Last edited by Matheus428; 30-01-2005 at 15:04.
it will hit but they dont like 16v pistons!
111 BHP@6,300 - 121 Ib-ft@2,500 - 3,200 from a 1400 SR with modified C14SE head, weber 32/34 on varijet inlet manifold, magnex 2" bore S/S exhaust system! Woohoo
Its aftermarket forged ones, is not Vauxhall. The 16V pistons don´t need have the cutouts for be 16V pistons, depends the lenght of the piston. Have standard 16V engines that don´t have cutouts in pistons.
How far do the pistons come up in the bores at TDC? All the way to the top?
what valve lift and c/r are you going to run?
what kind of a t*ss*r puts signatures in .....huh???
pistons in all 20XE engines will have cutouts in the pistons.
i think stickers measured them as coming .5mm above deck.
and yes that hole you sign, should have restrictor in.
Then, i don't know. I will remove the dump pulley for see the TDC point in crank pulley, then, i will can know exactly with the pistons stay in max top position.How far do the pistons come up in the bores at TDC? All the way to the top?The valve lift will be standard of C20XE(i will use standard C20XE cams), about the CR, i think, will be the same of C20XE. But for know it, i will need measure the TDC point to the face of block, and calculate, if is the same of XE, i will have the same CR, and i will need remove the pistons for make the cutouts.what valve lift and c/r are you going to run?Thank you Odd. I will see if my pistons have more than 5mm above deck, if have, i think can use without make cutouts in this, agree? How many milimeters have the cutouts in pistons? 1mm? Is really low, correct?i think stickers measured them as coming .5mm above deck.
Example, if the cutouts have 1mm, and my pistons at TDC have 6mm, then, i can use the pistons without cutouts, correct?Humm..thank you so much for the picture Odd. I see other thing, the oil hole in XE block is bigger than NE, for put the oil restrictor in, then, i can't put direct the XE oil restrictor in my block, i will need work in the block(i don't want to do this, because i will don't disassemble the engine), or i can machinne the oil restrictor for smaller and can put in my block.and yes that hole you sign, should have restrictor in.
I have other idead too, i can put the oil restrictor in C20XE head, what you think?
The last question. Do you know how many milimeters of bore have the very small hole of oil restrictor?
Cheers and thanks friends!
Last edited by Matheus428; 23-08-2004 at 14:57.
I thought standard 20XE cams had too much overlap for turbo applications??
Yeap, the standard C20XE cams overlap are a bit agressive for high boost aplication, but, the big advantage of Double Over Head Camshaft engines is that, you can modify the overlap with vernier pulleys. You can advance the inlet cam, and retard the exhaust cam for get lower overlap, and less crossover mixture to the exhaust(when the inlet finish, the exhaust will begin open). Then, you can raiser or lower overlap according your turbo setup(turbine setup, boost etc..). Is not easy to do, but can do, and i will try it. The standard C20XE cams have a really good duration and lift for a turbo engine.Originally Posted by j1400
no, the valve cutouts are just right for piston 0.5mm above deck height. the coutout are nearer 2-3mm deep. so your piston will need to come 2mm below deck height to fit !Originally Posted by Matheus428
yes machine restrictor down to fit the hole on 8v block.
Damn..is a really deep the cutouts..in picture visual, i didn't imagine that. Well, tomorrow i will measure it, and we will know if i will it work or not the cutouts in my plane pistons.no, the valve cutouts are just right for piston 0.5mm above deck height. the coutout are nearer 2-3mm deep. so your piston will need to come 2mm below deck height to fit !
flat top pistons might increase the compression ratio too high ?? maybe you could use a thicker head gasket, this would keep lower compression ratio and give more valve clearence.
Hello Odd. Yesterday, i put my engine at TDC. and give a bad surprise to me. My pistons in TDC crossing the block!!! Like you see in the pictures, i think, they cross around 0,1 to 0,2mm! Then, i will need work a lot of the top of pistons to can running with C20XE head. Is impossible machine 0,9mm in top of piston, i think, its much, and can get fragile the piston. I will take off around 0,5mm from top of piston, and make a thicker gasket head, with 0,5mm more thicker. Give to me a total of 1mm more of space.
Look the pictures:
arent you going to turbo this engine anyway? those flat top pistons will make the compresson ratio over 11:1
the 16v pistons have a small dish, aswell as the valve cutouts.
Yeap, i will turbo this engine after(i will running with N/A first, for see if the fuel injection working good.. and saving money for new exhaust manifold for turbo. ), the CR is not my care, because here i have alcohol, i can running with 11:1 with high boost and no risk of detonation in alcohol. The problem of high CR in turbo, is not only detonation, is the less fisical space in chambers to a lot of mixture, and its make so bad for the rods. Because this, i would like running with lower CR. I would like running around 9,5:1 of CR in my C20XE turbo, with this CR don´t will spank so much the rods, and don´t will be much retarded the throtle response in alcohol.Originally Posted by 0ddball
Well, if i machine the top of pistons 0,5mm, and put a 0,5mm thicker gasket, i will get lower CR. Maybe will be less than 9,5:1, because i don´t will machine only in center of pistons, i will work in all top( i will slice it).
In your picture, i see, my pistons are 16V ones yet, the C20XE standard ones, crossing the block too, only stay below, is center, that is machined, and the valve cutouts. Then, my case is not so badder then.
I think, my forged pistons, stay in "default" mode, in the manual says for you work in top for have the cutouts or CR that you want. The maker don´t know what aplication of the pistons will have, then, give to you a "default" piston top.
Hi Matheus. You should be able to machine them and use them. You will probably find that you will want to add valve pockets to the pistons to make sure your valve clearances are ok. You can check the valve clearances with the head on, and a dial gauge anyway.
Hello Brian! How are you friend???Originally Posted by Brian_S
The problem to make valve cutouts in the pistons, is the fact, that i don't have XE piston here for use like example. Then, i will slice all the top.
About the dial guage, i know this tool, but i don't have it. Can i know turning the engine in hand(turn with a tool at crank pulley)? If the valves don't beats turning in hands, can beats in high rpm? Thats my doubt. Because after engine running, the parts be hotter, more expansion, much more rev... Because this, i will put a big gap for valve clearance. I will work 0,5mm in pistons and put more 0,5mm in the steel gasket. The standard XE gasket is 1mm? correct? Then, mine will have 1,5mm.
Do you know if the Ecotec head gasket are the same of XE?
Matheus S. Almeida
Sounds to me as though it would be easier to get new pistons. I guesss you could flat them down and add valve pockets but without an example you could get the pockets in the wrong place and break the valves the first time you turn it over.
If I were you I would just get the propper Pistons.
Hi Matheus, I'm good, but very busy at work so haven't been on here much lately. Glad to see your still modifying your car thoughOriginally Posted by Matheus428
The valve inclination is 22deg for the inlet and exhaust. Working with that figure you should be able to machine valve pockets correctly. Over here, dial gauges are very cheap, and are very useful to have around a garage.
I am unsure of the correct figure for a crushed XE head gasket, and I don't think the ecotec gasket fits, but again, I'm unsure.
You're right, turning by hand can mean that at high RPM you end up clipping the valves with the pistons due to rod stretch, heat expansion, and lifter pumping. It's better to be sure of what valve clearances you have. A set of vernier pulley's might help you to setup the engine properly too.
Good luck with it all, should be great.
I expend a lot of bucks($$$$$) in this pistons, and i will use it.. is a really good forged pistons, have guarantee for 600+bhp. I don't will trust in pockets, i will slice all the top. Thanks for the advice.Originally Posted by elthrinYeap, my turbo manufacter man, will make vernier pulleys to me with my standard XE ones.A set of vernier pulley's might help you to setup the engine properly too.Thank you very much Brian, you help-me so much. Some day, when i have money, i will pay to you a cup of coca cola(i don't consumpt alcohol! then, forget beer, alcohol to me, only in tank of my car!) there in England.Good luck with it all, should be great.
the last question, do you know what is the internal diameter of XE oil restrictor in block?
Matheus S. Almeida
Last edited by Matheus428; 30-01-2005 at 15:06.
maybe its better you slice the whole piston top, as then you will get a good compression ratio also
I will slice all the top, for have more security about valves clearances. The low CR will be bad only when my C20XE will be N/A, after turbo, i will compense it, with more boost..Originally Posted by 0ddball
Now, my problem is know how many bore have the internal hole of oil restrictor. i will need make my oil restrictor.