Cylinder #6 exhaust port resembles a volcanic cave

[944 boy]

So I pulled the heat exchangers off to see if they can at all be salvaged for the time being. I got looking at the exhaust ports and noticed some I liked and some that I didn't. Being new to the 911 motor I would like some expert eyes to give me an explanation. I am assuming that it could be a bad valve guide/seal. The motor has been apart at some point in its life. I am not sure on all the details of what has been done. Looking through the injector holes (new o-rings) all the intake valves looked fairly clean and shiny, I don't think I was able to get a good look at the back two cylinders especially #6. So it may be another story. Also the motor has only run about a total of 10 minutes or so in the last 8 years. So I have not even run it through a full heat cycle yet since I have owned it. As far as I know it is still a stock configuration 2.7.

Cyl. # 1



Cyl. #6

[James Brown]

yeah looks like crud, might be residual fuel carbon but, the valve guide is a tad wet. see the white edge of the carbon shows that it got real hot, might be oil carbon. since it faces down, you can scrape most of it out, make sure the valve is closed. i would definitely look at the #6 injector with zeal now or swap out #1 for #6 injector

[944 boy]

I rebuilt the Fuel distributor and did a flow check on the injectors. They were as even as i could measure with un-graduated containers.

I have the parts and tools to check valve clearances but have yet to do that as well. I will also be doing a compression test this weekend. I am mostly still checking out the motor for any MAJOR issues that require an immediate tear down.

[James Brown]

yeah it could be very old stuff that has been in there for a long time. Good that you flowed the injectors just clean and go!! Can you do a leak down test?

[Steve@Rennsport]

Looks like a worn out guide & seal to me.

[James Brown]

oil coking ya think