Update

[gatorman21218]

Hey yall sorry for the long absence. I've been busy but heres a summary of what Ive been up too. Ill give more details later.

This summer I rebuilt the engine. Long story short the pistons and valves made sweet love and I lost all compression.

I rebuilt the motor by myself except for the machine work. The block was bored .030 over to eliminate the taper but all the other bearings are normal sized. the pistons were fly cut to give me valve clearance.

I drilled out the 4 corner coolant cups to give better cooling in the head and used a 6.9L head gasket.

I installed a '93 factory turbo kit and used head studs when assembling the engine.

Originally I had a Typ4 cam(206 degrees) but that was a factor in blowing up the engine so I am now running a 202 cam.

I have about 5,000 miles since the rebuild and she is running great!!


More to come later( and maybe some pics too)

 

[Dieselcrawler]

bored a 7.3 .30 over?!?! brave man.

 

[gatorman21218]

yeah well I had them sonic test where it cavitates and it was more than thick enough. I tested the corner cylinders about 2 to 2 1/2 inches down from the deck towards the valley. I cant remember how thick it was but .030 over is only .015 on each wall which is paper thin. if it had cavitated that much the block was F***ed anyways.

 

[GOOSE]

Hey, good to see you posting, don't be a stranger. Your engine will get even better in another 5,000 miles. It takes that long for them to break in.

 

[1466IH]

A bit off topic but since cavitation was brought up, if you do have a problem is the block junk or can it be sleeved

 

[icanfixall]

Any idi block can be sleeved even if its been bored 30 over. When they are sleeved they are bored much more than that to fit the new cylinder. A few thousand more miles and hopefully it will be broken in. Just don't baby it Make it work for its food....

 

[racin460]

(drilled out the 4 corner coolant cups to give better cooling in the head and used a 6.9L head gasket.)
Can we here a little more about this is there a tech article on doing this and why?

 

[racin460]

Why did the type4 cam blow up engine?

 

[gonecrazyi]

I think it was because the engine was worn and a little sloppy causing the tolerances to beout of wack. B but its been a while since I've talked with him about it.

 

[icanfixall]

The coolant passages on the 6.9 head, block and gaskets have openings on the lower corners where the 7.3 has freeze plugs in the block and heads in that same area. The reasons why have been discussed between Mel and I many times. We both feel the reason these 7.3 coolant passages are blocked off is for higher temps so the exhaust is cleaner. Both the 6.9 and 7.3 head gaskets are inedtically drilled except for these lower corners. The match up exactly. I have bought both the 6.9 and 7.3 gaskets and measured them every way I could. The fire rings are the same. Just the coolant passages speken about here are differant. I Jim and I worked it out to use the 6.9 head gaskets on the 7.3 but to dril out the freeze plugs in the heads and block corners. The 6.9 gaskets are ported smaller than the coolant port size in the heads and block. I should try to post some pics so its easier to see what I'm refering to... Pics are neet..

 

[88 Ford]

Hey yall sorry for the long absence. I've been busy but heres a summary of what Ive been up too. Ill give more details later.

This summer I rebuilt the engine. Long story short the pistons and valves made sweet love and I lost all compression.

I rebuilt the motor by myself except for the machine work. The block was bored .030 over to eliminate the taper but all the other bearings are normal sized. the pistons were fly cut to give me valve clearance.

I drilled out the 4 corner coolant cups to give better cooling in the head and used a 6.9L head gasket.

I installed a '93 factory turbo kit and used head studs when assembling the engine.

Originally I had a Typ4 cam(206 degrees) but that was a factor in blowing up the engine so I am now running a 202 cam.

I have about 5,000 miles since the rebuild and she is running great!!


More to come later( and maybe some pics too)

Can you explain about the cam? Also are there different versions of the Typ4 cam? What is the difference between a 206 and 202?

 

[idipwr]

The coolant passages on the 6.9 head, block and gaskets have openings on the lower corners where the 7.3 has freeze plugs in the block and heads in that same area. The reasons why have been discussed between Mel and I many times. We both feel the reason these 7.3 coolant passages are blocked off is for higher temps so the exhaust is cleaner. Both the 6.9 and 7.3 head gaskets are inedtically drilled except for these lower corners. The match up exactly. I have bought both the 6.9 and 7.3 gaskets and measured them every way I could. The fire rings are the same. Just the coolant passages speken about here are differant. I Jim and I worked it out to use the 6.9 head gaskets on the 7.3 but to dril out the freeze plugs in the heads and block corners. The 6.9 gaskets are ported smaller than the coolant port size in the heads and block. I should try to post some pics so its easier to see what I'm refering to... Pics are neet..

So is the concnsus that this will eliminate the overheating issues with the 7.3? My truck has been plagued with it since new when worked hard. I want to upgrade to an aluminum rad, but it shouldn't be necessary. My buddies 6.9 and my psd won't get anywhere near as hot working twice as hard.

 

[icanfixall]

To the above posting.. My feelings are your compareing apples to oranges bringing a psd into the talks. As for a 7.3 running hot, well there are many reasons for that but cooling passages being plugged off are a big question. The coolant flow thru our idi engines is from the water pump into the cylinder jackets. It reaches the back of the block and flows up thru the heads. I'm sure some actually flows up thru the many coolant passages between the head and block as it travels but the majority flows like I posted. On the drivers side of the block at the rear end the coolant flows into the oil cooler. Then exits out the front of the cooler. Oil flows in the front to the back where the filter is. Now as both cylinder banks of coolant flow towards the front of the block the meet in the top front just under the injection pump. There is a channel across this area. Then all this coolant blends and sees the thremostat. Opening up the 7.3 plugged coolant passages can't be doing anything wrong. If it works in the 6.9 it will work in the 7.3. Many years ago it was felt that the corners would leak coolant to the passages were plugged off but only in the 7.3. Not the 6.9. Now another simple reason for running hotter than a 6.9 is the fuel needed to make the larger displacement engine work. Remember the radiaters stayed the same shape and size. Just the cibic inches were increased... This is where my thoughts are for the hotter running ingeines. Sadly I found this out too late to mod my 7.3 when I built it twice... I know its taking a big chance that what I have posted about here is correct. But so far the results are better than expected. Untill we actually have a 7.3 with this mod hauling heavy with before and after results are we going to have proof... But I firmly believe we should be running 6.9 head gaskets on the 7.3 and opening up the plugged off coolant passages. The gaskets are the same demensionally. Just one has the coolant passages open and the 7.3 doesn't.

 

[nine9six]

Sweet truck! I'm in your neck of the woods (Gainesville, Newberry Road) so if you ever see an old blue IDI with a Miami Dolphins plate that reads "86IDI" (get it? lol) that's me!

 

[gatorman21218]

Ill get some pics loaded up in a bit but Gary pretty much covered it. I actually used a 6.9 head gasket. So far ive seen a 5 to 10 degree drop at the overheat sensor.

As far as the cam went, there is no one answer other than I was just plain unlucky. The consensus is that my engine suffered a stacking up of min/max tolerances where it got so close it failed. Nothing is out of spec but they are at the margin. I do know the heads are at minimum thickness, and its speculated that the valves were at max protrusion, the block height is minimum, the pistons were tall etc. Also the engine "grows" as it gets to operating temp as much as .007". (ie valves, rods, pistons get longer)

The truck ran for 2 weeks with the valves hitting the pistons so it was just enough where it was touching but enough to bend the exhaust valves and lose compression.

the 202 cam is less aggressive than the typ4 cam. The way the typ4 cam works is it increases how long the valves stay open aka duration but it does not increase how far the valves open. The cam held my valves open just a bit too long allowing the pistons to contact them.

The typ4 cam is a good cam but Ive learned the hard way that with any modification in the engine you have to check for clearances. Its like jacking up the suspension in the driveway and then tear the roof off the cab when you pull in the garage. The second time around the machine shop used playdoh on top of the pistons and rotated the engine to verify the valve to piston clearance. We then fly cut the pistons (= shaving only a portion off the top of the piston) and recessed the valves to max to get me clearance.