Carbon buildup update

[Billy]

Ok I was in two minds whether to start this thread as it has become a topic of much heated debate recently.

But I thought people still might be interested on how Pippyrips old car is doing since it was first cleaned a few months back.

The car was at MRC recently and while there I asked Doug to clean the valves. This wasn't because I felt the car was down on power at all, I was just curious.

Here are the pictures from when the manifold was first opened














The manifold was then cleaned, ported and poilished.


Here are the pictures from when the manifold was removed again 2000 miles later









The manifold was cleaned once again and here are the pictures 6000 miles after that


















So thats where it's at now.

To me the there doesn't seem to be any difference between the 2000 mile and 6000 mile pics.

So while not preventing it completely I think the work MRC did definitely had a postive effect on reducing the buildup over time. Maybe this is as bad as itl'll ever get, we'll see.

Whether you believe this to be significant in power debate is upto you. All I will say is while I admit I'm no engineer, seeing the pictures from when it was first opened up compared to the last ones. If someone showed them to me and asked which engine do you think is putting out more power?

I would say the last ones. But like I said I'm no engineer so I'll admit I could be 100% off the mark.

But don't get me wrong, I love the car. It's single handedly the greatest thing I've ever owned, and it's not really an issue for me as I knew all about it before I even bought the car. I was just interested to see if the buildup continued to get worse.

But it doesn't seem to be.

Big big thanks to Doug and everyone at MRC!

[HYFR]

how much does the clean, port and polish procedure ? pm is prefer

[Billy]

Tbh David I'm not sure of the price on porting and polishing, that was done when Rob had the car.

The cleaning is 10 hours labour, so £58/hr+Vat

[Outtlaw]

Thanks for letting us know how its getting on, this is something ill consider having done later on.
The carbon build up doesn't look bad at all after 6000 miles, please keep us informed. Cheers Peter

[rAudiguy]

Billy,

I was under the impression from Rob that MRC had come up with a solution to prevent this from happening or at least reducing it futher and that this was fitted after the 2000 mile clean up?? A catch can of sorts? If it was then I guess it doesn't work but if it wasn't is this still something they are working on? either way it's a real shame to see how quickly these dam things get clogged up!

[Billy]

Hey Jim,

Well to quote Rob "MRC skipped the catch-can idea and went one stage further, completely blocking off the inlet from any oil etc and fitting a VTA filter.

The positioning of the filter (had to be up high to allow drainage) was a bit of an issue as it caused fumes to enter the cabin when stationary though I quickly learnt I could combat this by switching to recirculate when coming to a stop!

The bigger issue was when she was opened up again, although the valves weren't as bad they were covered again. The only explanation they guys could think of was it must be some of blow-by coming back form the cylinder head.

Ultimately, (if you do want to keep your valves 'clean') the only option is to manually clean them every once in a while."

The carbon does seem to buildup again, but it doesn't seem to have got worse from 2000 miles to 6000 miles.

[ArthurPE]

so the bottom pics are after 6000 miles?
I would expect that looks like any DI car with 6k miles, honestly
I'll be curious to see it at 25k miles or so...

edit:
so the crankcase is completely isolated?
so the oil can't be coming from the blow-by...

it has to be coming from the valve seals...and perhaps a bit from ring leakage...but most of that would be burned...

since it appears to be the seals I would expect formation to be linear...
5k miles 1 mm
10k 2 mm
15 3 mm
...
until it is restricted enough that the velocity has increased sufficiently to scour them to prevent further growth, self limiting, like all of good mother natures (physics) processes...

[Billy]

so the bottom pics are after 6000 miles?
I would expect that looks like any DI car with 6k miles, honestly
I'll be curious to see it at 25k miles or so...

Well maybe Arthur, I don't know.

It just struck me that there was no difference between the deposits of 2000 miles or 6000 miles.

Doug even mentioned he'd seen worse after only 5000 miles.

I too am curious to see how it pans out in the future so we'll just have to wait and see.

[ArthurPE]

Well maybe Arthur, I don't know.

It just struck me that there was no difference between the deposits of 2000 miles or 6000 miles.

Doug even mentioned he'd seen worse after only 5000 miles.

I too am curious to see how it pans out in the future so we'll just have to wait and see.

good point...was the breathing system removed prior to the 2k inspection?
ie, when they were previously cleaned
or was it removed at the time of the 2k inspection?

if it was removed then, it may be the problem, becasue there appears to little growth from 2k to 6k...

[Billy]

I honestly don't know Arthur, maybe if Rob see's this he'll have a better idea.

[ArthurPE]

I honestly don't know Arthur, maybe if Rob see's this he'll have a better idea.

that would be some very telling information...

the filter canister they used, much oil in it?
do you have a pic of the set-up?

[SR71]

As I understand it, what Billy is saying is the first pictures are from the car with about 25K on them?

Off the back of the 2000 mile result, didn't Doug return the car to its default config because it was clear that even blocking the return line to the manifold was not stopping the deposition?

I'm curious about the discolouration of some of the valve stems?

Is that significant?

[ArthurPE]

the first pics are after 25k miles, prior to intial cleaning?
the second set, 2k miles after that? and then cleaned again?
the third set 6k miles after that?
first pics have 25k miles, no cleaning
second 2k miles, after cleaning
third 6k miles, after cleaning
correct?

hopefully he'll let us know when in the sequence of events the breathers were disconnected...

[Billy]

Yes thats correct, athough the work first began at 20k miles.

I think maybe your right SR71, and the car was returned to default after the 2000 mile experiment.

[Terry1948]

I ought to go on confused.com. Is it a fact that all FSI engines suffer from this type of carbon build up? and no one has noticed this before because there has been no significant power loss or any other engine problem to warrant opening it up and thus seeing the build up. I am not an engineer.