Piston Swap
#1
Posted 18 December 2012 - 02:45 PM
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
Posted 20 December 2012 - 12:10 PM
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
Posted 22 December 2012 - 11:30 AM
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
Posted 22 December 2012 - 06:17 PM
1.3 campro uses high compression piston.
Not sure if the gain worth the cost.
#5
Posted 23 December 2012 - 04:28 AM
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
#6
Posted 24 December 2012 - 02:59 PM
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
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
Posted 27 December 2012 - 09:56 AM
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
Posted 04 January 2013 - 05:01 PM
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
Posted 04 January 2013 - 10:32 PM
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.