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Engine Specific Info and Questions => IDI Engine => Topic started by: Alcaid on January 05, 2010, 07:45:43 am
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Hi,
The cold-start issue one gets with the Franken engines (1.6TD with AAZ head) due to the lower compression kills that option for me as I live in a cold country (Norway). Using AAZ pistons would increase displacement and compression somewhat, but would it be enough?
Are the cylinders thick enough for 79.5mm pistons? (76.5mm stock) Or even bigger oversized AAZ pistons?
The 1.6TD is running 76.5mm bore and 86.4mm stroke (1588cc total displacement)
The 1.9TD is running 79.5mm bore and 95.5mm stroke (1896cc total displacement)
The 1.6TD with AAZ pistons would then have a total displacement of 1716cc
How much would it effect compression, anyone got numbers for the volume "above" the piston stroke? (piston bowl, squish gap, pre-chamber)
Are the pistons even interchangeable with regards to wrist pin, piston height and so on?
Love to hear you opinions :)
Best Regards
Petter
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the pin height and diameter are not the same. you would have to make special rods probably. and i doubt you can bore the engine 3mm without hitting the water jacket. even if you didnt hit the jacket, i still wouldnt do it unless you threw liners in it also.
why even do this? it would be 1000 times easier to just run a straight AAZ. than to build a complete custom engine. if aaz pistons and crap fit in a 1.6 EASY, there would be more people doing it.
ok, that sounded a little rude. i know why you want to do it, cause nobody else has. but it just doesnt seem feasible. Aki-76 was running some sort of HUGE piston in his high boost engine.
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Isn't that how the 1.7L engines are made? 1.6 stroke but 1.9 bore?
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The reason I wanted to do it was because I like the response of the shorter stroke engine and I don't want a crank pulley failure. Just putting in a bone stock AAZ sound so boring :P
Is it possible to run the 1.6TD pre-chambers in the AAZ head?
Anyone know of pre-chambers sized in between that can be used?
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I think there is a thread in the FAQ covering the different precup sizes, although it may only be their volume...
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Found it, thanks:
CC's above piston and compression ratio / pre cup cc volume (http://www.vwdiesel.net/forum/index.php?topic=12633.0)
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Aki-76 was running some sort of HUGE piston in his high boost engine.
Noup.i use 1Y piston,6mm lower compression height as aaz and 1Y rods,6mm longer than aaz orginal parts.Piston size is orginal 79.5mm.Engine is not ready yet :-[
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Aki-76 was running some sort of HUGE piston in his high boost engine.
Noup.i use 1Y piston,6mm lower compression height as aaz and 1Y rods,6mm longer than aaz orginal parts.Piston size is orginal 79.5mm.Engine is not ready yet :-[
for some reason i thought you built a 2.1 stroker with some sort of huge oversize piston.
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The reason I wanted to do it was because I like the response of the shorter stroke engine and I don't want a crank pulley failure. Just putting in a bone stock AAZ sound so boring :P
Is it possible to run the 1.6TD pre-chambers in the AAZ head?
Anyone know of pre-chambers sized in between that can be used?
i hear you about the quickness of the short stroke engine, thats most of the reason im partial to my 1.5's
and about the precups, i know TD's and 1.5's use the same diameter pre cup. thats it tho, i dont think any others interchange.
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you could always talk to a company like JE pistons and get a custom set made...
maybe something like the 1.6 bore to stuff in the 1.5? sounds boring at first but what if you copy like an aaz piston?
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1.6 and 1.5 have the same bore
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you could always talk to a company like JE pistons and get a custom set made...
maybe something like the 1.6 bore to stuff in the 1.5? sounds boring at first but what if you copy like an aaz piston?
JE custom pistons = expensive ;)
I was more thinking in the direction of using used AAZ pistons or cheap a$$ prothe pistons. But if it doesn't fit, it doesn't fit :(
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I had for a while pondered the idea of boring a 1.6 block and using AAZ pistons and rods on a 1.5 crank(which would come to proper deck height) but realized that the 1.5 used smaller rod journals, which ruins it.
if it did work it would be 1.6L but shorter stroke.
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I have my thread updated and if you are patient then you can watch the lemming make the leap for you :-[ I will be doing some heavy modification though. Although you won't have to do all that I am "dry sump pan, oil res., vnt setup, meth injection, custom block heater of the 1,000 watt variety, etc." it will still be a pretty nice build. I understand your concern for cold starts but if you sit back and relax maybe I can give you some good news. My thread newly updated with pictures can be found here:
http://www.vwdiesel.net/forum/index.php?topic=22148.195 (http://www.vwdiesel.net/forum/index.php?topic=22148.195)
Good luck and don't give up on your dream,
Kevin 8)
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We have 10degF/-12degC today, so the Franken combo wouldn't exactly be ideal to say the least :P (Good thing I have my PD150 4Motion Golf for winter fun ;D)
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We have 10degF/-12degC today, so the Franken combo wouldn't exactly be ideal to say the least :P
Itīs been -32C for few days, even stock TDI wont start :(
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my car started no problem in -40*C. Mind you I have a block heater an oil pan heater and a battery blanket. :P
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what is your setup though? is it the frankenmotor? and since when did we start calling it that, not too sure I would want something called that sitting in my engine bay :o JK I plan on running a special oil heater in my reservoir, and dual batteries mounted in the trunk for double the current output, as well as the special 600w or better block heater. 8)
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what is your setup though? is it the frankenmotor? and since when did we start calling it that, not too sure I would want something called that sitting in my engine bay :o JK I plan on running a special oil heater in my reservoir, and dual batteries mounted in the trunk for double the current output, as well as the special 600w or better block heater. 8)
this forum has been calling them franken engines since before you were around here...
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just for reference, JK means: "joke" no intention of offending anyone or thread jacking.
thanks,
Kevin
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means just kidding
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Bringing an old thread to life just to add to it that there is OEM pistons that will give the 1.6TD the 1.7litre displacement :)
Pistons are from the 1.7D KY engine with the same deck height and wrist pin size as the 1.6TD
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yea, but are they even available in the USA?
i thought people were just using 1mm o/s pistons to get a 1.7D?
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KY is pretty rare everywhere. You need 3mm oversize to get 1,7.
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so that pretty much throws that possibility out the window..
maybe someone could try sourcing the correct size pistons thru prothe? i know he gets his pistons thru some sort of oem supplier for isuzu..
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i thought the 1.6 gets too thin of cylinder walls for this
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i know i wouldnt bore 3mms out of my cyls..
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Correct size for what? 1mm oversize? What brand pistons prothe sells?
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I had a block that was bored to it's last and was too worn,..
so I bought 1.7 TD pistons from a guy on here.
Half money up front and half when they arrived from europe. It was cheaper than buying pistons and finding another block.
It's taken me years to bring this project to completion,.. and it will take another one before it's a daily driver. Kind of a side project.
but I did hear it run last week. Cold as hell but it started right up and revved before i quickly shut it off. Winter might be a good/fun time to break it in.
Bored out to 79.98mm, it just clears the AZZ gasket.
I didn't know I was getting first oversize, would have rather left that extra .5mm on the walls and got standard pistons.
The pistons hit the edge of the oil squirter bases it was so wide.
Got almost all of the wiring and stuff done that will allow me to start it from the driver's seat.
Waiting for a waterpump pully and battery.
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I had a block that was bored to it's last and was too worn,..
so I bought 1.7 TD pistons from a guy on here.
Half money up front and half when they arrived from europe. It was cheaper than buying pistons and finding another block.
It's taken me years to bring this project to completion,.. and it will take another one before it's a daily driver. Kind of a side project.
but I did hear it run last week. Cold as hell but it started right up and revved before i quickly shut it off. Winter might be a good/fun time to break it in.
Bored out to 79.98mm, it just clears the AZZ gasket.
I didn't know I was getting first oversize, would have rather left that extra .5mm on the walls and got standard pistons.
The pistons hit the edge of the oil squirter bases it was so wide.
Got almost all of the wiring and stuff done that will allow me to start it from the driver's seat.
Waiting for a waterpump pully and battery.
you can bore the cylinders 3mm?!?! how thin does that leave the cyl walls? about as thick as some tough paper?
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Correct size for what? 1mm oversize? What brand pistons prothe sells?
correct 1.7TD pistons.. or atleast the same size as what comes in the 1.7
the pistons we get from prothe, come from an ISUZU oem supplier..
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I had a block that was bored to it's last and was too worn,..
so I bought 1.7 TD pistons from a guy on here.
Half money up front and half when they arrived from europe. It was cheaper than buying pistons and finding another block.
It's taken me years to bring this project to completion,.. and it will take another one before it's a daily driver. Kind of a side project.
but I did hear it run last week. Cold as hell but it started right up and revved before i quickly shut it off. Winter might be a good/fun time to break it in.
Bored out to 79.98mm, it just clears the AZZ gasket.
I didn't know I was getting first oversize, would have rather left that extra .5mm on the walls and got standard pistons.
The pistons hit the edge of the oil squirter bases it was so wide.
Got almost all of the wiring and stuff done that will allow me to start it from the driver's seat.
Waiting for a waterpump pully and battery.
you can bore the cylinders 3mm?!?! how thin does that leave the cyl walls? about as thick as some tough paper?
That's something I'm not too sure about.
I have another block but haven't cut it open yet.
77.48 to 79.98 is 2.5mm,.. and standard would be less than that; 2 mm.
The walls are very thick at the top, where it counts. Hoping there is enough meat left in the rest of the cylinder walls.
The gassers bore out to 83mm, that's 3mm more and I don't hear of cylinder wall cracks being a problem, even when modded.
Statements on here showed that people in europe have tried it and bent rods before breaking the walls,
although there might have been a cracked wall on an engine that was really beat on.
It's an experiment, a bigger risk than I intended because the original block had a crack and I had to use a hydrolic block that was on it's first bore,..
something that would have worked great with normal/oversized TD pistons so it's not like an block that couldn't be used again.
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I had a block that was bored to it's last and was too worn,..
so I bought 1.7 TD pistons from a guy on here.
Half money up front and half when they arrived from europe. It was cheaper than buying pistons and finding another block.
It's taken me years to bring this project to completion,.. and it will take another one before it's a daily driver. Kind of a side project.
but I did hear it run last week. Cold as hell but it started right up and revved before i quickly shut it off. Winter might be a good/fun time to break it in.
Bored out to 79.98mm, it just clears the AZZ gasket.
I didn't know I was getting first oversize, would have rather left that extra .5mm on the walls and got standard pistons.
The pistons hit the edge of the oil squirter bases it was so wide.
Got almost all of the wiring and stuff done that will allow me to start it from the driver's seat.
Waiting for a waterpump pully and battery.
Got any pictures of the block with the big bores?
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Back in the old days, I had a ford 300"-6 that I bored .050" and used 390 pistons. Worked great but was sensitive to overheating. I also heard that on some over bored high horsepower engines, that the cylinders would flex and that they would actually loose power. Sounds like you guys will be running #500 of boost,nitrous,&nuclear waste for max power. Hope she don't go boom.
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That's something I'm not too sure about.
I have another block but haven't cut it open yet.
77.48 to 79.98 is 2.5mm,.. and standard would be less than that; 2 mm.
The walls are very thick at the top, where it counts. Hoping there is enough meat left in the rest of the cylinder walls.
The gassers bore out to 83mm, that's 3mm more and I don't hear of cylinder wall cracks being a problem, even when modded.
Statements on here showed that people in europe have tried it and bent rods before breaking the walls,
although there might have been a cracked wall on an engine that was really beat on.
It's an experiment, a bigger risk than I intended because the original block had a crack and I had to use a hydrolic block that was on it's first bore,..
something that would have worked great with normal/oversized TD pistons so it's not like an block that couldn't be used again.
Very interesting. I wonder what those of us with AAZ blocks could get away with, and what pistons we could appropriate to do it with...
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AAZ blocks have siamese cylinders, so i wouldnt want to go too big on the bores on those engines. might run into issues with the walls getting too thin in the siamese portion.
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there was someone building a 2.1 i think using ford escort pistons, i think i made a thread for it a while ago, i think the biggest you can go on a vw block tho is 2.2 with alot of clearancing and thats with a gas engine, and no chance at a rebuild if the bore gets screwed
http://www.vwdiesel.net/forum/index.php?topic=19163.0
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i was just thinking of this earlier and figured i would post it, really the best way to build a 1.7 would be to use a 1.6 crank in a decked aaz block with stock aaz pistons and rods. you would have to figure how much the deck needs cut down, but by using the aaz rods and pistons which are longer you get a better rod length ratio so the revability will be better. plus then you are using an aaz block that is actually made to have the larger bore, and you are using all much more available parts. but then again, who decreases displacement haha
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i think? the 1.9 has bigger rods, at both ends.. as well as longer..
i know the 1.9 is 16mm taller than a 1.6 (deck height)
but im not sure how long the AAZ rods are..
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only the wrist pin end is larger, so with the aaz rod it would work. i think 1.6 rods are 136mm and 1.9 are 144mm. the only goofy part would be decking the block
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Or don't deck it and get crazy low compression ratio and .75" lift cam and boost that sucker like mad! :)
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i don't think there would actually be 16mm, some where in between i guess.
1.6 stroke
86.4mm
1.6 rod length
136mm
1.6 deck height
220mm
wrist pin center to deck
220-136-86.4/2= 40.8
1.9 stroke
95.5mm
1.9 rod length
144mm
1.9 deck height
236mm
wrist pin center to deck
236-144-95.5/2=44.25mm
so then u add half the 1.6 stroke to the aaz rod length, and aaz pin center to deck, and thats how tall the block should be
86.4/2+144+44.25= 231.45mm
so 236-231.45=4.55mm off the deck and u have a 1.7
someone double check my math but that all makes sense to me... who knows if the 1.7 would actually run better tho
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Warning, the stream of conciousness below may contain blasphemy.
So, if I'm reading all of the above correctly, I could assemble an AAZ block with a 1.6 crank, measure piston protrusion (actually recession at this test) and then have the block decked about 4mm to get me to spec for a one hole head gasket. That does sound very interesting, although I would like to point out that the OP mentioned raising the CR of the frankenmotor to improve cold starts as his motivation, and and this short stroke 1.9 block would still only recover about a third of the lost compression.
So now to run with this thought a little, wouldn't the same details apply to a 1z/ahu, and maybe later TDI as well? Is this the obvious answer to some people's search for a tdi piston for the 1.6? I'd love to get some deck thickness measurements on both the AAZ and early TDI engines.
I do really like the idea of a 1.6 crank in an AAZ, free breathin, free revving 1.7l. That said, putting a 1.6 crank in an m-TDI sounds almost perfect to me.
Anyways, I'm just thinking out loud.
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if you deck the block that much, how much deck are you going to have left? i think its either going to be paper thin, or an open deck, like a honda engine..
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it would work on a tdi, too but tdis can't rev like an idi because they burn the fuel slower, also don't tdis have a trigger wheel on the crank, so it would need to be a tdi-m, honestly even on an idi it's probably pointless to lose the displacement, it would just be fun to build something different.