In the process of installing my Cosworth IM, I found that the frontmost intake valve seems to have A LOT of buildup on it. Here is a pic. It's the valve closest to the timing chain.


Going to do a compression test now...

Car drives/idles perfectly fine, and I haven't noticed any loss in power. Seems to me it could be a weak/failed valvespring... any ideas?

 

Cant you clean it out it easily?

What filter u have on ur greddy tt intake? Maybe its letting sludge in....

 

If it was gunk in the intake charge, I would assume both valves would have at least something on them. The right valve looks really clean.

Is it only this cylinder?

Tom

 

Yes, only the one cylinder. Talking to my buddy who builds engines, he thinks it's my PCV line feeding crappy, oily air to that valve since that's the valve closest to where the PCV feeds into the intake manifold.

I have an APS TT with the K&N style filters. I don't think it's an air filter issue since it's only 1 out of 12 intake valves.

Just ate lunch, compression test to come...

 

Then that other valve right next to it would get some residue also. It has to be a leaky valve. A leakdown test would allow you to detect escape of air through that valve to confirm. Though if the compression comes through fine I wouldn't worry about it. You're just losing some power depending on the size of the leak.

 

Losing power is the story of my life with this car...

 

+1 on leaky valve. If you look at the pattern it appears to be spreading from the valve seat, not coming through the intake.

 

Leaky valve stem seal?

:edit, sorry didn't read the replies before I posted:

 

Phunk brought over his leakdown tester and we didn't really resolve anything. The front two cylinders both showed about 20-25% leakdown on his gauge. He thinks his gauge might be on it's way out though, so who knows. The small air hiss coming from the front intake runner was exactly the same as when we did the next one back.

So basically another cylinder with perfectly clean valves showed the same results.

The car has been running perfect, so I'm just going to put it all back together and enjoy it.

 

Do u think u need a retune with that plenum?

 

Yes, I'm going to re-tune it, along with my new meth injection...

I sure hope the Cosworth flows enough more air to necessitate a retune

 

^ it does.... I need a retune after installing mine.

 

The meth should clean that out

 

Could you please try Zmax oil/ fuel additive, run it and re inspect.. Im wondering if Z max actually works.. lol It wouldnt hurt..

 

The intake valves already have fuel being sprayed right onto them. They should always be shiny clean.