I noticed this while driving around. I'm used to hearing my engine on Diesel. Now that I'm on a two tank system I can hear a difference once I'm over to grease. It sounds like it's more advanced than when it's on Diesel. It's got a much more diesel truck clack kind of sound and a little noisier when I step on it. It literally sounds like Advancing the timing.

I've heard that the cold idle advance does something to the return pressure on a Stanadyne Injection pump to create advanced timing. I wonder if the thicker V.O. is causing something similar. It really does sound advanced.

Wondering if anyone else has a similar experience?

I haven't noticed any change in my 87 f250, but I'll try to listen.
Mike

The HPCA (housing pressure cold advance) actually drops the housing pressure to zero. If your timing seems to advance when your add bio-diesel, I would check the viscosity of your fuel.

Timing is determined by the difference between transfer pump pressure and housing pressure. The HPCA valve keeps the housing pressure constant (about 3 to 4 PSI) so if the fuel is too thick, then transfer pressure will rise and cause the timing to advance.

Transfer pressure advances and housing pressure retards timing. The snubber relief valve (used to adjust for viscosity) should maintain transfer pump pressure but it has it's limitations. In my 6.2, bio actually quiets down the engine. That would indicate a slightly retard situation but have seen both happen. It depends on the engine.

Bill

My97 6.5T GMC sounds quieter on Filtered WVO,50-50% D2

Thx R0n

My 6.2L sounds the same on diesel as it does on WVO. Unless I forget to turn on the feeding lift pump or something Do you notice a fuel pressure change?

On the www.ford-trucks.com pre-powerstroke (pre-94 or 95)forum, they talk about a method of timimg by ear where you advance the timing until you get the beginning of a powerstroke rattling at start-up that should go away when warm. I do notice this on my 87 f250.
My question is: does heating our oil to 170+F cause our engines to run to retarded (pc=timing challenged) and if so is this bad?
I don't have a fuel pressure gauge to know what if any changes occur with heating.
Mike

I have been adding around 1 gallon of diesel to 30 gallons of SVO in my 92 ford. I started doing this based on this same topic discussed here and on the burnveg.com site. What I gather is that adding diesel helps keep the timing on SVO near the same as on diesel. I have noticed that I now get the typical diesel "knock" with the blend which is a good thing. I know many people claim that one benefit of running SVO is that their diesel is now 'quieter'. I do not believe that is a benefit based on the information I have been learning about regarding a diesel engine and timing.

quote:

On the www.ford-trucks.com pre-powerstroke (pre-94 or 95)forum, they talk about a method of timimg by ear where you advance the timing until you get the beginning of a powerstroke rattling at start-up that should go away when warm. I do notice this on my 87 f250.
My question is: does heating our oil to 170+F cause our engines to run to retarded (pc=timing challenged) and if so is this bad?

That's an interesting interesting question.

You should PM Dana Linscott and invite him to resond to it.

He has significant experience with IDI fords.

Thats how I set up my GM 6.2. Advance it till it sounds like a Ford then back off a couple of degrees.

Bill

my 96 6.5td definately sounds a lot different when on oil, it is a lot quieter, idles super smooth and even at 3500 rpm it purrs, not sure if its normal, but thats how she goes for me, it does make a hell of a clatter if the oil is not hot enuf yet though, like at 100f it doesnt sound nice, but at 140f and up it sounds good. i guess thats what i get for being in a rush to switch over. but thats what she sounds like for me, just my 3 cents.

I also have a 1996 6.5 Suburban, and it's smoother and quieter on VO, as the person above describes.

Not to hijack the thread, but if the engine is quieter is that not a possible sign the timing is off?

My two cents - my '94 6.5td is also much smoother and quieter on WVO. I too thought that was a good thing. If not, someone please advise on how to improve the performance.

See this thread for some details about quieter is not better on WVO.

quieter is not always better

Very informative - thanks for the link!

In my experience around diesel engines and WVO blends I have found that when the engines are cold, the clatter is more prevelant on the blends than diesel fuel.

Years ago, on a 2 cycle Detroit diesel, I discovered that if you overfueled the engine, you could induce detonation, due to puddling fuel auto igniting spontaniously.

In my later experiments with WVO blends, I've found that when the engine is cold, puddled fuel will spontaniously ignite under anything more than idle power. The extra "clatter" is detonation. Waiting until the engine has warmed up doesn't allow the fuel to condense on cold surfaces within the combustion chamber and there is no "extra" clatter.

I run single tank unheated systems in the various vehicles and haven't altered the injection timing from stock specifications.

While diesel engines are more robust than their gas counterparts, detonation can damage some internal components if allowed to continue.