Jump to content

Welcome to Autoworld Forum !

Sign In or Register to gain full access to our forums. By registering with us, you'll be able to discuss, share and private message with other members of our community.

Close
Photo

Piston Swap


  • Please log in to reply

#1
snmrz76

Posted 18 December 2012 - 02:45 PM

snmrz76

    3rd Gear

  • Members
  • 3 posts
greetings everyone.
after years of neglect due to economic reasons, i finally decided to send my 2008 HL for a complete engine overhaul. and since everything is going to come off for cleaning / replacement, I've decided to swap the stock pistons with brand new ones from the S4PE (1.3L Campro) in order to bump up the compression ratio for that added ooomph for my bone stock motor- tear it open, clean up the mess inside, stuff in the new slugs and rebuild it back with stock everything else.

my mechanic told me that it should be a straight forward swap since both S4PH and S4PE share common blocks, heads, bore diameter, camshafts and valves. so there isn't any risk of the valves hitting the pistons.

the question is,
1)how much of an increase in compression is it going to yield, using stock head gasket?
2)will i still be able to feed it with RON95?
3) am i going to be sitting on a time bomb and setting myself up for a bigger mess????

#2
mosh

Posted 20 December 2012 - 12:10 PM

mosh

    Tokyo Drifter

  • Members
  • PipPipPip
  • 3,557 posts
QUOTE (snmrz76 @ Dec 18 2012, 02:45 PM) <{POST_SNAPBACK}>
greetings everyone.
after years of neglect due to economic reasons, i finally decided to send my 2008 HL for a complete engine overhaul. and since everything is going to come off for cleaning / replacement, I've decided to swap the stock pistons with brand new ones from the S4PE (1.3L Campro) in order to bump up the compression ratio for that added ooomph for my bone stock motor- tear it open, clean up the mess inside, stuff in the new slugs and rebuild it back with stock everything else.

my mechanic told me that it should be a straight forward swap since both S4PH and S4PE share common blocks, heads, bore diameter, camshafts and valves. so there isn't any risk of the valves hitting the pistons.

the question is,
1)how much of an increase in compression is it going to yield, using stock head gasket?
2)will i still be able to feed it with RON95?
3) am i going to be sitting on a time bomb and setting myself up for a bigger mess????


err.. why downgrade ? most of the SP4E upgrading their component with SP4H parts or custom part ?

#3
jasondotcom

Posted 22 December 2012 - 11:30 AM

jasondotcom

    Fast & Furious

  • Members
  • PipPipPip
  • 1,185 posts
QUOTE (mosh @ Dec 20 2012, 12:10 PM) <{POST_SNAPBACK}>
err.. why downgrade ? most of the SP4E upgrading their component with SP4H parts or custom part ?


The pistons from 1.3L Campro are actually different at the top surface. 1.3 piston have flat surface compared to the 1.6 and thus giving slightly more compression ratio if it is fitted into the 1.6 block.

See here

http://bluedevil76.b...pro-engine.html

 


#4
Gunnerzz

Posted 22 December 2012 - 06:17 PM

Gunnerzz

    Tokyo Drifter

  • Members
  • PipPipPip
  • 3,102 posts
QUOTE (mosh @ Dec 20 2012, 12:10 PM) <{POST_SNAPBACK}>
err.. why downgrade ? most of the SP4E upgrading their component with SP4H parts or custom part ?

1.3 campro uses high compression piston.
Not sure if the gain worth the cost.


#5
slushmatic

Posted 23 December 2012 - 04:28 AM

slushmatic

    Veteran

  • Members
  • PipPip
  • 141 posts
QUOTE (Gunnerzz @ Dec 22 2012, 06:17 PM) <{POST_SNAPBACK}>
1.3 campro uses high compression piston.
Not sure if the gain worth the cost.

Hmmm... standard 1600 C/R is already 10:1 - not exactly low to start with.

If 1300 pistons takes the C/R over 12:1 then pre-ignition likely to be a problem.

Might be easier/safer, (and cheaper) just to use a thinner head gasket, assuming it's
advisable to raise the C/R at all dry.gif
'Do average things - get average results'

#6
snmrz76

Posted 24 December 2012 - 02:59 PM

snmrz76

    3rd Gear

  • Members
  • 3 posts
QUOTE (slushmatic @ Dec 23 2012, 04:28 AM) <{POST_SNAPBACK}>
Hmmm... standard 1600 C/R is already 10:1 - not exactly low to start with.

If 1300 pistons takes the C/R over 12:1 then pre-ignition likely to be a problem.

Might be easier/safer, (and cheaper) just to use a thinner head gasket, assuming it's
advisable to raise the C/R at all dry.gif



I'm no mechanic, much less an engineer. but if my calculations are correct (based on whatever limited info and knowledge i have) the new static comp ratio should be around 11.87:1, but my mechanic advised me not to worry too much since the dynamic ratio would be lower; the same reason that my stock motor (on 10:1) could run safely on ron 91 back in 2009, when it was still available at most gas stations. but again, even he cannot give an estimate for the new comp ratio, which is quite a bummer...

#7
jasondotcom

Posted 27 December 2012 - 09:56 AM

jasondotcom

    Fast & Furious

  • Members
  • PipPipPip
  • 1,185 posts
QUOTE (snmrz76 @ Dec 24 2012, 02:59 PM) <{POST_SNAPBACK}>
I'm no mechanic, much less an engineer. but if my calculations are correct (based on whatever limited info and knowledge i have) the new static comp ratio should be around 11.87:1, but my mechanic advised me not to worry too much since the dynamic ratio would be lower; the same reason that my stock motor (on 10:1) could run safely on ron 91 back in 2009, when it was still available at most gas stations. but again, even he cannot give an estimate for the new comp ratio, which is quite a bummer...


Kindly share with us the outcome. I am driving a Persona too, so i am always looking ways to improve the driving pleasure while maintaining as stock as possible.

 


#8
snmrz76

Posted 04 January 2013 - 05:01 PM

snmrz76

    3rd Gear

  • Members
  • 3 posts
QUOTE (jasondotcom @ Dec 27 2012, 09:56 AM) <{POST_SNAPBACK}>
Kindly share with us the outcome. I am driving a Persona too, so i am always looking ways to improve the driving pleasure while maintaining as stock as possible.


well, the job was all done by the 25th Dec. since then the motor is on 'pantang' sikit la. i'm advised not to breach 3k rpm untill the next two oil changes, what with the new bearings and piston rings... but thats ok since im not the racer type anyway, the whole idea was to just bump up low end torque for better drivability. so i'm happy to report that so far the results are qiute positive; the low end pull is a bit stronger. strong enough to be felt/noticed by a workmate of mine who is also driving a HL, when i asked him to test drive the rebuilt engine. how should i say this... the changes done (so far) are not going to blow fire out the exhaust but it will/does make the daily commute somewhat less strenuous, motor feels a wee bit flexible in the lower regions.

#9
slushmatic

Posted 04 January 2013 - 10:32 PM

slushmatic

    Veteran

  • Members
  • PipPip
  • 141 posts
QUOTE (snmrz76 @ Jan 4 2013, 05:01 PM) <{POST_SNAPBACK}>
well, the job was all done by the 25th Dec. since then the motor is on 'pantang' sikit la. i'm advised not to breach 3k rpm untill the next two oil changes, what with the new bearings and piston rings... but thats ok since im not the racer type anyway, the whole idea was to just bump up low end torque for better drivability. so i'm happy to report that so far the results are qiute positive; the low end pull is a bit stronger. strong enough to be felt/noticed by a workmate of mine who is also driving a HL, when i asked him to test drive the rebuilt engine. how should i say this... the changes done (so far) are not going to blow fire out the exhaust but it will/does make the daily commute somewhat less strenuous, motor feels a wee bit flexible in the lower regions.

Thanks for the update, can you please advise as to the condition of the original pistons/rings/bearings when they were removed? Also was there unexpected/excessive wear on the cylinder bores or any other parts?
This info would be interesting to fellow Campro owners I'm sure.
'Do average things - get average results'