Jeep Strokers

Most of you have have probably seen at least one of my threads regarding my stroker issues and I've got some info that you may find interesting. First off I''m 100% certain that the cam failure and valve spring failures had nothing to do with improper assembly or the fact I'm running a stroker, or that I'm cursed. Sometimes shit just happens. Okay? Alrighty then...

I'm a fookin' moron for running E85 in my heep! Yep I admit it. I read stuff on the WWW and believed that my rig was more than capable of running on E85 without further modification.
WRONG!!!!!

I got a call from the machine shop today and Robbie proceeded to tell me that all of my intake valves were useless because they were tulip-ed (like the flower). He also told me that they also should signs of getting very hot, so much so that the stems near the head were blue. He also told me that the cylinder head should signs of excessive heat as well.

Needless to say I has floored! I knew I was going to need a little machine work to replace a guide and a valve seat, but now I'm looking at at least 3 new seats and 6 new intake valves.

Here's a pic of the #1 combustion chamber. The yellow arrows point to the discolored area adjacent to the exhaust seat. The metal has yellowish color that turns to blue as you get closer to the valve seat itself. Hopefully the picture quality is good enough for you to see what I'm trying to describe.



Here's another chamber without the arrows added.


So what was the root cause? Insufficient fuel. Yep, that simple. In order to run E85 the Pulse Width must be increased to allow for more fuel to reach the cylinder. The extremely lean mixture burned so hot that the margin of the intake valves bent, giving it a concave shape.

So what now? 6 new intake valves, 3 new seats, removal of money from the bank to pay for it.

I know that some of you are wondering why the exhaust valves weren't affected and I asked the same question. Basically it's because the exhaust valve is smaller and the margin is larger than the intake valve. This should clarify it...


Just so there's no confusion, this is not a result of simple overheating. It's all about improper combustion as a result of poor fuel management. I've got no one to blame but myself for this one.

Flame suit is on, have at it folks.

hmmmm. ive read SSSOOOO many stories of people running E85 on normal stock 4.0 XJs with no ill effects. guess you cant believe everything you read online....

The problem is that you don't know about it unless you open up the motor or you have a major failure of a valve or piston.

Frank thats terrible.... Thank you though for the pictures and the input. I think its important for people to be aware of how dangerous a super lean condition can be. I really need to get a wideband O2 to see whats going on.....

Were the pistosn damaged at all? any signs of melting?

Nope...pistons are fine.

He's giving permission to flame. . .
Way to be a guinea pig. I don't recall reading of your impressions of the e85, so?

Something to consider, http://www.dragstuff.com/techarticles/r ... plugs.html A fine art that's not done enough.
John

It's a learning experience when you try something new.

Do you think that the pulse width can be adjusted enough to provied enough fuel to allow E85?

Only with a piggy back module and probably wide-band o2 sensors as well.

FrankZ wrote:Only with a piggy back module and probably wide-band o2 sensors as well.

That would correct the open loop afr, but in closed loop the pcm is still looking for 14.7