Thats AWESOME!!!!! I would PAY BIG money to have one of those over here, anyone know where I can get one???

The got a couple of questions, how does the cooling system work??? I am boat dumb, dont even own one, and the TWO that I have been on had paddles but I have heard that some use the water right out of the lake and then return the water to the lake, how will that work for cavitation issues??? be imposible to keep sca's in it.

MY first thoughts after I posted where valve train issues, causing bent push rods, the marks on the pistons prove either a sticking guide, rocker, or over filled lifters, the later I think is a long stretch. the post on therecalled rockers was something i was wondering about.

I also gave the wet stacking issue a second thought, (sorry Kwik to contradict you) I wonder if its an oil issue on these motors that causes a wet stacking problem. Like certain oils will do it and others wont???? the way these motor are so finiky, could be a possibility.

MadMedic, I am a fireman, and our trucks idle also for HOURS at a fire scene, the only one that revs up is the pumper truck. the grass rigs, and responce trucks just idle on the side with there lights on, never had a problem, but they are 6.2 chevys whole different beast.


get us some more pics of this beast, sounds so sweet.


Diesel Rod

 

i own a boat and am not boat dumb so my question is??? closed cooling system or open cooling system... open is very common on boats and if it had that my question is maybe this boat is running at to cold of a temperature and you are pushing it to hard. kind of like driving your psd like a bat out of hell before it is warm. it'll do it but it doesn't like too. if your boat has a engine water temp gauge what does it read when it is at operating temp.
does this engine have a thermostat? if so what degree is it?

 

The cooling system is of closed type.. Sea water runs in a heat exchanger that takes the hot fresh water's het over to the saltwater.. Then dumps the salt water thru the exhaust system..

Engine is with antifreese additive.

Engine is only 150 hours befor first bang.. And that was after oil change but many hours after.. Think it dont like the oil we use.. 2 time was right after oil change and 3 time was after 5 mins of idling.

PRoblem with this engine and mine (7,3 IDI. In a boat also) is idling temp.. The temp is only like 40 °C at idle and 90°C at higher rpm's
The engine has NOT been pushed hard at all. Before first broken push rods it ran only at 2800 rpm's Topp rpm is 3600
In the manual it says not to push it before warm or operating temperature. (90°C) Not to easy when temperature isnt right before you get the boat to go in plane..

Have only picks from my engine . 7,3 idi. Starpowr.

 

Even if you ran it hard when cold, this should have no effect on pushrods. It should accelerate wear on other components, like bearings, rings, and cam lobes.

Someone mentioned valve float, which certainly could account for valves kissing pistons and bending pushrods. However, at max rpm of 2800, the valves are not floating from excessive rpm.

Faulty rocker arms could do this, as was mentioned in a previous post. Weak valve springs, too. I guess oil could, but I don't see how. I know that diesel rated oil is required so that the anti-foam additives prevent the oil from foaming under the extreme pressure of the injectors - but how could this result in pushrods bending???

I don't know. I only wish I could make a suggestion. I really hope you find out soon.

 

Mybe youre on to something here with the faulty rocker arms ore weak valvesprings.. Engine was only used in 1 or 2 months of the year from 1995 until 2004. Can it be that the springs is gone?? from just sitting and not be used??? The boat was on land the other 10 - 11 months.. Not cranked ore anything

 

I have never heard of valve springs becoming that weak that quickly from non-use, but I wouldn't rule it out.

With all my experience with gassers (from pushrod motorcycles through gasser V8s) the only way to make marks on the pistons with the valves is to hold the valves off the seats. If you hold the valves off the seats and the pistons contact them you can have lots of damage, from bent valve stems and broken rocker arms to bent push rods.

In fact, I had a friend with an old BMW 1000 twin. He floated the valves and bent a pushrod (or three). When he put it back together again, he bent another pushrod because a bent valve stem (that he somehow didn't notice...???) was jammed.

Anyway, from here I can't diagnose the cause, but something is holding the valves off the seats so they can kiss the pistons (and bend pushrods).

Look back in a previous post - someone mentioned something about faulty rocker arms on some 7.3 engines - I don't have time to look it up right now or I'd point you to it.

 

There is something else in a hydraulic lifter engine - if the hydraulic lifters become pumped up, they can and will hold the valves off the seats. If it happens quickly I suppose it would be possible for the valves to kiss the pistons. Just something else to look at....

 

I have been thinking about this to all day and, I think its a sticky valve guide, or rocker. @ TDC on a motor, both vavles ARE open, and @ 2600 rpm its definetly not enough to float a valve and bend stuff. I think a sticky guide, or rocker is causing the rods to bend, could also be a lifter hanging up in its bore, that will cause the valve-piston timing to be off, and bend a push rod, just out of curiosty what ones bent??? intake, exhaust or a mix of each???

maybe I will have to admit to the wetstacking theory.


Diesel Rod

 

Almost every time its the Exhaust valves.. All the lifters are new.. We changed them after the first big bang
..
When we had the heads of it didnt seem to be anything wrong.. We checked the valves and springs/rockers. Valves was going wery easy in the guides. All the valves where checked

 

If you think its a sticky valve guide , then why isnt it on the same cylinder every time???
This last time it was cylinder number 6 and 7. Last time it was 1 and 2

Im starting to think "TO HIGH OIL PRESSURE" Reason is that its different rods each time , en its only 2 cylinders at the time.. Think about it, when the rods are giving up , the oil pressure is going down isnt it????
Oil pressure is 82 PSI (5,7 kilo gram)at 2800 rpm. What about the oil pressure valve??

 

Some pics of my 7,3 IDI marine engine.
Pic1
Pic2
Pic3

 

man, i sure would hate to take a wrench to that and scratch off all that pretty paint.

 

I painted it yellow because its easier to se if any oil is leaking in the future.. In a boat its not so good space to look around..

 

Did you go through the whole oiling systems (low and High) and check for any sludge or buildup on valves,pumps,lifters or other components? After sitting without running for that long of time stuff like that will bind and stick and might jam the pushrods.

Pretty motor though

 

Is there 2 oil systems.. Low and high???????????

The engine have 2 oil pressure gauges on it.. One reads 5,7 kg and the other one is reading 2,7 kg

We didnt clean anything.. It looks like unused inside the engine.. But what we cant see??? Dont know.

Thinking of the oil pressure bypass valve sitting in the block left side on top. Can this be cleaned??

Here is a picture. Parts from 14 tru 18