SBC cylinder #8 debri / mess

[mtrhead]

This is cylinder #8 on my 410 SBC. Car ran great with no known issues. The whole RH bank is rather dirty but no particles like #8. The other LH bank is rather clean or more normal looking. All gaskets were sealing and the car never blew smoke or burned oil. Maybe 2500 miles max

I was pulling down the heads to change setup. The setup is about 11/1 static compression with .037 squish The teardown happened after a good 2800 rpm highway drive for 45 minutes with little idling.

100% race gas since new. Cam 2 and sometimes leaded Turbo blue What are these pictures saying?

Thank you

piston top.jpg

combustion chamber.jpg

port view.jpg

[Carnut1]

Looks like ash from oil getting into chamber. If the back of the intake valve has coked oil it is from the guide. Oil in the intake port may be from leaking intake manifold gasket. Oil could be coming from the rings as well. Thanks, Charlie

[Newold1]

Charlie has covered all the most likely possibilities. It is obviously burning to much oil.
Could you post a pic of that cylinder bore as well as a few others that are not burning this much oil.
Is the valve guide on that exhaust or intake missing seals or have a lot of wear (slop)?
Is that intake port for #8 wet with oil?

[naukkis79]

Lead deposits, probably #8 is a bit leaner than rest of cylinders, burning hotter and making lead to more sticky. Personally I think nobody should ruin their engines with lead - lead will always make some harm to engine.

[mtrhead]

Lead deposits, probably #8 is a bit leaner than rest of cylinders, burning hotter and making lead to more sticky. Personally I think nobody should ruin their engines with lead - lead will always make some harm to engine.

That's what I was thinking and that's why I posted Leaded gas sometimes. I try not to burn it when possible but the local supply of Sunoco 104 ran out.

I will get pics this week of the other areas questioned. I will say the gaskets were fully compressed and in 2000+ miles never had to add oil.

[Newold1]

We know heavily leaded fuels can load up with some deposits like some of those, but why would that be so much worse on cylinder 8 only. It still looks in the pics that there are definitely more oil in the chamber than one would like to see.

[governor]

Will your fuel system allow you to run E85, it burns very clean with the correct tune. But I agree oil from guide seal or a ring issue.
Did you happen to run a compression ck before pulling it down?

Gov

[mtrhead]

Looks like ash from oil getting into chamber. If the back of the intake valve has coked oil it is from the guide. Oil in the intake port may be from leaking intake manifold gasket. Oil could be coming from the rings as well. Thanks, Charlie

Back of the valve was messy - all intakes on that bank looked wetter than one would expect. Gaskets were sealed

[Carnut1]

Check guide clearance. That looks like the problem to me. Thanks, Charlie

[mtrhead]

Check guide clearance. That looks like the problem to me. Thanks, Charlie

will do, also did a little google searching and it appears as if others had issues with these heads. The spring pockets are extremely deep and hold a significant amount of oil. Another company, ATK special orders these heads with casting/machining changes due to oil issues that sound similar and other head porters machine a ditch for oil drain back. Maybe I'm experiencing what ATK addressed with Profiler? They have less that 2500 miles - 100% street cruising - Brad Penn 10/40

[Carnut1]

Check guide clearance. That looks like the problem to me. Thanks, Charlie

will do, also did a little google searching and it appears as if others had issues with these heads. The spring pockets are extremely deep and hold a significant amount of oil. Another company, ATK special orders these heads with casting/machining changes due to oil issues that sound similar and other head porters machine a ditch for oil drain back. Maybe I'm experiencing what ATK addressed with Profiler? They have less that 2500 miles - 100% street cruising - Brad Penn 10/40

I have not worked on those heads. Good fitting guides ( I like them honed to size) and quality seals you should be fine from oil issues. Thanks, Charlie

[Newold1]

Back of that intake valve tells me that two things are not right with that oil entrance point alone.
1. Either valve guide clearances are so big it's sucking oil in even past whatever valve guide seal if there.

2. The valve guide seal is not working on those intakes.

What seals are being used? What is the measured valve stem to guide clearance?

[cjperformance]

Do you have rocker stud threads that cut thru into the intake port?
I have seen just 1 or a few that pull oil past the thread and into the intake port. Reseal the thread and all fixed.

[mtrhead]

Back of that intake valve tells me that two things are not right with that oil entrance point alone.
1. Either valve guide clearances are so big it's sucking oil in even past whatever valve guide seal if there.

2. The valve guide seal is not working on those intakes.

What seals are being used? What is the measured valve stem to guide clearance?

Bought the heads and valves brand NEW from one of the more popular head porters who used to post on here. Never checked clearance because he ported the heads and did the valve job. So no idea what it was setup at.

Bought FelPro viton seals new from Summit, New PSI LS springs with New Shaft rockers. NO HOLES through casting into the ports.
Assembled and ran for about 2 years. Never had visible oil burning or excessive oil consumption. So never expected this when I pulled the heads.

[Carnut1]

If they were set up correctly which is possible but the geometry is off that could cause guide wear issues an well.