New stock pistons

[jabran200]

O.k so all the pistons ringlands are cracked on my engine.

I called toyota and they want to know which size piston i want but I don't know which one to order.

Whats the best way to measure the bore? I used a vernier caliper I get 74.0mm and the readings below are in 2 decimal points.

here are some specs of the ones toyota offer.

Bore diameters:
STD mark 1 = 74.000-74.010mm
STD mark 2 = 74.010mm-74.020mm
STD mark 3 = 74.020mm-74.030mm
Limit before rebore = 74.23mm

Piston diameter:
STD mark 1 = 73.900-73.910mm
STD mark 2 = 73.910mm-73.020mm
STD mark 3 = 73.920mm-73.930mm

What are my options there isn't that much difference to them?

 

[350ep70gr]

O.k so all the pistons ringlands are cracked on my engine.

I called toyota and they want to know which size piston i want but I don't know which one to order.

Whats the best way to measure the bore? I used a vernier caliper I get 74.0mm and the readings below are in 2 decimal points.

here are some specs of the ones toyota offer.

Bore diameters:
STD mark 1 = 74.000-74.010mm
STD mark 2 = 74.010mm-74.020mm
STD mark 3 = 74.020mm-74.030mm
Limit before rebore = 74.23mm

Piston diameter:
STD mark 1 = 73.900-73.910mm
STD mark 2 = 73.910mm-73.020mm
STD mark 3 = 73.920mm-73.930mm

What are my options there isn't that much difference to them?

Your old pistons should be stamped with a number on the top. 1,2,3. Maybe you need to clean the carbon deposit to find out what number are yours. If it is over 50.000km engine and you plan to hone the cylinders then you can go up to the next number. So if your old pistons are mark 2 you can use mark 2 or mark 3. Usually mark 3. Most important think is the ring gap so mesure them to be in the specs.Mesure them about 20 mm in the cylinder by a feeler gauge.

Chris

 

[jabran200]

There is a letter and number on each piston and I can't make heads nor tails of them.

On the top of the pistons head there is number on the side where the valve recess is and on the opposite side a letter.

from cambelt side left to right.

Piston 1 -- B2
Piston 2 -- C1
Piston 3 -- A2
Piston 4 -- A2

I have a another engine that threw a rod and I can't understand that too.

Piston 1 -- A2
Piston 2 -- C1
Piston 3 -- A2
Piston 4 -- A1

Can someone tell me how I can make sense of those numbers?


On the underside of the piston insde the recess on the skirt there is a number as well which reads "11100" and on ther side of the skirt says "2"

Do I have to measure the ring gap if I am going to use new rings?

Thanks

 

[jabran200]

Just incase anyone is getting confused about what numbers I am talking about.

 

[350ep70gr]

Size 2 mate for the piston.
If you want to see also main and big bearing also check the botom where the sump seals near the gearbox and should be stamped there as a line with 4 digits and at the opposite side a line with 5 digits.

Chris

 

[jabran200]

Size 2 mate for the piston.
If you want to see also main and big bearing also check the botom where the sump seals near the gearbox and should be stamped there as a line with 4 digits and at the opposite side a line with 5 digits.

Chris

I figured it out after measuring them, the number on the picture above (next to valve pockets) is the piston size toyota designate.

I have ordered a number "3" toyota piston as well new rings all round.