Series 3 Engine still smoking after rebuild

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ZZ4X4

New Member
Posts
5
Location
Sachse,TX
Hi All,
I have a 79 Series III with a 19J 2.5 Turbo Diesel engine that I took from my 83 109 Santana. The engine was hard to start, running very roughly, and burning oil in distinctive puffs before I pulled it from the 109. I completely disassembled the engine and noted a compromised head gasket and light rust marks on the #2 cyl walls. I performed a hone job and cleaned up the valve seats in an effort to do a quick fix for the oil burning. I measured the cyl bore diameters and they seemed in range at 99mm . Noticed the timing belt was off one tooth compared to factory alignment marks. I reassembled the engine trying to correct the issues found. I installed new rings and valve seals, as well as a new head gasket. The new ring kit had three rings per cylinder but my pistons had 4 slots. I kept the lowest ring(oil wiper ring) intact from the old pistons since I didn't have new rings to use. The new rings seemed narrower than the old ones ( a little play in the piston slot) but the gap between ring ends was in spec at .010"). So after reinstalling the engine it is starting much better than before but is burning so much oil I feel like James Bond. So frustrating after all that work. Before I pull the engine again I'm throwing this out there to see if anyone had a similar experience and there are some things to check. I'm not seeing signs of cracked head or block ( no oil in water or vice versa). Can't imagine what the cause could be other than rings vs cyl walls clearance issue. BTW, the compression is 390psi +/- 5psi on all cyls. Why is this thing smoking so badly!!
 

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std bore is 3.562 -90.47mm plus 20 3.582-90.98mm, 99mm is way out,you need the accuracy to be measuring thou with bore wear not inches, it would seem you have the wrong pistons too bottom of skirt oil ring havent been used since the 70s, pulll head off and put some pics up,
 
Thanks jamesmartin, I hadn't considered that the wrong pistons may be installed -- but I shouldn't be surprised since everything else on the truck seems to be a hodgepodge of shady repairs. One of the pistons does look newer than the others so someone has definitely been in the engine before me. Also, my piston's rings ( number and widths) don't match any of the rebuild kits so I guess that should have been a warning sign ;-) . The engine was running terribly since the day I brought it home. Attached is a pic after I pulled the head ( before the overhaul). When I get back home next week , I'll see about pulling the head and posting more photos. On the 99mm, that's a typo. Should have been 90mm but I understand what you're saying about needing to measure in thousands.
Sounds like you agree the issue is most likely the piston / ring clearance causing the smoking.
 

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Ok thanks. Makes perfect sense. I was trying to get off easy by just slapping in some new rings and valve seals. Looks like if I'm pulling the motor again I should bite the bullet and have it machine honed or even bored .010? over. Then buy some new pistons with the correct rings.
 
Ok thanks. Makes perfect sense. I was trying to get off easy by just slapping in some new rings and valve seals. Looks like if I'm pulling the motor again I should bite the bullet and have it machine honed or even bored .010? over. Then buy some new pistons with the correct rings.
you need to find out what size it is first , if its std youd have to go plus 20 now, plus 10 was rarely enough in any case, if it needs it you buy piston/ring set and get block machined to those
 
The compressions are good, advice given to me (see stuck rings thread) is anything over 250psi (up to 400) is OK and no more than 50 psi differnce. I suspect the compression rings are doing OK but the oil rings are not. How is the blow-by / crankcase pressure. My compression rings were shot and oil rings were good, but oil consumption was horriifc due to crankcase pressure rather then burning. It was burning oil too but this was not the big oil loss, the big one was breather and crank seals due to pressure. As said above, there is a ring to groove clearance as well as a ring gap and piston skirt clearance. The old rings will have lost their spring so they may not be doing much. As you will see from my thread, there are no shortcuts, you will have to pull the pistons and get the part numbers then trace these. They could be Santana and OK but just different but you will need the correct rings. Where are you? I can hire you a ridge reamer for a very competetive price......
 
Yeah, the compression seemed very good to me so I found it odd that the oil could get past the rings into the combustion chamber. But I guess they put the oil wiper ring there for a reason. I'll check on crankcase pressure again but didn't notice anything blowing out of the breather. I'm in Texas so a bit far away on the ridge reamer rental. ;) Thanks for the offer.
 
I had to get it from the the States, where its seems every man and his dog has one whereas here they are as rare as rocking horse poo. The oil rings usually have holes behind them to let the oil flow back into the case, the compression rings do not as they seal so the oil would build up behind the rings on the down stroke. When I was looking for some specialist rings I found several suppliers Stateside so if the pistons are usuable a few google searches should flush out some correct rings.
 
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