Earlier I was asking about waterproofing the roof of our 1985 Eldorado. Now we have engine trouble. We will find out tomorrow if the issue can be delt with or we should consider a rebuilt engine. So how much difference would it make to put a 7.3 engine to replace the 6.9 that's in there now? Is it an option? I'm not the mechanic in the family so asking how I know best. Thanks.
I believe the OP was referring to the EARLY 6.9 International engine rather than the 6.0 boat anchor. The two 6.9s I've had seemed simple enough once the plastic injection timer was replaced with a metal one, but I'm far from being any sort of expert on just what I've read.
There is really not much difference, a slight increase in bore and about 10 extra HP, between the 6.9 and 7.3 versions of International's naturally aspiration IDI V-8 diesel. Both are 50,000 hour engines, which means they shouldn't need rebuilding for 200,000 to 300,000 miles, if getting regular oil and oil filter changes. Even then, problems with dirty oil are more likely to show up in the injectors, than in the engine core. New injectors are expensive, but not as expensive as rebuilding the whole engine.
A swap from 6.9 to 7.3 rebuilt core should be simple, as most of the ancillary parts transfer from one to the other.
The turbocharged 7.3 IDI is also more or less the same engine, with just another slight increase in power, something Ford felt they needed to do when Dodge and GM started turbocharging their diesel pickups. Controls and instrumentation will be more complex, to deal with the turbocharger.
If you are talking about changing to the later 7.3 Powerstroke, that was a much different engine, different engine controls and injection system, and the swap means buying a lot more ancillary parts. The IDI pieces (injectors, pumps, control units) don't swap over to the Powerstroke.
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edited 05/07/12 07:39am by tatest *
There would be virtually no noticeable difference between a 6.9 and a non-turbo 7.3 IDI. Ford only built turbocharged 7.3 IDI engines for about 6 months right before the Powerstroke was released in late 1973. Its very unlikely you will find one of them. The only fault with the 7.3 IDI is it has thin cylinder walls and corrosion can eat holes in the cylinder walls if the required coolant additive is not maintained.
I had a 1986 class C 27' MH with a 6.9 as our first RV. Ran fine but poor power. I added a Hypermax turbocharger kit and a Gear Vendors overdrive and that brought it to life.
That is all great info so thanks to all of you. The mechanic is busy for another week so we have time to read but I think maybe staying with repairing might be fine. We have no idea who owned this rig all those years so who knows if anyone took care of it. We have in the last two years. Had the water pump go out on our first outing, cost us big. Maybe those guys who replaced that did something that brought on the current problem, too far from home to go back, two years ago too. We do find it slow up the hills but maybe that won't change. We're used to it now. Everything else works though we do need to pay someone to tape the roof seams and coat it with something to prevent leaking. Than we're ready to hit the road.
There was not a diesel engine from Ford that is going to be much faster than the 6.9 on hills, until late in the history of the 7.3 Powerstroke (1999-2003) when that engine got a higher pressure turbocharger, intercooler, and improved injectors to boost power to the 250-275 HP range. You can't economically swap to that engine, the swap might cost more than your motorhome.
The water pump on the 6.9/7.3 International engine is one of the few parts that wear out. What is the problem that makes you think you need a rebuilt engine?
Compared to replacing a water pump, a rebuilt engine is really expensive: $3000 to $5000 for a long-block (you transfer the rest of the parts from your old engine) to almost double that for a complete drop-in engine. Most of the time when you have trouble with a low mileage (100,000 to 200,000 miles) 6.9 or 7.3 the problems are in parts that don't come with a replacement long-block.
Blown head gasket. I'm not a mechanic. We'll know more then the shop works on it. But fill me in. Thanks to the responses I am getting on this. Some other terms were used, I'll try to listen better and report back.
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