Well, the pistons that I had ordered came today. They look good, steel insert for the top piston ring, nice machined surface.
Some issues :
On the Renault, the injection bowl in the piston is offset towards the left of the engine on all pistons while on the VW TDI, cyl 1 and 2 are offset towards the left and cyl 3 and 4 are offset towards the right.
The Renault uses a tapered small end on the conrod.
The piston doesn't have a cutout for the oil spray nozzle.
Piston pin size 26 mm.
I think that that since the Renault engine has about 6mm less stroke than the VW, the bowl has to be machined larger to end up with a compression ratio of about 18.5:1.
It looks like there is enough material to machine the bowl offset about 4.5 mm towards the right on piston 3 and 4.
I CC'd the bowl in this piston and it is about 16cc up to the valve pocket.
Does anybody know how deep the valve pockets are in an early TDI? (I don't have one apart right now)
I will make an adapter to hold the piston in the lathe, so that I can accurately machine the bowls larger and also offset the bowl to the other side.
The connecting rods will need to have bigger bushings installed and I think that it is best to machine the small end of the rod to a taper, instead of machining the inside of the piston and possibly affecting the ovalty of the piston at operating temperature.
Since I am sleeving my engine, I have std size pistons (76 mm) which allows me one over-size for the future. They only come in 76mm and 76.5mm.
Lets all try to get this conversion to work, in harmony with each other, the world is already stressfull enough.
Herman
Lets all try to get this conversion to work, in harmony with each other, the world is already stressfull enough.
Herman
Other than "others" that tend to try and restate the obvious (of what others have said and try to take ownership of it....yesh.. CR, thanks, we know its a ratio... 1.2 info...yeap, your welcome for that) I'm all for that.
Hopefully one of you guys across the pond is able to get this up and going here soon since you have more ready access to things and seem to have the thought processes in line.
and itzdshtz....KUDOS to you for working with things the "right" way. Nice post and if you are interested in valve depression measurements...i can get those to you from a older junk TDI piston I have. Just shoot me a PM.
Joe
What I read and post in this thread, seems to be correct for me, there are no denigration of Prothe's product and no malicious comment about him, just warning statement to help his project.
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A liquid to measure the volume, water? or a special liquid?
i think the 1.6TDI could yield better fuel economy than the 1.9TDI at the cost of torque and hp. would be recommended for a rabbit or a mk2 jetta/golf. it would certainly change the way some people view their old 1.6 diesel block though :lol: :wink:
An 1.9L TDI in a MK2 golf get around 3.8-4L/100km.
I never used water, the process is incredibly simple, but hard to do if you want accuracy.
I acheived 2.9l/100km in my brothers golf MK3, its running extra lean because I'm fooling the ecu and making more boost than required all the time.
I guess a mk2 tuned for fuel economy could do way less.
(vnt15, 10mm pump on 187 injectors for instance)
I'm very interested in this thread, been reading for a while now.
If the financial backing was there I would be all over the project side and just go for it..
Watching closely.
the new Polo has to meet tough emissions standards, that and and the weight differential between the two makes that difference in consumption.
the new Polo has to meet tough emissions standards, that and and the weight differential between the two makes that difference in consumption.
don't forget driving habits too... i don't think i could ever achieve above 50 mpg... :twisted: