Rebuilt Engine 1st startup: intake port soot?

[Grubby]

I started up my D24t/240 project motor and it ran wonderfully. The engine is a rebuild, and this was its first startup. Afterwards, I took the intake manifold off, and noticed that one of the intake ports had more soot lining it than the rest, which were relatively clean. Not like solid black, just a good dusting of soot. I also noticed in each port, a thin, black drip of something burnt. Any ideas why this might happen? If so, is it typical for this to happen during a break in period, or do I have a problem? I'm probably being really paranoid, but just wondered what people thought.
Any ideas or explanations from you guys would be appreciated.
Thanks,
Abe

[Jason]

Sounds like a tight valve or the cam is slightly out of time. Where is the black stuff comming from.?

Jason

[Grubby]

Originally Posted by Jason

Sounds like a tight valve or the cam is slightly out of time. Where is the black stuff comming from.?

Jason

Jason the dark black stuff is coming from somewhere in the ceiling of the intake port. It is a very thin drip line and its present in all ports. I like your tight valve theory because none of the other ports are sooty. Why would a tight valve do that?

I will wipe them all out before I replace the intake and check it again when I adjust the valves. Its only been through two thermal cycles and hasn't been driven yet, just revived it up and down both times to make sure the thing was good. I will be driving it this weekend. I have to torque the head bolts afterwards so I will check everything out then. Thanks Jason.
Abe

[michaelovitch]

Originally Posted by Grubby

that one of the intake ports had more soot lining it than the rest, which were relatively clean. Not like solid black, just a good dusting of soot. I also noticed in each port, a thin, black drip of something burnt.
Abe

so it's all of them, with one more visible ?

it's all of them first
then, one of them more than the others.

soot is exhaust gaz exiting by the non closed intake valves during compression strokes maybe.

seats have been machined i guess.
the guy did valves adjustment ?

is it difficult to start the engine ?

why to torque the heads bolts ?
it's supposed to be done if you ran the engine.
the mls gasket do not need re torquing as i know.

are you sure your intake gasket is not leaky and let your head to suck soot ?

[Grubby]

Originally Posted by michaelovitch

so it's all of them, with one more visible ?

it's all of them first
then, one of them more than the others.

soot is exhaust gaz exiting by the non closed intake valves during compression strokes maybe.

seats have been machined i guess.
the guy did valves adjustment ?

is it difficult to start the engine ?

why to torque the heads bolts ?
it's supposed to be done if you ran the engine.
the mls gasket do not need re torquing as i know.

are you sure your intake gasket is not leaky and let your head to suck soot ?

Actually, this is a possibility: the intake gasket at that port could have been leaky because I didn't use a torque wrench on the bolts (I realize now I should have, and I will next time), but wouldn't I see soot on the gasket? I'll check it. Also, I'm not sure what you meant by torquing the head bolts: do you agree with doing this or not? I'm going to do that per the manual (90 degrees) either before or after my next thermal cycle. I plan to check the valve clearances too.

[michaelovitch]

the head gasket :

if volvo or equivalent oem
it's there

http://www.scribd.com/michaelovitch/...sket-mls-volvo


you don't need a torque wrench for the intake manifold.it's overkill here.
tighten from the center ang one left one right
then check from one side to an other.

if it's loose it will suck of course but you should check your valve first like it was said.
but it seems strange that all your valves are out.


are you sure it's not a residue of some assembly or cleaning product of stuff like that let by the builder ?

[Grubby]

Only one port has soot. The rest are pretty clean. I will be checking and adjusting them this weekend. Thanks for the link.