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Duratec Bore Score
Furyous - 10/6/17 at 04:20 AM

It seems like the more I look at my engine, the worse it gets.

I've taken the head off and it looks like something has got into one of the cylinders, possibly something small has broken off the piston. The cylinder wall has some scoring.

This is the worst one. It easily catches my fingernail.

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These aren't as deep but I can feel them when I run my finger over them.

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Is there anything I can do to save this? Or would it be easier to get a new engine?


snapper - 10/6/17 at 05:47 AM

It looks as if it's been stored dry and fired up with little lubrication.
There are not a lot of options but a heavy deglaze and new rings may save the day but you will need to properly gap the rings and take the sharp edge off the ring gap outer edge to stop it cutting on installation and first fire up.
Cleaning the bores of metal filings and hone stone dust needs to be thorough.

Did you do a compression test before stripping the engine? Was it burning oil?
I usually leave an engine alone if it's not burning oil and compression is even


Furyous - 10/6/17 at 09:37 AM

I did a track day in March but had to stop early because the engine was knocking. The con rod bearings were destroyed due to what looked like oil starvation. Two of them were so bad that they did some damage to the conrods. I took the head off to swap them out and found this. There's a little chip on the piston crown roughly in line with the deep score, although I can't tell if the chip was caused by some debris or if the chip was the cause of the scoring.

Might be easier to just buy another engine the way this is going. Trouble is, the 2.0 Duratec is usually around $2-3,000 or the 2.3 Mazda is $1,200+.


Dick - 10/6/17 at 09:56 AM

We see this a few times on zetecs and duratec engines plus others and find the most common cause is due to poor maintenance procedures. People remove spark plugs without taking basic care you must always remove all crap from around the plugs be for removal. Do not just undo them as any rubbish just falls in the hole.


mcramsay - 10/6/17 at 12:15 PM

I think in this case the damage to the conrods / bearings etc is more likely to blame rather than something falling in when you removed the spark plugs.


Dick - 10/6/17 at 12:55 PM

If the rings are still in one piece then damage to piston top indicates that it entered into the combustion chamber from above


Hornet - 11/6/17 at 09:04 AM

I had exact same scoring and honed for ages, gapped rings.... total waste of time. Wasted time and money! Better to get a new engine. A good engine here in U.K. Is approx £400 to £600. I wonder if it would be worthwhile looking at shipping costs?


Furyous - 12/6/17 at 10:58 PM

The sister in law bought a Mondeo last week. I wonder if she'd notice if I swapped the engines...

(Side note - her engine wasn't running right so she took it to a garage who charged $500 (£250) for 6 spark plugs and HT leads! That didn't even sort the problem! It turned out to be the coil pack, which I had a spare sitting in my garage... along with a spare set of spark plugs. I was pretty miffed they didn't talk to me first)

There's a 2.3 Mazda engine nearby for about £250, which I'm tempted to buy. I can't seem to find a lot of detail about tuning/power options, though. Everything I can see is a bit vague or about the 2.0.

From what I gather, the block and head ate identical but the extra height is in the cam cover from the vvt. What are the chances I could just use the solid cams from the 2.0?

What kind of power could I expect from the 2.3 with GSXR1000 throttle bodies?