8.1 tune review

[ryanvv355]

Can any of my peers here look at this tune and give me thoughts, engine has a small cam, unsure on cam specs anymore, but its not that aggressive. The engine went about 1000 miles after rebuild and put two pistons in the oil pan. Engine builder said the valves got hot and broke due too lean condition. Don't know if the blame game is going on. When I tuned it the max timing I saw at WOT was 23* and wideband was used in passenger side exhaust. AFR error was within 2%.

Truck is lifted on 30's with 4.10's. Not used to tow, just a driver.8.1.hpt

Thank you.

[jc052685]

Without knowing what the actual afr was during failure there is not much we could tell you from the tune other than the timing in that map looks safe.

When did the engine fail? driving down the road or running wide open getting on the freeway? If it was not under pretty reasonable load then it would be hard for a lean condition to hurt the engine. You should be able to gather quite a bit of information by examining the failed parts I would imagine.

[ryanvv355]

That's my thoughts exactly. I normally tune conservatively to avoid issues like this. I attached a picture of the valves, the broken one is broke clean, no sign of deterioration at the break. Engine builder says the valves are too blue and got hot.

Waiting for more info from the owner, this happened a few months ago. I told the engine builder the timing and AFR and he seemed to think that was OK, until now.

unnamed.jpg

Hell it could be China valves, IDK. Its all rebuilt so who knows the source of the parts.

I had pictures of the pistons literally in pieces in the oil pan.

[jc052685]

Well most all of the trucks (including your tune) will only go into PE above 90% throttle. That means they are targeting 1.0 lambda even at nearly wide open throttle even when pulling a trailer. They do this for fuel economy. Cant say I see anything wrong with the color of those valves from that picture. Most likely just a part failure.

[GHuggins]

3 of those exhaust valves did get pretty hot including the one that failed - the furthest to the right that appears hot actually discolored all the way to the rocker contact area... Is it your fault - well I would activate PE sooner, but I very highly doubt it... Either air flow to those cylinders was more which would show with reading plugs or you had individual injectors not flowing the same which would also show with reading plugs... BUT this could have been something that recently happened - maybe he got some high ethanol fuel or junk fuel that had trash that caused restrictions - can't really tell until it's back up and running unfortunately... You can inspect each injector for trash, but that's about it... He could of even had a fuel pump going out that caused this... Engine builder is just looking for somewhere to point their finger

[Custompowr]

I'm new to the forum here and to the newer style factory engines but that is a floating wrist pin engine correct? If you had a lean condition with the tune then all cylinders should show signs. Rod bearings (upper halves mainly) and pin bores show detonation. Obviously with individual injectors feeding the cylinders, a minor particle can skew all results of fuel output. Need more info on broken parts but sounds like a parts failure. Heat that high up on valve stem seems more like a guide clearance issue, not a tuning issue. Then again I'm new to this side of the the world (tuning), and street engines. Just some food for thought!

[ryanvv355]

Thanks for the replies, guys. I received more info from the owner. The truck was just restarted after fueling. He pulled out into traffic "at a modest throttle" and when he lifted is when it went. Also learned that the engine is at a different machine shop than originally built it. I trust the shop that has the carnage now. He told me he literally scrapped black goo out of the exhaust ports on all cylinders. Keep in mind this engine had under 2k miles on it.

Custompowr, I was thinking the exact same thing, too tight of valve guide clearance.