Teflon tape is perfectly fine in this application. I have used miles of the stuff on fittings under everything from 50-60 inches Hg vacuum to 10,000 psi with no problems whatsoever. If you have a problem with tape, it is either because you didn't use enough or you wrapped it the wrong way.

Lietuviai, it certainly sounds like you have a restriction somewhere in your line. Do you have a pressure/vacuum gauge on the line? If not, you should. Change filters first, as that is most likely the choke point. Otherwise, look for kinked/collapsed lines, plugged tank pickup, etc.

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Keep everything as simple as possible-but no simpler--Albert Einstein

I willing to agree that there is probably some sort of restriction somewhere since I have the lines running inside the car. The lines that are visible are fine but its the area running behind the rear seat and the up throught the firewall are suspect but I did my best to make special "anti-kink" sleeves in those areas.
I'm wondering also if the lift pump could be failing. The WVO is a little thicker than diesel but no much though. The car runs fine when switching to diesel, in fact instantly upon switching it and hitting the accellerator it shows no signs of trouble then. Its only when on the WVO does it stumble when trying to accellerate. So I'm assuming my filters are fine.
It sometimes feels as if I'm driving a 240 but at least the 240's don't stumble.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

Read about KISS and Occam's Razor with regards to cavitation and WVO.

The one modification I made to my car was an electric fuel pump back at the fuel tank. WVO is thick and difficult to move by vacuum, creates problems. These problems are compounded if you have a filter in the suction side of your feed pump. A flip of the switch goes a long way toward isolating problems and sometimes makes the difference in driveability.

I have previously posted information on these ideas.

Trying to speculate what your problem is becomes sort of like throwing darts in the dark without knowing many more details of your system. The presence of air bubbles seems to indicate the restriction is on the vacuum side somewhere, so if you are using the stock filter and plumbing, that seems to eliminate the filter. It is certainly possible your lift pump is going by the way side, but there again, the air bubbles indicate plenty of vacuum is present (thus the lift pump is working okay). If your fuel pickup for the WVO tank has a screen, by all means check that. What size hoses and fittings are you using? I guess there is a chance a piece of crud is stuck in a fitting somewhere.

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Keep everything as simple as possible-but no simpler--Albert Einstein

I'm running 3/8" line. I only see bubbles on the return line for now. I have seen some bubbles on the suction side but they are few and miniscule.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

It has to be drawing air into the line somewhere on the vacuum side of the pump. Any leak after the pump is going to be oil out, not air in. I wonder if it is possible for a pin-hole in the diaphragm of the pump to allow air to be drawn in. Might be worthwhile to check the oil level to see if it is higher than normal, suggesting fluids are leaking past the diaphragm into the crankcase. I not familiar with the primer pump situation on the 617's, but is it possible it is pulling air there?

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Keep everything as simple as possible-but no simpler--Albert Einstein

*watches from the sidelines*

Let me know if you need anything...I am always an email and drive away..

Brandon

An IP?

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

Are you using that clear high pressure vinyl hose like grease car uses and the hose on my website?

If so that is likely your problem. I had the same problem and it turns out that hose is to hard to form a molded seal over the ribbed style barbs like a rubber or silicon hose would.

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1984 300D / The only Benz I have

Completed weekend projects

1. R/R front crankshaft seal
2. R/R nearly the whole vacuum system
3. Converted to WVO www.greasemachine.com
4. Upgraded to electric power locks
5. Upgraded and rewired stereo/amp/speakers
6. Installed 2.88 differential

Baloney!!!! I've used that pvc braided hose for years on 3 veggie cars. Makes an awesome seal as long as you use 1/4" hose with 1/4" barbs, 3/8" hose with 3/8" barbs. The hose is made to seal over steel barbs or we'd all be up to our necks in water.

Problem is, many people converting are too lazy to make the barb and hose sizes match. Why? Because the Pollak (6 port only) switcher valves have 3/8" barbs and the car's filters/pump have 1/4" barbs. You can buy the conversion adaptors from HELP! products at your local parts shop. The 3 port Pollak doesn't have this problem.

Cheers,
Yoko

Just sharing my experience with the hose.

At first I was to “lazy” and pushed a ¼” hose into the 3/8 hose so I could connect it to the 1/4” barbs. It leaked and eventually popped off. I then used the correct adapters. It still leaked. I still couldn’t get a good seal, so I replaced the hose with standard 3/8 fuel line and ¼ clear Teflon (so I could watch for air bubbles and know when it was perged).

Works great and sealed tighter than a frogs ass hole!

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1984 300D / The only Benz I have

Completed weekend projects

1. R/R front crankshaft seal
2. R/R nearly the whole vacuum system
3. Converted to WVO www.greasemachine.com
4. Upgraded to electric power locks
5. Upgraded and rewired stereo/amp/speakers
6. Installed 2.88 differential

I won't use the PVC hose on any car application, but I do use it occasionally for various oil transfer hose applications. The biggest problem with it I have noticed is after prolonged exposure (less than a year, usually) to the oil, it gets really hard and almost brittle. Then any vibration can make it begin to leak around the barb.

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Keep everything as simple as possible-but no simpler--Albert Einstein

I'm using 3/8" polyethylene hoses with 3/8" barbs+hose clamps. I haven't noticed any leaks on the return side as this is where the pressure would be. I have noticed some wetness at the bottom of the Pollack 6 port diverter today. I'm suspecting I may have a defective diverter. I'm going to pull it this weekend and get a better look at it. At this point I'm planning to just run straight WVO in the main tank until I get everything working right. It starts OK on cold WVO with only a few extra cranks.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

Hehe Still looking..

Before changing parts how about doing a little diagnostic work? It is quite simple to install a vacuum gauge inline at the IP, then move it pre-filter then to the tank outlet. This will tell you if you have a restriction and/or the WVO is too thick. A little time spent figuring out what is wrong beats a lot of time changing parts and not curing the problem. RT

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When all else fails, vote from the rooftops!
84' Mercedes Benz 300D Anthracite/black, 171K
03' Volkswagen Jetta TDI blue/black, 93K
93' Chevrolet C2500HD ExCab 6.5TD, Two-tone blue, 252K