HaxbySpeed

I think the reason Mark's name gets mentioned every time someone asks about reprogramming is because he knows his chit! The same reason everyone reccomends RMbuilder for cams and valvetrain. Mark can tune through the mail, and although it could be optomized in the boat if you give him the correct information it will run flawlessly.

jeffswav

Everyone is telling you the same thing. If you put it back together the same way you will just blow it up over and over. Its your money

blue thunder

My first guess would be you had a tight bearing or two. Did you have oil temp gages? If not you should add them. The LM1 would be a very good idea. You'll need to set up a spot in the exhaust for it while you have it apart. Going from memory, the 365hp mag engine which is what your cam is for, had a recommended rpm range of 44-4800rpm. So 4300rpm would not be that far off and would not cause a rod bearing to fail. It is good practice though to alway prop for being able to hit the high end of the recommended range at wot. Cruiser or not, makes no difference.

PatriYacht

Vortech heads are detonation prone. They have smaller chambers which results in a higher compression ratio and they have a sharp point in the combution chamber between the valves. If it were my engine, I'd use a die grinder and lay that point back a bit. Just enough to smooth it into a nice rounded shape. Can't remove it completely, it's required to create mixture swirl in the chamber. Good luck.

tpabayflyer

Yes, I am intimately aware of the design of the vortec heads...... I did indeed remove the sharp edges and did some very minor deshrouding as the 2.19 intake is larger than stock. Also, there is a cast in "wing" just beneath the intake valve that must be for swirl so I don't think my porting and installation of the larger valves was worth that much power. I figure my C/R was right at 9-1 and the flat top pistons were zero decked. Using a .045" thick head gasket, I have good quench and resistance to detonation. These are small port heads and probably would run out of breath at anything much more than 4,500RPM. The plan here was to build the motor for torque and it has it in spades.

Obviously this combo failed so when it gets rebuilt, It will get tuned and A/F ratio and egt will all be monitored so as to avoid another failure. I will contact some of the previous posters that offered help and figure out a game plan and the best way to get this combo tuned. I will post back when I pull the pan and see how bad the carnage is........ TBF

ezstriper

I don't think the heads had anything to do with what happened..I think your engine screwed up...sounds like spun a rod bearing..if so what you did have nothing to do with that unless it was running so rich with fuel diluted the oil and killed a bearing....clearance, crank, something was wrong there ! or unless you hooked up oil cooler lines reversed and killed it that way...

jeffswav

If you run it lean, have bad fuel, run too much timing, or lug your engine you can take out the tops of the rod berrings pretty quick. Also if the oiling system was not upgraded from the beer can size oil cooler, that could do it too.

rexcramer1

Without recalibrating the ECM with all the changes that were made to increase airflow this engine would have been running WWWAAAAYYYYY lean, which means detonation. That coupled with the heavy load most likely killed the bearings, though a tight bearing is still possible.

Either way I think he is on the right track to getting her straightened out

tpabayflyer

Yes...... My seat of the pants guage tells me detonation was the problem and I bet running lean was the issue. I bet the top half of the rod bearings are hammered flat so I might get lucky and change them out if there is no debris in the pan. Now comes the question of how to reflash the 2000 L-29 engine ECU? My Harley has a power commander I just installed and there are a ton of maps available for all different combos..... It works like a charm! I would think I am not too far away from the stock 454 mag tune but I need to put this thing on a dyno and make sure I don't run lean again...........

FWIW, I did check the fuel and not a drop of water or contamination. Fuel was 89 octane no ethanol. Old fuel was drained and filled to top with fresh gas so no issues there. Timing was right at spec per my installer but i will double check to see how much initial there is now. I have not heard about the oil cooler issues but I am using the stock unit and it was cleaned and looks to be of sufficient size to provide good flow with no restrictions? I always had good oil pressure and no overheating issues.............................

The only way to be sure this is tuned correctly is using a dyno or on the boat with a laptop or some kind of scantool. I will research this and make damn sure all parameters are perfect. It will probably run better and fster as well! Thanks for the help and steering this newcomer in the right direction..
TBF

jeffswav

Sounds like you are getting on the right track, if you spun berrings you will want to tear it down and hot tank it. Then pitch the oil cooler, a 2"x18" would work well.
The vortec heads like a little less timing, from what you are used to. I have heard in the range of 32 deg total.
I once ran some E10 fuel through a fresh rebuild and took out my rod berrings. Thats why I through that out there, it may not apply to you.
I have a aftermarket Holley MPI system with wideband O2. I can program the PCM on the fly with a laptop. If you could have a bung welded in your exhaust that would be a good idea. I have the EMI exhaust and I have a bung welded in the risers.
There are a lot of guys on here that can help you with the Merc PCM. I would take there advise on the programing.
Let us know what you find with the engine.