piston query

B

*brunette_barbie*

Member +
piston number 3 has gone and have been offered a free piston but with number 2 on one side and 0 on the other. does it matter or do i need a number 3?
 
A

AdamB

Member +
They are all numbered as they are sized differently. You should measure the diameter of the bore and the piston and see if you have the correct clearence. If not you'll need the correct sized piston to match that cylinder.

Edit here are the sizes...

Size mark 1- 73.900-73.9100
Size mark 2- 73.910-73.920
Size mark 3- 73.920-73.930

All in mm.

If you need size 3, you will probably only be able to fit size 3 pistons, unless you overbore to suit different pistons. As the other size marked pistons will not give the correct clearences.
 
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M

Mikey4410

Member +
what i meant was as standard there all the same.like when you buy a forged set for instance,all four you get are the same.
 
A

AdamB

Member +
They are not all the same as they are different diameters. If you buy a forged set you should still measure the piston and cylinder to get the correct clearence, before going for any machining. Without measuring it is stupid in my eyes.
 
M

Mikey4410

Member +
so each and every piston in any given car is a different diameter ? for instance mine were 1mm oversized from standard and each forged piston in my engine was indentical
 
A

AdamB

Member +
Sometimes yes, which is why Toyota marked them differently according to size. As my first post in this thread shows the different diameters of the marked pistons. The size of the piston used on that specific cylinder is marked on top of the block, E series engine anyway.
I never said forged pistons would be different, but you should measure them to make sure you get the correct clearence. If your paying that money for pistons I wouldn't expect them to have the tolerence as a stock piston.
 
M

Mikey4410

Member +
so your saying from factory that starlets had different piston sizes in engines that were identical ? hmmm

i never said any thing about diameters and clearances ,i was on about single starlet engines having the same pistons in each cylinder in that one engine.thats all.i am aware of how clearances work etc,i have built many engines.

i am sure brunette barbie will find your info helpfull. all the best.mikey
 
A

AdamB

Member +
The manual says... "If replacing piston, ensure replacement piston contains the same size mark as cylinder bore size mark on cylinder block"

According to that quote you could have one engine with a variety of different size pistons.
So it is not quite as easy as saying, one piston fits all. As the diameters are different, therefore the piston-cylinder wall clearence would be different.

So by the looks of it you will need a piston size marked 3 to fit.
 
S

Skalabala

Member +
Some engines come with MK1 MK2 MK3 pistons all mixed in the same engine!
The blocks are bored on large scale and they are not all 100% the same. So they made different pistons. MK1,MK2,MK3 :)
Same with the bearings. Sometimes a STD bearing from spare shop wont work because it had a MK3+ from factory and the spare shop bearing can only go max with a 0.050mm clearance on the crank.
 
Jay

Jay

Admin
*brunette_barbie* said:
piston number 3 has gone and have been offered a free piston but with number 2 on one side and 0 on the other. does it matter or do i need a number 3?
Click to expand...

At the risk of confusing things further...

What size (1,2 or 3) is stamped on your old piston BB?

Cylinder three may not necessarily be a size 3. Could easily be a 1 or 2.

Jay
 
S

Skalabala

Member +
Or just measure the sleeve and then choose the correct piston.
And pull all of them and re-ring and freshen it up a bit. No harm to change big ends.
Oil pump is also important.
 
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