dean51267

Guys, I need some help, I am on my fourth set of motors this year, a $8K project has alread cost $27K and I just ordered two more motors so now it over $40K. What ever I am doing is not working and I need help to get it lined up.

History:

January 2006 started to do top end of motors, started with 60 hour 330 hp, Gen 5, 454's. Bottom ends had the big rods, steel crank, and forged pistons.

Took the boat to a reputable shop, after 3 or 4 times they got the motors right, we put dart heads, a comp cam retro hydraulic roller kit (236 dur / 540 lift) , lightening headers, air gap intakes, and new carbs. The motors made 440 hp on a independent shop's dyno and ran great. Each dyno was run with same components as on motor when in boat except headers (different kind, but still headers).

Put them in the boat in April and took her out, she was fine in the marina area, but under a load she got super hot, super fast. One motor spun a main bearing.

Felt like the other motor also needed to be looked at after being hot and lack of confidence, so pulled both engines. Took took them to a machine shop for total rebuild, new cranks, new rods, pistons, springs, everything balanced. Replaced oil lines and coolers, put them in the boat, valves were crushing pistons (these are 308 dart heads and flat tops, should be lots of valve clearance). (No Dyno this time).

Pulled the motors, new oil lines and coolers, rebuild motors, new pistons, re balance, all that. Put them on the dyno, 420 hp, ran them HARD, I told the guy with the dyno "if they are gonna break, break them here, do not let them get back in the boat without your complete confidence".... motors ran well on dyno...

Put them in the boat, after 4 hours run time one blows, am not sure what right now but #5 is full of oil. Last time they blew a different marine repair shop owner was with me on a test and turn mission, making very minor carb adjustments. We rant the motors pretty good (5200 rpm's) for 10 minutes or so, got more speed than we ever have, the idled around a bay talking shop, then headed back to marina at about 3200 rpm when it blew. Oil pressure and water temp never gave an indication of failure, also we never heard any unusual noises, one just quit. they are out of boat now, but not tore down. Still waiting evaluation....

Now my question, can lightening headers cause problems with this cam shaft (236/540)? Should I be looking at them as a source of problems? What am I missing, I am doing EVERYTHING I know to get this right, spending horrible amounts of money, following advice to the maximum extent possible, trying like hell to be the ideal customer, not asking for favors, or none of that mess. Asking EVERYON to baby sit the stuff and charge extra if needed.

I just ordered two new crate motors, going to try this again, but I can not keep doing this...

Your comments are appreciated...

GOODT

Dean,
Ive never heard of any problems with lightning headers ( doesnt mean there arent any just means I havnt seen or heard of any) certainly wont cause a valve to hit a piston

CPPerformance

Lightning recommends the cam to be no more than 240 duration @.050 based on a 454 C.I. engine with a standard Mercury header and 8" long collector. You can check it on their site along with more information about reversion at http://www.boatheaders.com/reversion.htm

We are a little more conservative and recommend no more than 230 degrees duration @ .050. In our experience anything over that is likely to have reversion problems.

The hard part is there is no set number that will give you the exact answer in your application, the only real way to find out is to try it. That's why we always recommend the more conservative number of 230.

So the problem is not necessarily Lightning Headers or any other brand for that matter, when it comes to reversion the cam along with a few other things is the real culprit.

It might also be worth your time to read the Keith Eickert article on the subject at http://www.keitheickert.com/tech_sup..._Reversion.pdf

Hope this helps.

Wobble

If there is water in the oil that's one thing, if not then you may have burned/detonated a piston. It's possible that your total jetting was ok for 5200rpm but was lean just running on the primaries at 3200rpm. The plugs should tell the story.

Hard to really get an idea until you get in the motor.

might be something as simple as a stuck needle and seat. Could be a stuck valve.

If you go to the dyno again, I'd really recommend having them hold the pull at 5200rpm for at least a minute collecting data every 10 seconds, watch the EGT's to make sure they are stable, likewise at the max rpm you can pull with just the primaries open.

I did this at my last dyno session and ended up a couple of jet sizes fatter than our best hp pull. Best pull was 600 final pull with the bigger jets was 584 i think.

Good luck

articfriends

iTrader: (1)

My 540 never reverted with lightning headers with a 228/234(might have been 236) cam and merlin heads,I switched to cnc ported AFR's and a cam thats around 236/240 (barely bigger) and it reverted so bad it would stall with lightnings. It doesn't sound like thats your problem though,Smitty

JJONES

Are you running electric fuel pumps?I went threw what you are going threw right now a few years ago!In three months i installed 6 motors,one would brake so i would fix it,then the other one would brake!Ran great in the marina and when running on the hose but once i put a load on them, either one would let go!Ended up being electric fuel pumps and lack of voltage at higher rpms which created a lack of fuel pressure when they realy needed more!It only takes a few seconds and kabum!CHECK ALL FUEL SUPPLY AND FUEL PRESSURES!SOUND LIKE A LEAN CONDITION UNDER A LOAD!GOOD LUCK

Ratickle

I also would start there if there is no water in the oil. Jetting, pressure, some auto drag race carbs go to lean at top end where a marine carb does the opposite, etc. Do you have oil temp gauges or EGT gauges? Usually lean will show up there before water temp.

dean51267

carbs are new ederbrock 750's, they were stepped up to run a little richer on the power circuit, other than that stock, the motor seems to like them as they came from the box on the idle and cruise circuit. The adjustment to run richer was a small one.

No, no electric fuel pumps, they are mechanical......

Talked with mechanic last night, he said when he pulled headers #5 was full of oil, and he found a piece of metal about the size of a pin head, maybe a broke ring, which means engines have to be bored and all, I pray this is not the case, these are still standard bore blocks.

I THINK fuel is okay, it was okay on Dyno, do not have oil temp gages, was in a conversation with Fred to order them. We had not really got the two motors lined out yet so we were working on those items.

I am not sure how to get EGT gages, I assume they would require an O2 sensor in the exhaust and of course these headers do not have a place for one.

I am calling fred today and getting to oil temp gages, will have to mount in the engine compartment, but at least I will have indication.

Any other thoughts?

SB

iTrader: (1)

Need more info then given on the cam.

Have we checked quality of fuel in tank?
Have we checked fuel tank pick-ups ?
Antisiphon valves ?
Fuel line size, routing, fittings, etc,etc ?
Was thA/F ratio checked on dyno ? With Wideband 02's or just the typical dyno fuel meter vs air flow meter readings ?
Are we using same fuel system on dyno as in boat ? Same with ignition ?

Do we have fuel psi guages on board we can check while running ?

Do we check plugs after a quick 1st run ?

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Is compression being set to high ?

IS the engine builder also a boat rigger of some sort ? Atleast understand it ?

Can we look at exact breakage from each motors and narrow down what has happened ?

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If it's an issue with boat rigging itself, new motors or different people's motors won't make a difference.

If it is just a tuning issue or engine assembly / parts selection issue, then some other builder may make you happy.

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There is more to engine building and rigging that meets the eye.

A problem must be pinpointed and corrected.

Root cause and repair.

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Good luck with you endeavors, must be a tough one to swallow. Really hard to help with an issue like this unless you have specific questions that you need help answering.

Wobble

I would ditch the edlebrock carbs and go for Barry Grant Sea Demons, haven't heard anything bad about them and RUMRUNNER here on OSO is head of technical services for them. PM him for more info.

Any cast header can be drilled for egts, tubular ones are more tricky. However this may not be necessary if you start with a quality marine carb.