View Full Version : Cracked piston.

06-08-2008, 06:20 PM
So I lost compression in Cylinder three, I figured it was a blown head gasket, tore her apart and it turns out I find the cylinder is chipped.

Should I scrap the engine or replace the piston?

Pictured below is the piston. (resized, smaller)

06-08-2008, 07:30 PM
^ Well that depends on where that chunk of piston went. Did it do any damage to the head or valves?? Usually in the past, I've only seen people replace the entire block when a rod bearing is thrown or when the actual block has a hole in it or warped. Ask some of your local machine shops and have them take a look at it and see if it would be feasible to re-build.
If you don't want to spend the $$$ to rebuild and can't afford much down time, go to a local junkyard to get an engine. You gave a GT, so that means you have a 5SFE. Those are easy to find since they came in the celica, camry, and mr2. Finding one with good mileage shouldn't be hard or expensive.

06-08-2008, 07:34 PM
ouch thats quite a chip, but as said I wonder where the piece went...

06-09-2008, 02:35 AM
I tagged my car wrong it's a ST not a GT. So the engine is a 4afe. The head looks alright (pictured below), the valves move. That piston is just wicked chipped, and I wasn't sure if I wanted to keep on deconstructing or go for broke and get a new engine. Thanks for the reply.
http://farm4.static.flickr.com/3190/2565255908_56e06b1ac8_o.jpg head.

06-09-2008, 05:05 AM
I tagged my car wrong it's a ST not a GT. So the engine is a 4afe.
I was wondering about that, because of the intake manifold. The ports looked different than when I took my 5sfe apart. Good luck tho :bigthumbu

06-09-2008, 11:45 AM
Eh... I hope it's as easy as it looks, it looks to be about a 3 on difficulty scale, the piston cylinder doesn't look scored (amazingly enough), and I can always hone it.

Just with my luck that three will become a 7.

06-09-2008, 06:25 PM
Ha I got the piston that was FUBARed out, pics to follow.

I may as well journal my experience under the hood.







So now I get to bore my piston cylinder , any tips?

Also the rocker(?) is hard as heck to move back and forth in the piston, that normal?

06-09-2008, 06:57 PM
Get a closeup of the side of the crown right where it's cracked if you can? Curious about how it failed.

06-10-2008, 12:06 AM
2nd pic, 5th and 6th are about as close as I can get with this camera and have the picture still come out crystal. Either the engine overheated and caused the issue or the rest I'm unsure of.

Car is a "project" car I picked up, so the history I'm unaware of other then the person before me kept messing with it trying to figure out the issue without actually tearing up the engine to take a look.

06-11-2008, 11:31 PM
well i jsut did a 4AFE rebuild and right now i'm getting 42mpg so even if it becomes a 5 or 6 on pita scale, do it right and take you're time and it will pay off big time.

p.s. get the head ported and decked while you're getting the block bored out.

06-12-2008, 12:42 AM
I thought the 4AFE had forged internals?

06-12-2008, 01:22 AM
I thought the 4AFE had forged internals?


As for Cost vs. Time : Price of a good low mileage 4afe is about $350.
You'll end up spending way more just to get the new parts.

Pull the engine, drop in a good used one. It should take about 4 hours start to finish from where you're at now.

06-12-2008, 04:07 AM
Yea I started pricing pistons, rings, oil pump. water pump, timing belt and tensioner, new head gasket, bearings, machining, tools, time and it'd easily come out to $600 for new parts, 300 for the machining and tools. Where as getting a new engine is engine plus $50 for a cherry picker and someone's truck.

06-12-2008, 04:11 AM
Is the 4AGE forged internals, or am I completely retarded?

06-12-2008, 04:40 AM
4AGE has forged pistons, dunno about the rest.

So cars with the 4afe, should I stick solely to 1st gen 4afes or can I do 1st and second gen?