IDI Rebuild

[metrojd]

Ok
I am kicking around the I dea of rebuilding a 7.3 I have out of a 88 to put in my 93 CC.
My question is is there a year that would be more superior than others??
Also would like to try to come up with a game plan on the do's and dont's.
I already plan on sleaving all 8 holes.
Pistions??
Cam??
Im guessing I would want Turbo rods.
Any suggestions??
How about decking the block and resurfacing the heads? How much is too much?
How about head gaskets? I know Felpro but I mean should I see about I dont know what they call it something about machining a ring seal?? or something like that??

I also have a set of DPS stage 1's and a moose pump, along with a intercooler I plan to install.

I appricate any and all the advise.
Thanks
John

 

[6 Nebraska IDIs]

wow you're thinking about going ALL OUT with this thing arent you.
The turbo rods are always a good idea.

 

[Diesel JD]

Don't mill the heads unless you absolutely have to. You want a set of new castings or remanned heads if it comes to that. The warpage limit is .006", if it was within those limits most would just not worry about it. As for milling, there is a minimum height which Icanfixall can familiarize you with if you ask I am sure. If they go below that height most would say they are boat anchors. Milling heads WILL cause an increase in compression. I know from personal experience.You seem to have the right idea on the turbo rods, but you should also get turbo pistons if you can. They are still dime a dozen for the 7.3 from what I hear. I would also add head studs(not cheap, but a must if you want to boost more than 13-15psi regularly). An intercooler also might be useful to help you get the most out of Mel's stuff and DPS stuff + control EGTs. Someone on the old site suggested upgrading everything as much as possible to '93-'94 specs and then you basically have a PSD without the computer. That isn't quite accurate but you get the idea. Good luck,
JD

 

[flatlander]

If I were starting all over again, which if I keep this damn truck, I probably will, I'd drop compression a couple of points and o ring the heads as well as using studs.

Problem is we all know that 10 psi is safe all day every day. 12-15 MIGHT cause problems down the road in a stock compression motor. How much will a lowered compression motor take and still be reliable?

Only one way to find out.

 

[icanfixall]

You are wasting money o-ringing the heads and block. The Felpro headgaskets can handle about 17 lbs all day long with a 21 1/2 to 1 compression ratio but you will need studs torqued at 110 lbs. The head minimum thickness is 4.795 measured from the valve cover machined rail to the head to block mating surface. The block deck to the centerline of the crank measurement is 11.137 to 11.141. You will need to machine a try bar that can be bolted into the main bores to get this measurement. The head warpage is .006 overall or .003 in any 6 inches of the length of the head.

 

[caterpillar]

I wouldn't even waste my time rebuilding a 7.3L, its a throwaway block, don't do sleeves, can gaurantee you'll never see 100k miles out of that block, you want to rebuild a block, an 86 6.9L is the block for you, put the money into that, go over to ford-trucks.com and enter the pre-powerstrokes, you'll find a man there named Dave Sponagule he has done the 7.3 rebuild three times and each one went to junk within 28000 miles, go over and talk to Dave at Ford Truck Enthusiasts he'll tell you everything you need to do he's a very knowledable man and his truck out pulls the cummins with a 10000 pound load behind him, thats the only way he races.

 

[Diesel JD]

I do agree that the 6.9 is the better block in terms of longevity, particularly if it has the needed upgrades like new head gaskets and head studs. Dry sleeves may or may not be the way to rescue a so called "throwaway block" you may have lots more knowledge on that than I do. It appears to have been effectively used as a cure for cavitated 7.3s and of course to rebuild 3208 CATs which were so popular no one seemed to want to ditch them when their time was up in marine apps. From what I've heard, the success or failure of dry sleeving is directly proportional to the skill and knowledge of the machinist. Its apparently not a real easy procedure in that you have to "step" the cylinder bore so the sleeve will be retained. Obviously a mistake here will kill the motor. You sure don't want to be somebody's guinea pig unless he'll give you a real break reflecting his inexperience(not likely!) One guy over at TDS DazedandConfused had a good machine shop make this mistake, and it lasted until about 2 weeks out of warranty and they told him pound sand. Maybe they're not so good on second thought....

 

[metrojd]

Trrow Away???

I wouldn't even waste my time rebuilding a 7.3L, its a throw away block, don't do sleeves, can gaurantee you'll never see 100k miles out of that block, you want to rebuild a block, an 86 6.9L is the block for you, put the money into that, go over to ford-trucks.com and enter the pre-powerstrokes, you'll find a man there named Dave Sponagule he has done the 7.3 rebuild three times and each one went to junk within 28000 miles, go over and talk to Dave at Ford Truck Enthusiasts he'll tell you everything you need to do he's a very knowledable man and his truck out pulls the cummins with a 10000 pound load behind him, thats the only way he races.

What makes it a throw away motor??
I thought the 7.3 was an inproved upon 6.9??
I have over 200,000 on the motor If I replace all the wear items,rings bearings, and sleave the block.
I dont understand why I wouldnt get atleast another 200,000 miles.
What goes wrong wit these other than cavation and Head Gaskets?

 

[Michael Fowler]

John,
There is a good late model 6.9 block and parts in the "For sale" sectioon. Or you could PM me.

 

[Agnem]

can gaurantee you'll never see 100k miles out of that block.

I think if we had all the facts, there would be some assumptions about this Dave person that we could make that might explain your rather uncharacteristic comment. John, I don't think there is any difference in a 7.3 from a 88 to a 93 with the exception of the changes made to support the turbo. Any year would be good. Out of curiousity though, why go to all this effort if you have such a good running truck as yours, and you've not tried your pump yet?

 

[metrojd]

peranoid

Mel,
The trip to Cape May NJ and all over eastern Pa seemed to make a few noises show up.
Mybe I am peranoid but there is a slight tick I dont rember hearing before and seems to nock a little louder than before.

The Travel trailer I took weighed almost 7,000 lb empty.
My truck did pretty good pulling it.
There were a few mountains over this way that we were going in to a head wind and the egts got up there.

Thank God for the GV I was constantly going from high to low to high to low.
The trip the truck stayed around 2,200 RPM and the EGTs were around 1,000
A little hotter that I wanted to run for so long and I just couldnt keep the RPMs down.

It seemed when I would get the RPMs down under 2,000 I would have to put my foot in it enough that the EGTs would start to climb.

Maybe peranoia I dont know, I just did a 500 plus mile trip over East and back on Saturday pulling my 16 ft trailer that weight 1200 lb empty and seemed ok.

I just did the fuel milage with the empty trailer keeping it around 75 mph I got about 13 mpg.

How about you got any pros ar cons on the Rebuild?

Thanks
John

 

[BROWNIEBOY525]

i am also a member on fordtrucks and there is not a person that i know of who knows more about the idi and these trucks then dave. he built one sick 6.9L idi thats pushing 20 somthing pounds of boost!!! i think he went threw three or four sleved 7.3 before he built the 6.9 and if i remember right none got over 40,000 miles.

 

[tonkadoctor]

I wouldn't even waste my time rebuilding a 7.3L, its a throwaway block, don't do sleeves, can gaurantee you'll never see 100k miles out of that block, you want to rebuild a block, an 86 6.9L is the block for you, put the money into that, go over to ford-trucks.com and enter the pre-powerstrokes, you'll find a man there named Dave Sponagule he has done the 7.3 rebuild three times and each one went to junk within 28000 miles, go over and talk to Dave at Ford Truck Enthusiasts he'll tell you everything you need to do he's a very knowledable man and his truck out pulls the cummins with a 10000 pound load behind him, thats the only way he races.

i am also a member on fordtrucks and there is not a person that i know of who knows more about the idi and these trucks then dave. he built one sick 6.9L idi thats pushing 20 somthing pounds of boost!!! i think he went threw three or four sleved 7.3 before he built the 6.9 and if i remember right none got over 40,000 miles.

Hmmmmmm, I wonder why his engines only last 28,000 miles

He may be good at building power but not the man I think I want to talk to about building for longevity. Of course the early cummins were dogs in stock form so

There's no reason a properly rebuilt and maintained IDI shouln't be good for another couple hundred thousand miles.

 

[Mr_Roboto]

What makes it a throw away motor??
I thought the 7.3 was an inproved upon 6.9??
quote]

The T444E / 7.3PSD is an improved block. The 7.3 IDI was bored out for more power and larger head bolts used for better head gasket holding. At that point cavitation was not as well understood as it is now. International basically made a mistake in overboring the IDI block.

Personally I would use a late 6.9 block over a 7.3IDI block. And a 7.3IDI block over an early 6.9 block since the 7.3IDI's flaws are fixable with sleeving.

 

[h2odrx]

i am also a member on fordtrucks and there is not a person that i know of who knows more about the idi and these trucks then dave. he built one sick 6.9L idi thats pushing 20 somthing pounds of boost!!! i think he went threw three or four sleved 7.3 before he built the 6.9 and if i remember right none got over 40,000 miles.

i have looked at what Dave had to say and in my best Cheech voice "Dave's not here"