Try to start Frankenmotor for the first time..... - page 2 - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.
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#15 by theman53 on 17 Jul, 2011 15:39
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sure 5 days. The longer it sits the better it will break stuff down, but I would think a couple days. Run it right through the pump, it will not hurt anything.
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#16 by RadoTD on 17 Jul, 2011 17:58
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I have no clue what's going on, but I want this thread to show up in my new replies link.
I hope you figure it out, that is all... -
#17 by regcheeseman on 18 Jul, 2011 02:09
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What's the history on the pump? Any chance it's 180° out? Have you tried different accelerator lever to shaft orientations? Diesel Purge is better than ATF.
It was a working AAZ pump body with and unknown TDI head (which looked fine)
There is the possiblity that it's 180 out, but highly unlikely. I will check though.
I took the top off the pump last night, everything looked right. I sucked out the diesel and checked the spill valve was moving (all fine), then I pump ATF through the inlet until it brimmed - it'll sit like that for a bit.
A pressure feed will be the first thing I try when it goes back together.
If that fails I've two spare GTD pumps on the bench. -
#18 by Alcaid on 18 Jul, 2011 02:13
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You kept the AAZ camplate i hope?
A friend of mine put a TDI head 180deg off in a mtdi pump, there was absolutely no chance to get that thing started at all. Not even a hint of combustion. -
#19 by regcheeseman on 18 Jul, 2011 02:16
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Yep AAZ camplate which was seemingly identical to the TDI one.Quote
A friend of mine put a TDI head 180deg off in a mtdi pump, there was absolutely no chance to get that thing started at all. Not even a hint of combustion.
It starts well. -
#20 by Alcaid on 18 Jul, 2011 02:28
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AAZ camplate has longer duration on the lobes than TDI, I've compared them visually myself.
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#21 by Mark(The Miser)UK on 18 Jul, 2011 04:04
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Yep AAZ camplate which was seemingly identical to the TDI one.
QuoteA friend of mine put a TDI head 180deg off in a mtdi pump, there was absolutely no chance to get that thing started at all. Not even a hint of combustion.
It starts well.
So engine is good, and problem is in pump. How much diesel do you get circulated for a minute of idle? Rig up a simple pressure gauge to read the internal pump pressure. I guess you can do this after your ATF experiment.
Having said all that , engines good, and that cloud behind you tells me that there is no shortage of fuel. So I now think it is somehow a gross error in timning. Try hand cranking with g/p's disconected [merely to save battery] and unnnnnnnnnnnnnnnnnnnnnnnbolt #1 fuel line at the injector, and look for coincidence of diesel pulse with
1) TDC and including
2) #1 compression stroke which means cam cover off...
Mark
Failing that help your local arable farmer with some crop spraying
EDIT I need to shoot my over keen 'n' button...
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#22 by regcheeseman on 18 Jul, 2011 04:48
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How much diesel do you get circulated for a minute of idle?
How much should I get circulated?
Back to the timing issue, it can't really be a slight timing issue, because I've wandered the timing about all around the '1.2mm sweet spot' and it only gets worse.
I think 180 prob is looking likely.... -
#23 by Mark(The Miser)UK on 18 Jul, 2011 07:05
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I think if you had about a pint that would be sufficient, but don't quote me.
Have you made up an adaptor for internal pump pressure? For a 107A pump I believe it was about 45psi at idle, but my pump was working at 18psi.
After some naval gazing I think that may have been better for my pump due to lower pressures needed for correct dynamic advance.
Here's my modified out bolt to allow both the out banjo, and the gauge banjo:
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#24 by regcheeseman on 18 Jul, 2011 09:43
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Tap a fitting in the top of the banjo would do it yes? VW quote 4 - 7 bar in their training manual.
As for the 180 issue. My running issues don't seem to match the symptoms of those that have done it by mistake in the past.
i.e. starts easy, idles smooth with no smoke and normal clatter, EGT doesn't even register on the guage (yes it does work)
i'll check it though. -
#25 by Mark(The Miser)UK on 18 Jul, 2011 09:55
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LOL 99 times out of 100, you'd be correct Andrew. Alas in this case [ie this bolt ] you are a big 1 in 100 wrong
Here's the naked bolt:
The important things to note, are the thin bolt head. Coupled with the mere 8mm gauge banjo, this gave me 3 whole turns of thread to hold the outbolt. Note the rough grinding of the outbolt by the return flow hole. This allowed the pump's banjo to travel up the bolt and still have the return flow entering the banjo.
The normal banjo seals against the bolt head with the seal I made. A second seal goes between the two banjos.
This second seal grips the bolt on the start of the unthreaded part, and actually tucks into a slight chamfer on the gauge banjo, and gets tighter as bolt nipped up.
The other side of the gauge banjo actually seals on the fine/machined face of the pump without a copper washer. [trying to pinch every inch, or should I say thou, to enable my standard, but spare outbolt to be used].
The clever bit IMO is that the internal pump pressure travels up the threads and enters the gauge banjo. Not a great volume, but we are talking static pressure, and minor leaks are overcome by the pumps massive reserves.The thread travel may supply potentially more than the true outlet.
It works, but whilst 3 turns are enough for testing purposes I would not trust it for a permanant fixture, which I don't think is needed in any event.
My proudest point in this design, is not the hand ground banjo, nor the hand filed bolt head, but actually the two seals which are made by using discs of those plastic milk bottles that we recycle weekly! The polythene melds round the bolts perfectly. If you click on the bolt pic you will see behind it's head the second [first sealing to the bolt like a skin...
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#26 by Mark(The Miser)UK on 18 Jul, 2011 10:18
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Tap a fitting in the top of the banjo would do it yes? VW quote 4 - 7 bar in their training manual.
I think you basically have a good engine, and it will burn anything it can, thus it will start from the vapour still hanging around when compression stroke comes back around.
As for the 180 issue. My running issues don't seem to match the symptoms of those that have done it by mistake in the past.
i.e. starts easy, idles smooth with no smoke and normal clatter, EGT doesn't even register on the guage (yes it does work)
i'll check it though.
As the fuel is not igniting properly because it is seeing lower pressures on the down stroke, it is basically lining the chamber walls with diesel.
Increasing the volume means more is going out the exhaust as fuel steam.
Engine is kept running by the dregs that are evaporating off the walls at the compression stroke.
I suppose if you 'exhaust gas recycled', it would shoot off down the road.
Didn't Hagar claim he'd started a diesel in reverse
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#27 by Mark(The Miser)UK on 18 Jul, 2011 12:12
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Mark, unless it is permanently installed, then your setup is not accurate. It is blocking the normal flow up the threads and measuring the pressure when flow is only through the orifice. Once you replace your setup with the actual pump out bolt, the flow will be both around the threads and out the orifice and consequently lower than your setup would display. While you might consider it clever it isn't functionally accurate.
How much flow do you think will run up a bolt that is fully inserted? IE what is the thickness of the wall of the pump?
I asume that in normal circumstances, the bolt does not penetrate much beyond the wall, therefore the bolt with only one banjo on, is inserted fully and penetrates to the depth of abot 11 or 12mm, which is about 8 threads.
If the metered release hole and the thread gap are of similar size [thread data is available in books ], then the thread capilary tube stretched out would be about 25 times 8mm, compared with perhaps 2mm metered hole depth.
I make that about 100 to 1 difference in pipe length, and so maybe 1% flow rate up the threads, I think that's right. If flow rate is proportionate to resistance. Either way it's such a small flow loss that the vane pump won't even know of the pressure gain...
Better than 1% error is my submission
If the elusive pedestal is not available then incorrect threading would also block the flow. Or does the original one block the flow too
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#28 by Mark(The Miser)UK on 18 Jul, 2011 14:53
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The flow rate through the thread is far less; High Reynolds No. stuff. I was working it out as I wrote, and I said even if it was greater, it wouldn't matter.The thread travel may supply potentially more than the true outlet.
Unless you mis-posted, you initially state that the flow through the threads may be greater than that through the orifice in the bolt.If the metered release hole and the thread gap are of similar size [thread data is available in books ], then the thread capilary tube stretched out would be about 25 times 8mm, compared with perhaps 2mm metered hole depth.
I make that about 100 to 1 difference in pipe length, and so maybe 1% flow rate up the threads, I think that's right. If flow rate is proportionate to resistance. Either way it's such a small flow loss that the vane pump won't even know of the pressure gain...
Better than 1% error is my submission
Are you saying that the flow rate through a pipe of consistent diameter is directly proportional to the pipe's length? A 1 meter long pipe will flow 100 times that of a 100 meter pipe of the same diameter?
Regardless, I'm glad you think it works well enough for you. I wouldn't recommend that system to anyone else. I'm done with this conversation.
I'm not saying it is 100 to 1 attenuation, but that it might be, especially where we are talking small bores and high viscosity.
Either way my way works, and what you stated I was effectively doing is incorrect:
Andrew said
"That looks like you are trying to read internal pressure from around the perimeter of the "out" bolt. If that is what you are doing, then it will not work. Once the fuel passes from the center of the bolt into the banjo it is no longer pressurized. You are reading the pressure of the fuel returning to the tank rather than the internal pressure of the pump ."
If you can't answer my polite question of what you think the error on the pressure will be to a vane pump that can pressurise over 200psi and maintain an excess flow rate beyond combustion of perhaps a couple of litres per minute, then don't bother. My method is an alternative for testing, it works and outbolts are as common as nuts on a tree, unlike pedestals and I'd recommend it to anyone and everyone.
Do you end all conversations that you butted into with "I'm done with this conversation" That's a bit 'durrish' really as you may have further useful and constructive things to say... Or not
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#29 by regcheeseman on 18 Jul, 2011 14:56
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Didn't Hagar claim he'd started a diesel in reverse
To lighten the mood, an anecdote.......
Back in the day when I was 16, we all had mopeds and would hang around youth stylee looking cool. One of the lads could bump start his DT 50 in reverse.
He would do it, blip the throttle a bit and ask a unwitting bystander if they'd like a go on his bike - most would jump at the chance.
They'd eagerly rev the bike move their weight forward to couteract the awesome 49cc thrust and dump the clutch.
Normally the bike would lurch backwards and the pilot would catch a petrol tank in the family jewels before taking a header over the bars.
Everyone would just fall about laughing.
meanwhile back in the here and now....
I've got a spare, joke LDA AAZ pump sat on the bench, completely standard. Shouldn't take long to slap that one in....
