94' 7.3 idi turbo

[rembrant88]

Okay. Here is something my neighbor told me today. He says that my 7.3 with the factory turbo is a better built engine than the older 7.3 and has upgrades besides the turbo. I don't buy it but I honestly don't know. I want to make sure in case I have it rebuilt so I get it strait.

 

[rjjp]

You have larger wrist pins, more cooling tubes in the oil cooler, and slightly larger (0.100") main webs.

 

[rembrant88]

You have larger wrist pins, more cooling tubes in the oil cooler, and slightly larger (0.100") main webs.

Well, that's good. I'm honestly surprised they made any changes at all. I didn't think the turbo added enough to warrant fear of failure. Now it makes me wonder why they did.....

 

[pdxfordguy]

got from wikipedia ...

In 1987, the 6.9 liter engine was supplanted by the 7.3 liter upgrade, with over 300,000 6.9s shipped to Ford and countless numbers installed into medium-duty trucks, school buses, and the like. This engine features numerous improvements over the 6.9 liter, with most of the changes located in the heads; the block received an increase bore and select-fit pistons, while the heads received an enlarged prechamber, enlarged valve stem shields, harder valves, and other minor upgrades. The front cover was revised to reduce seepage.

Finally, in 1993 Ford made available a turbocharged edition of the 7.3. The turbocharging system was produced by ATS, which produced three turbocharging systems for the International-Navistar IDI engine; The ATS 085 and 088 turbo kits, both of which are wastegate-less designs, and the ATS 093, which included a wastegate. The Ford factory turbo system utilized the 093 and was detuned from the ATS kit. ATS formerly sold a turbine housing upgrade kit but this appears to have been discontinued. This detuning job is believed to have been due to Ford's impending use of the T444E (Power Stroke) engine. A 7.3 liter IDI in good tune with an ATS 088 turbo kit makes approximately the same power as the T444E, though it makes it at higher RPMs due primarily to turbocharger design. Factory turbo vehicles received numerous additional improvements. Pistons had an enlarged ring, added intermediate rings, an enlarged ring land and wrist pin, as well as an anodized piston face; other improvements included tweaks to the injection pump and injectors, and an upgraded oil-coolant heat exchanger.

These engines are unusual today in that the fuel system is entirely mechanical, though this was the standard for diesels of the day and indeed for the earliest fuel-injected gasoline vehicles. The fuel system also utilizes indirect injection which made it quieter than its predecessor. The indirect injection fuel system makes this popular among drivers who choose to run vegetable oil rather than petroleum fuel (the dual fuel tanks that some Ford trucks are equipped with further makes running vegetable oil easier). Both 6.9 and 7.3 liter engines use the Stanadyne DB-2 injection pump fed by a cam-driven lift pump.

I guess it really does not explain why though ...

 

[rembrant88]

Thanks. That info does help explain it a little. I'm surprised they improved the pistons and beefed up the wrist pins considering the 7.3 wrist pins were already improved from the 6.9. I thought there would be a difference in the heads if anything. I guess they were going for durability rather than better performance.
It just doesn't make sense to me why they would go through that kind of trouble to slightly improve an engine that was getting only 5 or so extra hp. From my experience manufacturers tend to avoid the extra expense. But my experience is limited. Maybe International was trying to look out for the little guy and make a few improvements when they didn't have to.

 

[RANOVRU]

Block is stronger too, and slightly upgraded internals as mentioned.

Definately a stronger engine than the NA 7.3's.

 

[icanfixall]

Most of the above information just missed out on being completely correct... The block is not stronger than the na 7.3. It does not have a wider main bearing. The main web is supposed to be 110 thousands wider but I have never found this to be tru. All 6.9 and 7.3 engines use the same rod and main bearings. The turbo oil cooler did not have more tubes but it has more fins per inch which makes for better transfer of heat. The pistons never got more rings but they did get a differant keystone ring and the three rings thickness was encreased. The oil ring design was changed also for better oil coltrol. The piston pin size was increased from 28mm to 33mm in the turbo pistons. The G code injectors were used with the higher pop pressure. The exhaust valves material was changed to inconel because it works better in the added heat from the turbo. Compression ratios stayed the same too. All the turbo blocks have 1/4 inch main oil galley ports where any other idi block has the 1/8 inch ports. There is no way you can just look at a "turbo block" and know its all turbo inside. These are older engines and we just don't know what has been done by the previous owners. All the blocks and heads are drilled the same so any 6.9 will bolt up where a turbo or non turbo block was. The serial numbers only tell you what the engine is supposed to be. My information has been collected... discussed and seen by me over the years of being associated with this forum and these members. This is a great site for the truth on these engines. Nobody out there has more knowledge about these engines than we do collectively. I have searched for an engineer that helped to develope these engines and sug sections of the enfines but none have come forwards. I have many questions to ask... Mostly why is the 7.3 heads and block got a plugged up coolant passage and the 6.9 doesn't... For some odd reason we can buy new offshore heads that are better made than the oems but no 6.9 heads are available.. Why is that... I know a 7.3 head fits on a 6.9 but not the other way around...

 

[rembrant88]

Been without a computer for a while. Had to put it down.

Thanks for the info. I recently talked with my machinest and he agrees with you. I like the improvements that were made to the engine but I have not heard of any problems with a moderate boost on the stock 6.9 so I won't worry to much about it.

 

[icanfixall]

Most of the issues on both engines were the head gaskets. The oem early ones tended to leak. The new felpro or victor reinz are far supiour gaskets. I actually went almost 370,000 miles towing heavywith 12 lbs of boost the last 200,000 miles of that... On the oem passenger side haed gasket.. It never did leak. I di loose a cylinder to cavitation on the drivers side head but the shop would not replace the passenger side head gasket when th engine was out on the stand... Well it sucks for them thinking I was going to be back later for the side gasket.. It just never happened. No thats not the norm either but it did happen. A 6.9 boosting to 9 is not going to hurt a new set of head gaskets but.. Your that far into it may as well buy some added protection with studs. they are stronger than the stock head bolts and they can be reused over and over...

 

[rembrant88]

Most of the issues on both engines were the head gaskets. The oem early ones tended to leak. The new felpro or victor reinz are far supiour gaskets. I actually went almost 370,000 miles towing heavywith 12 lbs of boost the last 200,000 miles of that... On the oem passenger side haed gasket.. It never did leak. I di loose a cylinder to cavitation on the drivers side head but the shop would not replace the passenger side head gasket when th engine was out on the stand... Well it sucks for them thinking I was going to be back later for the side gasket.. It just never happened. No thats not the norm either but it did happen. A 6.9 boosting to 9 is not going to hurt a new set of head gaskets but.. Your that far into it may as well buy some added protection with studs. they are stronger than the stock head bolts and they can be reused over and over...

I will deffinitly get some studs for it. I put them on my 6.9 after I had the head bolts slipping and broke one. Those were the old bolts, but still. How much did you have into the 7.3 studs?

I was always told to pay the extra cost to sleave those engines and prevent that cavitation problem. I assume that would solve it. Probably what I'll do if I ever rebuild this one.

 

[icanfixall]

My first set of studs were the DPS studs from Ken. We collabrated in the making of those. They were the H13 material and were $600.00 as I recall. I got the first set and they loked like stainless steel material. The heat treat was terrific. Later on Ken had some issues with the company doing the heat treating and the studs broke even without running some of the engines... That was a problem for everyone. Then Ken stopped making them for a time. My other set was just a bulk buy from ARP and it was an odd amount.Because I already had the washers and 12 point nuts from ARP I only needed the 7 inch studs. My bill shows they charged me $287.30 for 34 studs but wait for it... They charged me another $8.61..... And then on top of that they gave me a $43.10 discount... No state tax either... Now I laughing all the way to the bank on this transaction... I didn't ask for any discount nor did I know anyone there of do an unnatural act on someone...;p I did have a person that told me to use his resale name and number but I just couldn't do that... Paying what they asked was what I was going to do and thats my story and I'm sticking to it.... The date on this bill is 1/25/08....

 

[rembrant88]

My first set of studs were the DPS studs from Ken. We collabrated in the making of those. They were the H13 material and were $600.00 as I recall. I got the first set and they loked like stainless steel material. The heat treat was terrific. Later on Ken had some issues with the company doing the heat treating and the studs broke even without running some of the engines... That was a problem for everyone. Then Ken stopped making them for a time. My other set was just a bulk buy from ARP and it was an odd amount.Because I already had the washers and 12 point nuts from ARP I only needed the 7 inch studs. My bill shows they charged me $287.30 for 34 studs but wait for it... They charged me another $8.61..... And then on top of that they gave me a $43.10 discount... No state tax either... Now I laughing all the way to the bank on this transaction... I didn't ask for any discount nor did I know anyone there of do an unnatural act on someone...;p I did have a person that told me to use his resale name and number but I just couldn't do that... Paying what they asked was what I was going to do and thats my story and I'm sticking to it.... The date on this bill is 1/25/08....

Ha ha ha!. Sometimes stuff like that happens and and you just go with it. I might talk to arp about those and get some ordered. I think the bolts are fine with the boost I'm running but if my engine blows a gasket I blow a gasket. So no chances here. You have a part # on those 7" studs? I assume the nuts I will have get separately also if you have a part number for those. So these other guys running studs? Anybody out there have the 7.3 bolts fail on you?