7.3 Cavitation Pin Holes
 

Any one out there have problems with cavitation pin holes allowing coolant to leak into cylinders?

I keep hearing that this is a problem with the 7.3.

My machine shop says I need to sleeve my cylinders when I get my engines overhauled to prvent this pin hole problem.

I havn't seen this subject discussed on this forum yet.

I'm afraid it has been discussed many times before. What I'm not sure about however, is if anyone ever had any good experience with sleaved engines. Dave S will be along shortly to tell you about his "adventure" with sleaved 7.3s.

I'm rebuilding my 6.9 right now, and all I'll do is a honing (244000 on it), but I have virtually no piston ridge. I can ask my machinist what he thinks about sleaving, maybe he can shead some light on the idea. Do you know for sure if you have cavitation? If the SCAs were maintained in the cooling system, you should be fine, unless you have to rebore it, then you are rolling the dice, since the 7.3 has such a thin cylinder wall to begin with.

From another post I see his 7.3 IDI is in a boat.

That would make it impossible to run SCA's unless he has a closed cooling system with a water to water heat exchanger.

Most boat engines I am familiar with run water from outside the hull through the engine for cooling.
That is the main reason marine engines can run more power than the same engine could produce in a vehicle.

I personally have nothing good to say about sleeves from my experience.
None of the local machine shops will install or have anything to do with sleeves either.

Block overbored, then the sleeves are pressed in with super locktite to glue them in place.
The head gasket fire ring rests on the sleeve, when the engine is operated the locktite lets the sleeve move.
A cracked block is the end result.

A 6.9 block bored 110 thousandth's makes a it a 7.3 block.

All diesel engines have cavitation issues because of the extreme cylinder pressures.
Cavitation is the result of the cylinder wall moving toward and away from the coolant.
Cavitation is more of an issue in the 7.3 because the cylinder walls are thinner.
Thinner cylinder walls means more movement and the cavitation has less distance to eat away the cylinder wall before coolant enters the cylinder.

I bought a complete drop in reman 7.3 turbo engine to replace my 6.9.
Three of them had cracked blocks in 28,000 miles.
They sent me a fourth, I tore it down before I installed it.
The sleeves were dropped below the deck in several cylinders of an engine that had never been fired, I refused to install it because my warranty was about to run out.
It took several months to resolve the dispute, but I did get a buy out in the end.
Took the money and bought a salvage yard 6.9 engine which I rebuilt myself.
I have 4000 in the rebuild, the complete drop in was 7000 dollars.

if he's in salt water my guess wuold be that he's running a sealed system with an heat exchanger.

Marine 7.3
 

You are correct, I am running a sealed system with heat exchanger.

I brought up the issue of the caviatation because I have read about it a number of times.

I think the 7.3 is a good engine and works well in my boat.

I have 3200 hours on these engines (since new) and run them all day at 2700 rpm.

I have had to rebuild the IP and change injectors and glow plugs but those parts are cheap and easy to access. I have also had to change rear main seals which is a pain in this installation.

With the high hours on these engines I expect to over haul them some day but oil use is low and performance is still good so that day isn't here yet.

Thanks for the comments.

Quote:

"With the high hours on these engines I expect to over haul them some day but oil use is low and performance is still good so that day isn't here yet."

IMHO 3200 hrs. is just getting broke in, you are running at constant rpm's and in a clean environment. I have seen diesels with over 10,000 hrs in farm tractors that run like new. Yes IP's and the other items you speak of are just maintenance Items,

What HP does the stickers on your motors say they are?



Ken in Central NY, now with over 58K on WVO

7.3 Marine
 

The engine were converted by Star Power out of Indianapolis and are rated at 200 hp @ 3400 rpm

They had the BB injectors which I repaced.

I must say that installing the G series injectors and tuningng up the IP really resulted in increased power.

The engines just roared to life and really pull.

Now I will install the turbos to go with the other mods. I have to get new transmissions because the original trans with not take that much power.

The new rating should be 250 hp.

has any one had any luck with liquis glass sealing pin holes? I preasure test and leaks down to 7lb. get water in oil , no oil in water, no water on top of piston when preasure checked and no bubles in rad. dfoes not run hot but lose4s water. no water out exhauet or poping out intake. HELP

what kinda turbo? factory ats is only about 5hp gain. they dont add as much hp as they claim. thats for sure.

lowellbaggerr,

Welcome to FTE and the IDI forum.

No water in the oil, leaks down to 7 PSI does not sound like cavitation.

I think your problem might be oil cooler O rings.

Do you get any oil in the coolant?

i get water in oil . on oil in water. preasure leaks down to 7-8 lbs and stays,does not run hot no poping back through intake.not,blowing any water out the exhaust or any bubbles back in rad.
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you can go to autozone and rent a radiator pressure tester. go ahead and put the pressure to 13psi and watch it leak down. try to crank the engine over once the pressure has dropped. if your engine wont spin, like its locked up then you have cavitation issues, if it spins and you get more water in your oil then its your oil cooler.

my local machine shop (b & r machine, knoxville tn) tells me that they have a VERY experienced customer that only works on 6.9 & 7.3 engines and INSISTS that every 7.3 block he brings in be sleeved whether it needs it or not and that this has been his practice for years. The customer continues to use the shop, so Im assuming they know what they are doing

As long as a lip is left at the bottom of the bore, so the sleeve can sit on it, and not drop in and hit the crank, everything is fine.

in a worst case scenario of antifreeze use, how many miles would you expect to have before problems with cavitation?