Don't throw those 1800 zetecs away just yet...
16-03-2011, 11:38 PM
#1
Don't throw those 1800 zetecs away just yet...
Hey all, just thought i'd share some info i found out today! i'm not the first person to have discovered this after a bit of looking on google, but its not the sort of info that appears straight away when looking for zetec turbos either.
Basically, i picked up a piston off my bench at work today, measured it and found that it would be an ideal piston for a cheap but strong 1800 zetec turbo. it just so happens that i have plenty of these blocks laying around waiting on the scrap pile
Anyway, the piston is from a 1.8t 20v audi! the bore size is 81mm, the pin size is 19mm, haven't worked out exact compression heights, but with a silver top rod (bushed down to 19mm for the pin) the piston sits somewhere up to 1mm further down the bore than the zetec item, but also has a 75 thou (just under 2mm) dish in the crown.
The other good news is that it is a mahle pressure cast piston, which is a process much like forging as far as i understand (don't quote me on that, i'm no mettalurgist), so should be far stronger than the standard ford item.
if anyone is interested, i may even make a working model and put the pics of the machine work up and whats involved. Just thought it was worth sharing this as its a very cheap way of getting a reliable low compression zetec without using spacer plates or skimming pistons.
Basically, i picked up a piston off my bench at work today, measured it and found that it would be an ideal piston for a cheap but strong 1800 zetec turbo. it just so happens that i have plenty of these blocks laying around waiting on the scrap pile
Anyway, the piston is from a 1.8t 20v audi! the bore size is 81mm, the pin size is 19mm, haven't worked out exact compression heights, but with a silver top rod (bushed down to 19mm for the pin) the piston sits somewhere up to 1mm further down the bore than the zetec item, but also has a 75 thou (just under 2mm) dish in the crown.
The other good news is that it is a mahle pressure cast piston, which is a process much like forging as far as i understand (don't quote me on that, i'm no mettalurgist), so should be far stronger than the standard ford item.
if anyone is interested, i may even make a working model and put the pics of the machine work up and whats involved. Just thought it was worth sharing this as its a very cheap way of getting a reliable low compression zetec without using spacer plates or skimming pistons.
17-03-2011, 01:01 AM
#7
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This has been discussed before but isn't that common knowledge.
This is where I first saw it
http://www.fiestaturbo.com/forums/an...urbo-vt181410/
This thread says they need some machining to fit zetec rods though.
This is where I first saw it
http://www.fiestaturbo.com/forums/an...urbo-vt181410/
This thread says they need some machining to fit zetec rods though.
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17-03-2011, 09:25 AM
#10
Im sure if a few of you got together then someone like PEC would do it.
Could get the correct compression height that way too as the length could be altered to suit if you were getting a batch made.
Find about 20 people that want a set and you're away
17-03-2011, 04:01 PM
#13
Its worth sticking uprated rods in if you're going for a built engine anyway, IIRC it was Martin Hadland that said he recommended sticking in some better rods once you tune the VAG 1.8T as they're not unknown to go tits up and are the weak link.
Cheers,
Grant
Cheers,
Grant
17-03-2011, 06:41 PM
#14
cheers for the responses guys! nice to see there are people that could make use if this info!
as for making rods to fit, obviously it would be the best/strongest option, but i'm trying to show that you can make an 1800 ZT on the cheap
right, got a few rough measurements today - the Compression height of the audi pistons is about 32.7mm, the silver top is 33.2mm. the audi also has a 68.5mm wide bowl, 1.9mm deep. all of this results in less compression, but i haven't had the chance to work out how much less yet - feel free to do some calculations of your own if you like
As for the bushes, you can either make phosphor bronze ones and have the pin floating in the rod, or make them from steel and have an interference fit pin.
thats all for now, still gotta find a set of pistons to play with
as for making rods to fit, obviously it would be the best/strongest option, but i'm trying to show that you can make an 1800 ZT on the cheap
right, got a few rough measurements today - the Compression height of the audi pistons is about 32.7mm, the silver top is 33.2mm. the audi also has a 68.5mm wide bowl, 1.9mm deep. all of this results in less compression, but i haven't had the chance to work out how much less yet - feel free to do some calculations of your own if you like
As for the bushes, you can either make phosphor bronze ones and have the pin floating in the rod, or make them from steel and have an interference fit pin.
thats all for now, still gotta find a set of pistons to play with
12-05-2011, 12:24 PM
#17
Ben
Is there any updates on this? I'm really interested in building one of these if it's as easy as you make it sound!
12-05-2011, 12:56 PM
#20
I've found that life I needed.. It's HERE!!
this is old news theres a guy on here that used to sell these piston for zt application infact i was gonna build a higher compression zetec with a gt28rs but binned the project after selling the car. I think you could make a very quick car around 280-300hp that would rev like a bike
12-05-2011, 01:24 PM
#21
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Very interesting, I was thinking of sticking a zetec in my triumph herald. If this works I can wait until my mate goes big turbo on his Cupra R and nick his pistons! :-D
12-05-2011, 01:46 PM
#22
Ben
this is old news theres a guy on here that used to sell these piston for zt application infact i was gonna build a higher compression zetec with a gt28rs but binned the project after selling the car. I think you could make a very quick car around 280-300hp that would rev like a bike
Ben.
12-05-2011, 04:18 PM
#23
no real updates except that i have stuck a bush into a rod and honed a block 
i'm going back to the 2.0, did a bit of working out last night though, this would make a 1800 about 8.5 or 9:1 with a little fettling of the piston.
you basically need to bush the rod back down to 19mm from 21ish, then taper the rod, taking about 10mm total off the top and 2mm off the bottom. alternatively you could modify the pin boss in the piston to suit the standard rod, but it'd probably be alot weaker than doing it the other way.
i'm going back to the 2.0, did a bit of working out last night though, this would make a 1800 about 8.5 or 9:1 with a little fettling of the piston.
you basically need to bush the rod back down to 19mm from 21ish, then taper the rod, taking about 10mm total off the top and 2mm off the bottom. alternatively you could modify the pin boss in the piston to suit the standard rod, but it'd probably be alot weaker than doing it the other way.
12-05-2011, 05:40 PM
#26
I've found that life I needed.. It's HERE!!
the s3 pistons i was gonna use were 81mm the 1800 zetec has a bore of 80.6 mm so need to be bored out the rod also needs milling out to take the pin iirc the vag pressure cast piston is good for 400hp+ and it gives a compression of around 8.5-1 iirc it was a while since i looked at doing this
12-05-2011, 05:49 PM
#27
I've found that life I needed.. It's HERE!!
theres a member on fiestaturbo.com who has done this his user name is freakpower
here a set he had forsale he says in the post you can run 25psi....
theres also a pic with the rod+pistons
http://www.fiestaturbo.com/forums/po...0audi#p1790810
here a set he had forsale he says in the post you can run 25psi....
theres also a pic with the rod+pistons
http://www.fiestaturbo.com/forums/po...0audi#p1790810
12-05-2011, 10:21 PM
#28
the s3 pistons i was gonna use were 81mm the 1800 zetec has a bore of 80.6 mm so need to be bored out the rod also needs milling out to take the pin iirc the vag pressure cast piston is good for 400hp+ and it gives a compression of around 8.5-1 iirc it was a while since i looked at doing this
the strength of the piston isn't really the issue in this setup, the limit would be the rod as you have to taper the top to fit inside the piston. i think it'd be plenty strong enough for 300bhp though. the Comp ratios i gave were an average depending on what gasket/head combo you use and wether or not you take any metal off the top of the pistons.
i might still give it a try if i get bored at work one day, as i do have an audi piston under my bench and i'm sure i'll have a zetec rod spare somewhere
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