need some advice please :)

[dat111]

my car decided to pop a comp 918 valve spring, sitting at a set of lights taking off and my car spluttered and farted and died, i just made it to some where i could pull over thank god!!

so got it towed home pulled the heads off and wadda you know. the bit** decided to kiss the piston, fast foward. pulled both heads off sent them away to be machine, valve grinded new springs and new stem seals ( it was blowing oil out the exhaust at WOT) and a new intake valve. i tought id post a picture and a few questions here.

how do i go about shaving the burrs off that (not sure if there is any) how do i clean the piston top and best way to get the block mating surface nice and clean and smooth? i was thinking a non scratch scotch bright pad?

i think the photo actually makes it look worse then it is..

thanks again guys. love how everybody is helpful unlike the other forums!

 

[Turtl3]

I would be very hesitant about cleaning the piston while its still in the block. Bits of debris can still get down between the top of the piston skirt-above the top ring, and the bore....thats not to say it cant be done, but i would be giving it a serious clean out after scrubbing all that carbon off with scotchbrite- aluminium oxide is still very abrasive. Id use a vacuum first and then compressed air and contact/carby clean after.

Ive always used sandpaper and a rubbing block to do the top of the block(can use a nice flat piece of hardwood and staple the sandpaper to it, or buy an actual rubbing block/pad from the local hardware or tool shop. But again...everything will need a really good clean. Shove rags in all of the oil and water galleries beforehand, vacuum the majority of the crap out first, and then remove the rags carefully.

To remove the burr from the piston itself, u could do it by hand with sandpaper, or use a die grinder with a buffing pad (scotchbrite pad).

A thorough clean afterwards will be the key to all this. Ive heard oven cleaner works well on carbon buildup but ive never tried it myself. Could also use normal degreaser and a nylon or wire brush...but dont go overboard with the steel or brass brushes.

 

[dat111]

Thanks mate, what i have clean off so far i have let down the holes :/ so i think ill go giving them a good vac with the wet and dry.

I was having a good talk to a friend and he said that it may of compromised that cylinder so im a bit scared. Its all so confusing.

I grabed a oil stone from Bunnings not sure if needed but tryed some 2000 wet and dry but i didnt want to "sand" the surface so i stopped and started using a plastic razor blade. I dont think that a bit of carbon on the pistons would matter to much

 

[Turtl3]

Well if it didnt drop a valve and u never removed the heads...it would still be running perfectly fine with that carbon on the pistons lol.

In regards to the stuff having already gone down the holes, i would do a coolant flush, and 2 oil+filter flushes- 1 before the car gets started when the heads are back on, and another after its been driven for a while.

If the engine rotates freely then that cylinder may be fine. I highly doubt there would be any...but have a look for hairline cracks on the piston face once its cleaned up. Theres no way to be completely sure if its free of damage unless u pull it out. U could check that the piston is still square in bore and check its height compared to other cylinders, but u will need dial gauges and depth micrometers...

2000 wet n dry will just clog up before it has an effect on removing the carbon. And it wont do much to help clean the block either

 

[dat111]

thanks for that turtl3.

im going to put the heads on, start it "run" the valve springs in upto operating temp and then drop the oil after do that and also filter. and also coolant, with the coolant lines what hose do i need to drop to get all the coolant of of the block?

 

[Turtl3]

I would do the coolant before running it cos there is no filter to catch all that crap. I would drop the bottom hose, remove the thermostat, jam the garden hose in it and run it until its clear water coming out the bottom...
This isnt a proper cooling system flush...just a flush to remove all the dirt and debris that has gotten into the galleries

I would also dump the oil for much the same reason before starting the car, even tho it does have a filter...and then do it agen after the 'running in'

 

[dat111]

somebody decided to do the close clamp up on the most retarded angle its actually turned up towards the fans are.. some bloody twat has done that -.-

where can i buy a drain tray? and wheres an appropriate place to tip it? would the garden be ok?

 

[Turtl3]

drain trays can be had at most auto stores...or just go buy a slimline black plastic storage container from bunnings...certainly do not put it on ur garden unless there is an area that u never want anything to grow in again haha.

now, im not advising this...but i know how often it happens...it tends to go down the drain at home. really it should be disposed of properly.

as for the angle of the clamp, i think u will probably find that it was done up before the fans went back in. just make sure u put it back in a more accessible position lol

 

[supercharged-ride]

When taking carbon off what i have done is to bring each piston level with the top, fill the other bores with clean rags and use a rotory wire brush on a small angle grinder (DO Not press hard into the piston) only enuff to remove the carbon, blow it out with air and clean the bore with clean rags and air when moving on the the next piston.
I know a lot will say not to do this but i have every time i have done a VRS set replacment (I have done 5 in my life time)and have never had any problems, lol maybe i'm lucky

 

[Turtl3]

Ive also found that using a drill instead of a pneumatic angle grinder is much more gentle on parts when using a wire/brass brush, as its rotating speed is 1000's of rpm less. Its also alot quieter lol