Vinny P

Dirtlawyer;

Can I ask who did the ECM re-mapping? If you don't want to post it, can you send it to me in a private message?

Turbojack

If the pistons are melting then lean on fuel was the problem. If parts of piston were broken off or if piston skirt, ring land is messed up then detonation due to other caused helped. I am also concerned about the high CR that you were runnig. That was not helping either. I would not go over 9.75 with out the computer. Of course the computer did not do you any good this time.

When you go back with motor make sure pistons have NO sharp edges on them along with the combustion chamber. Sharp edges will get the hottest & casue detonation to start.

Sorry to hear about problem. Has the block been messed up also or just the pistons?

dirtlawyer

Checkmate454mag - check your email. Don;t want to air out the dirty laundry on the board.....

TurboJack - you are correct. The problem is definitely a "leaning-out" issue. When we ran the motor on the dyno before we installed it in the boat and noticed a slight dip in the fuel delivery in the 3500 - 4000 RPM range. Neither my mechanic nor the guy that owned the dyno shop thought it would be anything to worry about. Obviously they were wrong.

Luckily the block was not messed up - I caught it early enough this time. One good thing about being a part of the rebuild process, you get to know your motor real well, and any variation in sound (i.e. pitch, crispness, etc.) can alert you of trouble - that's what happened last weekend - the wife thought I was crazy - i.e. I had no loss of power nor any other sign of trouble (i.e. water and oil temp were fine). I just heard a sudden change in the pitch of the motor.

Would you be concerned with the fuel pump as well as the ECU?

turbo2256

I have to ask if you are running steam lines. On the dyno attempting to pull serious power out of a BBC has most often resulted in a blown motor. guess what cylinder is usally the worst. With 3/8 steam lines the problem seems to be corrected.. As I have stated before #7, #8 and #2 in order hotest to coldest.
The rest of the cylinders look to be running about the same temps upon inspection and metal color combustion deposits plugs etc look cooler than #2 cyl

Turbojack

When you noticed different in sound was it after full throttel blast or just mid -high throttle cruise? Good idea to get fuel pressure gauge on dash to keep up with. Only problem I have is when I am running hard, I do not take the time to study gauges. I try to check out my knock sensor gauge but last year it cost me by notd paying attention to that one twice.

turbo2256

I also would go with a aftermarket laptop programable fuel and timing system. They seem expensive at first but after a few engines destroyed ......... witch cyl s showed dammage?

Turbojack

turbo2256
I have looked at that. I would like a system that when control sees motor in detonation, it would first add more fuel, if that did not stop detonation, then back down timming, if that did not stop detonation then rev control engine. That way you would know something is wrong & back out. May loose a friendly race but save a motor, time, money, in the long run.

If something like that is made (I have not looked into this in last year) & I could get tech support I would go for it.

turbo2256

I nhave decided to go with the Electromotive set up its about the only part I am now lacking if you havent check them out. I plan to use the oxysensor if possible but will have pyrometers installed also as backup, boost retard, they also have provision for knock sensor if i remember correctly. They have systems that can very timing and fuel delivery to each cylinder.

Vinny P

Turbo2256;

Do you have the contact information on that Electromotive set-up you are running?

turbo2256

703-331-0100 ... Not running one yet. Still have to purchase one I am still collecting parts for the engine crank, rods, pistons , intercooler/s and Electromotive stuff is all thats left for the engine ...Of course theres all the little things that add another 10 g before one is done.