I'm knocking the dust off and old project. Finally got shop built, got some time off. Hopefully, I can get some things done. I have a 6.9 idi, that's gonna be sitting on a 89f250 4x4 frame. Already started on the suspension, years ago. It has the front shackle relocate, and the rear shackle flip kit. H/A installed. Got to finish it up. Starting on rebuilding the motor now. Gonna have some questions. I've got lots of goodies for it, that have been in storage. I'll post my questions as I get to them. Hopefully you all can get me though. I'll start with the engine build.


1st question. My book says get new oil cooling jets? Never reuse? Why? It's just a cooling jet?

 

Oh, and i'll post pics of my process. For those interested.

 

The Block




The Manual




Inside Mic




Outside Mic




The Plungers


Some pics of the start of all of it.

 

Now for a serious question. What are my limits for .040 pistons and cylinder bore? My book only goes to .030? I did take the standard service limits and add .040 to them. Just want to make sure they are right.


I miked the cylinders 1/2" down from the deck, and 1/2" below BDC. Like my book says.


1st number is inline with wrist pin, second is 90 degrees to wrist pin.


#1
Top 4.0409, 4.0408
Bottom 4.0406, 4.0404


#2
Top 4.0414, 4.0418
Bottom 4.0408, 4.0411


#3
Top 4.0408, 4.0408
Bottom 4.0406, 4.0406


#4
Top 4.0414, 4.0413
Bottom 4.0411, 4.0408


#5
Top 4.0407, 4.0405
Bottom 4.0405, 4.0408


#6
Top 4.0413, 4.0413
Bottom 4.0411, 4.0411


#7
Top 4.0415, 4.0415
Bottom 4.0401, 4.0408


#8
Top 4.0411, 4.0409
Bottom 4.0406, 4.0409


Pistons 1.5 inches down from bottom ring 90 degrees to pin. These are new pistons.


4.0337
4.0336
4.0338
4.0337
4.0336
4.0336
4.0334
4.0337


I might be including to much info. but I figure if you fellas see something you don't like, you might be able to save me some pain. I did double check all measurements.

 

Wow! no replies? I figured you guys would be all in on this with advice! LOL Patience they say. Well in the mean time, here is some pics of my rods. I have a concern with them. Two of them are different. Same part number, just different castings it looks like? This motor was a rebuilt "Goodwrench" motor. Just for info. I'm sure they used parts stock, that they had on the shelf. But, should I be concerned? should I search out some all matching rods?

 

Anybody? Any input? On any of it?

 

The only input I have is on the cooling jets. The reason they say to replace them is that they can come apart. Are they important? They squirt oil at the piston to help cool them down. You decide. Personally I put welded jets into my psd.

 

if i remember correctly, a 7.3 is a .030 over 6.9 so at .040 over you will be a little bigger than a 7.3

 

That's what I'm thinking. This motor was already .040 over when I got it. I jumped the gun, and bought piston .040. I should have just found another block in the first place. But this motor was running well, when I took it down. I do have head studs for it. But, I am putting a Banks turbo on it. Do, you think it will be disaster waiting to happen?

 

I understand their importance, just don't understand, how they can come apart? They are one piece, bolted in? Maybe these are welded? How can I tell? Or, can I weld them?

 

nope. i have 494,000 + miles on my truck and it has never been opened.
if it was a .040 over 7.3, i would call it a ticking time bomb with a 100k life expectancy.
but a .010 over 7.3 is not a big deal in my opinion.

 

iirc the tube is a press fit into the flange. That is where they are known to fail on the psd's. It's not real common but has happened in the past. The jets in your pic look very similar to the ones that came out of my psd. You could probably weld em up if you have the skill.

 

Wow. This thread needs some help. First off, mid-year 1985 and later blocks had re-useable bolt in style piston oilers. Check your block s/n by the IP. If yours is 237016 or higher you have the bolt in type.



Below that they are a press in design with an interference fit. They were designed to be replaced, but nos replacement oilers are getting very hard to find, and run about $50 EACH if you do find them. The installation tool and alignment tool are long obsolete and impossible to find. If you need to remove press in oilers for bore work, pay very close attention to the position of the tip, and be sure they are aimed correctly upon installation. The risk of re-use, of course, is that they are prone to falling out which results in oil pressure loss and a ruined engine. However, RacinNdrummin on this site recently did this and used red lock tight. He had to take the engine apart for other reasons after 3,000 miles and they remained extremely tight. So if you are very careful it is possible. If you have the bolt in type, be very careful not to loose the bolts. They have special threads.

Now, just to set this straight... A std 6.9 bore is 4.00", a std 7.3 bore is 4.11, so equivalent to a 110 over 6.9. Your 40 over isn't even close. You should have lots of cylinder meat left.

The rods for NA engines were all the same from '83-'94. Over the 11 year run there will be some casting differences but I would not worry about matching rods. These engines had pretty lousy balance from the factory, and in my opinion it is money well spent to have the rotating assembly balanced at a machine shop. If anything, do that before trying to find matching rods.

Good luck on your build. For whatever reason you thread/title didn't catch much attention, but there is a lot of knowledge and good help on this forum, and some really great build threads and good reading.

 

Mine are bolt in oilers. See the pic of the rods, you can see them piled up just above them. This motor was a rebuilt motor in the first place. So, I hope it is a good version of a block. It does have a few things I noticed on cleaning it up. one of the roller lifter holes is sleeved, and it was already bored to .040. I just cleaned it up some.


I'm glad to hear .040 is ok. That did have me worried.


As for the rods, don't know if this matters, but I will be turbo charging. But, not racing or pulling or anything like that. Maybe pulling a small camper.. That's about it.


And 10-4 on that last part! This site is what got me interested in these old diesels a few years ago. Most of the parts that I have bought for this build was at the direction of my fellow FTE folks. It's gonna be an awesome truck, to me anyway.

 

The NA rods are plenty strong. On the 6.9's the limiting factor is head fastener strength. 7/16" can only get you so much clamping load. If you are going to turbo it, get ARP head studs and over torque them a little, (100-110 ft lbs) and keep the boost in the mid 20's or less and you will be just fine.

At some point start a thread that says "build thread" (or re-title this one by editing your first post) a post up a few pics of your truck. That will attract more attention and you will get more input. Is it the white CC in your avatar? It looks nice from what I can see of it