MX5 engine

[richie]

Hi Everyone
I don't know if anyone can help, but i have stripped off the inlet manifold today so that i can get it blasted and painted.
What i have noticed is that i have a black sooty kind of sludgy mess on the inside of the manifold but mainly around the butterfly area.
The engine appears to be running OK and didn't show any problems as i drove it home for 60 miles.
so does anyone have any suggestions as to what the cause is and is it some thing to worry about.

Richie

[slimy]

I don't know the particulars of the mazda engine, but on other engines they're usually recirculated crankcase gases, burnt to reduce pollution rather than simply vented to the atmosphere. It can lead to some build up of sludge in and around the inlet manifold, and as you say near to the throttle butterfly due to the airflow.

You might expect that on a fairly high mileage car (>50k miles), it does just build up over time. I've never found it anything to worry about, just wipe it off.

[richie]

Hi Slimy
Thanks for your help with this, that exactly what i am going to do and just see how the engine performs over time.
Richie