help piston damage (pics)


Darragh_K said:
If the piston is ever going to rub the walls it will be at the thrust sides , perpendicular to the crank.
Click to expand...

Of course i just didnt know if he'd taken pictures of one side at different angles or each side buddy

If it was oil problem then you must have wear elsewhere as well, you say you changed shells once have you inspected them yet?
 
...so, Im guessing here, there is such a thing as taking to much time to build an engine...
 
sorry, I feel gutted as well. Just completed mine and I can hardly imagine what you are feeling. hang in there.
 
took the engine out this afternoon and took it down to the machine shop, stripped it, new shells aren't brilliant, few scores, on the crank as well, probably from debris and the oil pressure insult !

checked the bores with a dial gauge, 3.5 thou clearance as quoted on the
je spec sheet, although one of the bores had only 2 thou one way and 3.5 thou the other

jed thinks it has got hot at some point(causing bore to distort) but i've no idea when ! possibly from turning over dry ?

he is going to hone it friday and see if it comes out, if not i have a spare engine so will start again with new bore, re-ring,(pistons cleaned up nicely need, to re-measure) different crank which i have, and new shells

second time lucky

at least it will be warmer than last winter lol

cheers
 
Nah the pistons would never expand that much from turning over dry more likely ran lean. Might want to check fuel pressure and make sure it's not dropping off at high demand you may need to upgrade pump or check the fuel reg for problems if not stock fpr.
 
Check the reg wouldn't be uncommon to see one of those go faulty. What make is the reg? Easiest thing to do would be watch the fuel pressure gauge while performing a power run on Dyno be a nightmare if same problem occurred again so best to double check everything
 
Install a wideband and run full closed loop fueling if you ECU allows you to. You need a wideband regardless.
 
Its not used for the engine ecu unless you wire it to use it and program it appropriately

Its more use for you to keep an eye on things however i doubt it will be much use on a rally stage, you arent going to be looking at it much! If you are going to buy one get an AEM ;) fastest and most reliable i have ever used

It must have got mega hot to distort the bores! The blame must lay with the machine shop or mapper, who mapped it?
 
What did I say at the start? And what causes pistons, cylinders to get hot? Det. I have seen that sort of damage a million times before on poorly tuned engines, like I said again anything mapped on the rollers should be finished off on the road/track. Oh and also dont just tune it with wideband, an engine can still det/knock with the correct afr's. Too much ignition timing etc, you really need to listen for it.
 
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