pistons question

[TRDemon]

Would a 4AGZE piston fit in a 4AF block?

[Flashmn]

Yes they would, not sure about if you have to make valve clearances... But keep in mind, used pistons wont seal properly, because they have already worn out to the cylinder "shape" of the donating engine.

[TRDemon]

but aren't they low compression then mine

[TRDemon]

and please i wouldn't use used pistons

[Pineapple]

Used piston is ok as long as you change all the rings. The piston shouldn't touch the bore and get worn. One of the skit will get worn and scratch but you can sand it down and smooth it out a bit.

[Flashmn]

It will cause pistonslap.

[TRDemon]

So what is the real differentance between these pistons ( 4AF piston and a 4AGZE piston) besides compression???

[Pineapple]

Pistonslap? Didn't know anything about that. Feel free to educate
I polished up my pistons after I took them out, bad idea?



I didn't use sand paper.

[Flashmn]

4A-GZE pistons are forged, 4A-F are not.
Pistonslap is when the piston rocks in the cylinder tube... causes premature wear for one. Happens when your piston is too small for the size of the bore (thats why when you bore your block, you have to get oversized pistons, toyota carries atleast 3-4 oversizes). it rocks back and forth (its not a big rock) but you can hear it from the sound, the engine goes sort of like chunkchunkchunk, sounds like a diesel.

[Flashmn]

from www.pistonslap.com

Excessive piston slap occurs when the clearance between the piston and the cylinder bore is too great. The piston to cylinder bore clearance becomes too great either through wear, mismatched pistons and cylinder bores at manufacturing or, a combination of both. The audible noise associated with excessive piston slap is due to the perpendicular impact of the piston against the wall of the cylinder bore. Audible piston slap is typically loudest when the engine is first started up. The pistons then expand with heat reducing the piston to cylinder bore clearance thus, reducing the perpendicular impact of the piston against the cylinder wall and its resulting noise.

[Kwanza]

4AGZ pistons have been tried in a 7AFE and because of the F head's combustion chamber design, the 4AGZ pistons actually increased the compression significantly. As for piston slap... it's not a common thing to happen simply because most people don't buy pistons with a crap load of miles. It's fine to use used pistons so long as they're within spec. You're supposed to check those things to prevent an occurance such as piston slap... If it's not within spec, bore it out and get oversized pistons. Just cause you're gonna run used pistons doesn't mean piston slap is gonna happen... I've set-up motors with used pistons and never had any problems...

[Flashmn]

I've set-up motors with used pistons and never had any problems...

Well good for you.

[TRDemon]

so would it be ok to charge my 4AF engine using the stock pistons for say 3psi

[Flashmn]

if I was to turbo my engine (who knows, maybe I am) I'd go for about 5-8psi and hope for the best

[Pineapple]

4AFE blow above 12PSI.
With low PSI all stock is ok as long as you're not burning oil in the first place. Compression test all cylinder to make sure they're all good.