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Engine Specific Info and Questions => TDI Engine -General Info => Topic started by: voodoo on November 29, 2008, 02:43:49 pm
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there is no substitute for a real 1.9 tdi
reinventing the wheel with inferior parts is a bad idea
influencing others to waste time money or effort on a bad idea would be wrong for me to do so I removed the post.
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Interesting idea.
Probably the very first thing to do is a bit of math: will you be able to get in the neighbourhood of 20:1 compression with that configuration ? Diesels have a very long stroke and the pistons actually protrude above the block deck at TDC, all part of getting to 20:1.
Some bigger mechanical plumbing issues to look into:
- does the ABA block have holes in the right place to mount the IP bracket
- will the standard diesel IM shaft fit the ABA block (diesel IM pulley runs on the back of the timing belt and so the gear that drives the oil pump is cut in the opposite direction)
The above are deal-breakers... and perhaps others will think of more.
There's some design things to think thru as well:
- the TDI pistons have a very specific cut-out for proper combustion
- dunno if ABA pistons/rods/crank/mains would stand a 20:1 pounding for long
Definitely an interesting idea... looking forward to what others come up with here.
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0000
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I dont think the bloc, piston and rod last long.
Have you really look at a Diesel piston compare to gaz?
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because the 1.5L diesel is mostly a converted gas engine with different pistons and head and 23:1 compression, same 11mm head bolts and if that works then I cant see why a more modern engine would not work as well.
There's a great paper floating around from the originial dudes that worked on the VW diesel design that speaks to the considerations made as they worked this... I'll see if I can dig up a working link.
The block looks the same because they wanted to reuse some of the bulk casting molds and some other gasser parts (oil pan, etc) but there are many many differences as well.
In any event, everything else is moot if you can't get somewhere around 20:1 compression... I'd recommend you start with the math and see if you can get it to work.
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0000
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Here are some of the 'issues' that I can come up with off the top of my head for this project:
1. Diesel EGTs can reach 1200+ F for sustained periods of time, are the ABA pistons capable of living in those conditions?
2. Would the thrust that is developed during the power stroke be too much for the con rods, crankshaft, bearing webs?
3. Since the CR of the ABA is around 10:1 and TDI's run around 19:1, can the ABA block withstand a doubling of the cylinder pressure?
These are just a few things I came up with quickly.
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In case Search leads someone here some day... here's a thread with the original SAE design paper that explains lots of what the original designers of the VW diesel thought thru:
http://www.vwdiesel.net/phpBB/viewtopic.php?t=17187
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Don't forget the 11mm head bolts were barely acceptable for a 1.5. I predict major HG leaks. The TDI pistons are developed for swirl. You will get crap burn with gas pistons.
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Thanks Vince, I just read that SAE paper through!
What size head bolts do TDI's use? The SAE paper stated that the swirl chamber design distributes combustion pressure much more evenly than DI.
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TDI's use 12mm
that paper is cool! explains how the governor works as well as many others!!! thanks!
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0000
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I wonder if you could do an over bore and install TDI pistons in your block?
I cant remember what the TDI bore is but I think it's close to the ABA.
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which is stronger ARP 11mm head studs or OEM grade 10.9 12mm diesel stretch bolts?
the last febi brand set of 12mm bolts I bought came from taiwan
are the people who bought ARP 11mm head studs complaining about constant head gasket failures after the installation of ARP studs?
the end goal for this is a 50 hp no turbo diesel with 17:1 compression and any engine with a TDI head.
you could try buying some prothe TDI pistons to help keep the cost down, but thats the only way i see this working...
i personally think you will have better luck trying to get the 1.6TDI idea of his working.
i could somehow see the injector burning a hole into the ABA pistons over time...
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....
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something i said?
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wtf?
:roll:
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Another one of "Those" threads.
"Im taking my ball and going home"
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what the frick is this?
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........................ ....... :cry:
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there is no substitute for a real 1.9 tdi
reinventing the wheel with inferior parts is a bad idea
influencing others to waste time money or effort on a bad idea would be wrong for me to do so I removed the post.
hmmm... this is the first time reading this thread. Was this about converting a gas block to run diesel?
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there is no substitute for a real 1.9 tdi
reinventing the wheel with inferior parts is a bad idea
influencing others to waste time money or effort on a bad idea would be wrong for me to do so I removed the post.
hmmm... this is the first time reading this thread. Was this about converting a gas block to run diesel?
yea... pretty much