piston slap

[Faisalicious]

what up peeps, just wondering if someone can help me, i just got my car from the shop, its a D16Z6 with 75.5mm vitara pistons, eagle rods, arp head studs and stock head. I took it for a tune but now my car sounds rough and i kinda hear a piston slap. now the tuner played with the dizzy, so is the timing or the dizzy causing the roughness and the piston slap or is it something else?
Any help would be great..
Here is a short video:

http://www.youtube.com/watch?v=dMsI8hLXc2A

 

[got traction]

its normal for those pistons and it should quiet down a little after its warmed up. its because of the floating wristpin. which way did you face the arrow on the piston? towards cam gear or flywheel?

 

[Faisalicious]

towards the flywheel

 

[AE Motoring]

or could be the clearances are too loose. But sometimes it should go away once the car is warmed and the rings have expanded

 

[got traction]

from what i've seen it seems that the guys who face arrow towards cam gear have a litte more slap than those who face towards flywheel. but anyway, yours could be a little worse due to a loose p2w clearence, but regardless you should be okay.

 

[s_crowley 17]

interesting, I thought you were supposed to always have them facing flywheel

 

[got traction]

interesting, I thought you were supposed to always have them facing flywheel

stock honda pistons have arrow facing cam gear. so when i built my motor we put arrows facing cam gear. i've seen people do it both ways with vitara pistons and it dosent seem to affect performance at all

 

[PhntmSk8r]

You can get away with it with vitaras because of how dished out they are. Since intake/exhaust valves are different sizes it's not something that could be done with an avg. comp ratio, or high comp ratio piston.

 

[Faisalicious]

i will try to get another video caz the sound is still there, even when the car is warmed up, but thanks for the answers

 

[Faisalicious]

so i took it to my mechanic, it seems fine now, but he did a comp test and the results are 95 for three cylinders and one cylinder is 150 (BTW they are vitara piston so they have low comp). I just did the whole block, but i think i have to re-do the piston rings, caz the rings are the problems.
what you guys think? he said i can leave it like that but its better to change it.

what you guys think??..

 

[xxsenceo89x]

^^ how do you know its the rings? Go with the cheaper s**t first. It could also be valves or the headgasket.

 

[Faisalicious]

i dont know, he checked everything and he said its the rings..

 

[got traction]

so i took it to my mechanic, it seems fine now, but he did a comp test and the results are 95 for three cylinders and one cylinder is 150 (BTW they are vitara piston so they have low comp). I just did the whole block, but i think i have to re-do the piston rings, caz the rings are the problems.
what you guys think? he said i can leave it like that but its better to change it.

what you guys think??..

95psi sounds about right for vitaras. The reason these pistons are loud is because of the p2w clearance, and because they have a floating wristpin. How many miles are on the motor now? you do know it takes a long ass time for chromoly rings to seat right?

 

[Faisalicious]

well the block is fresh and its over bored caz my vitara pistons are 75.5mm, i also have eagle rods and ARP head studs, all the bearings, seals, valves, water pump, oil pump, timing belt, thermostat are brand new as well..
one of my friends said that the cylinder or the piston that has 150 might be a problem and might brake my crank shaft caz it has more compression than the other 3 cylinders, is this true ??

and if its the 95 psi on the three cylinders are normal, why do i have one cylinder at 150 psi??

Thanks in advance..

 

[NIKE H34D]

interesting thread, in to learn some stuff from traction

 

[got traction]

well the block is fresh and its over bored caz my vitara pistons are 75.5mm, i also have eagle rods and ARP head studs, all the bearings, seals, valves, water pump, oil pump, timing belt, thermostat are brand new as well..
one of my friends said that the cylinder or the piston that has 150 might be a problem and might brake my crank shaft caz it has more compression than the other 3 cylinders, is this true ??

and if its the 95 psi on the three cylinders are normal, why do i have one cylinder at 150 psi??

Thanks in advance..

it wouldnt break your crank shaft....BUT 150psi on a vitara motor is kinda odd. That kinda compression number is what you would expect on a stock piston. who built the block? what were the clearances? were the rings gapped and staggered?

 

[got traction]

interesting thread, in to learn some stuff from traction

 

[Faisalicious]

my mechanic built my block but im not sure about the clearances and if the rings were gapped. And what do u mean by it takes a long time for the rings to be seated? i mean how long ? caz my engine is still new, should i drive it for like 1500 kilometer or miles then re-do the compression test again ? caz what i did was i got the car then went for tuning right away? clutch is also new if that helps lol

 

[got traction]

my mechanic built my block but im not sure about the clearances and if the rings were gapped. And what do u mean by it takes a long time for the rings to be seated? i mean how long ? caz my engine is still new, should i drive it for like 1500 kilometer or miles then re-do the compression test again ? caz what i did was i got the car then went for tuning right away? clutch is also new if that helps lol

when i built my block i had to put oil in the cylinders for it to even fire. i would say drive it for a while and then do the compression test again. see if you can find out what the clearances were from your mechanic.

 

[Faisalicious]

i already asked him but he doesnt know caz the machine shop did that. But i will agree with u and i will drive it for awhile, do you know for how many miles ? is 1500 good enough ??..