sorry to hear it. ouch. i think you blew a hole in a piston also. the gasoline doesn't have the lubrication qualities of oil and wouldn't stop your rings from seating in my opinion. even if they didn't seat yet i don't think a breather would blow off and enough crancase pressure to blow oil out, only a blown pison would. you may consider yourself lucky though because you didn't have a crankcase fire.

jdelo,

I am quite sure you are right about the piston scenario since it would idle like garbage and the blow-by would be synchronus with the bad hole... To get the temprature up I fed
H2O to the headers directly from another source and from still another souce fed the engine with the sea pump disabled, the
feed being on the engine side of the sea pump... By using a
water hose you can regulate the quantity and temprature by
actual flow... Only thing is watching the temprature and holding
at about 220 degrees for .5 hour... Some folks suggested more
temprature but the only thing holding me back was fear and
common sense... Hope this helps...

Karl

Heres an update as of last night. I talked with the engine builder and here's what he said. did a leakdown and compression check. all cyl checked out fine except for the #4 cyl. zero compression. I said to him hole in the piston? he said looking at the spark plug I don't think so. He's pulling the engine today. I will know the exact cause of failure thursday. It's ironic the EGT probe is installed in the #4 cyl 1250 is the highest temp I saw. in fact when the failure happened the pyro was reading 1150. stay tuned

The results are in.
Holes punched in the pistons. all eight # 4 and # 2 are the worst.

The guy who built the motor even though he didn't do the ECU remapping is going to help ease the pain.
It's now time to go see the guy with the computer and see what he has to say.

Sounds like terrible luck you had, I replied to your other post about the fuel injection, and it sounds like you need a system that would constantly adjust to the demands of the motor. I have been researching this to build one for my boat. Also the Holley Commander 950 is a good system. I don't think preprogrammed PROMs can accomodate blower motors in boats well enough to not have this come up again. I know a guy who blew his blower motor up three last year. The bright side, just learn from the mistake and don't repeat it. Good luck.

jdelo,
did you look at all eight pistons? they were all melted or cracked? did you happen to notice if any exhaust valves were bent. i've melted pistons all the way down to the rings before too but it was only three cylinders out of eight. all eight with holes is pretty rare. what i'm getting at is if your springs were too light it may have caused some valve float at high rpm's. just another possibility to look at. sorry to hear about your engine. that sucks. Fran

excaleagle42

Let's me explain it to you this way.

2,4, 1,5, with holes burnt through # 4 took the worst hit. the rest were about to go. JE pistons All in the same location the valve relief.
What really sucks is the GM ECU. If you make any modifications to your engine from what I understand, thier are only three people in the USA who can go in and make changes.


jdelo

“What really sucks is the GM ECU. If you make any modifications to your engine from what I understand, thier are only three people in the USA who can go in and make changes.”

jdelo’
can you explain more in detail what you mean? did you mean, three independent people in the USA who can legally go in and make changes, or three people who have the knowledge or the tools? don’t get me wrong, i don’t know any thing about it. it’s just, that doesn’t seem to make sense to me, with 10s of millions of GM ECUs in the US why would there only be three? they would need more than that at just one GM plant. where did you here that?

Dean,

Here's how I understand it. GM PowerTrain designed the MEFI 3 for Mercury Marine. Merc didn't want anyone to have access to the software because of Warranty issues. Only a select few had access to it due to thier inluence with mercury Marine. One guy on the East coast one Guy in the Mid west and One guy here in arizona. Go and ask your local merc service guy. I bet he will tell you the same thing or we will not know what your talking about.

what sucks is that every member on this board who has the GM MEFI-3 fuel management system, is at the merci of a select few. Guys who what to make modifications or just want to tinker are Sh@t out of luck.

Check out this thead.

www.diy-efi.org/gmecm/html_archives/archive_num_12c/msg00384.html