Scrap the 7.3 for a 6.9? How much do I need to worry about cavitation?

[DNR0721]

OK. Kicking myself for not doing more research on these older engines.

I bought a '92 F250 XLT w/7.3 turbo to put into my dually gasser. Now I'm afraid to dump any more time and money into this 7.3. I bought it without seeing or hearing it run - yeah I know - STUPID!!!

Anyway, I just don't know if it's worth it to even find out if the block has pinholes (cavitation). If it doesn't, I still don't know the history of the truck/engine and it may just be a matter of time before I get cavitation.

If I use the right coolant additive, replace the downpipe, install an intercooler, can I safely rebuild the engine and expect many years of use, or should I go right now for a 6.9 I know is running?

 

[justinray]

Add the coolant additive after tearing off the heads and inspecting the cylinder walls and you'll be shining like a diamond.

 

[88 Ford]

If you check it out and it looks good you should be good like justinray said. I'm also not sure why everyone adds the additive to the coolant when you can swap over to iirc the extended life stuff and not have to worry about monitoring the levels in the coolant. Am I wong about the extended life stuff? Cus I swear I heard that it prevents cavitation and that is why they use it in industrial engines...

Also as far as building a 6.9 or 7.3, there are pros and cons to both. I would say keep what you have. Cavitation is minimal especially if you prevent it.

 

[Kevin 007]

If your engine is ends up running fine without any coolant loss or presurization and such, then start using the right coolant and you will stop the advancement of cavitation in its tracks, pretty well. Then you should be just fine. you can't reverse the possible damage that cavitation has done but you can slow it down if not, stop it fully! don't worry about it that much. Oh, replace the oil cooler oring before you put that motor in!!

 

[DNR0721]

OK. I'm hoping for the best. Getting the block hot tanked and pressure tested this weekend. We'll see.

 

[ocnorb]

Is there any anti freeze left in the block that you could do an SCA test on?

Not sure, but it might give you some piece of mind. Tested a junkyard 7.3 out of a '92- it looked real good. Seems like by '92 it should have been a fairly well known issue..??

 

[gdhillon]

If you check it out and it looks good you should be good like justinray said. I'm also not sure why everyone adds the additive to the coolant when you can swap over to iirc the extended life stuff and not have to worry about monitoring the levels in the coolant. Am I wong about the extended life stuff? Cus I swear I heard that it prevents cavitation and that is why they use it in industrial engines...

Also as far as building a 6.9 or 7.3, there are pros and cons to both. I would say keep what you have. Cavitation is minimal especially if you prevent it.

I'm curious about this to

 

[88 Ford]

OK. I'm hoping for the best. Getting the block hot tanked and pressure tested this weekend. We'll see.

What all are you doing to the internals? Are you dropping the compression at all? Anything else special you are doing?

 

[88 Ford]

I'm curious about this to

For sure. Tomorrow I'll have to find the article that talk about it but there is definitely a reason that heavy duty trucks use it. Cus it prevents it I'm sure...

 

[gdhillon]

Ya the guys at pete told me that to and after a certain amount of kms to add some cat elc (I believe its extended life coolant)...I'm sure I've read about it on here before to

 

[DNR0721]

What all are you doing to the internals? Are you dropping the compression at all? Anything else special you are doing?

I was not planning anything special besides ceramic coating the piston heads. No changes planned to the heads or cylinders. I was planning to bore, but with reminders from members in the forum about how thin the walls are already, I decided against that.

Would dropping the compression help? I imagine less compression = less heat and stress on the cylinders themselves. Power loss as well?

 

[DNR0721]

Is there any anti freeze left in the block that you could do an SCA test on?

Not sure, but it might give you some piece of mind. Tested a junkyard 7.3 out of a '92- it looked real good. Seems like by '92 it should have been a fairly well known issue..??

There might be some still in the radiator, but it has been sitting outside. Will air exposure alter the test?

 

[92F350CC]

I hear the CDR helps contribute to cavitation, so doing a road draft tube might help.

 

[Kevin 007]

Cavitation and head gasket stress, as extra oil in thr back two cylinders = more heat = more stress. I hate CDR valves But if you keep em clean they usually work trouble free.

 

[icanfixall]

A CDR valve does not contribute to cavitation. Funny fact about these 7.3 engines. The back cylinders on each side of the block are bored larger than the front 6. Its about 1/2 of a thousands but its differant. No machine shop will do that when they bore a 7.3 during a rebuild. Internationals reasoning was the angle the block sides causes the oil sucked into the intake will migrate to the rear cylinders creating more combustion heat. Sounds like some black magic engineering going on one late nite way back then. In those larger bored cylinders they still used the same size pistons...