Decarbonizing advice please

Hey Guys,

Can you please give me few tips on how to get rid of the cylinder wall & piston crown, etc etc carbon/soot buildup?
I know I can pour little bit of water in the intake of fully warmed up engine.
I'm wondering whether there's more effective method/chemical I can either pour
into the intake or add to petrol to brake down all the carbon soot crud from the engine bore.
Of course, I can pull the cylinder head out and do a manual scrubbing, but that bit too much work for me right now.
Compression readings are bit too high(180-190 range) on all cylinders & I can clearly see soot on the cylinder wall when I point a light at it through the spark plug hole.

Any tips, advice are very much appreciated.

thanks

P.S. Vehicle is an RB30 Patrol, carby.

i did that cleaning of the engine once to and old engine... long story short ended up rebuilding it. the carbon could be helping your cause, i removed the carbon then it started blowing lots of smoke of the blue variety.

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Originally Posted by garett

i did that cleaning of the engine once to and old engine... long story short ended up rebuilding it. the carbon could be helping your cause, i removed the carbon then it started blowing lots of smoke of the blue variety.

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Yeah, the thought has crossed my mind, but the compression is bit too high for any comfort, do you think?

I thought getting the compression down to 170 or near there might be healthy for the head gasket & head.
I'm also bit worried about timing mishaps & fuel consumption 'cos of the hard soot inside the cylinder(especially on the piston crown).

How did you clean?

google Subaru engine cleaner or upper engine clean

Found this stuff.

http://www.ebay.com.au/itm/Subaru-up...25.m3641.l6368

and this

http://www.supercheapauto.com.au/Pro...rb-366g/348781

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Originally Posted by garett

google Subaru engine cleaner or upper engine clean

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May be I can scrape off the soot on the piston crowns by inserting a flexi stem brush through the spark plug hole, attached to a drill?!!
Does that sound like good idea to you?
I mean, if the soot on the cylinder wall is helping me with a better pistion ring seal, then I shouldn't remove the soot on the cylinder walls, but remove the crud from the piston crown only?!
After that, I reckon I can use a vacuum clean to suck the dust out?
Thanx

Quote:

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Originally Posted by dom14

May be I can scrape off the soot on the piston crowns by inserting a flexi stem brush through the spark plug hole, attached to a drill?!!
Does that sound like good idea to you?
I mean, if the soot on the cylinder wall is helping me with a better pistion ring seal, then I shouldn't remove the soot on the cylinder walls, but remove the crud from the piston crown only?!
After that, I reckon I can use a vacuum clean to suck the dust out?
Thanx

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I would definitely NOT do this. There is no chance you will be able to clean all the loose carbon out and it wont be long until you have lowered your comp pressure by a shit load. You're better off doing nothing at all than trying this in my opinion.

Sent from my SM-G930F using Tapatalk

as above use the subaru cleaner or just leave it alone, 180psi is perfectly fine and more comp is definetly better than not enough

Thanx guys.
I did a bit with water today. It appeared to have "helped".
I've had no blow-by for past few days, and blow-by is back on high revs. :D
Water must have broken off a bit of soot on the piston walls, but I reckon it can't
do much with the piston crown's buildup of soot.
I'll leave it alone.
The good thing is that I was able to get the rich idling carby to idle closer to blue flame(Gunson) by playing with ignition timing & mixture screw. Timing is 15BTDC, and it idles fairly ok with blueish flame.
Only issue is it's pinging for a fraction of a second when I pump the accelerator.

What do you call high revs?

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Originally Posted by nissannewby

What do you call high revs?

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3.5 - 4k ?

Dont they red line at like 5500 or something around there?

Quote:

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Originally Posted by nissannewby

Dont they red line at like 5500 or something around there?

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Yeah, red line starts at 5.5k & the gauge shows upto 8k. I guess RB30 is one of those engine's we can rev safely upto 5k.