Cracked Pistons :(

E

elton

Member +
Hey mates,

Had 78-85psi across all four cylinders after compression test. Decided to strip the engine and found out that piston no.2 and no.4 are cracked at the ringlands below the intake side (the two grooves for the valves) of the piston.
Smoke comes out from the breather hose, but not much from the exhaust, only sometimes.

Current mileage is 195k km, stock boost, stock turbine, stock everything.
Took the injectors for flow testing and no problems.

Question is, why is it cracked, and whats with the low compression?


Sent my block and crankshaft to the machine shop and they said the block needs reboring and crankshaft needs regrinding.
Both the bore and the journals loook fine to me, no scratches or signs of wear.
I dont have a bore gauge nor a micrometer to measure em myself.

Is the machinist trying to rip me off?

I have a few options :
1-Change the block
2-Get new stock pistons, rings, and bearings
3-Get oversized pistons, and oversized bearings

Question -
-Wanna try avoid replacing the block for legal reasons in my country.
-I'm on a budget, forged not an option. Are oversized original toyota pistons available? Is it to be 75mm or 74.5mm? What does oversize 0.20 of a piston means?
-Can stock sized pistons go with oversized .20 ringS?
-Shall i take option 2 or 3?
-Am i gonna put the reliability of the crank and block on the line if i choose option 3?
 
TurboDave

TurboDave

Member +
How about buying a second hand engine and just dropping that in, is that an option?

As far as I know standard pistons are only available in one size 74mm.

The ringland damage would have been caused over time mate at ~115,000miles its a pretty decent milage, If your running standard I'dd just put it down to wear over time.

Doesnt explain your low compression on the non cracked ringland cylinders though?
 
E

elton

Member +
Even if i buy a second hand engine, legal issues :).
Better only a block.
I already have a spare head
 
E

elton

Member +
engine number :). Has to be in the registration card, customs form, etc.

lotsa hassle with third world mentality ppl/
 
Chris@CCM

Chris@CCM

Member +
the car must have ran lean dude ill what be get it check with by a tuner once its up and going . i would just fire a new set of pistons and rods it in there pritty cheap
 
1

1bar

Member +
Make sure you get the number 3 toyota 74mm pistons as they are the stongest off them all. it has the -03 on the label, and the 3 stamp on the pistons denotes the larger of 3 measures for standard size, and the best for rebuilds, because the bore is already worn.
 
S

starlet666

Member +
alot of the time forged pistons are the same price as standard pistons..... so i would probz lash out the extra little bit of cash and just drop forged slugs in it.....
or change to another complete motor and go in and change the details on the car.... change engine number and so forth.... its not that hard to change an engine number either...... its been done b4 ;)
 
E

elton

Member +
thanks guys.


But here in MAlaysia, a set of new original pistons /w rings costs like, 180USD?
A set of forged, dont know man.

1bar, no3 pistons means oversized? I'm sourcing for 74.5mm oversized ones
starlet666, in my country, no pocket money means FAIL :)
 
E

elton

Member +
what i meant was, that, if we change engine block, we gotta to send to the authorities for inspection. However good our car is, we will never pass, without some 'pocket money' n a pack of fags.
 
S

starlet666

Member +
fill the number in with metal file it flat and stamp it the same as the last one..... have done it to one of mine b4.....

and whats so bad about a 1.3 litre.... im pushing just under 300bhp.... it is 250hp atw outta mine....
 
You must log in or register to reply here.
Top