sleeving a 7.3

[djnsj]

I'm wanting to sleeve a 7.3 block down to 6.9, maybe at .030 over. I've got to blocks to choose from, one that's still in the truck that I assume is original. Lost a freeze plug so I'm hoping the block is ok and assume that it's not been bored already. Or I have a rebuilt block out of another truck that after tearing it down I found it's been bored +.030. Can a liner be used in a block that's been bored already? Also anybody able to recommend a place in SLC,UT area that can do liners? Does anybody know of 6.9 pistons w/the turbo wrist pins?
Sorry for all the questions, just trying to get ideas lined out in my head before I jump in. Thanks.

 

[Agnem]

You'll get a good answer soon. We have a few guys here that have become quite the experts on rebuilding and what not.

 

[fellro86]

I don't know quite how they are doing the sleeves these days, but it would seem that there is some problems with them dropping down. These motors weren't intended to be sleeved, so apparently they don't cut a ridge at the top to keep them located. If you were going to sleeve, I don't see the point in going to a 6.9 bore, and I don't think you will have a lot of luck finding any to do so. If it was originally a 6.9, then maybe, but to reduce your bore to one won't really do much for you It will slow down the cavitation problem, but I'm not sure it will be of enough benefit to be worth it. Do you need sleeves, or were you just looking to try to avoid cavitation?

 

[icanfixall]

Sleeving these blocks works fine if done correctly. First off don't let some shop machinst tell you they bore the block and cool the sleeve in the freezer and use super glue to hold it in the block. The super glue acts as a heat transfer barrier and the motor will run hotter than normal so that wont work. The sleeve needs an interferance fit usually 2 or 3 thousands. Now the sleeve is cooled in liquid nitrogen but be careful of this. It will burn you because its around -270 degrees. Now when it stops boiling its as cold as its going to get. Then its dropped into the block and now you need to hold it in place. They will be very loose fitting because they have been shrunken by the liquid nitrogen. Usually some allthread with strongbacks top and bottom works. Thats about all you need. The bore must be straight to the crank and at least a 1/4 to 3/8 lip is left at the bottom of the bore so the sleeve has something to land on. The deck is milled but only enough to even things out. There is a distance from the crank centerline to the top of the deck that must be maintained. Its 11.137 to 11.141. About sleeving down to 6.9 yes you can do it but you need to contact Mahle about pistons first. I don't recall if they can build a piston with the large pin size so ask first. Its really not needed to downsize the 7.3 but you can. Yes, the bored out block and still be sleeved. The sleeves are much thicker than a 30 over bore. Make sure you have the middle hardness material sleeve. Some are very soft and they wear out fast. These blocks have a high nickle content and are ******* the boring tools. It takes a long time to bore these blocks. If you try to speed up the bore the tool chatters and the cut is really bad. Now finding someone that can do it right is the biggest next thing to do. You might give Promar a call in New Jersy. They seem to know what they are doing from what they printed but a few questions are helpful too.

 

[djnsj]

Thanks for the ideas. I was looking at sleeving the bored out block just to get back some cyl. wall thickness. Since it's going to have to be worked on, I wanted to get it all done at one time, and not have to worry about it again. Going down to a 6.9 or 6.9+ was to gain more cyl. wall. One thread from a while back talked about that as being the best of both worlds, 7.3 block w/ bigger head bolts/studs with a 6.9 bore to get more protection from cavitation.
While I enjoy working on my trucks, with oil up to my elbows and smelling more like diesel than the local truck stop so bad that my wife makes me strip down outside and leave my clothes there (I think she'd rather I stayed outside with the smelly clothes too) I'd rather be driving them instead.

Any shops in AZ that can be recommended for the machine work? I'm from there, and I've still got parts and stuff to bring up from there anyways, so taking the block down there wouldn't be a problem, if there's someone that can really do it.
Thanks again guys.