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Author Topic: VW TDI - convert to one cylinder?  (Read 22511 times)

jzeeff

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VW TDI - convert to one cylinder?
« on: August 29, 2009, 04:25:19 PM »

Old VW TDI diesels are available at reasonable cost and are fuel efficient at around 1800 rpm.  But they still produce more HP than I need.  Is it possible to remove 3 of the cylinders and run on 1 without vibrating itself to death?     


compig

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Re: VW TDI - convert to one cylinder?
« Reply #1 on: August 29, 2009, 05:18:35 PM »
All cylinders would need the rods and pistons intact for the engine balance to be preserved. The unused cylinders would need the injectors removing so there would be less pumping loss. The pump feed's to the unused injectors would need to be disabled or perhaps just returned to the fuel tank. The valves could be removed to reduce this even further and this would also reduce frictional losses in the valve gear.
« Last Edit: August 29, 2009, 05:31:40 PM by compig »
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oliver90owner

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Re: VW TDI - convert to one cylinder?
« Reply #2 on: August 29, 2009, 06:43:20 PM »
I would prolly remove 2 pistons and rods leaving one to reasonably balance the working pot.

Remove compresion rings, but leave the oil scraper to just give the piston in the unused hole some stabilisation in the bore, drill holes in the piston crown.  Remove valve lifters from 3 pots.  Presumably injection pump needs to pump at zero pressure back to tank or pump inlet for three outlets.

Might need to lose weight from the working piston to achieve better balance.

I would have thought max torque would be somewhat higher than 1800rpm, so not on the best part of the curve.

Don't think the turbo is gonna be usable!  So pump would probably over-diesel the engine.

Cooling will be c**p.  Oil to big end drillings will need to be plugged.

It would need a governor. 

Overall, I reckon a decent single cylindered engine would be a better bet.  Or even running the VW slower and not bother with taking pots out of use.

Regads, RAB


Tijean

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Re: VW TDI - convert to one cylinder?
« Reply #3 on: August 29, 2009, 07:03:57 PM »
There are also issues with intake and exhaust manifolds. The TDI I have is very dependant on computer control and you would have to find a way to regain control of pump manually. The turbo could well be eliminated. Motor mounts could become a problem as your power pulses would be a lot more noticeable with the missing cylinders. It could be done but a lot of problems to overcome. They pull very well down to below 1500 so direct coupling to an 1800 gen would be ideal for that engine intact. Since most of your friction would be the same, I doubt you would save a lot of fuel. It is one efficient engine and you might not gain by neutering it!

Pulling a crated 10-1 lister on a trailer 400 miles behind my car knocked me back to 55 miles to the imperial gallon. If you only generated 5 or 7 K and were willing to go to a belt drive gear up I bet you would beat the pants off any lister for fuel cost per KWH.
Frank

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Doug

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Re: VW TDI - convert to one cylinder?
« Reply #4 on: August 29, 2009, 07:33:38 PM »
Rob built a gen set with an older VW Rabbit engine. I believe they were rated at 58 hp peak.....
I think they would be a better choice and reliable its also a precup engine.

If you asked about 20 Hp of it at 1800 rpm I think that would be a very reliable alternative
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rcavictim

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Re: VW TDI - convert to one cylinder?
« Reply #5 on: August 29, 2009, 08:51:58 PM »
Rob built a gen set with an older VW Rabbit engine. I believe they were rated at 58 hp peak.....
I think they would be a better choice and reliable its also a precup engine.

If you asked about 20 Hp of it at 1800 rpm I think that would be a very reliable alternative

Doug is right.  I put together a plant using a 1.5 litre, 4 cyl diesel IDI from a 1980 Rabbit.  I run it at 1800 RPM and it makes 9 kW of E, 3 kW from each of three phases.  I can not get any more power out of it at 1800 RPM so that suggests I am making about 18 HP.  My alternator is similar to an ST head but 3-phase and puts out 480 VAC.  I use a large xfmer to reduce this to 208 Y and 120 volts per leg.

I started out with a similar 1994 Jetta engine at 1.6 litres.  Unfortunately this engine had insufficient oil pressure and massive blowby, but in the short time I had it running it seemed to make slightly more power than the 1.5L.  Either of these engines would be a good choice for a generating plant. I have a 1992 Jetta with a 1.6 TD engine in like new shape having low hours since a rebuild.  I am thinking of using that as is as a drop in replacement.  The turbo will be effective at 1800 RPM and I think it will easily make 15 kW of E.

I managed to break an eyebrow shaped piece out of the thread that holds #4 injector in the 1.5 head.  For a time I ran the engine with 3 cylinders.  Noisy as a gattling gun with the air being forced in and out of that open injector hole.  The energy needed to make that noise caused the rack to be more open than on four cylinders and fuel economy went down as well as useable power. I have a mechanical speed regulator on this plant.  I didn't put more than a couple of hours on it in that mode.  It also vibrated a lot on 3 cylinders because of the imbalance of power strokes and the lights flickered horribly. I was lucky enough to be able to arc weld with stick, the broken off piece without removing the head and it now holds an injector once again and runs great.

I do not recommend shutting off any cylinders in a 4 cylinder VW diesel.  These engines are very economical, even with all four holes lit up.

When I do not need power from the engine for shop equipment but wish to continue running it for a bit of heat and light I wedge a piece of precut hardwood into the governor linkage to the rack.  It throttles the engine down to about 1200 RPM.  Even at this speed there is enough AC that the incandescent lights hooked up and the resistance heaters all continue to put out at a reduced rate.  Fuel use in this mode goes way down.  You can get about 2-3 kW at this speed (40-45 Hz) IIRC.

I like the VW engine in that it is very much quieter than the big singles I have.  I am leaning towards the singles though for any additional plants because they cost much less in parts and rebuild time when maintenance is required.  You can buy a Changfa 1115 for what the parts and machine work on the head will cost to rebuild a VW diesel.  You can buy a Changfa 195 for what an injection pump rebuild will cost for a VW diesel.

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jzeeff

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Re: VW TDI - convert to one cylinder?
« Reply #6 on: August 29, 2009, 10:07:26 PM »
Thanks.  Here is the BSFC map I was looking at:

http://pics.tdiclub.com/data/500/ALH_BSFC_map_with_power_hyperbolae.png


20HP at 1300 rpm might be ok.
« Last Edit: August 29, 2009, 10:15:07 PM by jzeeff »

rcavictim

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Re: VW TDI - convert to one cylinder?
« Reply #7 on: August 29, 2009, 11:03:43 PM »
Thanks.  Here is the BSFC map I was looking at:

http://pics.tdiclub.com/data/500/ALH_BSFC_map_with_power_hyperbolae.png


20HP at 1300 rpm might be ok.


That page appears to be restricted for viewing ONLY BY TDI club members.
-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

jzeeff

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Re: VW TDI - convert to one cylinder?
« Reply #8 on: August 30, 2009, 12:02:19 AM »
Strange - I'm not a member. 



should also work.
« Last Edit: August 30, 2009, 12:05:39 AM by jzeeff »

mobile_bob

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Re: VW TDI - convert to one cylinder?
« Reply #9 on: August 30, 2009, 12:24:38 AM »
if i am reading that right, the bsfc is about 197 or so at 1800, but that is mechanical kwatt output

factor by .8 for belt driven genset and your electrical will be closer to 246 gr/kw/hr which isn't bad, but
not a huge improvment over some other engine driven gensets in the hp class/range of the vw ??

comments?

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jzeeff

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Re: VW TDI - convert to one cylinder?
« Reply #10 on: August 30, 2009, 01:11:53 AM »

Most single cylinder diesels are around 250-290 g/kwh before belt losses.  But I agree that it would take a lot of hours to be worth it.

http://www.changfa.com/ehibition/ehibition_default3.asp?pro_id=257


panaceabeachbum

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Re: VW TDI - convert to one cylinder?
« Reply #11 on: August 30, 2009, 02:59:46 AM »
now your making me want a v-dub enine

rcavictim

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Re: VW TDI - convert to one cylinder?
« Reply #12 on: August 30, 2009, 04:19:39 AM »
According to the TDI Club website, yes I can get to the website and forums, just not the particular page with the fuel use diaphragm, the newer VW TDI engines need to run on unleaded diesel !   :D
-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

Tijean

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Re: VW TDI - convert to one cylinder?
« Reply #13 on: August 30, 2009, 01:29:47 PM »
According to the TDI Club website, yes I can get to the website and forums, just not the particular page with the fuel use diaphragm, the newer VW TDI engines need to run on unleaded diesel !   :D

If you have access to a computer programmer you can easily make it think a lot of the needs are being met, Lol! The computer believes what it wants to hear and the engine is not too observant either. (within reason)

The newest models depending on configuration use a liquid urea injection into the catalyst but I thought sulphur was the culprit not lead.

Have never had trouble with fuel system and neither has my son on the two of his, but parts are very expensive if you do. You'd quickly know you were not buying listeroid parts.
Frank

10/1 Jkson, ST5 gen. head

buickanddeere

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Re: VW TDI - convert to one cylinder?
« Reply #14 on: August 30, 2009, 02:46:00 PM »

Old VW TDI diesels are available at reasonable cost and are fuel efficient at around 1800 rpm.  But they still produce more HP than I need.  Is it possible to remove 3 of the cylinders and run on 1 without vibrating itself to death?     



  It's a good idea, only problem is that it won't work.