Engine Decarbonising
- Thread starter graham.webb
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edh
New member
OK Oli - here's the info... bear in mind this is a 234K engine, nothing done to it as far as i know apart from new cams etc.. 5 years ago. Uses a little oil on track, running Mobil 1 10w60. I bought the stuff from a local garage - just looked on the Forte website for my nearest. I also bought a bottle of gas treatment, which goes through the fuel system but I haven't used it yet. I checked compressions first - engine hot 180, 190, 175, 170 I stuck in the flush and ran the car for about 15-20 mins. After that I checked the compressions on 1,3 and 4. 1 and 3 hadn't changed much, up by 5 psi or so, 4 had gone up considerably. I decided to stick a few ml of the fluid into 1 and 3 and leave it overnight. This morning with oil drained, fresh oil filled, engine warmed, compressions were 192, 198, 180, 187 So a healthy increase in most, but still low in #3. The car has also had a cleaned K&N air filter and new plugs, so not surprisingly is running nice & smoothly. Had a quick run out, and the car is still fast [
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Indi9xx
New member
Glad you have seen an improvement Ed. When we get a problem 944 engine with low compression or oil consumption we often divide a flush or gas treatment between all 4 cylinders and left them over night, made sure the cylinders are clear, span the engine over and then put in the plugs and run it again, warmed it up and then ran another compression test. We have seen far more engines saved by this than we have seen remain condemned, our rule of thumb is whenever the bores look ok, the bore treatment tends to recover the engine, if the bores are scored it isnt going to work. The interesting thing is that we have seen similar results from using the flush or the gas treatment in the bores. The main thing is that this seems to soften the carbon or deposits that build up around the piston rings and allows the rings to spread under pressure like they should, with mild deposits I think this is possible with just the amount that reaches the piston rings from the flush in the sump, however when the deposits are heavy the bore treatment seems to do the job. It will be interesting to see if you see any improvement with the gas treatment through the fuel system.
edh
New member
Jon how much are you putting in each cylinder? (I only stuck a few ml - less than half a capful) - and how do you know the cylinders are clear? Now I have new oil, could I try more flush / treatment in #3 or do you advise an oil change afterwards? (I don't want to ditch £50 of Mobil 1 []) Ed
]) EdThat is interesting, thanks Ed. I'll be trying that soon. (Interestingly, I tried some fuel treatment a while back when it failed an MOT on emissions putting a deliberately strong dose into a few tanks of fuel. Emissions came down a lot, but I had also changed the FPR and engine temperature sensor.) If the Forte management board are reading this, then I guess I will be part of the Smiffy-Blip! Oli.
Pondering on this a little more, and particularly Simon's DIY-clean method, is there any reason why you shouldn't make up a mix of 50% fuel, 25% water and 25% acetone and pour this into the fuel tank when it's pretty much dry? Or even mix up equal parts of acetone and water and put this straight into a nearly-empty tank, on the basis that it will mix with the fuel that is already in there? Oli.
Veerzigzag
New member
This is a very interesting thread and at 160k miles I thought it a good idea to formulate a plan based on the many and various comments. Measuring compression routinely is an obvious start point, to be followed by appropriate treatment based on the results. If any pressures are low, the squirt of fluid through the plug holes, leave to soak, clear before reinserting plugs, run engine and then re-test is simple enough. Here's a very basic question though: presumably it is not a good idea to turn the engine over with the HT leads disconnected, so is there a simple method of stopping the sparks while taking the compression readings??
Yeah, I pulled the mail dizzy lead to stop mine sparking. So, after adding the treatment, you have to remove it before turning the engine over? How would you do that?
How do you tell if the bores are scored? By taking the head off? Or do you need a presumably pricey little camera on a wire? I'm rapidly heading towards a DIY service on mine, and would like to clean the engine up in the least intrusive way possible, and this thread is giving me some excellent advice! Thanks guys.
Veerzigzag
New member
The coil would then still be trying (but failing) to produce a spark and hence producing a very high internal voltage, which doesn't do much for coil longevity. One answer is to remove the LT wire to the coil but then that might mess up the engine management system. I guess the safest answer is to connect the (removed) plugs to the HT wiring and make sure the plug bodies are grounded, but I am not sure if that is overkill and would be interested to hear what the experts do.
Indi9xx
New member
Sorry, not checked back here for a bit. For a direct dose to the bores, we would split a gas-treatement or engine flush between the 4 cylinders. The next day it pretty much will all be gone, if not all.. drained past the piston rings and will have ended up in the oil. For any remaining in the bores, spinning over the engine with the plugs out and absorbant rags over each spark plug hole will get rid of any fluid remaining, or at least enough to make sure the engine will not suffer any hydrolocking.. but usually very little if nothing hits the rags.. its more a precaution than anything. To disable the ignition and injection during cranking, just pull the DME relay from the fuse box, this will cut out fuel pump, ignition and ecu power. For checking the bores for scores, we have always used an endoscope/borescope, once a really expensive gadget and our original one came from being an ex demo unit from a medical supplier, but now they can be bought quite cheaply, even for a snap-on one. Not sure if there would be long standing issues with acetone and fuel being in the tank, in particular I might be worried about the water settling out, causing any corrosion in the fuel lines, fuel pump, pressure regulator, fuel rail and injectors.. in theory the water when mixed would not be airated, so corrosion would be missing part of the chemical triangle for oxidisation.. Someone here may be able to shed more light on this. The other worry with fuel tanks is if the water acetone mix may be especially tasty to biological organisms.. May sound crazy, but over the years I have seen biological organisms flurishing in blooms within windscreen washer tanks and have read about similar problems with diesel fuel tanks, so might be worried about this kind of issue if the mixture was in your permanent fuel system for more than a short time However chemistry is not my strongest subject, engineering, physics, thermodynamics and computer science are my academic passions, not chemistry and biology, which like analogue electronics or the two stroke engine are pure witchcraft and not entirely to be trusted! One other thing is that I have not used this kind of mixture under load, such as driving the car on the public highway, so I might be worried about how the mixture may effect combustion under load.. on the one hand the water content should supress detonation, however on the other hand the BTU of the Acetone may throw things the opposite way.
Veerzigzag
New member
Thanks Indi9xx for the detail in the first part of your post above - very helpful to have the procedure for the through-the-plug-hole process, and the DME-removal tip.
George Elliott
New member
Jon, sometimes a local Engineering College or University can help with these things, its a case of making your idea their idea, and dressing it up into a project which the Insurance Risk Assessor will look at differently. The academics will calculate all sorts of stuff that you just know is OK. And they will have a really interesting project as opposed to studying the wipers on a Prius. [
] a word of thanks from me too for the info you have taken time to add here. George 944tI'd be cautious about putting significant quantities of acetone in the fuel tank - you might find it degrades the fuel hoses/seals - if it was only in there for a short time it would probably be OK, but I'd want to look up what the hoses and seals are made of first... And as Jon says, leaving the water in the tank would give you a big risk of corrosion - again, not an issue if it was only in there for 30 minutes or so... IMO The mixture would probably seperate into two layers over time- a petrol layer and a water/acetone layer.
My car is being serviced at the moment and I got them to split a Forte flush between the cylinders and leave it overnight as Jon recommended. I know the car had a replacement HG about 18 months ago and not huge usage since then so was hoping for the numbers to be relatively near the 145 mark for a Turbo. The before numbers varied from 137-141 so I was happy with that and the after numbers vary from 141-144 so I'm very happy with that. The garage told me that they drained off a sample of relatively clean Mobil 1 first and then compared it to the "black filth" they drained out after the treatment. Apparently the smoke coming out whilst it idled through was horrendous too! It then got an oil change to cheapy GM 10-40 and run through before another oil change to Royal Purple 10-40 a new filter and a new sump plug with a temp sensor installed in it:
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