Rebuilding a 7.3 IDI Turbo

[CalebHa]

That scratch a tough one to argue fault. It can be a scrape from a prior HG replacement, engine rebuild, or any sort of rough-handling of the block by the shop, or yourself.

Last time I had something machined (albeit heads), 0.005" was considered a minimum cut. I think I would try to use that figure to calculate piston clearance height and resulting CR (also see about available HG thicknesses). If acceptable, I'd prefer to have it machined. You're far enough in it seems dumb to cut corners.

I am sure I did not do the damage but I agree that it would be something that would be hard get them to fix. There is a similar scratch on the other side that touches the new sleeve they put in, I am not very concerned about that one because It is so minor and you can't feel it with your nail but you can see it. They also scraped the **** out of some other sides of the block.​

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I know I should just take it to the machine shop but I don't want to deal with them again and the only other one that I know is good Is expensive and far away. I am curious on the JB weld idea though, I heard from someone that if it's done right can hold up just fine. I also read on a forum about taking a punch and building material up around the fire ring. Are any of those things anyone has had experience with? Or anyone else with any good bad ideas?​

 

[WrenchWhore]

You were talking about head studs earlier. Looks like Amazon has 7.3 studs for about $300. Not the worst compared to ARP. XOTIC is the brand. Reviews seem good but only has 6 of them. Apparently well packaged and professional looking. Just something to consider. From what i've gathered here head studs are a great upgrade for the 7.3 but not mandatory like a 6.9 you're putting boost through.

 

[FrozenMerc]

Most shops are hesitant to cut the deck on diesels as piston protrusion is a very critical dimension. However, since you got the Mahle pistons that sit 10 thousandths lower in the hole, you have room to cut. That said, if you don't want to deal with the machine shop again, you can get a some 2 3/4" psa sand paper strips for long board sanders (I prefer the 3M green corps, 150 grit for this sort of thing). Stick the sand paper to a nice straight piece of heavy wall 2" x 3" steel tubing and deck the block by hand. Make sure to keep the tube level and don't role it. You will only end up taking a 0.001" or 0.002" off, but it should clean up all the little knicks and scratches, remove the staining from the engines previous life and leave behind a nice surface finish that the will help the gaskets seal.

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[CalebHa]

Most shops are hesitant to cut the deck on diesels as piston protrusion is a very critical dimension. However, since you got the Mahle pistons that sit 10 thousandths lower in the hole, you have room to cut. That said, if you don't want to deal with the machine shop again, you can get a some 2 3/4" psa sand paper strips for long board sanders (I prefer the 3M green corps, 150 grit for this sort of thing). Stick the sand paper to a nice straight piece of heavy wall 2" x 3" steel tubing and deck the block by hand. Make sure to keep the tube level and don't role it. You will only end up taking a 0.001" or 0.002" off, but it should clean up all the little knicks and scratches, remove the staining from the engines previous life and leave behind a nice surface finish that the will help the gaskets seal.

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I like this idea, I'm going to give it a shot with a few changes. I'm going to get a piece of glass large enough to cover the whole deck and a few large sheets of sand paper, I'll throw a few weights on top to make sure I have even pressure. I anticipate hours and hours of sanding in my future but hopefully I can bring the whole deck down a few thousandths. After I'm done I'll check it to make sure I don't have any low spots.

 

[Kizer]

I'm going to give it a shot with a few changes. I'm going to get a piece of glass

Have you considered a piece of granite?

If there’s a local fabrication shop, it would probably be pretty inexpensive, more durable and just as flat as glass.

FYI: The darker colors, of granite, are typically more dense than the lighter colors.
I would not recommend using marble.

 

[2stroke]

I have a set of new pistons for IDIT

 

[The_Josh_Bear]

Funny you guys are willing to do something like sanding a block around here! Amazing, so much hate about that on youtube and other places. I gave it a shot on a Volvo S40 2.5T block still in the car. It was tight and sucked but worked well eventually.

You're right that on a cast iron block this will take time!
I went with this granite surface plate. It's been really handy for other things too, but probably more than you want to spend. I used 3M spray contact cement to adhere the sandpaper to the block.
I took the head in for truing, I was shocked that the machine shop only went down to 100-grit sand paper. But when I asked "isn't that a little coarse?" They about laughed at me. I guess 20 years in business with no comebacks means 100 grit is ok.

In my opinion, you NEED a machinists straight edge to be sure everything is going correctly. And a feeler gauge thin enough to test with it.

I did a few dozen passes with dry cylinders, tried to clean them up, and I wasn't happy with blowing them out with air. Didn't seem to get all the fine grit.
Googling around I found the best way to deal with the dust and cleanup was by covering the cylinder walls in Vaseline. Later you can roll the engine over and all the Vaseline/metal dust will be pressed up to the top of the cylinder and easy to wipe up.

I hope it goes well for you!

 

[Nero]

Just to also toss out my experience with goofy things we do to block decks, I always use a knife sharpening stone on block decks to smooth out any high points. Typically where push tube holes are I've found they pucker out a little, usually 0.001" - 0.002 but enough to throw off a straight edge. Mind you this is on a Cummins 9 liter block, and I do it so I can get an accurate liner protrusion measurement with a deck skid dial indicator.

 

[rwk]

That would be correct about the 100 grit, 30 plus years ago, a friend worked for Clark equip, he told me NOT to try and get a real smooth surface while I was decking some Mopar heads for a friend, Clark had a surface finish requirement for heads and blocks it was fairly rough, it helps the head gasket grip and seal to the block and head. Clark equipment mfg. fork lifts and other heavy equipment, they were renowned for their durability.