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1.8L pistons in 2.0L beta I

19K views 23 replies 11 participants last post by  prairieboy84 
#1 ·
So these will fit right in and increase compression ratio to 10.6:1? I did a search and that was all I could find. Anyone have anymore info on this? I'm also going to be using the intake cam from the 1.8L. Thanks!


[Edited by BENTLEY on Apr 26, 2005 1:18 PM]
 
#2 ·
I thought the 1.8 had lower compression than the 2.0???
 
#4 ·
i believe they both have 10:1 compression...

however since the 1.8's stroke displaces LESS air, it needs a slight dome on the piston to make less volume in the combustion chamber.

a true 2.0 4 cylinder will displace 500cc of air per cylinder. so at TDC you would need a 50cc combustion chamber for 10:1.

now with a true 1.8 it would displace 450cc/cyl. so to make 10:1 it would need a 45cc combustoin chamber.

we know the 1.8/2.0 heads are identical in volume and swappable (some small differences but none that matter in this situation). when hyundai came out with the 2.0 they didnt want to redesign the whole head, just flatten the piston crown. much less r&d there ;):

however from my calculations- unless the wrist pin height changed then youre probably going to be pushing over 11:1cr.

youre probably not going to find a whole lot of info on it but i sure would swap them out myself if i had the 2.0 and staying NA. 11:1 isnt too bad and if the quench area of the piston is any distance from the deck then it will be even lower than that anyways.

good luck.
 
#5 ·
Why does webtech list the specifications the same?:puzzled:
 
#7 ·
so same specs...?
 
#9 ·
if you put the 1.8L piston in a 2.0L you should have a compression of 11:1 ??
 
#10 ·
I have done the homework on various occasions and the beta 1800 and 2.0 pistons are one and the same. Identical... the 2 motors share the pistons.
The only difference between the 2 engines is the crank angle, which affects the stroke...

the 1800 beta has a shorter block and shorter conrods as well.

When my 2.0 beta broke, I tried to convince myself that the crank from the 1800 would woirk in the 2.0 block...yes it would... but your compression ratio would be WAY low... the car basically wouldnt have enuff pressure to even start...
Also if you try put the 2.o crank with the 1800 block, your pistons wouldnt even make one full crank turn... the pistons hit the head.... with the 1800 conrods or the 2.0 con rods.

So its either, or... not a mixture of both.

Grant



[Edited by lostbuoy on Nov 11, 2005 12:55 AM]
 
#14 ·
1.8 and 2.0 pistons are different. someone post a pic of a 2.0 piston crown and i will show you a pic of a 1.8. they are different. the rods are different. if you put 1.8 pistons in a 2.0 block with 2.0 rods and a 2.0 head you will increase compression. if you put 1.8 pistons in a 2.0 block with 1.8 rods, then yeah you will have almost no compression and the engine wont start.

seriously someone get a pic of a 2.0 piston crown.
 
#15 ·
so 1.8L pistions in a 2.0L will bring my compression up about how much???
 
#22 ·
look you can use 2.0L forged pistons, put in a 1.8l the commpression may go down a bit. the 1.8 and 2.0 pistion are the same size but the top of the pistion changes.
 
#23 · (Edited)
11:1 is a LOT of compression. This will show you a very noticable increase in power. However you will HAVE to run high test. And that might not be good enough. Above 11 is verging into race gas areas. Currently building a NA for my friends Cobra, all the info I've seen, read, spoken about with guys that have been building cars for decades says...stay below 11 and you'll be fine on pump gas. Above...maybe...maybe not. What is the stock compression for the beta? 9:1? Does anyone make a decent quality 10 or 10.5:1 piston head? Also you can find compression gains by having the head and block deck planed. That can gain you a half point or better depending on how much you have milled off. Given the process is pretty cheap, it may be a more cost effective means of gaining compression.
 
#24 ·
running 1.8 pistons in the 2.0 block is bad idea unless you have some way to control how much timing & fuel your motor will end up with also add in that your stock coils will not produce enough spark under the added pressure of the chamber to fire your plugs even at a .50 gap so your adding in a cdi box so after getting the pisotns,ecu,ign,tune & various other parts to acomodate running that high compression youve just run 3/4 the cost of slapping on a junkyard turbo kit

other options wich is a better choice to remain in the 10:1 (wich is streetable compression) but allow more power would be to have the head milled wich in turn adv/ret the cam timing ( makes/moves power)
then figureing out quench of your head gasket add that to the cc's that have been milled off say 5 ish (not exact number) you can now port and blend the chamber of the head to allow for a better flow of the air and fuel coming into the cylinder
when you port & blend the chamber you loose compression with a mill first you dont
 
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