I have a 7.3 that badly needs the rings replaced. Burns a quart per 75-100 miles. I am wondering if I should just get standard bore size rings and put them on the stock pistons or if I should go with .010 over pistons and rings. Does anyone know if a hand held reamer will be able to ream out that .010? I do not want to take the motor out, and have to take it to a machine shop. Does anyone have experience with this? Thank you in advance.

 

i wouldnt try to ream out .10 because you will never get the cylinder exactly true top to bottom. I would measure your bores and pistons, then go from there. if still in spec, install a new set of standard rings, if not, id have a machine shop make more clearance in the block

 

Have you checked your cdr valve,it can cause excessive oil usage.How does it run,good power?How does it start,If your suspecting rings then usually some starting problems go hand in hand with that problem due to low compression.It might be worth your while to do a compression test before you tear into it.

 

I do also have some leaking at the oil cooler, one of the seal rings seems to have died. Compression was between 320-400 on 7 cylinders, 1 was about 285. Yes, I do have starting problems. It will not start unless I crank it twice for about 15 seconds each time. A little easier using the heater. I removed the CDR and was able to see cleaning fluid flow from one chamber to the other, so I do not think it is clogged. Am I missing something in my testing of the CDR valve? Do you guys think that the cylinders could still be OK for stock rings considering the oil usage? The reason I ask is that I have a chance to buy either the stock or oversize now at less then 1/2 price. I would need to buy them now and wait untill spring to actually get into the motor. Thanks.

 

I think if you are burning that much oil, just putting some rings in it is not going to do much. Chances are there's more wrong than that. What kind of milage on the engine? Machine shops bore and hone blocks for a reason. If you want any kind of life out of your repair job, your best to do it right or buy lots of cheap oil and don't do anything....Don

 

If you are burning oil because your cylinders are worn, then you won't have to ream 0.10 out of them. Maybe you only need to take out .004 or so. But you have to measure to find out. Maybe rings would do it. Second as csramsey said it is important to get the same size top to bottom. Reamers work best with alot of oil flowing over them. They can take out 0.10 if you take the time. But it is hard to control them. I have one and it is hard to use. I only use it if I have to. I also have a boring bar that will bolt to the block so you don't have to pull it out. But you still ream the last .01 or so. Cylinders don't wear perfectly round. They can go oval or cone shaped or both. It is hard to correct that with a hand held reamer. I would go talk to your local machine shop and ask what they can do with the block still in. You can spend a little now and do it right or you can spend alot later to replace the block. Also by the time you strip the engine down to use a reamer, the whole top is off and the pan and crank are out. The block is almost out at that point. If it was me I would pull the engine, strip it while it is out and take the block to a machine shop. Check the crank, and do the heads. That way they can dip the block, check for cracks etc. You would be good for years. Good luck with it.

 

First forget boring any 7.3, they are already too thin in the cylinder walls. I know some have done it but but but.... If your wanting to do it right have the block sleeved and rebuild it...or find out where the oil is going for sure before panicking. Check your CDR valve as stated above look at the air cleaner hold down bolt and screen is it covered in oil (dripping wet).

 

no, the air cleaner screen s not wet wth oil.

 

Daryl can you post which cylinders had what compression. ie 1357 pax side 2468 drvrs side. Do you have any leaks at the valve covers, rear/front seal, any oil in the coolant. The leak on the oil cooler itself could do it or the filter area, how about the bell housing, an accumulation of small leaks can amount to a qt pretty quickly.

 

1=320

3=400
5=320
7=285

2=400
4=320
6=400
8=320

I definitely have oil burning, very noticeble blue smoke. I probably have some more leaks too. I purchased it in florida with 130k miles on the odometer. Since then I found out that it changed owners in 95 with 131k miles on it at the time. The milage could be anything at this point.

 

PLC7.3 is right. I have pulled many gas engines and motorcycle engines apart, but I am new to diesels and didn't think of the thin walls. Thanks for the reminder.

 

My next step would be to check out the valves on the #7 piston.Remove the valve cover and look to see if there is any slop in the valves,a bad valve will give a low comp reading,and oil consumption as well.

 

Has anyone priced sleeving a block recently?

 

Most info reflects about 100 per hole....... some shops will do as required ie 1 or 2, I would advise do all 8 at once.......unless you like Russian Roulette.

Your #7 is 15lbs below differential minimum.....lowest should be 75% of highest.

 

do you guys think I should still consider the rings as the main culprit in the oil usage, or do you think other things could be causing it?