Thin crack on top of Ross Piston, but still good Compression

[dragrush]

While doing a compression check I noticed a small hairline crack on the top of one of my ross pistons (few thousand miles on them) The compression turned out to 150 on all cyl with FP2x cams. Im guessing the crack is just surface deep. Still runs fine and everything. No smoke coming out of exhaust (except once after first starting it I had a strange problem after a boost leak test, but thats another thread) Im not really sure if I should replace it or not or keep driving and see if it gets worse. Dont really have funds or time to pull the engine out.

Anyone else have a problem like this or opinions what I should do with it?

 

[BigBeans]

I wouldn't take the chance.

If you're absolutely positive it's cracked, i would replace it.

One piston is cheap compared to the damage it will do if it fails.

 

[ziggo0]

That piston exploding would be equivalent if not worse than throwing a rod, there goes your rod/crank/block and possible valve train damage. Just replace it now!

 

[greengoblin]

Time to pull them out. Don't be silly.

 

[dragrush]

Im going to get a new one. Just a question to people that have done it before or what you recommend. To replace a piston would it be easier to keep the block in the engine bay? or should I just pull the whole thing out?

 

[97gst_spyder]

How do you know its cracked? Camera or something?

 

[dragrush]

shine a flash light down in the cylinder...Im going to do a leak down test, to see if air is getting by before I take it apart.

 

[viprez586]

I don't know why there is a debate here (OP).

A crack in a piston is obviously a point where it was stressed. A stress point doesn't get better over time. Hone cylinder wall and replace. There is no other option until it becomes a much more expensive one.

 

[MOTOR-RX]

I also agree being cheap now is going to bite you in the ass.

I had a friend do piston rings on his car with out removing motor, but i dont know how long it took him or if it was easier.

BTW how long have you owned that car i think i have seen it before in that area. I jsut moved to denver from crystal lake a little bit ago

 

[rush2252]

You are seeing a crack in a piston with a flashlight and your naked eye but its still reading 150psi? Something doesnt seem right. I would pull the head and make sure that its not your eyes playing tricks on you.

 

[tkelly27]

Pull the head. Lines or shelfs in carbon deposits can look like a crack. There isn't anything to cause them, so there generally aren't surface only cracks.

 

[turbodsm007]

Speaking of ross pistons check out mine that I just pulled out...its fubared ..don't know how, maybe detonation or to much piston slap...they were kinda abnormaly loud under a cold start..Does it look like something I should talk to ross about??????

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[KBR]

Speaking of ross pistons check out mine that I just pulled out...its fubared ..don't know how, maybe detonation or to much piston slap...they were kinda abnormaly loud under a cold start..Does it look like something I should talk to ross about??????

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let me ask you this, is your pistons stock size? did you bored out the cylinder or just honed it? from the pix, it looked like its Detonating PLUS a huge piston slap. like the bore is either to loose or tight. or possible that the bore itself is not perfectly honed/bored straight.


also, theres nothing wrong with ROSS pistons. as long as they are measured and installed the right way and with the right clearances, the pistons should be fine. not unless you detonate the shit out of the pistons OR from improper installation.



aite, peace.

 

[turbodsm007]

I gotcha, I liked my ross pistons, its just sux that i was only able to make 284whp and 275 torque on them.....and im running the FPgreen ... I blam it all on the AFC ..I know ..dam AFC...it can only do so much...

 

[viprez586]

Ouch, looks like piston to wall clearance was incorrect. Hence why your ringland took the bite.

 

[BigBeans]

Ouch, looks like piston to wall clearance was incorrect. Hence why your ringland took the bite.

Agreed.

The leading edge of the piston seems decent, so that kind of sidewall damage didn't result from detonation.

 

[Kickerbeast]

If that is the only one that looked that way, I would measure all the pistons and see if they didn't box one wrong or something. That sucks though.

Edit: Measure you cylinders too. Maybe someone had a one piston meltdown and they bored only one cylinder. That sounds like something a "previous owner" would do. Make sure it isn't oval either.

 

[dragrush]

BTW how long have you owned that car i think i have seen it before in that area. I jsut moved to denver from crystal lake a little bit ago

I had it for about six years...im in crystal lake area a lot


I had my pistons installed my SBR and Professionally tuned. Few degrees of knock here and there, not enough to crack even a stock piston. Why the ross cracked with a few thousand miles on it...I dont know

 

[95eclipser]

No doubt in my mind to replace it while it has a hair line crack... honestly sounds like alot of miss fire
glwe

 

[my98gsx]

ah, if it was me and i had a cracked piston ide just take the head off and fill the crack with jb-weld! allow a few hours to dry and then - good as new!!!!!




... Just Kidding everyone, I wouldnt take the chance, if its damaged get it out ASAP before it causes more damage to anything else.

 

[#40Fan]

I have personally witnessed a piston welded while still in the engine after a valve broke. This was a carbureted 429 Ford. Still ran a 10.3.

Would I do it...no. By the time you get a head off, there isn't much more to drop the pan and pull the rod.

 

[hayourwifeleftu]

pull that head off and see if your realy seeing what you think you see. toungue twister sorta

 

[Kickerbeast]

pull that head off and see if your realy seeing what you think you see. toungue twister sorta

That or grab a nice borescope and get a good look at it. But in the long run, the best thing is to pull the head.

 

[viprez586]

I have personally witnessed a piston welded while still in the engine after a valve broke. This was a carbureted 429 Ford. Still ran a 10.3.

Would I do it...no. By the time you get a head off, there isn't much more to drop the pan and pull the rod.

OOh I can almost feel the piston warping OOR.