I have a 1993 7.3 turbo engine that I'm rebuilding. The block had to be bored .030 thou over stock to clean up the bore. I had the machine shop pressure test both banks after boring and found there to be a pin hole(s) in no 6 cylinder. The machinist then tells me he has a non turbo block he will sell me, or sleeve #6 on mine. He tells me that if his block tests good then it would be a much better block then mine sleeved, and proceeds to bore it out .030 thou to clean it up. The non turbo block pressure tests good after boring. I asked my machinist if the block will get pin holes after with dca in coolant, he says definitely not. My worries are that it will get cavitation after I rebuild the engine, since the pistons/rings wear on the bore, and that the cylinder bores could be very thin. Should I run this block or should I find a 6.9 to rebuild? How thick do these bores come new? Also are there 6.9 pistons with turbo sized pin hole? Thanks.
7.3 rebuild
- Thread starter BigDiesel
- Start date
well my recomendation is have all cylinders in youre motor sleeved you could have an issue down the road with wear and all that but chances are not too high on his block but i wouldnt trust it you have all 8 sleeved youre set
also the 7.3 had pinhole issues from stock so making the walls thinner id say is a bad idea also do you do all youre own work? because if not then can you trust youre mech to keep up the sca?
also the 7.3 had pinhole issues from stock so making the walls thinner id say is a bad idea also do you do all youre own work? because if not then can you trust youre mech to keep up the sca?
Yes I do all my own work and run dca in my current 7.3, and test it once per month. I don not want to sleeve since the machinist said that sleeving essentially ruins the block and if needed only sleeve the bad pin holed bore(s).
Knuckledragger
blowing chunks and grabbing porcelain
Sleeving the block does not significantly affect the performance or rigidity of the block. If the machinist told you different, he is either misinformed or worse. The bores on any block do not do anything but hold compression of the pistons. They are cast relatively thin to effect better cooling.
All strength issues are handled by the bearing girdles and exterior cast surfaces (as well as gussets inside). If sleeving were bad for the engine, no one would ever do it. If you can afford it, sleeve all 8 holes for peace of mind.
All strength issues are handled by the bearing girdles and exterior cast surfaces (as well as gussets inside). If sleeving were bad for the engine, no one would ever do it. If you can afford it, sleeve all 8 holes for peace of mind.
That block is usless without having all the bores sleeved. The machinist better know how to sleeve a diesel block. The block when bored has to have a ridge at the bottom to prevent the sleeve from sliding down. The sleeves should be froze in Nitrogen before installing so they are tight after installation. Sleeve size .002 to.003 larger than the bored size. # 4-6-8 are the bores prone to cavitation. There is no way to measure the wall thickness. If that block cavitated on #6 no way would I trust the others, you can bet that engine was run without SCA in the coolant. Boring out .030 has really thinned up the walls, almost read a newspaper thru them. 
To make the 7.3 the same 6.9 casting was used and only bored out, no change was made to the casting until way later years I'm thinking 1997.
To make the 7.3 the same 6.9 casting was used and only bored out, no change was made to the casting until way later years I'm thinking 1997.
icanfixall
Official GMM hand model
I agree with the above posting in all areas.... Just make sure the sleeve is installed properly. If the sleeve is just dropped into the cylinder it must have around 3/8 inch lip at the bottom for it to rest on. Otherwise it will slide down and hit the rotating crank... There is a better sleeve available. It has a flange on top so it can't slip doen in the cylinder but... You need to machine the block larger at the top so it fits. Then the bottom step must be cut the same length as the seated flange at the top... So both top and bottom of the flanged sleeve must seat perfectly at the same time... Thats hard to do for most machinsts but its the best type of block sleeving. Usually a 2 thousands press fit is used sucessfully with cast iron sleeves but... Make sure liquid nitrogen is used to freeze the sleeve. That way it will shrink more so it fits the bore thats 2 thousands smaller then the sleeve is.
He has ordered the .030 pistons already but hopefully I can talk him into sleeving all 8 to std. The machine shop does mostly industrial diesels, and he said he has done countless sleeves on all types of parent bore engines but still dislikes them. He charges 120 a hole to sleeve is that reasonable?
jonathan
Full Access Member
120 is fair my machine guy charges 100 a hole
ya if large long service diesels were designed with replacable sleeves why would sleeving be bad?
also if that one is through how do you know the others arent dangerously close?
many remans fail due to this issue
sleeve all or none
also any 7.3 reman that needs bored needs sleeved unless a full histroy is known
but if he told you not to do it dont let him do it find another person
also if he is over charging for his useless service pay only fair amount use youre best judgement on it though
also if that one is through how do you know the others arent dangerously close?
many remans fail due to this issue
sleeve all or none
also any 7.3 reman that needs bored needs sleeved unless a full histroy is known
but if he told you not to do it dont let him do it find another person
also if he is over charging for his useless service pay only fair amount use youre best judgement on it though
Well, I talked him into sleeving all 8 cylinders. He was hesitant to do it but he said it was my decision. He said if was him he would only do 6,8 since he has seen most of the pin holing happen in those cylinders. I also asked him about how he sleeves them, and he says he leaves a step at the bottom of the cylinder and then presses them in with .003 interference fit. The sleeves he uses are melling, and he says they are not as hard as the block.
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