YES and discolored like from lean/heat but widebands show rich, 3 different widebands have verified this at different sessions.

maybe a day or two

did you bevel the exhaust ports?

If the porting was done wrong it would cause that edge to be rounded. But if

JRs is Ito's shop then thats not even a possibility.

Well its has to be either bad housings or bad porting. What else woulc cause that rounding?

You ask about the the OMP failing. I am hoping your premixing. I doubt this is your main problem but it could be contributing to it.



you should run 8 oz. of premix per tankful.

We're not sure if mike's exhaust ports were bevelled, we'll have to talk to the builder about it.



This is something the tuners asked about also. Please elaborate on the effect that not beveling would have. The leading edge of mike's seals have a slight convex curve to them on the sections that are outside the exhaust ports. The part of the seal that passes over the exhaust port does not have the same convex shape. Instead the curve seems to have been worn down so that top of the seal comes to a point with two straight sides rather than an overall arc.



Non exhaust port area shape:

<span style='font-size:14pt;line-height:100%'>)</span>



Exhaust port area shape:

<span style='font-size:14pt;line-height:100%'>></span>



In the last photo I attacked you can make out where the two planes ( / and \ ) come to a point. The each face (symbolized by a "/" in the previous sentence) of the point is black in color. By contrast the area where the two planes meet is silver in color and at the same height as the center of the convex curve for the edge of the seal that does not pass over the exhaust port.



Bear in mind that the difference is extremely subtle, but then again all these motors had less than 2,000 miles on them.

Well it does appear the oil injection is working as you can see where it is clean in the center of the burned apex seal. And yes you should be premixing.

Does it look like this? or does the apex seal hit a sharp flat edge?



https://www.nopistons.com/forums/upl...1071187191.jpg

We're not sure. We're thinking of using a medical scope to see if we can catch a glimpse of the seals through the exhaust port. If we are able get access to the equipment we'll check out the port edge too.

Just got back from NYC/LI.....



Hey Mike,

Sorry that the motor isn't working again. I'm clueless as to why the engine keeps eating up apex seals. For those that are curious about this, here're some findings I notice on his car.



First, I don't think there was any fuel issues with the car since we verified the spark plugs almost every 3-4 pulls (reclean them before putting back in). On the first couple of pulls where I dial the a/f in so that I could barely see it register on the wideband. After we pulled the spark plugs out, we notice a very minor color difference with front and rear plugs (not even very noticable unless you looked at it very closely). Knowing mike's engine has suffer melting front apex seals, I decided to richen up the primary injector by 8% (2.7% overall in total fuel). We made 2-3 more pulls (a/f ratio was below 10 where we couldn't even register). Pulle the plugs back out and saw that the front was richer than the rear, I then lean out the front offset to 5% over the rear (1.8% overall in total fuel), make a few pull and then recheck the plugs. It was still running rich, so the final offset adjustment ended to be 2% (.7% more than the rear). Which is negligible (if you think about it). Now that we know both front and rear offset is dial in, we then slowly lean out the a/f to try to tune it out. I tried to tune his car to around 10.5:1 because of mike's past engine history. There was a few times where it the a/f hit 10.7-10.8 but not many time has it get close to 11:1 a/f ratio. As we started to make more pull, the engine vacuum started to drop. It wasn't much noticable at 11psi but when we slowly turning the boost up, the vacuum drop was definately noticable and was evident that the issue still exist. We pulled the plugs out again to check, everything seems fine and shows signs off running rich. The only thing I could really think off is the exhaust port or the shape of the port causing it to run higher EGT than normal. I couldn't verify that w/o knowing what the port looks like but after looking at the worn out apex seals (after the tuning), it seems like that it couldn't have been caused by lean a/f ratio but rather very high EGT at the manifold or the exit of the port. I wish we could have made another pull on the dyno to see how hot the exhaust manifold. Also the turbine wheel and see if there are any abnormal wear caused by extreme thermal conditions.