Focus Fanatics

Focus Fanatics (http://www.focusfanatics.com/forum/index.php)
-   SPI Performance (2000-2004) (http://www.focusfanatics.com/forum/forumdisplay.php?f=42)
-   -   Who's replaced the head and not piston(s)?? (http://www.focusfanatics.com/forum/showthread.php?t=303643)

jscot 12-04-2012 11:55 AM

Who's replaced the head and not piston(s)??
 
Going to put myself out for some bashing here! Just wondering who's willing to admit that they cleaned up a piston after a dropped valve seat and put a fixed head on, and the aftermath! Any burned out pistons?

I just did on my 2001 and it's running great. I went back and forth for awhile but needed to get this thing back on the road so just cleaned up the damaged piston (no noticeable damage to cylinders) and put a new head on.

I know many who have been through this have at least thought about it.

Pulling the head was pretty easy, so I figured, why not? Total rebuild was a whole 'nother level and just didn't make sense for this car.

I did replace timing belt and tensioner, new gaskets and plugs of course.

I think it'll be fine, I'm expecting another 100,000km.

Lots of info on head removal already on the site, so I won't go over my experience, but feel free to ask any questions.

I was toying with the idea of a used head, but the 2 Foci at the wreckers had both been scrapped because of the heads! Don't know why anyone would scrap an otherwise good car over this issue. Not that hard of a (half-assed) fix!

Let the bashing begin.

sam fisher 12-04-2012 02:08 PM

at least its running lol. imo u gotta do wut u gotta do to make things work .

Sent from my N860 using FF Mobile

amc49 12-07-2012 03:33 AM

Piston won't burn out, it breaks. The pistons are cast and extremely brittle under the right conditions. One of those conditions would be if impact was done on outer edge of piston up to 1/4" in, cracks there often let big pieces of the top piston ring land come loose later at any time depending on how cracked. You could be driving a time bomb but no way of knowing when it could happen. Could last forever, could break tomorrow, I've seen many cast pistons do it.

Depending on where piston was in stroke it could have yielded skirt to crack or maybe even break off a tang too, but you can't see that from the top. You could easily have a broken ring in there too.

You're the one that looked at it, your skillset now determines the outcome. I've done that too and on some the damage was only cosmetic and harmless, others no way. When person insisted on running it, it broke in a week.

You're in the hands of the SPI god now.

fakitol 12-07-2012 05:20 PM

Did u clean the intake manifold and the dual stage runners?

a_2000_se 02-10-2013 05:00 PM

When you drop a valve seat the chunks get caught between the piston and head. It does a good amount of damage to both but the outer edge of the piston gets beat up pretty good. Enough to compress the lands and pinch the top ring so it no longer floats. A ring that doesn't float will probably wear out quicker than it should.

As someone else pointed out - did you clean out the broken valve seat parts from the intake/exhaust and EGR?

Donnyd21 02-10-2013 08:15 PM

I would not chance it, I have done 2 SPI rebuilds and put new pistons in one and used in the other.

I do have good piston/rod assemblies if anyone is interested, just PM me

amc49 02-10-2013 09:12 PM

That is a cast piston, if the ring land has pinched then the cast has been yielded enough to VERY possible let sections of piston come loose next to do same thing again. Piston castings are very brittle, they take a lot of punishment but not that type. You can take one and easily crack pieces off by simply striking it with a hammer.

jscot 02-19-2013 12:32 PM

Thanks guys for the input. I did clean out the intake and smoothed out the piston crown. Running strong after a few months. I'll keep you posted!
Have had an issue with sucking air around the intake manifold when hot, but I'll post a new thread on that.


All times are GMT -5. The time now is 09:59 AM.


http://www.focusfanatics.com/aboutus/copyright.asp