there's already a bunch mixed with the compressed air, and it all goes off at once, creating a ball of flame and a pressure spike. That creates most of the rattle you hear. Since the injector continues spraying for a while, and since it's sprying into the ball of flame, it doesn't make any more noise. Biodiesel (or any other high cetane fuel) ignites sooner, so less fuel has mixed with the hot compressed air, so there's a less dramatic pressure spike, so the rattle is quieter.

My Rover injectors have a pilot spray jet, next to the main injector. Part of the purpose of pilot injection is to gently ignite the fireball in preparation for subsequent main injection. It's considered old technology now that electronically controlled injectors are able to pulse injection charges that meter minute "pre-ignition" quantities into the cylinder.

In theory, since biodiesel ignites sooner, the timing can be changed (retarded) to move the peak pressure closer to the sweet spot. To counter balance that theory, the biodiesel may burn slower (according to some old reports), so the timing should be advanced to move peak pressure to the sweet spot. In reality, changing injection timing shouldn't be done without means to measure the cylinder pressure cycle. Guessing on diesel injection timing is one classic way to ruin an engine.

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Quieter engine on VO is not better

Postby td2dv » Sat Jun 14, 2008 8:21 am

'The test of the pudding is in the tasting'
It would be interesting to have an exhaust gas analyzer in the tailpipe and see what would result from small changes in pump timing. The VERY interesting exercise would be to do this with different blend mixtures.

'78 240-D, WVO/10%RUG

[Moderator note: not sure if it was intentional to yell or not, but I changed the text size back to normal, Good info stands on its own, yelling not needed]
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