charcoal/carbon layer an all intake related parts

[Nacho-RT74]

dissasembling my carb for a better tune up found all the throttle plate, intake and even intake ports at heads ( I removed intake to check some stuff more ) got a more less thick and HARD to remove charcoal/carbon layer sticked all around.

I didn't proceed to clean everything but just the carb. This layer was even on air vents at carb on top plate

what could cause this on a 10 months engine ( daily driver )

I'm getting worried about this.

I couln't remove everything, not even with EasyOff

[A383Wing]

Sounds like exhaust has been getting in there....does intake have an EGR valve? If not, maybe the intake is cracked where the exhaust crossover goes between the heads.

Bryan

[mhinders]

Big overlapping cam, or leaking intake valves?

[BSB67]

Backfire.

With all of the issues that you have, have you ever verified the balancer TDC mark to be correct?

[Nacho-RT74]

I still haven't got any backfire.

at least when when I assemblied the engine, damper mark was aligned with TDC perfectly.

mhinders, cm is 282HDP crower, 112 centerline. I don't thing big overlap.

intake is eddy 2186 but sealed EGR provisions. I got it used... craked ?? ouch. that would be bad and hard to check. How I can check for that ?

[mhinders]

The Crower 282HDP seems like a pretty hot cam, can't find any detailed info though. Yes, I think this one will blow exhausts into the intake at low rpms...

[cdr]

A CAm with lots of overlap & a really crappy exhaust system will cause that

[cdr]

also an over advanced cam with crappy exhaust will be real bad on intake reversion ,ie exhaust pushing up into the intake 

[Nacho-RT74]

14º initial, 2.5" exhaust HP manifolds, no crosspipes

[Nacho-RT74]

The Crower 282HDP seems like a pretty hot cam, can't find any detailed info though. Yes, I think this one will blow exhausts into the intake at low rpms...

never would think this is a HOT cam

[cdr]

14º initial, 2.5" exhaust HP manifolds, no crosspipes

not ign timing,,,,,was the cam deg in when it was installed ? i see you have been having pinging problems,an advanced cam can cause high cyl pressure also

[firefighter3931]

The Crower 282HDP seems like a pretty hot cam, can't find any detailed info though. Yes, I think this one will blow exhausts into the intake at low rpms...

The HDP 282 is not really that hot of a cam profile and it does have wide lobe centers (112* lsa) and a nice split (8* extra exhaust duration) so it's a restrictive exhaust (manifold) friendly grind. Short overlap 

I'm thinking the detonation issue is tuning related ; specificly the fuel curve. 

It would be interesting to see the A/F ratios with the engine under load to observe how lean it is under those conditions. 


Ron

[Nacho-RT74]

Dunno if you have read all my pinging thread Ron... It looks is mixture related and I'm still playing with that.

[Nacho-RT74]

14º initial, 2.5" exhaust HP manifolds, no crosspipes

not ign timing,,,,,was the cam deg in when it was installed ? i see you have been having pinging problems,an advanced cam can cause high cyl pressure also

not degreed just flat point to point at 0 degres. The summit roller timming set gave me to advance or retard 4 degrees. I just went 0.