Deposits in intake runner, what is this?

[BlurpleXJ]

Gents,

I've searched but I can't decide how best to phrase this to get a good result. I'm not exactly an experienced mechanic and learning as I go here. I dropped a fair amount of cash while I was deployed to have Russ Pottenger build me a stroker. It was then shipped to Tennessee where I had a shop install it in my '98 XJ. Now I've got hands on it, and have more than 3,000 miles on it. I've been chasing what I thought was an exhaust leak so I pulled the header and intake manifold to find that the fourth piston from the front has black deposits in the intake runner.

First, pistons 1-3 from front, which look fine:

intake.jpg

Second, piston 4:

intake 2.jpg

Should I be concerned about this? I also have what I think is a CCV issue that is coating the inside of my intake manifold with a fine coat of oil, trying to decide if that could cause something like this since #4 is closest to where the CCV enters the manifold as far as I can tell. I haven't pulled the plugs yet because I was racing a rainstorm to get the thing put back together. I'll be doing that shortly.

Specs, in case you need them:
Keith Black IC944 pistons for a 0.02 overbore (21cc dish)
12-wt crankshaft from a 258
Heat-treated Comp Cams 68-232-4
Stock style rocker arms
Comp Cams valve springs/keepers
Oversized intake valves (2.0 from 1.91)
Oversized exhaust valves (1.55 from 1.50)
Melling standard volume oil pump
Comp Cams two-row timing chain
Five-angle valve job, ported head, port-matched 99+ intake
24 lb/hr injectors from Five-o Motorsport

Thanks for any wisdom yall can provide.

[gradon]

You are most likely correct. Look inside the front valve cover hose, where it connects to the intake tube, throttle body, and intake manifold under the throttle body to see the oil trail.

[Russ Pottenger]

Hi Jon,
Glad to see you're back and safe. I left a couple of messages with Tyler but never got back to me.
Shoot me a call/email.

Yes check your CCV real good. The problem is always accentuated during the initial break in procedure as
there's always going to be some initial blow by as the rings start to seat in and seal.

[jsawduste]

To add to Russ's comments. The amount of reversion these engines see is substantial. The single inlet feeding 6 cylinders is one of the reasons. Plenum size is another. The black sooty deposits under the TB are clear indicators of the factors involved.

[SilverXJ]

I'd check the CCV, but what jsawduste is also correct. If noting is found with the CCV I wouldn't worry about it.

[Russ Pottenger]

Doublecheck and make sure you're using the vacuum port on the manifold closest to Throttle Body.
The reason is the other vacuum port is more centered over number 4 intake runner.

Your valve cover has 2 90°elbow's. The front one is open. The rear elbow is restrictive. I'd consider replacing it with a open elbow like the front and put a straight inline PCV valve and 3/8 hose.
The "best" location for the vacuum port would be on the side behind the Throttle Body. That way it pulls from the plenum not the runner.

[BlurpleXJ]

Thanks guys. Good to have a more experienced perspective on this stuff.

Hi Jon,
Glad to see you're back and safe. I left a couple of messages with Tyler but never got back to me.
Shoot me a call/email.

Yes check your CCV real good. The problem is always accentuated during the initial break in procedure as
there's always going to be some initial blow by as the rings start to seat in and seal.

Russ, good to hear from you. I forgot how often you frequent this forum. I'm sorry to hear that Tyler was unresponsive. I'll get in touch via email. I haven't had any problems I for which I'd point the finger at your engine work, so I've avoided getting in touch directly with you over small stuff. However, I'm chasing a few issues getting the whole package to work together, and would value your advice.